How to design an LED protection circuit

by Lily Hathaway electronic engineer

LED lights that are everywhere in life are convenient for our lives, but who knows how to design an LED lighting circuit? Light-emitting diodes (LEDs) are fragile devices that are vulnerable to heat, mechanical shock, electrostatic discharge, and lightning, especially when used outdoors.

Due to the increased use of LED strings for lighting and backlighting, R&D engineers are required to pay more attention to the reliability of LED strings. High-brightness LEDs, due to their sapphire substrate, are very sensitive to voltage transients caused by nearby lightning strikes. This paper designs a solution to the surge overvoltage protection problem of LED lighting circuits:

Overvoltage events and voltage transients can occur on the AC input side of the circuit. They are usually caused by nearby lightning strikes, but they can also be generated by transient state changes on the power line. A typical protection device for overvoltage conditions is a metal oxide varistor (MOV) that can be combined with a transient voltage suppressor (TVS).

Circuits used for power protection also need to be isolated from the ground to prevent possible shock hazards (these specifications are included in IEC/UL60950-1, UL1449 and IEC/UL6500). The figure shows the solution to meet these requirements. This design incorporates a metal oxide varistor with a transient voltage suppressor.

LED lighting equipment is low cost, high performance, low maintenance, and their life span can last for tens of thousands of hours. There are various adverse electrical hazards in the working process. It is very important to improve the high reliability of LED lighting. It is recommended to use surge protection circuit composed of varistor and TVS to provide surge overvoltage protection for LED.

The above is some methods for designing a protection circuit for LED lighting, which requires our professionals to be familiar with each part to ensure the high efficiency of the product.

Here is a full introduction to LED, please check and learn it if you want.