According to the analysis of the specific application situation of the LED display module, in the LED display module, the electrolytic capacitor has the worst temperature characteristic. At present, ordinary electrolytic capacitors generally have a nominal value of minus 40 degrees. When the temperature is minus 40 degrees or lower, the characteristics of electrolytic capacitors will become very poor or even fail completely. This is because when the temperature is minus 40 degrees or lower, the viscosity of the electrolyte of the electrolytic capacitor becomes larger and even crystallization occurs.
In view of the problem of capacitor failure, the following measures can solve the problem.
1: For particularly cold areas, a low temperature electrolytic capacitor of -55 degrees is used or added to the module, so that the capacitor can still work normally at minus 40-45 degrees. In addition, tantalum capacitors have very good low temperature characteristics. For display screens in cold climates, 1-2 tantalum capacitors can be added to the LED module to ensure good filtering characteristics at low temperatures.
2. Add temperature control device and air conditioner or heating device in the display screen. The temperature control system ensures that the display cannot be turned on in an ultra-low temperature state. In severe cold weather in winter, before the display is turned on, use the air-conditioning system or heating device to heat the inside of the display for a period of time (1-2 hours) in advance, so that the temperature inside the display is above minus 25 degrees, and then turn it on again Display power supply.
3. Add a transient voltage suppressor diode (Transient Voltage Suppressor) to TVS for short on the unit module PCB or power terminal. TVS is a high-efficiency protection device in the form of a diode. When the module fails in the ultra-low temperature capacitor, the TVS diode can absorb high-voltage burrs to avoid damage to the board components. The clamping voltage of the TVS diode can be chosen to be around 7.0V.