Method for analyzing LED lighting driving problem

Non isolated circuit is relatively simple, does not require transformers. MP4000 is also the only one to do soft switching IC. What is a soft switch? As we all know, the efficiency of a power supply depends on the loss. Soft switching control of the LED driver IC provides efficient solutions as well as dimming. First look at the MP4000, 1-30W non isolated LED driver. Non isolated circuit is relatively simple, does not require transformers. MP4000 is also the only one to do soft switching IC.

What is a soft switch? As we all know, the efficiency of a power supply depends on the loss. Where does it come from? The two aspect, one is the conduction loss, the two is the switching power supply switching losses, including drive losses. What does this have to do with it? With frequency. General switching losses are the integration of current and voltage. The traditional approach is hard switching, switching losses are relatively large. When the voltage is down, the current has a cross section. This is a soft switch IC, is how to achieve it? As we all know, the critical conduction mode, through the electric drive side, will lead to the discovery of the critical voltage mutation, so the detection of the current back, which is zero current mode. Zero current can bring efficiency, such as the efficiency of 90% compared with competitors, can save the switching loss and conduction losses.

In addition, the two part of the pipe, if it is CCM hard switch, you need a very fast reverse recovery, but this model does not need MP4000. Japan's voltage is 100VAC. MP4005 is very simple. One is 190V, one is 220V, the impedance is 4.85. Control mode is also a soft switching technology, so it can provide a very good efficiency, peripheral devices are very simple. This is for the United States and Japan market driven by non isolation. AC-DC large resistance loss. MP4001 SmartLDO direct power supply to IC. Only the voltage in the range of 15-30V can be charged, the other is blocked, the charging time is very short. So SmartLDO can provide very little loss of the program. If you do 3W, 5W with MP4001 can provide very high efficiency. Non isolation does not require PFC, especially for low power applications. But when the development of more than 8W power LED driver, you need to provide PFC.

MP4020/4021 series is a SingleStagePFC isolation scheme. Compared with the traditional contrast, the cost can be saved a lot, as well as a high PFC value, in addition it is also a critical conduction mode, conduction loss will be relatively small. Dimming can not go down and how to solve the problem if the conduction angle is cut off a lot of time, the start will often be a problem, for IC speaking, because the voltage is very low, dimming can not go down or there will be flashing. MP4030 provides a good solution.