AUDI Q5 Navigation for SUV Car

One of the features that a Sports Utility Vehicle (SUV) must have is a navigation system that will match the usefulness of the car. The Audi Q5 is a compact SUV vehicle with a navigation system that matches the car’s features and design. SUV’s are usually used by the whole family or a group of persons that travel together and should have a navigation system complete with modern day features. The AUDI Q5 Navigation system belongs to this category and has all the features that give the driver the convenience of a directional gadget that will take him to his desired destination.

The AUDI Navigation System provides 3-D maps displayed in its 7-inch high definition monitor and is conveniently voice activated. The system is integrated with an entertainment program of voice activated radio, DVD and VCD players which can be played simultaneously with the navigation system. The system has slots for SD cards for keeping data for both navigation and music storage. Music storage is allotted 10 gigabytes which is equivalent to 4,000 sound tracks which can be played through the gadget and heard in ten speakers installed in the car.

For rear parking of the car, the display monitor shows the rear view with excellent clarity. The installed camera and distance sensors help in parking and there is a program that determines the distance and speed of the vehicle in front when the car is cruising in roadways. The system is equipped with the mechanism that helps to keep the vehicle in the correct lane by triggering an alert sound when car goes off the lane. The navigation system displays a 2D or 3D map of the route the driver wants to take when going to a specified destination. Alternate routes are also made available should the driver wants to take a different route.

The AUDI 5 in dash Navigation system automatically connects to the Traffic Message Channels and gets current information on the traffic conditions of the current route being used. It will signal the driver to an alternative route if the current route is plagued by a traffic jam. The navigation system has a 40 gigabyte memory in its hard drive and contains 3D maps of almost all cities in Western Europe and maps of all other places that have been stored in the disc. Information for navigation and music can be sourced from USB, DVD or CD Discs, and SD memory cards.

Autocarplaza is a car DVD navigation online store, you can buy your BMW Navigation DVD, AUDI Navigation, Mercedes BENZ Navigation, TOYOTA DVD Navigation, or HONDA navigation from here with reasonable prices.

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Posted by novaking at 2013年09月04日10:53

Fashion in 2013 with Surprises

Whether we prefer to admit it or not, how we appear does influence the way we're and we feel. We can fall in love using a piece of accessory or clothes for no cause. A part of how our personal style evolves annually is about hair, beauty, clothes and accessory trends. Magazine pages along with the streets inspire us and each year we make an effort to understand the trends and to adapt them to our own style. In 2013, fashion trends for girls and guys is filled with surprises.

I will begin with women. For this year, the cape is a great winter layering staple. But capes could be an unexpected as well as a pleasant surprise inside the warmer months, also. Burberry Prorsum's runway proved that the cape is much more desirable than ever: Duchess Satin, in seasonal colors.Oriental style fascination was brought in to the coming warmer months of 2013 by Prada's Japanese-inspired runway of Geisha girls, with contemporary influences: kimonos and oriental print. Women like leather and, in 2013, leather is right here to remain. It's not just for winter; it operates across the seasons so you are able to wear your leather skirts, for example, in spring as well as summer.

Spring brings the chance to show off legs in mini mod dresses so you are able to attempt some playfully retro pieces, like 1950s style: pencil skirts, costume trendy jewelry, vintage-style hats. Or, you shine with metallic hues like gold, bronze, silver, leather, silk. So, in case you have invested in metallics through 2012, keeping them it is a must.

Style trends for men will likely be very surprising this year plus the whole appear is actually a compact. Metallic and fluorescent colors are making a comeback this year. These can be incorporated into each and every style of clothes, formal or casual. The major style will probably be skater boy, with signs of fluorescence and metallic in it. First, the skater boy style emerged as a a part of street style. Comfort and freedom of movement are extremely crucial to skaters and this style makes it possible for the physique to breathe and to move. The clothes that form this look are shorts, loose shirts, baggy jeans and T-shirts. If you want to be a contemporary skater boy, you will need to wear these garments with prints, simply because prints are style statements. For instance, T-shirts can have camouflage print, fluorescent graphics and camouflage print.

The men's bomber jacket is usually a winter staple that turns into a fall classic. You may layer it over a suit jacket, with out maintaining to dark colors. Or, you could build a sexy look with a velvet. A few of the fall/winter requires leaned to the bohemian style, other to the dandy. Retain in mind: dark blue can be a clear statement this year; is the on-trend replacement for black.  
タグ :fashion trends

Posted by novaking at 2013年07月26日16:02

$5 LCD Monitor to Touch Screen

According to Extremetech reported, Ubiquitous Computing Laboratory, University of Washington staff invented a technique, just a five-dollar into the wall sensor can all LCD monitor into a touch screen.

This technique is referred to as uTouch principle is detected close to the LCD display hands caused by EMI (Electromagnetic Interference) to touch. According to reports, the electronic transmission wire in all rooms have unique electromagnetic signal, an EMI sensor plug to the wall outlet, will be able to read the electromagnetic signal in your room, just keep monitoring, able to detect changes in the room of electromagnetic signals. These changes not only be derived from the switch or the closure of the outlet device, but can also be derived from his hands close to the LCD monitor when EMI change room.

Judging from the video provided by the laboratory, this technique is more obvious delay, but it does do a touch screen form, allegedly detection rate has reached 96.4%, although this figure can be done more high, but some of the "click", the "irresolute back" and the like are difficult to detect small movements lead to the detection rate.  

Posted by novaking at 2013年05月10日12:52

Lead-acid Battery Development

The Ministry of Industry and Information Technology, Ministry of Environmental Protection, the National Development and Reform Commission and other five departments have jointly issued "on the promotion of the development of lead-acid batteries and secondary lead industry norms Opinions, clearly the backward production capacity will increase efforts to eliminate, by 2015, lead scrap acid battery recycling and comprehensive utilization rate of more than 90%, the lead recycling accounted for more than 50%, promote the formation of the National Lead resources recycling system.

Analysts believe that after following the May 2012 lead-acid battery industry access conditions, lead-acid batteries and secondary lead industry policy once again introduced, showing the determination of the Government to promote the industry to speed up the integration is conducive to business mergers and reorganizations, and promote industrial upgrading, increased industrial concentration.

Tired of environmental pollution
As a great environmental destructive metal elements, lead in the field of environmental protection has always been "eco-killer," said. Especially in recent years, our children's blood lead when the event occurs frequently in newspaper reports of lead contamination of groundwater, ordinary people a time to smell the mere mention of lead, have the focus of contradictions points to lead-related enterprises, lead-acid batteries manufacturers a lot of complaints.

In fact, since the 1860 French Prandtl invented the use of lead as a battery electrode, lead-acid battery is over 150 years old. Lead-acid batteries with a reliable, mature production technology, lower prices, and the use of the process do not need to add water, maintenance and so on, have been widely used in many fields. At present, most of our electric bicycles and electric vehicles are also used in this battery.

Since there are many advantages, the history of human use and very long, why the relevant state departments will often be the lead-acid battery industry "heavy" attack?

Industry experts, waste lead-acid batteries contain lead paste, waste sulfuric acid and other chemical substances, if any emissions interested in soil and groundwater caused serious pollution, and this pollution will last for many years. The same time, in the lead-acid battery is also equipped with the high solubility of the acid, the acid contains a certain amount of lead, indiscriminate discharge of contaminated land and lead generating steam to cause harm to human health.

And the pollution it is precisely China's lead-acid battery industry to longstanding industry ills. After years of development, the rapid expansion of China's lead-acid batteries and secondary lead industry has now become a global lead-acid battery production, consumption and export of power. However, due to the part of the small scale, backward technology, low levels of pollution control, leading to frequent incidents of lead pollution, a serious threat to the health of the masses and affect social stability.

With the whole society on the importance of environmental issues as well as all kinds of domestic industry to continuously improve the environmental threshold, in recent years, the lead-acid battery industry in the restructuring and development of the crossroads.

Comply with the dual demands of industrial development reality and the masses of green growing louder, "opinions" on the promotion of the development of lead-acid batteries and secondary lead industry norms put forward a series of measures to accelerate industrial restructuring and upgrading, involving increase backward production capacity out efforts, strict industry access and production license management, and strengthen the management of project approval.

Accelerate the pace of industrial restructuring
It is understood that the lead-acid batteries in electric car market to occupy a higher share, although to some extent by the impact of the lithium battery technology, but cost-effective lead-acid batteries to ensure that the mainstream position in the short term can not shake. With the rapid development of electric bicycles, electric tricycle industry, the demand for batteries there will be greater room for growth. The same time, China's automobile industry development space, The great car ownership and the new car battery replacement and supporting steady growth will drive the demand for automotive lead-acid batteries.

"At present, the performance lead-acid battery business to the inventory is still quite obvious. Lithium batteries because of its high price, for a moment, can not replace the lead-acid battery, so if the downstream consumption continues to grow or remain strong in 2013 lead-acid batteries production is expected to synchronize strong. "industry analyst Lin Zhechen said., the domestic market demand driven capacity expansion's sake, lead-acid batteries do not have the possibility of being out of the market in the short-term. Future national level management priorities of the lead-acid battery industry is bound to fall out of backward production capacity, promote structural adjustment.

Lin Zhechen views represent a considerable part of the point of view of the lead-acid battery manufacturers. The point of view of these manufacturers to be reflected in the views on the promotion of the development of lead-acid batteries and secondary lead industry norms.

Eliminate backward production capacity, the lead-acid batteries and secondary lead industry as countries key industries and eliminate backward production capacity, immediate phase-out of the opening ordinary lead-acid battery production capacity, and not be eliminated by the end of 2015 by the Environmental Protection verification, does not meet the entry the conditions of backward production enterprises. Prohibit the backward production capacity transferred to rural areas and central and western regions. Encourage qualified enterprises merger and reorganization.

Strict access, to strengthen the lead-acid batteries and secondary lead new change, the expansion project for the record management, prohibits the important ecological function areas, lead pollution exceeded the regional and heavy metal pollution prevention in key areas of new, rebuilt and expanded to increase the lead pollutant emissions project; non-key areas, new, revision, and expansion of the lead-acid batteries and secondary lead companies to comply with the regional lead pollutant emission control requirements. Construction of lead-acid batteries and secondary lead gathering parks, should be carried out planning environmental impact assessment, and strengthen the planning and control of the park, and strictly implement the protection distance requirements.

In addition, the five departments in the future will increase financial support by the central government in 2012-2015, eliminate backward production capacity incentive funds to eliminate backward production capacity to support the national lead-acid battery business. And the implementation of tax incentives. Continue the use of waste lead-acid battery production secondary lead enterprise, the implementation of preferential tax policies for of VAT Jizhengjitui 50%.

To build a recycling system
It is understood that China's "national list of hazardous waste, used batteries containing mercury, cadmium, zinc, nickel and lead, heavy metals impressively. Frustratingly, even in the highest penetration of cleaner production Beijing, is also only a few units qualified disposing of used batteries, digestion capacity.

