The reason why LED is very popular in the market is because of its high efficiency and low energy consumption. Therefore, it is widely used in display lighting and signal indicators. However, the wide application field also challenges the environmental adaptability of the LED itself. When working outdoors, the LED drive circuit is very vulnerable to overvoltage and overcurrent, causing failure or damage, and causing damage to property and personnel. . Therefore, when producing an LED power supply, the complexity of its working environment must be considered, and a protective design must be made to reduce the incidence of failure. This article briefly discusses how to protect the LED drive circuit.
Friends who are familiar with LED circuits must know that LED drive circuits are generally composed of the following parts, including AC input, rectification, DC / DC conversion, and other modules. The protection measures need to be adjusted according to different modules. For example, different modules and currents need different effective protection measures in the event of a surge.
LED driver circuit surge protection application
The surge protection scheme at the AC input end of the AC power supply can be designed using a combination of varistor (MOV) or gas discharge tube (GDT / SPG). In the case of grounding, the concept of simultaneous protection of differential common mode as shown in Figure 1 can be adopted. A varistor (MOV) connected in parallel between LNs can effectively suppress the surge overvoltage generated by the differential mode. Class circuit protection, using MOV or MOV + GDT / SPG circuit connection to ground between L / N-PE can effectively release the common mode surge energy to the ground, preventing the surge from being introduced into the subsequent circuit and Damage; if there is no ground wire in the power supply, as shown in Figure 2, you can directly connect a varistor in parallel between the LN lines for differential mode protection.