Tips for Improving Lighting Driver Power Efficiency

Tips for Improving Lighting Driver Power Efficiency

1. First of all, of course, choose a high-efficiency topology

This is the beginning of solution selection. For example, for PWM and QR PFM, if soft switching can be used, try to use soft switching topology (soft switching has low loss). When customers put forward efficiency requirements, it is necessary to evaluate what kind of topology to choose, and of course, the cost must be comprehensively considered.

2. Choose the switch device reasonably.

This is the balance between cost and performance. What kind of customer requirements determine what kind of device to use, but it must be reasonable. If you want efficiency, there is no doubt that COOL MOS and low VF output diodes are the best choice.

3. Optimize transformer parameter design to reduce eddy current losses caused by ringing.

This is more difficult. First, you need to master the basic knowledge of electromagnetism and design a reasonable transformer. The most important thing is patience. Even if you can only think of increasing the efficiency by 0.5%, you should try it.

4. Choose a good electrolytic capacitor

Many people ignore this. The loss of electrolysis is very large. Teacher Chen Yongzhen has a detailed explanation in an article.

5. The main current loop PCB should be as short as possible.

LAYPCB experience and layout, this is nothing, the quick way is to look at more works of big manufacturers.

6. Optimized design of input EMI

If it passes the safety regulations, this part requires more consideration and it mainly depends on experience.

7. Startup part power consumption design

Under the premise of efficiency, we have to consider that many chips currently have HV starting pins, and the starting current is getting lower and lower. This requires more knowledge about new devices. Of course, there are also external circuit lossless starting, etc., which I think is not suitable for LED driving.

8. Chip auxiliary power supply optimization

This is pointed out in ST's L6562D application document. 15V is the best, but LEDs generally have a wide voltage output, so my choice is to add a linear voltage regulator to make the chip work at 15V to reduce losses.

9. Optimize the SNUBBER circuit parameters to minimize the loss.