China Battery Industry Association, has done a statistical. According to the recommendations of the association submitted to the authorities of used lead-acid battery recycling deposit system, is currently engaged in recycling of used batteries to individual workshops based, accounting for more than 80% of the number of recovery; followed by the self-employed to the small smelters.
Side waste batteries and can not remove it, the other side is the production capacity has rapidly risen. The battery industry in 2012 to run the report released in February this year, the Ministry of Industry and Information Technology said in the four major categories of varieties of battery pack, lead-acid battery production year-on-year increase, the cumulative production of 174 863 000 kVA, an increase of 27.3 %. Among them, domestic plumbing Province, Henan Province, the annual output reached 5.55 million KVA, an increase of up to 95.73%.

How to resolve conflicts? As heavy head part of the "opinions", the "Opinions" regulate the recycling behavior. According to norms of self-employed waste lead-acid battery recycling behavior, crack down on illegal dismantling and the indigenous refining lead behavior. Improve hazardous waste operating license system to encourage production enterprises through its retail network organization recycling of waste lead-acid battery, support production companies, sales companies, professional recycling companies and secondary lead companies to build a recycling network. Strengthen the collection of waste lead-acid battery, storage, transport the whole process of supervision. Support large-scale, standardized Lead recycling demonstration projects.

In view of the above, the China Battery Industry Association also recommends that battery manufacturers establish broad recovery mechanisms. Many well-known production of home appliances, recycling and subsidies, it can avoid the destruction of heavy metals on the local environment. In addition, and actively develop cheap, safe and reliable performance of alternative products, such as lithium-ion battery.  

Posted by novaking at 2013年04月23日11:13

Switching Power Supply Design

Switching power supply design should meet the technical performance indicators: output / input voltage ratio (UO / UI), the output power PO converter efficiency eta, output voltage ripple △ UO input voltage source voltage Ui electromagnetic interference ( EMI) amplitude limit. During the optimization design, the inequality constraints to represent the performance indicators (to meet a certain inequality constraints, which means that the design results to meet a performance index).

The main circuit of the switching power supply design, should be calculated and selected main content: select the main circuit structure, selection switch (transistor, power MOSFET or IGBT) and model of the rectifier diode voltage and current specifications to determine the form and parameters of the input and output filters; calculate the core specification of the magnetic components (inductors, transformers, current transformers, etc.), the size of the windings, and the specifications of the wire, as well as the selection of the capacitor.

Switching power supply control circuit compensation network should be designed to meet the transient performance indicators of the power supply, so it is a transient design. Switching power supply transient performance indicators are: the stability of the power system, fast (recovery time) on overshoot and undershoot transient response, power disturbance (of disturbance including input voltage transient disturbance, the load transient perturbation of a sudden or sudden load reduction). The main circuit parameters and switching power supply transient response performance has greatly transient design should be carried out after the completion of the main circuit design.

The main contents include: the optimal design of switching power supply transient select the feedback control mode (voltage feedback voltage, current feedback, called single-loop to control and bicyclic control) compensation network (that is, the proportion integral differential or PID amplifier) circuit form, the optimal design of PID parameters.   

Posted by novaking at 2013年04月10日11:44

Lithium Battery Protect Design

In order to prevent affecting the battery life of lithium batteries in the abnormal state of the overcharge, over-discharge, over-current, typically by a lithium battery protection device to prevent damage of the abnormal state of the battery. More widely lithium battery applications, from portable devices such as mobile phones, MP3, MP4, GPS, toys to the need to continue to save gas meter data, its market capacity has reached hundreds of millions of only a month.

The lithium battery protection circuit of the device shown in Figure 1, mainly by the battery protection control IC and an external discharge switch M1 and a charging switch M2. When the P + / P-end connected to the charger, the battery normal charge, M1, M2 in the conduction state; when the control IC to detect charging abnormal, M2 is off to terminate charging. When the P + / P-end connected load, battery discharge normal, M1, M2 are turned on; when the control IC to detect abnormal discharge off the M1 termination of the discharge.

Several existing lithium battery protection program

Figure 2 is based on the principle of the lithium battery protection design of a common lithium battery protection board. In SOT23-6L package control IC package SOP8 double switch M1, M2. Vary due to the manufacturing process and manufacturing process of the switch control IC , Figure 2, two chip made ​​from a different process, usually these two chips is also provided by the chip manufacturers.

In recent years, the industry has a few chips packaged together to improve integration, reduce the trend of the last program area. Lithium battery protection market is no exception. A and B of Figure 3, two lithium battery protection looks in Figure 2 two chip integrated on a single chip, but in fact its package internal controller IC and the switch chip is still separate and different from manufacturers, the program is only two together sealed together, commonly known as "core unity.

Two internal chip actual still from different vendors, the shape can not be a good match, resulting in the final package shapes, in many cases, can not adopt a common package. The relatively large size of this package, they can not save external components, so this "core one" program actually Province, not too much space. In terms of cost, although the cost of two packages is reduced to the cost of a package, but this package is usually relatively large, some not generic package, some in order to reduce the package size, chip stacking package in the form, so traditional compared to the two-chip solution, the cost advantage is not obvious.

Figure 4 is a true controller chip and switch chip integrated single-chip solutions in the same wafer. Switch tube in the schematic diagram of the traditional scheme 1 is an N-type tubes, and between the B-and P-In Figure 1, commonly known as cathodic protection. The program in Figure 4, for technical reasons, the switching tube can only be changed to a P-type tube, connected between the B + and P +, commonly known as the positive electrode protection. Complete program of protection board with this chip, users need to be replaced in the detection protection board test device and philosophy. Although reduced packaging costs, but the cost of the chip has not been reduced, there is no real cost advantage in the the mature traditional program with a large quantity competition. In contrast the the cathode protection concept incompatible with the traditional program became the promotion process huge obstacles.

Although the above "core one" program and Single-chip cathode protection program to the user in the size and cost of the program has brought certain advantages, but the advantage is still not clear. These programs at the same time bring some drawbacks, therefore, in the process with the the mature traditional program competitive customers, eventually only to reduce the margin space to compete on price. Because the truly original cost of these programs and there is no obvious advantage, control IC and the switch chip price cuts as the traditional program, the program of these two core one "or positive protection program has not been able to shake the market domination of the traditional program position.

Market in recent years there have been many ups switch tube chip manufacturers, in order to reduce costs, the package originally hit gold wire into a play copper the switch tube nor with ESD protection. Although these products and brand performance switch compared to some differences, but because of the cost advantage quickly seize the secondary market, but also for the traditional program with two cores one "and cathode protection program of competition in the market The win made ​​a great contribution.

Fully integrated lithium battery protection program

The SyChip Microelectronics patent through independent research and development of a number of devices and circuits combined with unique technology, the control IC switch tube integrated on the same chip, the introduction of the world's smallest lithium battery the protection program XB430X products. This series of products using traditional N-type switch, consistent with the principle of cathodic protection of traditional programs, the protection board manufacturer or the manufacturer of lithium batteries do not need to replace any test equipment or philosophy. The series chip itself is a lithium battery protection program without the need for any external components can be realized lithium battery protection function. In order to prevent the noise of the VCC line, it is recommended in when using XB430X series chip between VCC and the negative terminal of the battery connected to a capacitor, as shown in Figure 5.

XB430X series chip integration is very high, not only to the traditional control IC and the switch integration, and the principle of Figure 1, R1, R2 is also integrated into the same chip. Integrated chip is very small, the smallest market generic SOT23-5L package. The chip series switch resistance is very low minimum internal resistance of up to 40m? With the best available switch resistance quite. When using the smallest package SOT23-5L, continuous charge and discharge current up to 2.5 amps instead of a heat problem. Continuing to charge and discharge current greater than 2.5 amps, it is recommended that SOP8 package products the XB430X series.

XB430X have all the protection features of the traditional protection programs: overcharge protection, over-discharge protection, overcurrent and short circuit protection. Moreover, due to the control IC with the switch tube integrated on the same chip, readily detect switch chip temperature control IC. A result of long-term use in high-temperature environments, or charge-discharge current exceeds the normal charge and discharge current when the battery reasons, but did not reach the overcurrent protection threshold when the chip temperature is too high, you will start over temperature protection, in order to protect the chip and battery supplier. In addition, the built-in switch tube with ESD protection, can significantly improve the yield of protection board and battery in the process.

XB430X internal control IC and switch tube from the same production process, the same vendor, package selection of the most mature and versatile package, thus consistent performance than traditional programs, two cores, one "program, the positive protection program should be much higher.

XB4301 series chip, the completion of the final battery protection program only two components (see Figure 5), compared with the five components of the traditional program, the capacity and efficiency of each placement machine can be increased to 2.5 times. Compared with the traditional program, protection board manufacturers not to buy the resistors and switch chip, to streamline the resource chain, but also in the production of the protective plate to reduce the two resistor pads and switch 8 welds, thereby greatly reducing the production costs of the protective plate.

Posted by novaking at 2013年03月21日17:28

Properly Install Geared Motor

Correct installation, use and maintenance of the geared motor, an important part is to ensure the normal operation of mechanical equipment. Installed planetary geared motor, must be strictly in accordance with the following requirements and steps installed correctly:

The first step: Be sure to install the motor and geared motor are intact, and to check whether the size of each part of the motor and geared motor connected matching.

Step 2: unscrew the geared motor flange outer dust-hole on the lid, adjust the PCS system clamping ring so that the side of the hole and the dust-hole alignment, insert hex wrench. Thereafter, removal of the key of the motor output shaft. Prior to the installation of the motor input shaft positioning boss and deceleration into the the machine connected parts of the anti-rust oil wipe clean with gasoline or zinc sodium water.

The third step: the motor and deceleration into machine natural connection, the connection must guarantee consistent the geared motor input holes with the DC motor input shaft concentricity, and both the outside flange parallel, to do so can not only extend the life of the geared motor and can be obtained than ideal transmission efficiency and low noise. In addition, non-time installation hit with hammers and other heavy objects, to prevent damage to the bearings or gear axial force or excessive radial force. Connected to motor and geared motor flange mounting bolts tightened after tensioning bolt clamping ring tighten the PCS system.

The fourth step: geared motor installed turned by hand should be flexible, without catching phenomenon. Boot before tightening the various joins screw, load test should not be less than two hours, the operation should be smooth, shock, vibration, noise and oil leakage, and found that the problem should be immediately removed. Should be used regularly check each fastener is loose, to ensure proper operation.  
タグ :Geared Motor

Posted by novaking at 2013年03月15日17:15

White LED Life

White led detailed graphic analysis, and how to improve white LED package

In order to obtain a sufficient white LED beam, has developed a large-size LED chip, trying in this way to achieve the intended objectives. But will actually applied on the white LED electric power continues to exceed the above 1W beam decreased, the luminous efficiency is relatively reduced by 20% to 30%, to improve the input power and the light emitting efficiency of white LED must be overcome problems are: to suppress the temperature rise; to ensure The life ; improve luminous efficiency; luminescence properties equalization.

The increase in power will use white SMD LED package thermal impedance drops to less than 10K / W and abroad have developed high-temperature white LEDs, an attempt to improve the problem of temperature rise. More due to high power white LED heat than power white LED high number of times, even if the white LED package allows the high-calorie, but allows the temperature of the white light LED chip is certain. Suppress the temperature rise of the specific method is to reduce the thermal resistance of the package.

