Switching power supply apparatus and controlling method for the same

• US 5,963,436 A
• Filed: 09/11/1998
• Issued: 10/05/1999
• Est. Priority Date: 09/12/1997
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yoshida, Koji
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US09/152,020
• Time in Patent Office: 389 Days
• Field of Search: 363/16, 363/17, 363/95, 363/98, 363/131, 363/132
• US Class Current: 363/17
• CPC Class Codes: H02M 1/38 Means for preventing simultaneous conduction of switches
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current

Abstract

The switching power supply apparatus of the present invention comprises first and second switching units connected to a DC power source and connected to each other serially, third and fourth switching units connected to the DC power source and connected to each other serially, and a transformer including a primary winding connected to between a connecting point between the first and second switching units and a connecting point between the third and fourth switching units, wherein the first and second switching units is controlled so that the first and second switching units are in an ON-state complementarily after a first predetermined dead time period in which both of the first and second switching units are in an OFF-state, the third and fourth switching units is controlled so that the third and fourth switching units are in the ON-state complementarily after a second predetermined dead time period in which both of the third and fourth switching units are in the OFF-state, and the first through fourth switching units are controlled so that a short-circuited time in which the primary winding is short-circuited is set between the first and second dead time periods.

Claims

1. A switching power supply apparatus comprising:

first and second switching units which are connected each other serially and to a DC power source,

third and fourth switching units which are connected each other serially and to said DC power source,

a transformer including a primary winding connected to between a connecting point between said first and second switching units and a connecting point between said third and fourth switching units, and

a control circuit which controls the operation of each of said first through fourth switching units so that

said first and second switching units are in an ON-state complementarily after a first predetermined dead time period in which both of said first and second switching units are in an OFF-state,

said third and fourth switching units are in the ON-state complementarily after a second predetermined dead time period in which both of said third and fourth switching units are in the OFF-state, and

said first through four switching units shortcircuits said primary winding during the periods of said first dead time and second dead time.

2. A switching power supply apparatus in accordance with claim 1, wherein said second and fourth switching units are controlled to be in the ON-state so that said primary winding is short-circuited.

3. A switching power supply apparatus in accordance with claim 1, wherein said first and third switching units are controlled to be in the ON-state so that said primary winding is short-circuited.

4. A switching power supply apparatus in accordance with claim 1, wherein said first and third switching units are operated so as to shift said ON-state and said OFF-state setting timings of said first switching unit by a half switching cycle from said ON-state and said OFF-state setting timings of said third switching unit, respectively.

5. A switching power supply apparatus in accordance with claim 1, wherein each of said first through fourth switching units is configured with a switching element and a diode connected to said switching element in parallel so as to connect in a reverse direction for said DC power source.

6. A switching power supply apparatus in accordance with claim 1, wherein each of said first through fourth switching units is composed of a MOSFET.

7. A method for controlling a switching power supply apparatus comprising first and second switching units connected each other serially and to a DC power source;

third and fourth switching units connected each other serially and to said DC power source; and

a transformer including a primary winding connected to between a connecting point between said first and second switching units and a connecting point between said third and fourth switching units;

the method comprising the steps of

controlling said first and second switching units so that said first and second switching units are in an ON-state complementarily after a first predetermined dead time period in which both of said first and second switching units are in an OFF-state,

controlling said third and fourth switching units so that said third and fourth switching units are in the ON-state complementarily after a second predetermined dead time period in which both of said third and fourth switching units are in the OFF-state, and

short-circuiting said primary winding during the periods of said first dead time and second dead time.