Simple LED Driving Circuit Diagram

The constant current output circuit is very suitable for driving LEDs. The high output voltage supports one LED string, so there is no need to consider distributing current between LEDs, and can provide protection in case of load disconnection, overload, short circuit and overheating. The efficiency of the circuit in the whole working voltage range is very high (more than 90%), which has the advantages of small and light weight, low cost and small number of components required. It can meet the conducted EMI limit of en55022b, and the EMI margin is greater than 10dbuv.

The circuit adopts a linkswitch TN device in the low-end step-down converter configuration, which can provide 130mA constant current and 70V DC output voltage under the AC input voltage of 90 132v. This power supply is very suitable for driving LEDs that must be driven by constant current rather than constant voltage. Fuse fu1 provides protection in case of serious fault. Capacitor C1 and common mode choke L1 can reduce conducted EMI. Diodes VD1 VD4 provide full wave rectification, and high voltage capacitor C2 maintains stable DC bus voltage.