The specific method to improve white LED service life is to improve the chip shape, a small chip. White LED emission spectrum contains wavelengths below 450nm short wavelength light, the traditional epoxy sealing material can easily be short-wavelength light damage, high power LED light accelerated the deterioration of the sealing material. Switch to the siliceous sealed ceramic package material, white LED life can improve a few.

The specific method to improve white LED luminous efficiency is to improve the chip package structure, to achieve the same level with the low-power white LED, the main reason is the current density is increased by more than 2 times, not only is not easy removed from the large chip light, the result will resulting in luminous efficiency than the low-power white LED, and improving the electrode structure of the chip, in theory, can solve the above-described light extraction.

Luminescent characteristics homogenized specific method is to improve the white LED package, generally considered long as the phosphor material to improve the white LED uniformity of the concentration with the production technology of the phosphor can be overcome the above distress.

Reduce thermal impedance, to improve the heat dissipation problem are:
(1) Reduce the chip-to-package thermal impedance.
(2) Inhibition of the package to the printed circuit board thermal impedance.
(3) Improve the the chips heat dissipation smooth.

In order to reduce the thermal impedance, many foreign led manufacturers LED chip provided in the surface of the cooling fins made of copper with a ceramic material, as shown in Figure 1, by welding the radiating conductor of the printed circuit board connected to the use of the cooling fan forces the air-cooling fin. German OSRAM Opto Semiconductors Gmb experimental results confirmed the above structure of the LED chip to the thermal impedance of the welding points can be reduced 9K / W, approximately about 1/6 of the conventional LED. Encapsulated LED 2W of the electric power applied to the LED chip temperature higher than the welding point 18 ℃, even if the temperature of the printed circuit board to rise to 500 ° C, the temperature of the LED chip is also only about 700 ℃. Once the thermal impedance is reduced, the temperature of the LED chip will be influenced by the temperature of the printed circuit board, this must be to reduce the thermal impedance of the LED chip to the welding point. Conversely, even if the white LED has to suppress the thermal impedance of the structure, if heat from the LED package can not be conducted to the printed circuit board, the LED temperature rise will make the light emitting efficiency decreases, so Panasonic Company developed a printed circuit board and package integration technology, the side length of 1mm square blue LED to overlying chips manner packaged on the ceramic substrate, the ceramic substrate can then paste in the copper surface of the printed circuit boards, including printed circuit boards, including module The overall thermal impedance is about 15K / W.

Longevity problem for white LED, the LED manufacturers in the countermeasures taken is to change the sealing material, while the fluorescent material is dispersed in the sealing material, the material degradation and the rate of decrease of light transmittance can be suppressed more effectively.

As the epoxy absorption wavelength of 400 ~ 450nm light percentage up to 45%, the siliceous sealing material is less than 1%, epoxy luminance half-time of less than 10,000 hours, siliceous sealing material may be extended to 4 million hours (Figure 2), almost the same as with the design life of the lighting device during use, this means that the lighting device without replacing the white LED. However, the the siliceous sealing material is a soft, flexible material, the processing must be used that will not scratch the surface of the sealing material production technology siliceous and easily attached Fenxie addition process on the siliceous sealing materials must be developed in the future can improve the surface characteristics technology.

Although the siliceous sealing material can ensure that the white LED has a service life of 40,000 hours, lighting equipment industry, however, has a different view, the main debate is the life of traditional incandescent and fluorescent lamps is defined as "brightness down to 30% or less", brightness The half-time of 40,000 hours of white light LED, if converted into brightness down to 30% or less, and only about 20,000 hours. There are two longer component life, the countermeasures are:
(1) Inhibit the overall temperature rise of the white LED.
(2) The stop using the resin encapsulation.

The above two countermeasures can reach a brightness reduced to 30% of the requirements of the service life of 40,000 hours. Inhibition of white LED temperature rise the cooling white LED packages The method of the printed circuit board can be used, mainly the encapsulating resin under high temperature, coupled glare rapid deterioration, in accordance with the Porto-Vilnius rule, the temperature is reduced 100 ℃ Life will be extended to 2 times.

Stop using the resin package can completely eliminate the deterioration factors, because the white light generated by the LED light is reflected within the encapsulating resin, if used may change the chip side surface of the light traveling direction of the resin material reflecting plate, the reflecting plate will absorb light, so the amount of light extraction will dropped, and this is the main reason for using a ceramic and metal packaging materials.

There are two methods to improve the luminous efficiency of the white LED chips: one is to use an area 10 times larger than the small chip (1mm2) in a large LED chip; Another is the use of a plurality of small high luminous efficiency of the LED chip are combined into a single The body of the module. Although the large LED chip may obtain a large beam, but the negative impact of increasing the chip area, for example, light-emitting layer within the chip uneven limitation, the light-emitting portion, and the chip internally generated light is emitted to the outside will be severely attenuated. To solve the above problem, through the improvement of the electrode structure of the white LED, overlying a chip package, plus integrated chip surface technology has reached 50lm / W luminous efficiency. Large white LED package shown in Figure 4. About the equality of the light-emitting layer of the chip as a whole, since the emergence of the comb-like grid-like p-type electrode, the electrode also developed optimization direction.

About follow-chip package, due to the light-emitting layer can easily exhaust heat, plus the light emission of the light-emitting layer close to the package end to the external electrode sheltered troubled American Lumileds cooperation Toyota has officially cover a chip package , the processing of the chip surface can prevent the light emitted towards the outside of the chip from the chip's internal reflection occurs at the interface, provided on a sapphire substrate is removed in the light parts of the concavo-convex structure, the chip external light extraction efficiency can be improved about 30%. The chip side improved large LED chip packaging entity emitted light toward the reflection of the package above the plate road, high efficiency to remove the chip internal light package size is 7mm x 7mm.

Small enhancement of the luminous efficiency of the LED chip seems to be more effective than the large LED chip module. For example, Japanese CITIZEN combinations of eight small LED chips reach 60lm / W high luminous efficiency. 0.3mm x 0.3mm Nichia produced small LED chip, a package module uses up to 12 chips, each LED chip using the traditional gold wire bonding package, applied power is about 2W.

The problem of uneven luminance and color temperature of white LED must be screened in the use of optical characteristics similar to the white LED. In fact reduce the unevenness of the white LED light-emitting characteristics of the LED chip emitting characteristics of the same, and the implementation of the concentration of phosphor material uniformly distributed management is very important.

LED chip light-emitting characteristics, the manufacturers are very active chip screening, light-emitting characteristics equal treatment LED light features to reduce the problem of uneven, such as Matsushita Electric Company has reached the same characteristics of the target through the screening of the chip. The follow-chip manner, 64 LED chip package on a substrate, and finally then were covering the phosphor. LED chips during processing first encapsulated in the light emission characteristics of sub-substrate test, followed by the light emitting characteristics of the same chip transplant encapsulated in the main substrate. 8 LED chip on a substrate, even if the light emitting characteristics of the LED chip is not uniform, the total light emission characteristics of the eight LED chips in the package between the unevenness will become very small.

The white LED is usually directly coated LED chip with a sealing resin containing phosphor material, the concentration of the phosphor material in the sealing resin may occur deviation finally result in uneven distribution of the color temperature of white LED. Therefore, the resin sheet containing the phosphor material is combined with the LED chip, through strict management due to the thickness of the sheet, and the concentration of the phosphor material, so the color temperature of the white LED uneven distribution of degree less than the traditional way of 4/5. The industry that the use of the phosphor sheet with the light-emitting properties of the LED chip to change the thickness of the concentration of the phosphor sheet, you can make a white LED color temperature change of control in the expected range.

Although gradually increase the possibility of application of white LED lighting in the area with white LED luminous efficiency, but obviously, single white LED luminous flux is low, so the package unlikely to achieve a single white LED lighting lumens. For this human problem, the solution can be broadly divided into two categories: one is the more traditional use only LED light source module, which each white LED drive power and general use (for 20 to 30mA); another type of method is the use of a larger area of ​​the chip, traditional 0.3mm2 size chip is no longer in use at this time, while the use of a size of 0.6 ~ 1mm2 chip, and use a high driving current to drive so The light-emitting components (typically 150 ~ 350mA, up to 500mA). But no matter which method is used, the will must handle high heat in a tiny LED packaging, if the components can not be dispersed these heat, in addition to a variety of packaging materials will be due to the different expansion coefficient between each other and reliable products issues, the luminous efficiency of the chip as the temperature rises, and has significantly decreased, and causing life shortened significantly. Therefore, how to disperse heat from the component to become the important subject of the current white LED encapsulation technology.

For the white LED, it is most important that the output of the luminous flux and light color, so one end of the white LED must not shading, while the need to use the effect of high transparency of the epoxy resin material coated. However, there is the epoxy almost all thermally non-conductive material, for white LED packaging technology, its white LED chip under metal feet to disperse the heat emitted by the component. Opinion, the current trend, the metal foot is mainly a high thermal conductivity coefficient material mainly consisting of, e.g., aluminum, copper or even ceramic material, etc., but a great difference in coefficient of thermal expansion between these materials and chip, the direct contact, it may be because stress generated between the material at elevated temperatures and cause reliability problems, so usually coupled with a material between the intermediate material of appropriate conductivity and expansion coefficient as the interval. Matsushita Electric company only made of white LED is still in the metal material and the metal line module on a multilayer substrate made of the composite material to form a light source module, the high thermal conductivity of the substrate effect on the use of a light source, so that the output of the light source in the prolonged use able to maintain the stability. Lumileds production of the materials used in the white LED substrate of copper having a high conductivity, and then its connection to a special metal circuit board, it can be both circuit conduction and increase the effect of the heat conduction.

The high-power white LED chip manufacturing technology, packaging technology seems to have become a mainstream technology for high brightness white LED, the largest chip manufacturing technology and packaging technology, however, is not just the chip area bigger, if they want to apply white LED high brightness lighting field, technology has yet to be studied further.

White LED in general lighting field, there are still many problems to be solved, first white LED efficiency, such as the the GaInN Department of the green, blue and near-UV LED efficiency is still a big development margin. In addition, the internal quantum efficiency of the integrated energy efficiency is the most important item, and the internal quantum efficiency by the active layer of the non-light-emitting the percentage light emitting recombination percentage decided, it can lock the focus to this part in the non-light emitting recombination, and managed to reduce the crystal defects. And to reduce the dislocation density of the UV LED can indeed significantly improve internal quantum efficiency, the future need for the UV LED to further reduce the dislocation density. However, this countermeasure of green, blue LED does not have a significant impact.

Green and blue LEDs at low current densities (around 1A/cm2) have the maximum quantum efficiency, the quantum efficiency in the high current density will decrease, as shown in Figure 7. LED can be driven with high current density as possible while increasing the output power of the component, so the early unlock the mechanism and cause of decrease of the quantum efficiency in the green and blue LED high current density from the cost viewpoint, not only is the material The physical characteristics of exploration on the need for future applications, the study also has a key role. The present study shows violet LED (wavelength of 382nm) is applied, the high current density (50A/cm2), the quantum efficiency is not lowered.

