Current resonance type SMPS circuit e.g. for TV system

摘要

The supply circuit has switching elements (Q1,Q2) which interrupt either a voltage or a current output by a d.c. supply unit (D1) and deliver the resulting voltage or current to primary windings (N4,N1) of an isolating transformer (T1) and a non-isolating transformer (T2). A defined a.c. voltage is produced by the isolating transformer. Control is performed by a d.c. current output device (D1,C1) contg. a rectifier (D1) for rectification of an a.c. supply voltage, an isolating capacitor (C1) arranged on the output side of the rectifier to eliminate noise, a secondary winding of the non-isolating transformer (T2) and a smoothing capacitor (C2). The smoothing capacitor is charged by a circuit contg. a diode (D2) and a choke coil (L1).