Power supply circuit

• US 20040145930A1
• Filed: 12/24/2003
• Published: 07/29/2004
• Est. Priority Date: 12/27/2002
• Status: Active Grant

• Current Assignee: Yamaha Corporation
• Original Assignee: Yamaha Corporation
• Inventors: Noro, Masao
• Granted Patent: US 7,209,374 B2
• Time in Patent Office: Days
• US Class Current: 363/127
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 3/33576 having at least one active switching element at the secondary side of an isolation transformer
• CPC Class Codes: H02M 7/217 using semiconductor devices only

Abstract

There is provided a power supply circuit having a simple configuration which is capable of eliminating an adverse effect due to pumping operation. The capacitor-input positive and negative power supply circuit is comprised of diodes, switching circuits connected in parallel with the diodes, and control circuits that control the switching circuits such that the switching circuits conduct during a time period over which the diodes conduct.

Claims

1. A capacitor-input positive and negative power supply circuit comprising:

at least two rectifier devices;

at least two switching circuits connected in parallel with respective ones of said rectifier devices; and

a control device that controls said switching circuits such that said switching circuits conduct during a time period over which said rectifier devices conduct.

2. A power supply circuit as claimed in claim 1, wherein said rectifier devices comprise four rectifier devices forming a bridge rectifier circuit, and

wherein said switching circuits are connected in parallel with at least two of said four rectifier devices.

3. A power supply circuit as claimed in claim 1, wherein:

the power supply circuit is a switching regulator having a primary side and a secondary side,

said switching circuits being connected to said secondary side of said switching regulator; and

said control device controls said switching circuits such that said switching circuits conduct in a same timing as a drive signal for driving said primary side of said switching regulator.

4. A power supply circuit as claimed in claim 1, comprising a detector circuit that detects a time period over which a sinusoidal wave inputted to said rectifier devices exceeds a predetermined level, and

wherein said control device controls said switching circuits such that said switching circuits conduct during the time period detected by said detector circuit.