The conventional white LED are the side length of 200 to 350 μm square chip packaged into a ball pillar shape, after the required order to obtain the lighting beam, then is encapsulated a plurality of white LED components are arranged in a matrix shape. Simply to high output power for the purpose of especially developed area ratio the conventional chip 6 to 10 times, dimensions up to 500 μm to 1 mm of the white LED Although the package obtained after several hundred milliwatts (tens of lumens) of output power, increase the dimensions of the chip, but the white LED light within the absorption ratio increased external light extraction rate decreased. For example, AlGaInP LED Dimensions of the chip is 0.50mm x 0.50mm, 0.22mm x 0.22mm increase external light extraction rates have reduced by about 20%. If the switch TIP structure, internal result of multiple reflection so that the internal light absorption rate decreased, the external light extraction efficiency is improved significantly. The GaInN LED also has the same effect. How to improve the external light extraction efficiency of the LED chip LED used in the field of general lighting. In addition, the considerable disadvantage of high thermal impedance (150 ~ 200K / W) for the high brightness output. LED internal quantum efficiency of the active layer temperature dependence great addition to the low thermal resistance packaging technology, the use of heat sinks become hot spots for future R & D exclude active layer of heat.  

Posted by novaking at 2013年03月06日17:32

2013 LED Chip Oversupply

"It's like a dozen hungry wolf, hoping to grab a piece of meat, everybody dog ​​eat dog." The person in charge of the Yang First, a epitaxial silicon plant just experienced a price war of 2012 delay chip market at home and abroad, is still a lingering fear.

Inventory, or we get rid of the pain, "Yang boasted Road," We still have about four or five months of inventory currently, domestic chip plant turnover days is about 120 days, more miserable is 180 days. companies pay now pay drawn, material buy back, electricity affordable has been pretty good. "

Fierce price war, is evident from several listed companies has announced the 2012 results notice.

The electricity of Hua Canguang performance forecast released in 2012, the company forecast net profit of about 84 million yuan -9000 million profit attributable to shareholders of listed companies, compared with a decrease of approximately 27.8% -32.6% 124,651,500 yuan over the same period in the previous year. The electricity of Hua Canguang said that since 2012, due to the impact of continued market competition, the LED chip sales price decline than expected, decreased significantly compared to 2011, resulting in chip sales over last year, net profit is lower than the same period last year level.

Another listed company Silan situation is not optimistic. Wholly owned subsidiary of Hangzhou SILAN AZURE Technology Co., Ltd. Product prices have decreased significantly compared to the same period in 2011, led to the company's net profit decreased significantly compared with the same period in 2011.

Even so, starting the year in 2013, the the delay chip industry at home and abroad is still no shortage of "showstopper".

The "photoelectric poly Chan first entered 3 sets of 69 AIXTRON machine, according to the 2013 planning on more than a dozen sets of MOCVD . " Yang said, because the enterprise is also able to get the local government thousands of yuan each MOCVD equipment subsidies, price in accordance with the the currently AIXTRON69 tablet press, doing poly Can the photoelectric now purchase a device can earn more than 100 million.

January 28, chip Godfather "Richard Chang helm SG Hao Rui new LED epitaxial wafer and chip production project successful trial production in the aerospace base. In addition, Shanghai's ultra-silicon semiconductor Co., the layout of the LED chip project in Chongqing also completed and put into operation by the end of January.

In addition to the new entrants, the leading enterprises of Taiwan chip Epistar also expansion.

Epistar and Lite-grain products Changzhou factory joint venture expansion will increase by 8 sets of MOCVD.

In addition, Veeco has announced the receipt of the orders of the developed crystal lighting (Xiamen) Co., Ltd., ordering multiple reaction chamber and single reaction chamber MOCVD equipment, including new models MaxBright.

Managing Epistar Dr. Zhou Mingjun, said: "This latest expansion in Xiamen in order to achieve our goals, so that we maximize the LED backlighting, automotive and general LED lighting market share of."

"The Epistar layout or step by step calculates capacity and actual demand, I personally think it is a relatively conservative." Yang said, "In contrast, the continental extension of plant basically no matter what will happen tomorrow, first crazy expansion to say. "

Two years of the chip as a whole will be in an oversupply situation, we will definitely decline in value, "industry sources," especially over the past few years a large investment in the epitaxial chip companies, such as BDO Runda. Far as I know, They chip bargain phenomena of most serious. "

The chip market long-term oversupply expected, also in the middle reaches of packaging companies reflected.

"Most of the packaging factory feel that years later the market will not be missing chip, and the chip prices will be lower, so years ago not to consider stocking." Yang ready to catch to digest some inventory before the Lunar New Year, but the results are not optimistic . "Some packaging factory to advance the Lunar New Year holidays."

"Chip prices have been down, and in 2013 we will definitely continue to fall, the decline may be only a little smaller than 2012. The Shenzhen Crystal OPTOELECTRONICS Co., Ltd., general manager of GONG Wen told reporters. "Because of this, we certainly will not stocking."   

Posted by novaking at 2013年02月28日12:32

Innovative LED Desk Lamp

Angular shape filled with all-metal LED desk lamp skinny

Once upon a time beauty became popular skinny beauty, even the table lamps are also unique skinny design, this is the designer Michael Samoriz design pure metal lamps, LED table lamp resembles bone closely linked to overall by five clear water chestnut minimalist stylingcomposed of the LED light source design in the distal, like flexible joints as table lamp can be systemic flexibility to adjust the most special shape, angle and range of the best light-emitting desktop, accustomed to seeing a bulky and cumbersome desk lamp, LEDthis LED lamps, lighting house described is not attractive enough.

The interesting DIY Coils LED Desk Lamp

Usually have the volume of a ball of yarn preferences to meet your winding fun time to roll out the systemic winding as this mummy desk lamp, designer Craighton Berman can do it yourself coil table lamp, table lamp cord layerscable hollow around the lampshade, built-in LED bulbs lighting also wound was interesting, to avoid direct glare of LED light, the most important thing is can begin their own DIY, the line table lamps wound such personality, on the living room table but not simplechoose orange wire, to make the room more than a trace of warm colors.

Simple bare style LED table lamp

How exposed will look good, this is also a test of the lighting designer. Often exposed too much, it will make lighting products look stiff and cold, the messy cable blunt metal poor quality material. Milan designer Giorgio Bonaguro gives the best answer, called "Tweety" lamp has simple lines framework bulb, lamp holder and wires are exposed, but not unobtrusive LED bulbs installed the lights Xiao Ming after instead, in the semi-obscured light board, exudes a soft, warm light. Different color shade and power cord with, and give people more choices, this lamp design 2011 the Salao Design Design Awards. LED lighting House think the same is worth DIY lamp, simple lighting structure at a glance, the strong hands of the guy is worth a try, can be used as floor lamps, table lamps, as well as hand-held work lamp finished.


Posted by novaking at 2013年02月20日12:38

Lighting With Low Ceilings

Lighting a allowance with low ceilings can be a challenge, abnormally if you wish to bottle its beheld appeal. With the all-encompassing ambit of LED Lighting options now available, ascent to the challenge, and extenuative money in the process, has never been easier.

While low ceilings are generally associated with aeon backdrop and cottages, usually in aggregate with board beams, it is not aberrant to acquisition them in avant-garde houses as well. In the above they accommodate appearance and charm, but in the closing they are an impracticality.

The problem, according to experts, is award accessories that accommodate abundant light, after creating an obstruction. Your accessories should acquiesce a vertical ambit of at atomic 6ft 8inches from the attic in adjustment to anticipate collisions. That agency there isn't any allowance for the added traditional, below luminaries and absolutely no chandeliers, contrarily you may acquisition your houseguests bumping their heads. This won't do your houseguests or your big-ticket accessories any favours.

Instead, use even or semi even fittings. These sit collapsed adjoin the axle and actualize added headroom. There are affluence to accept from and all are accordant with LED Lighting.

A beautiful and detached advantage are LED Downlights. Downlights appear as either absolutely led chip units or as a abstracted ball and accoutrement combination, which alcove into the ceiling. Circular holes are cut into the axle into which the accessories are inserted. As earlier barrio can be a huge blaze risk, so it is important to accomplish abiding all your accessories are fire-rated. You will aswell accept greater section of apperception as LEDs accomplish beneath calefaction than acceptable beaming bulbs.

LED Strip Lights are absolutely a contempo addition and are generally disregarded if it comes to calm designs, but they will do the job just as well. Their baby and bunched architecture makes them perfect, decidedly amidst board beams area there isn't abundant space.

If you adopt acceptable design, try application bank sconces as an another to acceptable luminaries. These advice actualize the apparition of acme by bulging ablaze up the walls and beyond the ceilings. A agnate aftereffect can aswell be accomplished with attic continuing lamps. These can be acclimated in aggregate with Tiffany-style lamp shades and bolt apparel to actualize a nice bohemian feel. Because LEDs abide cool, you won't charge to anguish about abhorrent bake marks either.

Remember, abstain application bulbs with a attenuated axle bend as these will actualize too abundant glare. Opt instead for advanced bend bulbs, such as the GU10 24 SMD LED.


Posted by novaking at 2013年01月28日17:28

Choose & Install LED Lamp

LED light band can be regarded as one of the home improvement lighting products indispensable 6:00 elements need to pay attention at the time of purchase. LED lights with the production of low-threshold, there are a lot of factories and workshops have this project, causing the LED lights with the market quite a mixed bag, production and product quality is uneven. People do not have the knowledge and experience easily deceived to buy inferior lights with. But the experience still have a way to identify formal manufacturers to produce LED lights with LED lights with cottage version (meaning depends on manual work products produced in the rental) from the appearance, at a glance out. Let's talk about how to identify the quality of LED lights with good or bad in their eyes :

1. See the solder joints. Regular LED lights with manufacturers to produce LED lights with SMT chip technology, production of solder paste and reflow process. LED lights to bring the solder joint is relatively smooth and the amount of solder will not solder an arc to the LED at the electrode extends from FPC pads . Amount of solder joints cottage LED lights with uneven, mostly a dot wrap welding foot, at the same time there will be varying degrees of icicles, which is a typical phenomenon of manual welding.
2. See FPC quality. FPC sub copper and rolled copper two Bonded Copper foil is projecting a closer look, then look out from pad with FPC connection. Rolled copper is close and FPC as a single entity, and can be bent without pads off. Bonded Copper if bent too much appears pads off, maintenance when the temperature is too high can also cause the pads off.
3. See LED lights with the cleanliness of the surface. If the LED lights with SMT production, surface cleanliness is very good, and do not see any impurities and stains. However, if the use of hand-welding process production cottage LED lights with its surface no matter how cleaning will be residual traces of stains and cleaning, the FPC surface at the same time there will be flux and tin slag residue.
4. Look at the packaging. The regular LED lamp with trays packaging, antistatic volume generally 5 m roll or 10 meters a roll, and then the outside and then anti-static moisture-proof bags sealed. Cottage version of LED lights with cost recycling volumes trays, then no antistatic moisture-proof bags, look carefully roll trays can see the appearance of clear labels left marks and scratches.
5. Look at the label. Regular LED lights with bags and roll trays above will print labels instead of printed labels. Cottage version of the label is printed, specifications and parameters are not unified.
6. See Annex. Regular LED light strip will be enclosed inside the package instructions and lamps with specifications, while also equipped with LED lights with connector or deck; cottage version of LED lights with box without these accessories, because Some manufacturers, after all, could save the province.

