Patent Number: 6,295,211

Title: Switching power supply unit having delay circuit for reducing switchingfrequency

Abstract: A switching power supply unit includes a DC power supply, a transformerhaving a primary winding, a secondary winding and a feedback winding, amain switching element connected in series to the primary winding, and acontrol circuit connected between the feedback winding and the controlterminal of the main switching element, so that a DC output can beobtained. In this switching power supply unit, there are provided avoltage generating unit disposed on the primary side of the transformer tooutput a voltage according to a load power, and a delay circuit forreducing the switching frequency by delaying the turn-on of the mainswitching element according to a voltage output from the voltagegenerating unit thereby to prolong the OFF time of the main switchingelement.

Inventors: Nishida; Akio (Kyoto, JP), Tani; Ryota (Otokuni-gun, JP), Nakahira; Koji (Kyoto, JP)


International Classification:

Expiration Date: 09/25/2013