DC-TO-DC CONVERTER

• US 20110007529A1
• Filed: 06/28/2010
• Published: 01/13/2011
• Est. Priority Date: 07/10/2009
• Status: Active Grant

• Current Assignee: Sanken Electric Company Limited
• Original Assignee: Sanken Electric Company Limited
• Inventors: USUI, Hiroshi
• Granted Patent: US 8,411,466 B2
• Time in Patent Office: Days
• US Class Current: 363/21.12
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33576 having at least one active switching element at the secondary side of an isolation transformer

Abstract

The present invention includes: a plurality of switching elements connected in series and connected between two ends of a DC power supply; a first control circuit to alternately turn on and off the switching elements in response to a constant oscillation frequency signal; a series circuit including a primary winding of a transformer and a capacitor connected together in series, and being connected to a connecting point between the switching elements, and to an end of the DC power supply; a rectifying/smoothing circuit to rectify and smooth a voltage in a secondary winding of the transformer thereby to output a DC voltage; a control switching element connected to two ends of the primary or secondary winding of the transformer; and a second control circuit to control the DC voltage at a predetermined voltage by turning on and off the control switching element.

Claims

1. A DC-to-DC converter comprising:

a plurality of switching elements connected together in series and connected between two ends of a DC power supply;

a first control circuit configured to alternately turn on and off the plurality of switching elements in response to a constant oscillation frequency signal;

a series circuit in which a primary winding of a transformer and a capacitor are connected together in series, the series circuit being connected to a connecting point between the plurality of switching elements, and to an end of the DC power supply;

a rectifying/smoothing circuit configured to rectify and smooth a voltage which occurs in a secondary winding of the transformer, and thus to output a DC voltage;

a control switching element connected to two ends of any one of the primary and secondary windings of the transformer; and

a second control circuit configured to control the DC voltage at a predetermined voltage by turning on and off the control switching element.

2. The DC-to-DC converter according to claim 1, wherein

the secondary winding of the transformer includes a first winding and a second winding,

a series circuit including a first rectifying element and the control switching element is connected to two ends of the first winding,

a series circuit including a second rectifying element and the control switching element is connected to two ends of the second winding, and

the second control circuit controls the DC voltage at the predetermined voltage by turning on and off the control switching element based on a voltage of the first winding, a voltage of the second winding, and the DC voltage.

3. The DC-to-DC converter according to claim 1, wherein

a plurality of rectifying elements bridge-connected together are connected to two ends of any one of the primary winding and tertiary winding of the transformer and are connected to the control switching element, and

the second control circuit controls the DC voltage at the predetermined voltage by turning on and off the control switching element based on the constant oscillation frequency signal from the first control circuit and the DC voltage.

4. The DC-to-DC converter according to claim 1, wherein

a first series circuit and a second series circuit are connected together in series between two ends of the secondary winding of the transformer in a way that polarities of the first and second series circuits are reverse to each other, the first series circuit including a first rectifying element and a first control switching element, and the second series circuit including a second rectifying element and a second control switching element, and

the second control circuit controls the DC voltage at the predetermined voltage by simultaneously turning on and off the first and second control switching elements based on a voltage of the secondary winding and the DC voltage.

5. The DC-to-DC converter according to claim 1, wherein

the secondary winding of the transformer includes a first winding and a second winding,

a series circuit including a first rectifying element and a first control switching element is connected to two ends of the first winding,

a series circuit including a second rectifying element and a second control switching element is connected to two ends of the second winding, and

the second control circuit controls the DC voltage at the predetermined voltage by alternately turning on and off the first control switching element and the second control switching element based on the constant oscillation frequency signal from the first control circuit, and the DC voltage.