What Should pay attention to when Buying LED lights

1. Different brightness requirements for different occasions and different product requirements of LED brightness. LED jewelry counter lamp on a number of large shopping malls, we will have high power led and some have attractive, but also decorative effect LED spotlights and LED colorful lights with different products can be divided.
2. Anti-static electricity force: the antistatic ability antistatic ability LED, long life, but the price will be higher. Usually the the antistatic best higher than 700V.
3. Wavelength, and the color temperature is the same LED, the color will be the same, this combination of large quantities along lamps particularly important. Same lamps which do not produce much of a color difference.
4. The leakage current is the current LED reverse conductive, we recommend using a small leakage current LED products.
5. Waterproof ability is not the same requirements for outdoor and indoor LED lights.
6. LED light-emitting angle of the LED lamps greatly different lighting requirements large, we recommend 140-170 degrees like LED fluorescent put. Other we are not here for a detailed explanation.
7. LED chip decided LED core quality the LED chip brands, foreign brands (such as CREE , Nichia , etc.), and China Taiwan (Huga Epistar etc.). Different brand price difference is also very far away.
8. LED chip size also determines the LED quality and brightness, try to choose when we choose a bigger chip, but the price difference.

LED strip lamp shade installation instructions

First, Main structure
LED strip light shade is made of high thermal conductivity of 6063 aluminum, high-grade appearance beautifully light source with imported Bridgelux chip 5050 SMD LED. Suitable for jewelry, display counters, the villa home lighting, shopping malls, hotels, office buildings, leisure facilities, decorative lighting and other lighting places, ideal lamps instead of the traditional fluorescent tubes.

Second, the structural parameters
Input voltage: 220V
Operating voltage: 12V
Power : 13.2W
Light bar length: 1m
Output Luminous Flux : 1040lm
Color Rendering Index : 85
Light source: LED0.2W * 66pcs / m
Color temperature :2700-7500K
Exterior Color: Silver
Operating Temperature: -20 ℃ ~ +60 ℃
Operating Humidity :10-90RH
Electric shock rating: Ⅱ
Use the drive : constant current drive, stable performance, safe and reliable
Light distribution types: 120 °
Light distribution: selected light source, the LED light color better, uniform focused spot , variegated shadow dark areas
Connection: terminal link

Third, the steps
1. Check lampshades, light bar, finishing supporting the various parts and accessories are complete;
2. The lampshade according to the counter length matches the length of the processing interception, and then ends the processing 45 ° chamfer
3. At both ends of the counter lampshade about inner separately open the through hole having a diameter of 3.5mm, in order to be connected and fixed pad;
4. About Lamp slot at both ends of the lower part of distinguished two M3 holes for connection and triangular block;
5. To install the shade into the appropriate size light bar, connected together through the triangular block;
6. Fixed block groups adhesive in the corresponding left and right the lampshade openings at the inside of the glass;
7. With screw connection shade fixed on the counter;
8. Mounted on the mast;
9. To install the driver. Note that the input and output ports, installation connecting the light bar to pay attention to the positive and negative connections. The red line cathode connection, black for negative connection.

Fourth, note

1. An LED driver and LED light bar installed correctly ;
2. 12V 3.2A drive LED strip then I can not exceed 4m, 12V 5A LED light bar can not exceed 5m driver pick me up;
3. Must cut off the power supply before installation operation;
4. Product installation must be installed by professionals.   

Posted by novaking at 2013年01月22日12:41

Power LED Lighting Design

Whether power or small power LED lighting applications, generally consists of power supply, LED drivers, LED, lens and substrate sections, one of the key components is the LED driver, it must provide a constant current output in order to ensure the LED emits The light does not flicker, not occur LED color cast phenomenon, it is generally accepted 24V-48V DC voltage input, but also has some advanced LED driver can be directly accepts AC input of 220V electricity. Most customers require the use of high-performance LED driver to meet the PF value> 0.9 and +85 efficiency LED lighting specification forthcoming .

The main design challenges for LED lighting applications include the following aspects: heat, high efficiency, low cost, dimming, flicker-free, wide range dimming, reliability, security, and eliminate a color cast. These challenges require integrated use of appropriate power system topology architecture, drive circuit topology and mechanical design to solve.

Diodes, Asia Pacific Marketing Director, said: "For a designer, the biggest technical challenge is the high efficiency requirements, optical design, thermal management, and improve the reliability of some applications, such as high-brightness LED streetlights. Beam after the right we now offer series of LED lighting solutions covering applications from 0.1W to 250W.

"In addition to selecting the right LED products, LED lighting system, a complete LED lighting design but also including optical design, thermal design, product design and electrical drive design LED low-voltage devices, high-voltage AC power supply converted to LED using low voltage constant current driver will be faced with many challenges. "before the ON Semiconductor China area senior application manager Zheng were pointed out:" further said that, in order to ensure the advantages of LED lighting, LED electrical drive must be reliable, efficient, safety and low-cost. therefore, for a variety of LED lighting applications, you first need to select the correct driver circuit topology. "ON Semiconductor now from 1W to 500W power range of LED lighting solutions can provide.

In order to drive rapid take-off of the LED lighting market, National Semiconductor Corporation (NSC) has recently targeted an enormous incandescent direct replacement market, which uses LED lights directly replace incandescent lamps in existing home or other application markets, and launched a a direct mains for the market to enter the LED chip LM3445.

However, the NSC Asia Pacific product marketing manager for power management incandescent lamp has been available for many years, for many of the texts for the technical standards, our home lighting system has also followed many of the texts for the technical standards, the Wu Zhimin, said: not overnight can be changed over. example, based on issues such as cooling and lighting angles, the original old-fashioned lamp socket or device is not appropriate to install LED bulbs but in addition to the technical problems, the cost-effectiveness is also LED lights can not The popularity of the biggest causes of the price of incandescent light bulbs and neon tubes of about US $ 0.6-0.7/Klm, but the price of LED lights still up to U.S. $ 40-50/Klm. "

As mentioned above, the LED lights must be able to be installed within the original old socket, therefore the heat is a must overcome. But strictly speaking, it can take advantage of mechanical engineering technology to solve the problem, the responsibility of the LED system manufacturers to develop new technologies, maximize the LED brightness (lumens amount) per unit of power generated. Wu Zhimin said with confidence: "We can provide the efficacy of the most efficient LED driver to ensure that the entire lighting system to minimize the amount of heat."

The relatively high cost of LED lighting market is still difficult to scale take-off of the main obstacles. For example, Infineon power management business unit director of product marketing Alexander Sommer said: "the majority of less than 25W typical LED lighting applications marker lamps, marker lamps, as well as replace standard incandescent and halogen lamps but with compared to existing fluorescent and incandescent technology, LED initial cost is still a major obstacle to enter the mass market. "

Cytech products and design department engineers Xu Rui package also agree that the cost of major commercial challenges. He said: "various power LED lighting systems are on the circuit can be achieved, the technical challenges from the requirements of end-use applications, used in automobiles, for example, to take into account the optical design and the overall thermal design. Commercially deploy challenges mainly from the LED the cost. "

Thermal considerations LED lighting design

25W of LED lighting systems are generally designed for spotlights like reading lamps, corridor lights, living room, family dining lamps in applications such as customers generally want this type of application design is the more compact as possible, so the PCB can be placed The design space is relatively small, so the temperature inside the packaging space when used for a long time may be very high. Designer unlikely to install a cooling fan within its thermal design becomes very critical and important.

"Most of less than 25W low power LED lighting applications require a certain degree of miniaturization, which often leads to higher power density, despite power is not great. Adequate thermal management measures must be provided by an improved mechanical structure. Addition, high electrical efficiency helps reduce power consumption. "Alexander Sommer noted that" If the need to further reduce the thermal resistance, which can be electrically isolated to do, because it can achieve a maximum efficiency of heat transfer. These methods also allow to achieve optimized lumens output. "

The idea is to prevent LED long work overheat problem of another dimming solutions. Fairchild's high voltage IC product marketing manager, said: SangCheol Her compared to fluorescent and incandescent lamps, dimming solutions is an important way to reduce the LED power consumption, the use of such programs dimming controller. Especially for small 25W of LED driver solutions, thermal problem is inevitable, due to the small PCB size package space is limited, so the program is more important. "

In fact, in this power range, the LED lights will replace halogen lamps and compact fluorescent lamps (CFL). In addition, advanced technology, in order to get rid of the heat problem, you must remove sensitive to temperature changes, passive components, such as electrolytic capacitors. However, most LED driver solutions are derived from the power supply topologies and on this basis, it should take into account the temperature limits, because most products are usually based on commercial standards, but the lights must ensure that can adapt to the harsh environment, such as industrial environments.

LED lighting design of the architecture of choice for
LED lighting systems architecture of choice depends on your design goals is a low-cost, high-efficiency, or the smallest PCB area. In general, less than 25W of LED lighting system does not require power correction, so you can take a simple topology architecture, such as PSR or Buck topology. 25W-100W LED lighting applications require power correction, it is generally a single-stage PFC and quasi-resonant (QR) PWM flyback topology. More than 100W LED lighting applications generally use efficient LLC topology and two-stage PFC.

Less than 25W power LED lighting solutions the PSR or Buck topology can be used, mainly because this power range for small design, the emphasis on the simplicity of the design solutions for medium power (25W-100W) suitable for single-stage PFC quasi-resonant ( QR) PWM, flyback topology. "SangCheol of Her high power solutions (> 100W) suitable LLC, QR PWM, flyback topology design. LLC and QR better performance from the point of view of efficiency, ; PSR program without secondary feedback, simple design, the size is also smaller than other programs. "

Cheng Chung also said: "The main applications of less than 25 W LED lamps in indoor lighting, they are mainly low-cost flyback topology. Transformation of ON Semiconductor NCP1015 and NCP1027 monolithic integrated circuit integrates a built-in high-voltage MOSFET and PWM control can effectively reduce PCB area and the volume of the lamp, provide a maximum power output of 25W (230V AC input). "

Less than 25W LED lighting applications for non-isolated input to output conversion ratio is low, so simple buck converter can be the choice of a low-cost and small size. Isolated valued efficiency topology architecture, like quasi-resonant devices Infineon CoolSET ICE2QS Series flyback topology is a good choice. "Alexander Sommer said. Infineon is the first company to offer digital quasi-resonant flyback controller IC suppliers.

25W-100W power range typical LED lighting applications, street lighting (district roads) and in public places such as parking. Power conversion efficiency, cost-effective implementation of PFC function and high color quality is the most important of the three major technical challenge. For example, commercial lighting and street lighting applications, longer service life and lower maintenance costs resulting is helping to overcome the higher initial cost of entry barriers. 25W to 100W LED lighting applications power factor requirements, and therefore need to increase the power factor correction circuit.

