Previous LED lamps with a constant voltage power supply, do not understand the performance of the LED, small light in accordance with the manufacturers to the data of each bead to give to 20MA, weve tested, lamp beads, always burn, and before we know the manufacturers The data is not reliable, we reduce the current use. It was in 2002, do MR16 bulb, billboards and the like applications. I began in 2007 to do the constant current driver, what HV9910, PT4107, PT6901, SN3910, IR, the test more, but the first is the QX9910, some goods, but there are many defective products QX9910 aging The product is also less stable, often have flashing lights, there are still some remaining souvenirs. In my view, in order to do the driver first to get a good chip.
In 2007 when the original, constant current IC is difficult to find, the price of your bizarre, an HV9910 8 yuan, an IRs S2540 25 yuan, in fact, a half-bridge chip, used to intimidate people, but also Japans chip is also used to intimidate, in fact, is the general constant voltage ICs, boring chip away a very long detour, and seriously affected the progress.
HV9910 series in the second generation IC is also very popular, but for technical reasons, the high pressure directly into the IC, easy to blow. Later came out a lot of imitation, imitation is the best SMD802 multiple output short circuit protection, have been widely adopted, with the replacement, this IC is now obsolete.