Switching Power-Supply Device

• US 20140376271A1
• Filed: 09/19/2013
• Published: 12/25/2014
• Est. Priority Date: 06/25/2013
• Status: Active Grant

• Current Assignee: Sanken Electric Company Limited
• Original Assignee: Sanken Electric Company Limited
• Inventors: Chiba, Akiteru
• Granted Patent: US 9,287,791 B2
• Time in Patent Office: Days
• US Class Current: 363/21.01
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/335 using semiconductor devices only
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A switching power-supply device, includes a first terminal; a first winding connected to the first terminal; a second winding, which is connected in series to the first winding and is magnetically coupled to the first winding; a first capacitor connected in series to the second winding; a transformer including a primary winding connected in series to the first capacitor and a secondary winding magnetically coupled to the primary winding; a rectifying-and-smoothing circuit connected to the secondary winding; a second terminal, which is connected to an opposite end of the primary winding opposite to a connection end connecting to the first capacitor; a first switching element, which is connected between a connection point of the first winding and the second winding and the second terminal; and a control circuit, which controls first switching element to turn on-and-off.

Claims

1. A switching power-supply device, comprising:

a first terminal configured to connect to one end of a DC power source;

a first winding connected to the first terminal;

a second winding, which is connected in series to the first winding and is magnetically coupled to the first winding;

a first capacitor connected in series to the second winding;

a transformer including a primary winding connected in series to the first capacitor and a secondary winding magnetically coupled to the primary winding;

a rectifying-and-smoothing circuit connected to the secondary winding;

a second terminal, which is configured to connect to the other end of the DC power source and is connected to an opposite end of the primary winding opposite to a connection end connecting to the first capacitor;

a first switching element, which is connected between a connection point of the first winding and the second winding and the second terminal; and

a control circuit, which controls first switching element to turn on-and-off.

2. The switching power-supply device according to claim 1, wherein a ratio of the number of turns of the first winding and the number of turns of the second winding is in a range 1:

1 to 1;

4.

3. The switching power-supply device according to claim 2, wherein the ratio of the number of turns of the first winding and the number of turns of the second winding is in a range 1:

2 to 1;

3.

4. The switching power-supply device according to claim 1, further comprising;

a series circuit, in which a second switching element and a second capacitor are provided in series, wherein the series circuit is connected in parallel to the first switching element, and

wherein the control circuit controls one of the first switching element and the second switching element to turn off while the other one of the first switching element and the second switching element is turned on.

5. The switching power-supply device according to claim 4,

wherein the control circuit controls an output voltage by varying a ratio of a on-time of the first switching element and an on-time of a second switching element for a unit time.