"This circuit can be used to the traditional two-stage structure, the active non-continuous mode power factor correction (PFC) circuit plus a DC-DC PWM conversion circuit, such as power factor correction controller ON NCP1607, NCP1607 external circuit is very simple and can provide very good performance. "Zheng were before", it is recommended for high efficiency, low cost and small size LED program is a single-stage PFC circuit, it can simultaneously achieve low voltage DC power factor and isolation output, and has significant cost advantages, will become the mainstream of the medium-power LED lighting program. Semiconductor NCP1652 optimal control scheme for single-stage PFC circuit. "

Shenzhen Shiqiang Telecommunications is using the Silicon Labs C8051F3XX series of 8-bit MCU to be implemented in software PFC. The company assistant market manager Huang Feng Sun said: "our home city electric (180V-260V) input 10W-30W low power LED lighting applications developed all-digital LED lighting program, available software controlled manner to achieve up to 0.95 of PFC value. Hardware PFC compared with the set of software solutions in the premise to guarantee the same performance indicators, and also has a higher flexibility, adaptability, and scalability. "The program uses LED driver MIC3230 maximum output current of 350mA maximum drive 12 1W LEDs, can well meet the needs of indoor lighting.

Alexander Sommer said: "For the efficiency and performance of 25W-100W power LED lighting application requirements in a very wide input and / or load range (dimming) has recommended an independent with the PFC stage quasi-resonant flyback topology. typically can achieve up to 90% efficiency. "

100W or more applications, including the main road and highway lighting (It should be up to 20K lumens brightness or more, and a 250W power supply input) and professional applications, such as stage lighting and architectural floodlighting. A key driving force in high-power applications using LED reliability and low power consumption of the low cost of ownership. For example, the system efficiency can be compared with a metal halide and low pressure sodium lamps. The initial cost is more likely to continue in the short term barriers to entry in the market.

Cheng Chung pointed out: "For more than 100W of LED application, we will use the active non-continuous mode power factor correction circuit and half bridge resonant DC-DC converter circuit. Launched a new integrated controller, which integrates active non-continuous mode power factor controller and high-voltage driver half-bridge resonant controller. "

The half-bridge resonant controller operates at a fixed switching frequency and a fixed duty cycle, and the circuit does not require output side of the feedback control loop. This makes the resonant half-bridge DC-DC converter circuit ZVS and ZCS state at the highest efficiency. The DC output voltage will follow the output of the power factor correction circuit.

Alexander Sommer stressed: "higher power level of 100W or more LED lighting applications, the efficiency becomes more important, it is recommended to use the LLC resonant topology, it can achieve more than 90% efficiency, we recommend that you use Infineon's new 8-lead pin devices ICE1HS01. "

Regardless of how the output power of the LED lighting system, the selection of the LED drive circuit will largely depend on the input voltage range, the accumulated voltage drop of the LED string itself, and sufficient current required to drive the LED. This has led to a variety of different possible LED driver topologies, such as buck, boost, buck - boost and SEPIC type.

Linear Technology Power Products Division, Product Marketing Director Tony Arm strong, pointed out: "each topology has its advantages and disadvantages, which standard buck converter is the most simple and easiest to implement programs, boost followed by a buck - boost converter, SEPIC converter is the most difficult to achieve, because it uses a complex magnetic design principles, and designers need to have a a superb switch mode power supply design expertise. "

All in all, the end product application determines the topology of the LED, then according to the topology of the LED and the input power again reasonable choice Buck, Boost, SEPIC, or Buck-Boost structure. "In general, 25W choose Buck more power tend to choose Boost structure. Efficient both general can do more than 85%, LT3755 can be done up to 97% efficiency. Consider driving part BOM cost more should consider the overall system cost. "says Xu Rui package," As competition intensifies, from time to time there will be a lower BOM cost of the program, but not necessarily the most appropriate design products in accordance with this standard does not recommend PCB area is mainly controlled by the main components, a low-power LED lights maximize the use of high integration programs. To choose the technology of high-power high integration products and simple external circuit. discussed here are DC-DC solution. "

Beam after the right also pointed out that: "In order to achieve high efficiency requirements, should consider the use of the switch-mode LED driver, the majority of these customers prefer to choose the buck LED driver, because the total efficient from a lowest BOM cost perspective to consider switching type LED converter is not the cheapest of these customers may try to use linear constant current LED driver which can provide the lowest BOM cost efficiency may not like the switch-mode LED driver as high as from the smallest PCB board area of ​​the viewpoint, usually optional switch mode converter, because they generate less heat, and even the related components will be smaller volume. "

Analog, PWM and TRIAC dimming scheme

LED dimming solutions and norms have been changing, and until now has not been fixed, so now the market there are three dimming PWM, analog and SCR (TRAIC) program. PWM and analog method is relatively simple, but need to build the infrastructure of dimming and dimming controller.

Analog dimming scheme, the drawback is that the adjustment range of the LED current is confined between a maximum value to the maximum of about 10% (10:1 dimming range). As the LED's chromatography with current, so this method is not suitable for certain applications.

The PWM dimming solution is based on a certain fast enough to cover up the visual flicker rate (usually higher than 100MHz) to switch between zero current and maximum LED current. The duty cycle change the effective average current, which can achieve up to 3000:1 dimming range (limited only by the minimum duty cycle). As LED current either is at a maximum, or off, so that this method has the advantages of the LED color misregistration occurs can be avoided in the current changes in the analog dimming such LED color misregistration phenomenon is very common.
SangCheol Her optimistic about the market prospects TRIAC dimming program thyristor (TRIAC, 2 lines dimming) will become a very popular solution, because this technology can fully use the traditional system without any changes, he said: Moreover, it can also be extended to 3-line dimming in order to avoid the defects associated with the low power factor values. "

TRIAC dimmer today is a very hot topic of the industry, initially, TRIAC dimmers designed for incandescent, but most users want the same TRIAC dimmer alternative LED lights dimming. Leung said after the right: Diodes Zetex currently available to provide customers with full dimming solutions (including PWM, analog and TRIAC), ZXLD1362 LED driver Used ADJ pin to analog and PWM dimming, which brought to customers a great deal of design flexibility. "

However, Cheng Chung before that, TRIAC dimmer applications on the market should only be transitional, in the long run, you should use PWM dimming. He said: "The main point decisive factor as follows: 1) PWM dimming from zero to the most light, there will not be flashing phenomenon. 2) the performance will be better. Dimming output power with a power factor correction circuit , which is in line with the mandatory requirements of the global lighting power factor, although generally from 25 W, but the United States need a mandatory power factor correction circuit lights starting at zero watts such as the TRAIC dimming sacrifice power factor and increase the complexity of the circuit. Therefore, using the PWM dimming can provide the best performance of the selection, the future trend. 3) costs will be better with the duty cycle of the PWM adjustment, does not require much additional control circuit cost. "

Alexander Sommer also optimistic about the PWM dimming scheme prospects, he said: "analog dimming LED's PWM dimming method has the following advantages: 1) more efficient; 2) regardless of the degree of dimming allows LED has been optimization and constant current getting off work group; 3) LED color tone consistent throughout the dimming range (color shades like lumen output with LED operating current change). "

Xu Rui package frankly: "personal feel, the modulation choice should not be determined by the power of the LED. Should decide on the application requirements of the end products. Example, the display backlight or LED decorative lights may choose PWM dimming color consistency and high brightness level but for general home lighting or commercial lighting, analog dimming or TRIAC can also choose, but will produce a color cast, and the dimming level will be low. "

Beam after right said: "In order to achieve continuous dimming, flicker-free, most customers prefer to choose the PWM dimming, because it provides greater dimming range and better linearity. Depends on you are using dimmer frequency flicker can be minimized. analog dimming easier to achieve, because it requires only a DC voltage, flicker-free dimming of the LED. Generally speaking, dimming range narrower. "

Constituted by a plurality of high power LED lighting applications, ensure that each LED has a uniform brightness without any flicker has also become a major obstacle to the design, but the PWM method is easy to solve the blinking problem dimming. "If the duty cycle of the PWM modulator can be maintained constant, handy, there should not have the problem of uneven brightness of the lights." Said Wu Zhimin, "National Semiconductor's LED driver can not only ensure that the output current uniform size, but also to ensure screen high brightness contrast from these aspects, our LED drive than its class on the market better and winning. "Tony Armstrong pointed out that, in short, the end-user dimming method used in very a large extent, by the end use of LED itself to decide. For example, the LED for the back lighting to display the car infotainment system, ambient lighting brightness range is very wide, both sunny extremely bright, but also whether the January night darkness, can be described as vastly different. Because the human eye is extremely sensitive to slight variations of the ambient lighting conditions, and therefore need a wide dimming range of 3000:1. This will require the LED driver circuit using PWM dimming method.

However, he added: "LED street lamps either in the ON state or in the off state, and therefore need only a limited range of dimming can. In this case, the only use of a kinds of simple analog dimming method will be able to meet the requirements. "

As mentioned earlier, less than 25W of LED lighting applications replace standard incandescent and halogen lamps. In this power range, an application is the most likely alternative to TRIAC (TRIAC) gradually cut into the wall dimmer control incandescent or energy-saving lamps. Market leading and trailing edges cut dimmer overall compatibility challenges, from the perspective of EMI TRIAC dimming poor to.

DCM PFC single-stage PFC flyback topology like Infineon TDA486 3G is an appropriate choice. "Alexander Sommer think," 25W and above power range of LED lighting applications that require the best cost-effective non-dimming applications, oriented to the professional market. dimming control method selection will depend on the replacement or new installation type digital lighting control (such as DALI or wireless solutions) allows more precise control dimming level, and more more functionality, such as sunlight down light duty cycle induction. replacement installation may be required to be compatible with the old analog 1-10V dimming controller. "   

Posted by novaking at 2013年01月15日11:02

VuePix C7 Stage Screen

Recently, a C7-screen VuePix new appearance. C7 screen with dual-screen mode, you can select the transparent mesh screen, select the entity screen. Control Panel SMD3528 (3 in 1) LED screen, arranged in a matrix resolution of 7.2 pixel pitch.

Designers also specifically set for the screen a unique angle system (5 angle selection device), so that the user can highlight a curved screen effect regardless of the horizontal angle or vertical angle or direction of the concave body convex body direction. In addition, C-Series panel also has advanced the IP waterproof protection systems.  

Posted by novaking at 2013年01月08日17:55

Pressure Sensor Applications

As behind each medical procedure has a real science, complex medical devices for the diagnosis and treatment of secondary diseases of the airflow, and the silicon pressure sensor also exist behind a science. The three ways to use the airflow and silicon pressure sensor for medical applications is: anesthesia machines , sleep apnea machine, and hospital diagnostic equipment.

Anesthesia machine

Pharmacy for the equipment used in the anesthesia machine brings a unique set of challenges. These chemicals are usually viscosity accumulation may be generated within the device. In the manufacture of such equipment must take into account such factors, and take appropriate restorative measures. Medical equipment for patients is very important, so you want to choose a sensor offers excellent sensitivity and accuracy in the entire service life of the equipment. Select only able to meet the performance requirements, but also long-term stable performance of the sensor, we can ensure the normal use of the sensor during the entire life of the medical equipment. If you choose the right sensor, can achieve a 10-year sensor life cycle.

