Blocking DC=DC converter with sec. series opto-coupler - which provides complete galvanic sepn. between transformer sec. winding and cyclically switched circuit on prim. side

摘要

The operational cycle is started by closure of a switch (M) earthing the prim. winding of a transformer (U). The timer (T) is actuated by a Schmitt trigger (K) when the sec. winding current passes through a zero, or falls below a predetermined threshold. The signal for comparison is amplified (V) from the output of a photoreceiver (E) linked (L) to the infrared-emitting diode (S) in series with the sec. winding from which a storage capacitor (C) is charged rapidly during each cycle of operation. ADVANTAGE - High efficiency is achieved with guaranteed galvanic isolation between prim. and sec. circuits.