The previous LED lamps used constant voltage power supply. At that time, they did not understand the performance of the LED. According to the data given by the manufacturer, each small lamp bead was given 20MA. After our test, the lamp bead was always burned, and the manufacturer’s data was known. Unreliable, we have reduced current usage. At that time, in 2002, I made some applications such as MR16 small light bulbs and billboards. I started to do constant current drive in 2007, what HV9910, PT4107, PT6901, SN3910, IR, and more tests, but the first success is QX9910, some goods have been sold, but QX9910 has many bad products, after aging The products are also not stable, there are often flashing lights, and there are still some remaining souvenirs. I think that if you want to be a good driver, you should first find a chip.
At the beginning of 2007, constant current IC was difficult to find, and the price was also expensive. A HV9910 would cost 8 yuan, and an IR S2540 would cost 25 yuan. In fact, it was a half-bridge chip, which was used to swear, and what Japan Some of the chips are also used to swear. In fact, they are ordinary constant voltage ICs. I have been detouring on these boring chips for a long time, which has seriously affected the progress.
The HV9910 series is also very popular in the second generation of ICs, but for technical reasons, high voltage directly into the IC, easy to bomb. Later, a lot of imitations came out. The best example is SMD802, which has multiple output short-circuit protections. It has been widely used. With the replacement, this IC is now out of date. A lot of ICs have not died before they are officially put into production.
In 2009, the BP2808 was introduced. This non-isolated IC has been used for several years. It is difficult to make a power supply for 1000 pieces. Because the BP2808 is a third-generation IC with stable performance, it can output more than 30W. Power, and long-term use, more efficient, easy 95%. This kind of driver chip has a common shortcoming, that is, EMCT EMI is not good. After long-term exploration, we believe that adding two differential mode inductors at the input end of MOS power can solve EMC, and there are several solutions for EMI. Add a magnetic bead to the drain of the MOS tube, but this method increases the loss in exchange for it. My method is to add more than 100P ceramic capacitor to the drain source (SD). This method can Effectively improve efficiency and control EMI.
Jingfeng is constantly advancing, and now it has introduced BP3105. In the wide voltage range, the constant current accuracy is 1%, which defeats all domestic and foreign solution companies. The first domestic dimming constant current IC: BP3109 is also good. Its design is that the brightness is cut off under certain conditions, avoiding the flashing phenomenon and the cost is very low. I heard that there is a better IC launch in the second half of the year.
BP2808 is also copied, but Jingfeng Mingyuan has now adjusted the price. The third and second hairs are still stable with the original factory. This imitation IC has a problem when it supplies samples. The test four burned two lights. Board, there are a few that promote me to me, I dare not use it.
But now the cheapest IC in China is core-connected, and the CL1100 primary control small power supply, adapt to the lamp cup series. Core Alliance is started by copying board, so the cost is low, so the price is cheap, the performance is acceptable, the stability is also very good, so the shipment is very large, and it is also one of the most popular chips. Of course, the company also has more High power chip.
GR8210, a product of Taiwan's Luda Company, performed well during the test, and its efficiency and power factor were very good. It improved EMC on the basis of BP2808, but it was not ideal in the case of large shipments. There are more than 10% of defective products inside. In addition, the same series connection method, when the number of parallel changes, the inductance must also be changed, so the requirements for the inductance are extremely high, the advantage is that the EMC is internally controlled and easily over EMC. The cost of this kind of IC is relatively high, and there are not many mass productions yet. It is not suitable for water and soil.
The low-cost DC-DC has the lowest cost of MC34063. A chip is only 0.23 yuan. After using it, it is 3*1W. 1*3W is not bad. It is hard to say that the current is big.
This primary-side drive circuit was first developed by the US IWTT company. It is recognized that the performance is the most stable and the cost is not high, but the domestically produced chips of comparable performance have been successively produced. The IW3620 is better than the L6562.
There are still many domestic and foreign companies, and there are hundreds of them. There are original ones and some imitations. There are some things I know to do well.
Angbao: Some products such as OB2203, 2263 are easy to use, but I heard that some engineers are not successful, and there are occasional bombings, but I think this chip is still good. If you can't do it, you can't blame the chip. achieve.
Xinpeng, Silan Micro is a famous factory, and has launched several functional chips. Many companies have made L6561 and (L6599) half-bridge chips, and most of them are still very useful.
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