Engineers should consider the patient's respiratory rate. The range of patients including adults to health from poor health, slow respiratory rate, rapid breathing rate and lung capacity larger adults. Sensing portion need to be very sensitive, in order to correctly measure the patient's inspiratory and expiratory and anesthetic gas delivered to the air stream. Therefore, it will use two (or sometimes three) airflow sensor to measure the specific pneumatic subsystem. The designer should probably all important subsystem in the device to set a specific airflow sensor.

Plus anesthesia of Pharmacy and high humidity sensors together will result in harsh environment, so that the the expiratory circuit in the differential pressure sensor is superior airflow sensor. The adaptability of the gas medium pollution caused by the differential pressure sensor for moisture, anesthetic agents and other materials to be stronger. Should be used in the case of need to be high-pressure delivery source, or sensor requires direct contact with concentrated oxygen or anesthetic pharmaceutical sensor and dielectric isolation. In this case, stainless steel pressure sensor may be selected, and the dielectric isolation is the best, because it is more durable. If you should consider the need for a portable device, the airflow and the pressure sensor to use low power consumption, which can be reduced to the required size of the power supply and help limit on the total weight of the unit. Install the sensor at the manifold to the air flow channel, can help to reduce the design size and weight.

Another consideration is the output. Digital output, such as I2C and SPI protocols, so that the resolution of the sensor and the microprocessor integrated optimization of. Still exist on the analog output of the demand, the main reason is involved in some safety circuit rectifying demand does not allow software. The user might want to use original sensor output to trigger an alarm or security situation. It is very important to the ability of these two options provide both digital and analog. Finally, the response time of the sensor for the efficient delivery of narcotic pharmaceutical to a patient is essential. Use of current technology, anesthesia machine manufacturers to achieve a response time of 1ms.

Sleep apnea machine

Sleep apnea machine when it comes to the total error band, usually greater concern is the comfort and convenience of the patient, not demanding performance requirements. Since they are usually used in conjunction with the humidifier, so they need to be operated under conditions of high humidity and to maintain a stable performance. They must be durable, because they are usually the use of all kinds of people operating in the home environment. The requirements of the user of the device is mainly focused on the accuracy, stability, portability, and unit size / weight. Requirements on the noise is also very important, because this device is used during sleep. The need to use a lower pressure drop of the airflow sensor, because if the voltage drop is too high, the motor strength greater (pressure drop is equal to the impedance of the sensor), thereby increasing the noise and to shorten the life of the motor.

Therefore, the engineer should select able to sense the differential pressure or air flow sensor at a low rate. The sensor supplier should be able to measure the peak of the patient's breathing, or the turning point between the inspiratory and expiratory. For more complex sleep apnea machine, sometimes select airflow sensors instead of pressure sensors, because the ventilator needs to be more sensitive to the level of the low airflow. Once you determine the pressure, air flow, and the media needs in relation to consider the accuracy and stability of the demand, including total error band. Home sleep apnea machine must be durable, because external factors will affect unit performance.

For price reasons, usually select the enhanced digital products. With the purchase of the sensor has been enlarged compared to later add components to adjust the signal size will be more expensive. The same time, if you do this, then, for integration time will be shorter, which allows designers to more quickly realize the sensor, and the ultimate device to market faster. The design of the device according to the different types of sleep apnea, mechanical requirements (such as size, installation and research hole) may also bring some impact, because customers want to get smaller, elegant, and portable equipment. We may also need to consider the customer calibration function, especially of CPAP (continuous positive airway pressure) applications to maximize product performance, to best match the patient's breathing pattern.

Hospital diagnostic equipment

Hospital diagnostic equipment, including mass spectrometry, chromatography (eg, for gas, liquid and high performance liquid chromatography), laboratory automation systems and analyzers, such as for the use of blood, hematology, immunoassay and clinical chemistry analysis instrument. Key factors in the hospital diagnostic equipment selection sensor, high-resolution, high-precision and high stability are to focus consideration. The device needs to be able to detect even the smallest object quality. Thus, the diagnostic device generally has the highest resolution requirements, usually 16 or higher. Sensor accuracy and stability is very important to obtain accurate data and accurate data for the laboratory test results is essential, and is directly related to the life and safety of the patient.

Determine the need to detect the full range of pressure and flow and the increment is the primary factors to be considered. Application of the sensor in the field of hospital diagnosis may also require having the compatibility of the other medium with a clean, dry air outside. In some diagnostic equipment, the gases released from the plastic or adhesive, although the quantity is minimal, will contaminate the sample and the test results generated bias. Accuracy, especially for linearity and hysteresis error is concerned, are very important. Because of the sensitivity of the system as a whole, and the sensitivity of the sensor used is concerned, so it should try to reduce the hysteresis. 0.25% accuracy error is the best (non-linearity and hysteresis error), and 0.5% is usually allowed to exist maximum.

As described above, high resolution is critical, which is why the user of the diagnosis and analysis equipment may choose without amplified sensor to obtain as much as possible to the core / the raw sensor output, and to create a compensation and amplification algorithms reasons. Some sensor manufacturers through high-resolution A / D converter with amplified products. Note that the resolution A / D converter is not the resolution of the sensor manufacturer - the need to consider the resolution of the sensor itself. If the resolution of the sensor is lower, then the the extra digit A / D will only provide extra useless data.

Stability is very important, because the drift may unexpectedly affect the sensor reading. If the sensor device, the drift (calibration equipment prior to shipment), and the results will be deviations. Sensor in the process of manufacture and installation enabled, you must consider how to guard against the influence of the thermal and mechanical stresses, because this will affect the stability of the device performance. In hospital diagnostic applications, for the error associated with the drift and instability, 0.5% or lower is the maximum acceptable. And other medical applications is different, for the diagnostic equipment, the size is not a particularly critical factor, because most of them are bulky, inconvenient moving equipment, and is fixedly placed in the laboratory. Should first consider the resolution, accuracy and stability, followed by physical factors, such as output, dimensions, installation, and research hole and electricity demand.   

Posted by novaking at 2013年01月04日13:00

Nokia Windows RT

Nokia Developer Windows RT tablet plan came the news is not the first time foreign media has brought us further news. According to technology website The Verge quoted sources as saying the disclosure that, very similar to the Nokia display screen of the tablet with the Microsoft Surface RT screen and support 3G network, the formal launch of Mobile World Congress in February next year at the earliest.

10.1-inch touch screen

According to technology website The Verge reported, sources disclosed, said to them, Nokia tablet will be equipped with a 10.1-inch touch screen panel, and the screen is very similar to Microsoft's Surface RT (which may mean that the retina screen legend is not exist), and is also equipped with HDMI interface and USB interface, support 3G network.

Nokia Tablet computer really attractive, however, is unique shell design. According to the related statement, the tablet Nokia will launch a special "jacket" usual, when combined, will make the Tablet PC look like a book. Opens, this jacket can be used as the Tablet PC's keyboard and the use of outriggers.

Outstanding battery life

Nokia tablet for this special "jacket" built-in battery and provides two USB ports to expand the connectivity of the device. Nokia tablet they are satisfied with the performance of the battery life, able to provide about ten hours of battery life, in a short period of time but also fast charge to 50% of the battery capacity.

According to sources say, Nokia's first tablet will run on the ARM chip architecture, and powered by Microsoft's latest operating system Windows RT. At the same time, the leak news from the past show Nokia Tablet PC will likely be powered by Qualcomm Xiao Long S4 dual-core processor, built-in 800-megapixel camera, and will provide a variety of colors to choose.

MWC2013 Assembly Release

Other features of the Nokia Tablet no more messages, but U.S. carriers, AT & T will be the starting cooperation channels in almost not much suspense. Past news that Nokia plans to launch the tablet in the first quarter of this year by Taiwan's Compal to undertake the production of initial large shipments of approximately 200,000 units. Just because Microsoft will launch its own Tablet Surface, causing Nokia to postpone the plan, and decided to focus on the smart phone market.

According to the latest news, Nokia will be the fastest MWC2013 Mobile World Congress in February next year, launched the tablet. Nokia declined to publish for comment, a company spokesman said: "The company does not comment on market rumors and speculation."     

Posted by novaking at 2012年12月31日12:15

Switching Power Supply Switch

Switching power supply switch tube from the conduction to the cut-off, strictly speaking, is a very complicated process, but when we work principle analysis, will first try some non-major problem simplistic. For example, when the power switch tube turned on or off, we put it as an ideal switch its work only two states, on or off. But fact the switch tube conduction and off is a very complicated process, which in addition to ON or OFF, there is a high frequency can not be neglected, that is, the switch conduction is from the cutoff region to the enlarged area, and then by the enlarged area to work in saturation region. This process requires differential equations can be solved here, I do not want to introduce to you, too complicated.

Simply put, the power switch turn-on and turn-off time are needed. Generally simply switch conduction time ton into the turn-on delay time td and conduction rise time tr and switch off time toff to divided into close delay time tstg (or close the storage time) and shut down the decline time tf.

Figure 1 is a power switch turned on and off during the test waveform in fact the test waveform in Figure 1 is also simplified the actual waveform, the rising edge of the waveform is generally a rate of change of the positive index curve, while The falling edge of the waveform is a rate of change is a negative exponential curve, for simplicity, in Figure 1 are replaced with a straight line.

Switching power supply in the first cycle, the output voltage of the the filtering energy storage capacitor charge because the charging current is large, the load will be heavy (or equivalent load short-circuit), so the switching power supply in general should take a soft start measures the beginning of the duty cycle is very small, before slowly become normal, that began when the output power is very small, then slowly larger. Or the beginning of time, low operating voltage, then slowly increased to normal.

Strictly speaking, the switching power supply is always working in the non-steady-state, the so-called only relatively stable. For example, the process of switching power supply regulators is this: When the output voltage increases, after sampling, the sampling circuit outputs an error signal to a pulse width modulation circuit, so that the duty cycle is reduced, so that the output voltage is reduced; when After the output voltage is reduced, compared After sampling, the sampling circuit will output an error signal to a pulse width modulation circuit, the duty ratio is increased, so that the output voltage increases, so that repeated cycle, the output voltage of the switching power supply will always be at a certain the frequency of the average value of the voltage up and down swinging, but the average of the output voltage relatively stable as that so-called regulator.

For the current flowing through the the switching transformer primary coil is not a stable value, are generally a sawtooth wave rectifier output current. LED constant current drive , is generally means after filtering by the filter output current is relatively stable, and this stability is also means average, while the input current of the filter are generally a sawtooth wave.

Switching power supply start cycle is generally considered to begin from the switch conduction operator, which mainly depends on where you want to analyze the circuit cut refers switching power supply circuit when work, this can be considered If you need to analyze the various points of the waveform, you must take a device in the circuit waveform as a reference point (or sync) from the power switch is turned on to start work.

