US 2008/0175027 A1Published application

Switching power source apparatus

AssigneeSanken Electric Co., Ltd.

InventorsMasaaki SHIMADA, Masaru Nakamura, Akihiro Uchida

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Abstract

A switching power source apparatus includes a switching element connected through a primary winding of a transformer to a DC power source, a start circuit for a control circuit, a rectify-smooth circuit of a voltage of a secondary winding of the transformer, and a rectify-smooth circuit to rectify and smooth a voltage of a tertiary winding of the transformer into a source voltage for the control circuit. The start circuit supplies a first starting current to start the apparatus and stops the first starting current once the apparatus has started. If the source voltage to the control circuit decreases to a turn-off voltage after the apparatus has started, the start circuit supplies a second starting current that is smaller than the first starting current. If the source voltage to the control circuit further decreases to a predetermined voltage that is lower than the turn-off voltage, the start circuit supplies the first starting current.

Claims3

Dependent claims

A switching power source apparatus comprising:

a switching element connected through a primary winding of a transformer to a DC power source;
a control circuit configured to control ON/OFF operation of the switching element;
a start circuit configured to supply a source voltage to the control circuit so that a starting current passes through the control circuit;
a first rectify-smooth circuit configured to rectify and smooth a voltage generated by a secondary winding of the transformer into an output voltage and supply the output voltage to a load;
and
a second rectify-smooth circuit configured to rectify and smooth a voltage generated by a tertiary winding of the transformer into a source voltage to be supplied to the control circuit, wherein the start circuit is configured to:
supply a first starting current generated from the DC power source to start the apparatus, and once the apparatus has started, stop the first starting current;
if the source voltage to the control circuit decreases to a turn-off voltage after the apparatus has started, supply a second starting current that is smaller than the first starting current;
and
if the source voltage to the control circuit further decreases to a predetermined voltage that is lower than the turn-off voltage, supply the first starting current.

7 more elements

Dependencies are inferred from the claim text.