China's LED driver power market is growing

　　As a supporting industry for LED, the industry dynamics of LED driver power supply are closely related to the demand for LED products. With the gradual popularization of LED lighting and the improvement of the prosperity of the LED industry, the LED driver power supply industry has great growth opportunities.

　　As far as current technology is concerned, due to the mismatch between civilian standard voltage and the lower operating voltage of LED devices, LED driver power has become an indispensable part of LED products. The stability of LED driver power is an important factor in determining the performance and life of LED products, especially in the harsh outdoor LED lighting field (such as LED street lights, LED tunnel lights), which needs to be able to resist the interference of wind, rain, lightning, high temperature, etc. to LED products. Industry insiders indicate that 60% of LED street light failures are due to driver power problems.

　　LED driver power design is not difficult, but you must have a good idea in mind. As long as you do calculations before debugging, measurements during debugging, and aging after debugging, I believe anyone can do a good job with LED.

　　1. LED current size

　　Everyone knows that if the LEDripple is too large, the LED life will be affected, but no expert has ever said how big the impact is. I asked the LED factory about this data before, and they said that 30% or less is acceptable, but it has not been verified later. It is recommended to control it as small as possible. If the heat dissipation is not well solved, the LED must be used at a reduced rating. I also hope that an expert can give a specific indicator, otherwise it will affect the promotion of LED.

　　2. Chip heating

　　This is mainly for high-voltage driver chips with built-in power modulators. If the current consumed by the chip is 2mA, and a voltage of 300V is applied to the chip, the power consumption of the chip is 0.6W, which will of course cause the chip to heat up. The maximum current of the driver chip comes from the consumption of the driving power MOS tube. The simple calculation formula is I=cvf (considering the resistance effect of charging, the actual I=2cvf, where c is the cgs capacitance of the power MOS tube, and v is the gate voltage when the power tube is turned on. Therefore, in order to reduce the power consumption of the chip, you must find a way to reduce c, v and f. If c, v and f cannot be changed, then please find a way to distribute the power consumption of the chip to devices outside the chip, and be careful not to introduce additional power consumption. To put it simply, just consider better heat dissipation.

　　3. Power tube heating

　　Regarding this issue, I have also seen someone posting on the forum. The power consumption of the power tube is divided into two parts, switching loss and conduction loss. It should be noted that in most occasions, especially LED mains drive applications, the switching damage is much greater than the conduction loss. The switching loss is related to the cgd and cgs of the power tube, as well as the driving ability and operating frequency of the chip. Therefore, the heating of the power tube can be solved from the following aspects: A. The MOS power tube cannot be selected based on the on-resistance alone, because the smaller the internal resistance, the larger the cgs and cgd capacitance. For example, the cgs of 1N60 is about 250pF, the cgs of 2N60 is about 350pF, and the cgs of 5N60 is about 1200pF. The difference is too big. When choosing a power tube, it is enough. B. The rest is the frequency and chip driving ability. Here we only talk about the influence of frequency. The frequency is also proportional to the conduction loss, so when the power tube is heated, the first thing to think about is whether the frequency is a bit high. Find a way to reduce the frequency! However, please note that when the frequency is reduced, in order to obtain the same load capacity, the peak current must become larger or the inductance must also become larger, which may cause the inductor to enter the saturation region. If the inductor saturation current is large enough, you can consider changing CCM (continuous current mode) to DCM (discontinuous current mode), which requires adding a load capacitor.

　　4. Reduce the operating frequency

　　This is also a common phenomenon for users during the debugging process. Frequency reduction is mainly caused by two aspects. The ratio of input voltage to load voltage is small and the system interference is large. For the former, be careful not to set the load voltage too high, although the efficiency will be higher if the load voltage is high. For the latter, you can try the following aspects: a. Set the minimum current to a smaller value; b. Make the wiring cleaner, especially the key path of sense; c. Select a smaller inductor or choose an inductor with a closed magnetic circuit; d. Add RC low-pass filtering. This has a bad effect. The consistency of C is not good and the deviation is a bit large, but it should be enough for lighting. In any case, frequency reduction has no advantages, only disadvantages, so it must be solved.

　　Compared with other LED sub-industries, the LED driver power supply market has relatively few participating companies, the industry concentration is high, and the market competition is not so fierce. At present, mainland LED driver power supply companies are mainly engaged in the production of street lamp driver power supplies, and the market for high-power LED street lamp driver power supplies is mainly concentrated in large-scale companies. As the market for public lighting such as LED street lamps will grow rapidly in the next few years, high-power LED driver power supplies may continue to grow. In addition, with the increase in indoor lighting, the demand for small and compact indoor power supplies will gradually increase.