How to improve the power efficiency of LED electronic display?
LED display screens generally have a large area and a large overall power consumption, so it is particularly important to improve the power usage of the electronic screen. Then, in order to improve the use power of LED video screens, LED display manufacturers remind that the following problems need to be solved:
1. Reasonable selection of switching devices: This is the balance between cost and performance. What kind of customer requirements and what kind of devices should be used, but it must be reasonable. If you want efficiency, no doubt COOL MOS, low VF output diode.
2. Many people ignore this when choosing a good electrolytic capacitor, and the loss of electrolysis is very large.
3. On the premise of the efficient design of power consumption in the startup part, it must be considered. At present, many chips have HV startup pins, and the startup current is getting lower and lower. This point is to know more about new devices. Of course, there are additional Circuit lossless startup, etc., I don’t think it is suitable for LED driving.
4. The main current loop PCB should be as short as possible: LAYPCB’s experience, and layout, this is nothing, the quick way is to look at the works of major manufacturers.
5. Optimize the transformer parameter design: reduce the eddy current loss caused by ringing. This is more difficult. First, you must master the basic knowledge of electromagnetics, design a reasonable transformer, and the most important thing is patience. Even if you think of improving the efficiency by 0.5%, you should try it.
6. Chip auxiliary power supply optimization This point is pointed out in ST’s L6562D application document that 15V is the best, but LEDs generally have wide voltage output, so my choice is to add a linear voltage regulator to make the chip work at 15V to reduce loss.
7. If the optimal design of the input EMI part exceeds the safety regulations, this part is more elegant, mainly because of experience.
8. Select a high-efficiency topology This is the beginning of the program selection, such as PWM and QR PFM. When customers put forward efficiency requirements, it is necessary to evaluate what topology to choose.