Non-insulated switching power supply for a high voltage light strip

摘要

Disclosed is a non-isolated switching power supply for a high voltage light strip. The non-isolated switching power supply includes a full-bridge rectifier circuit (10), a switching tube Q2, an electrolytic capacitor C2, an energy storage inductor L1, a diode D4, and a PWM circuit (90). The PWM signal output of the PWM circuit is connected to a control electrode of the interrupter Q2, the interrupter Q2 and the diode D4 are connected in series between the two outputs of the full-bridge rectifier circuit (10), a negative electrode of the interrupter is also connected to a positive output + VCC the full-bridge rectifier circuit (10) and the energy storage inductance L1 is connected between the negative electrode of the electrolytic capacitor C2 and the positive electrode of the diodes D4. The non-isolated switching power supply uses a completely new circuit design; the voltage of the energy storage inductance L1 is held at 130 V by pulse width modulation of the PWM circuit, so that the electrolytic capacitor C2 always outputs a high voltage of 180 V, and the cost of the power supply is low. According to the invention, the non-isolated switching power supply further comprises a relay (RELAY1) and an input protection circuit (100), wherein the contacts of the relay (RELAY1) are connected in series between the positive electrode of the electrolytic capacitor (C2) and the positive output of the non-isolated switching power supply, and wherein the input protection circuit (100) is connected to the coil of the relay (RELAY1) to control the switching on and off of the contacts of the relay (RELAY1).