[China Building Materials Network] LED lighting has been rapidly developed in the near future, and LED has been widely recognized as a clean and clean light source. LED light source has long service life, energy saving, simple and convenient application, and low cost of use. Therefore, it will be used in a large number of home lighting applications. According to the survey, the annual global sales of home lighting fixtures is about 50 billion.
1. The nominal input voltage range of the driver chip should meet DC8-40V to cover the application surface. The withstand voltage should be greater than 45V. The output voltage of the simple bridge rectifier will fluctuate with the grid voltage when AC12V or 24V input. Especially when the voltage is too high, the output DC voltage will be too high. If the driver IC cannot adapt to the wide voltage range, it will be broken down when the grid voltage rises, and the LED light source will be burnt.
2. The nominal output current requirement of the driver chip is greater than 1.2-1.5A. As the LED light source for illumination, the nominal working current of the 1W power LED light source is 350mA, and the nominal working current of the 3W power LED light source is 700mA. Larger ones require more current, so the driver ICs used in LED lighting must have sufficient current output. The driver must design the product to work in the best working area of ​​70-90 full output. Driver ICs that use full negative output currents have poor heat dissipation in the narrow space of the luminaire, which is prone to fatigue and early failure.
3. The output current of the driver chip must be constant for a long time, the LED light source can be stably illuminated, and the brightness will not flicker; the same batch of driver chips are used under the same conditions, and the output current should be as uniform as possible, that is, the dispersion is small, so High-volume automated production line production can be effective and orderly; for the output current has a certain discrete drive chip must be selected before the factory or put into the production line, adjust the resistance of the current setting resistor (Rs) on the PCB, so that The constant current driving board of the LED lamp produced by the same has the same brightness of the same kind of LED light source, and maintains the consistency of the final product.
4. The package of the driver chip should be beneficial to drive the rapid dissipation of the chip die, such as bonding the die directly to the copper plate, and having a pin extending directly outside the package for direct soldering on the copper foil of the PCB. Rapid thermal conductivity (Figure 1). For example, on a silicon die similar to 4X4mm, it takes a long time to pass 300-1000mA current, which inevitably has power consumption, which will inevitably heat up. The physical heat dissipation structure of the chip itself is also crucial.
5. The ability of the driver chip itself to resist EMI, noise, and high voltage is also related to whether the entire LED lamp product can pass smoothly.
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