Usually sampling at the beginning of the first cycle of the switching power supply circuit is basically not working, because the output voltage on the filter capacitor is charged, the need can be charged to the normal after several cycles, only the output voltage reaches the normal, the sampling circuit to work properly. However, the sampling circuit is not working properly before the absolute value of its output voltage is equal to 0, which can be considered a special case of the error signal output (negative maximum). In such cases, switching power supply does not have a soft-start circuit, when the switch work, the duty cycle will easily transformer saturation, and damage to the switch.


Posted by novaking at 2012年12月27日16:57

2012 Top 10 Fun Invention

Around us, there is always a lot of whimsy guy, they make the world more fun.
1. The electronic pet dog

Electronic pet dog

People still remember the electronic pet? The Bandai latest design of a new toy software can become typical virtual electronic pet. People simply from Download TechPet phone application software, through the touch screen can electronic pet dog feeding.

2. Google Glasses

Google glasses

Simply put, this is a computer built-in spectacle frames. Piece of glasses with a half-inch (1.3 cm) screen, you can use it to shoot and share photos, video chat, check appointments, access map and the Web. By 2014, consumers can buy Google glasses.

3.3D Intelligent Printer

3D intelligent printer

Download or create a new pattern, click on the Print button, and an area of a few 3D printer can extrusion ultra-thin plastic , print out the physical layer by layer, and you are willing to print the number of copies can be. Compared with the the MakerBot previous generation models, the latest Replicator2 efficient, more accurate printing software more easy to operate, and you do not need to assemble the machine. With Replicator2, anyone can set up a small factory at home.

4. Bamboo iphone speaker

Bamboo iphone speaker

This bamboo speaker can enlarge the the iphone phone's sound, and can enhance the three-dimensional, no external power supply.

5. The high-speed bat suit

High-speed bat suit

In October, the first wing mounted flight World Championship held in China, the flight wearing a bat suit who jumped from 5000 feet (1500 meters) cliff, gliding through a valley, eventually falling to the ground to open the parachute in 30 seconds flying within three-quarters of a mile (more than one kilometer). Only 20 are eligible to participate in the competition, Julian Boulle (JulianBoulle) South Africa won the championship and set a world record, his score 23.41 seconds.

6. Water jet backpack

Water jet backpack

French inventor the water sprinkler backpack design not only allows people jumped to the air 30 feet from the water, can dive into the water like dolphins.

7. Quantum invisibility cloak

Quantum invisibility cloak

The latest U.S. military investment in the development of the a "Quantum stealth" material, able to bend light waves in the coverage's body, so that people like Harry - Potter's invisibility cloak effect. The material is called "quantum stealth camouflage material, by bending light waves around the human body, so that the people covering the fabric is completely invisible status.

8. Automatic pneumatic tires

Automatic pneumatic tires

When tire pressure is too low, this Goodyear tire can be detected automatically turn on the built-in pressure detector in insufficient air pressure, allowing air to enter the trachea of a pump . The rotation of the wheels, the tire by squeezing parts at the bottom of the air is discharged from the pump in the trachea. When the air pressure to achieve the best state, the pressure controller off.

9. Solar Bonsai Charger

Solar Bonsai Charger

French designer to design a "electronic bonsai, it leaves 27 solar battery panels for charging mobile phones and other electronic devices, in the case of a sunny, four hours on the phone will be able to complete charge.

10. Small Artificial Indoor Clouds

Small artificial indoor clouds

This is not the image of the PS processing, the Dutch artist Ben De Nute latest invention - M. Stewart how to create indoor white clouds. This requires precise and meticulous planning and design: temperature, humidity and light must be just right. When preparing the conditions are ripe, M. Stewart, a smoke to manufacture this indoor artificial cloud. It lasted a very short time, but it is very beautiful, wonderful move.   

Posted by novaking at 2012年12月17日16:14

Touch screen laptop

According to foreign media reports, after the advent of the Windows8 system, touch screen than before, more useful. However, some of the technology industry pundits have been convinced that the touch screen does not apply to the laptop. They sometimes quoted Steve Jobs in 2010, said the sentence: "The touch surface do not want to put on end." Jobs was to explain to the world why Apple laptop did not use the touch screen technology.

Earlier this year, Apple CEO Tim Cook (TimCook) also said: "You can be integrated into the oven and refrigerator together, but the kind of things could not get the user's favorite."

This is the view of the leaders of the world's most profitable technology company. I am sure, but I do not know why, this month or stop to visit my MacBookAir screen.   I evaluation of various laptop for TheVerge, I recently tested a series of touch screen notebook product based Windows8 system. Well from the outset, I ready to greet disappointment, I'm ready for a rhetoric, such as Windows8 gesture control technology with the touch screen can be more easily operate a computer, but the whole idea is not how another example Windows8 interface to many impose unnecessary touch-screen control functions to the users, the users are certainly not like as, in particular, certain features traditional laptop has done very well.

As I Windows8 process become more aware of this system and I am increasingly convinced that the future development direction of the touch screen is the laptop, even if it's touch screen is placed vertically.

Jobs in 2010 publicly opposed touchscreen laptop, he relied only on decades of user experience research "gorilla arm syndrome" common sense, to say, is that if you are in front of the touch screen, arms stretched out and period of time, you will feel especially uncomfortable. However, there are a lot of assumptions, if you do not your arms stretched out in the air, ready to touch anything, but to stay in a very comfortable stance on the keyboard?

We view this problem has been wrong. The touch screen is not a keyboard or a mouse substitute, but a supplement. If I want to enter some content on a laptop, and I have enough room to stretch the arm, then, I would still choose the keyboard input. But if I was living in a crowded car or on the plane, or in line, and I have to do only with a very short reply to an e- mail, then use based Windows8 touchscreen laptop will easily complete these tasks.

But perhaps it is just an extreme example. In daily use, I found that no matter whether I was using the equipment with touch screen function, I will help to tap the screen, because I want to finish something faster, more intuitive.

If you want to start a program on the desktop computer, which mode of operation will be more effective? Crouching close to a special glass surface with your fingers gently slide easier, and then click on the icon above? Or find a visual icon and click on it easier? When you want to close a program, try to move the mouse pointer to the upper right corner of the dialog box that small "X" icon and click on it easier? Or with ALT + F4 shortcut keys easier? Or directly dropping the in the Windows8 page will process easier
Of course, these operations are particularly meaningful for the Windows system, because the touchpad experience under the Windows system has been very bad. This year, we tested some pretty good, relatively speaking touchpad, but on the whole in terms of those touchpad there is still a lot of loopholes, and also often occur without reaction. In contrast, these Windows8 laptop touch screen is like a fresh breeze is refreshing. Their poor performance is because I want to really try the touch screen, but even if their performance is not so bad, I think I would choose the direct control of the way through the screen. After all, with my MacBookAir touchpad is very general, and I always have to constantly remind myself not to go to the start bar on the touch screen.

Unfortunately, Windows8 been able to get outstanding performance and specifications of the display on the touch screen. Display greater resolution is lower, with a finger on the touch screen the easier to operate, because in that case, the icon will be relatively greater.

The problem is that the touch screen's low resolution makes icons appear. Windows8 does not seem to 1080p the small screen optimization, and even if you lower the resolution or DPI, so that you can get a larger touch targets, the Windows8 icon and has not changed much bigger. IE browser, you can quickly zoom zoom feature by clicking on the target, but Microsoft does not Windows8 system a similar shortcut scaling function.

Instead, Apple has a solution developed for this problem, and from the iPhone4 application. Retina display's pixel density is four times that of ordinary display, it will make the image look more sharp, but to touch the target, or the same size as before. iPad2 and third-generation or fourth generation of the iPad user interface is completely the same, just the image displayed on the display of a new generation of products more clear and sharp. Apple's 15-inch and 13-inch MacBookPro with Retina display is not a touch screen, but also with four times the pixel density of the same technology.

Apple did not develop the world's first MP3 player, the first touch screen smart phone, the first graphical user interface, the first tablet computer or first laptop solid-state drive. It is like when shot, etc. a mature technology, but the industry also do not quite understand how to properly use it. In this issue on the touch screen for a laptop, a similar situation may also occur. Perhaps Microsoft has verified this idea is feasible, but Apple now have another opportunity to get into the market, that is, the user interface is perfect and promote it.

Outgoing Intel CEO Paul Otellini (Paul Otellini) said Windows8 system is a semi-finished at the time, I believe he meant: Microsoft certainly see the direction of the development of the user interface, but no one able to be optimized for the next generation of touch screen user interface. If we now hear is true, Microsoft has a chance to correct the error, but the speed is faster than you think. Microsoft ready system upgrade once a year after the launch of Windows Blue If Microsoft is able to solve the problem of the user interface zoom adjustment, to find the Retina display alternatives or other user-friendly touch screen panel technology, Windows will be able to keep it in touch screen leader in the field. If Microsoft is able to seize this opportunity, in 2013, it can avoid Apple beyond.  

Posted by novaking at 2012年12月10日12:13

Gas Sensors Monitoring

Gas Sensors Used in Industrial, Civil, Environmental Monitoring
The gas sensor is a certain gas volume fraction of conversion into a corresponding electrical signal converter. There are a wide range of gas sensors. The application is quite extensive. Gas sensors have a wide range of applications in civil, industrial, environmental detection.

The gas sensor applications in civil mainly to detect a the civilian gas leak of natural gas, liquefied petroleum gas and city gas in the kitchen , detect microwave food cooking gas to automatic control of microwave cooking food; housing, building, meeting rooms and places of public entertainment to adhere to the carbon dioxide, smoke, ozone and unpleasant gas, automatic operation and control air purifier or fans; rise buildings used to detect fire signs and alarm. Currently, civilian areas is the main application areas of semiconductor metal oxide gas sensors. This is mainly because of the semiconductor metal oxide gas sensors are inexpensive, the performance can also meet the requirements of the home alarm.

Gas sensors in industrial applications are mainly used in the stone in the chemical industry to detect carbon dioxide, nitrogen oxides, sulfur oxides, ammonia, hydrogen sulfide, and chlorine and other harmful gases; semiconductor and micro- electronics industry to detect organic solvent and highly toxic gas phosphine ; hydrogen power industry detection power transformer oil metamorphic process; perishable food industrial inspection meat food freshness; detection of oxygen in the exhaust gases of cars and furnaces industrial control of combustion, to achieve the twin goals of energy conservation and environmental protection ; Highway Traffic detect the driver's breath in the ethanol gas concentration to prevent drunk driving and reduce traffic accidents.

Environmental detection of course, can not be separated from the gas sensor, such as the application sensor detects nitrogen oxides, sulfur oxides, hydrogen chloride, which causes acid rain gases; detect carbon dioxide, methane, nitrous oxide, ozone, Freon and other greenhouse gases; detection of ozone, ozone-destroying gases such as Freon; detect ammonia, hydrogen sulfide and gas unpleasant gas.

In summary, the gas sensors based on their different functions in the civil, industrial, environmental testing has a significant role. After further transformation of the sensor, the scope of its application will be more extensive. We will see in more situations gas sensor applications.   
タグ :gas sensors

Posted by novaking at 2012年11月27日12:21