From this ZTE incident, we know the importance of the chip, then the FPC factory Xiaobian will popularize the requirements of LED lamps for low-voltage driver chips.
1. The nominal input voltage range of the driver chip should meet DC8-40V to cover the application surface. The withstand voltage should be better than 45V. The simple bridge rectifier output voltage will follow the grid voltage when AC 12V or 24 V input.
Fluctuation, especially when the voltage is 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 1W power LED light source has a nominal working current of 350mA, and the 3W power LED light source has a nominal working current of 700mA.
Larger ones require more current, so the driver ICs used in led lighting fixturesmust have sufficient current output. When designing the product, the driver IC must be operated at 70-90% of the best working area of the full negative 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 dispersion of the drive chip must be selected before leaving the factory or put into the production line, adjust the resistance of the current setting resistor (Rs) on the FPC board, 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 facilitate the rapid heat dissipation of the driver chip. For example, the die (die) is directly bonded to the copper plate, and a pin extends directly outside the package for direct soldering on the copper foil of the FPC board. Rapid thermal conductivity. 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 lighting products can pass CE, UL and other certifications. Therefore, the driver chip itself must use excellent topological structure and high voltage at the beginning of design. Production Process.
6. The power consumption requirement of the driver chip is less than 0.5W, and the switching operating frequency requirement is greater than 120Hz, so as to avoid visible flicker caused by power frequency interference. Led green lighting promotes the development of driving chips to innovative designs. LED lighting is inseparable from driving chips, so LED light source driving ICs with multiple functions are required. Led lamps use AC power below 36V to consider non-isolated power supply. For example, 220V and 100V AC power should be considered for isolated power supply.
Directly using the AC100-220V driver chip, due to the application of the demanding requirements, there are higher technical requirements and greater difficulty, and countries are currently working hard to develop. The massive demand market for led luminaires gives all IC design companies the chance to succeed again, with rapid transformation and early product launch, and many opportunities to win.
Data source; http://www.kbrfpc.com