Energy efficient power supply with light-load detection

摘要

An output voltage of a rectification smoothing circuit is compared with a reference voltage. When a reduction in the output has been detected, an A/D converting circuit converts a result of the comparison which is negatively fed back by an output voltage feedback circuit to obtain a control signal for a bidirectional switch element inserted into a primary side of a transformer so as to turn ON or OFF synchronously or asynchronously with a commercial power supply via an intermittent control circuit.