DC/DC converter

• US 8,072,305 B2
• Filed: 03/13/2008
• Issued: 12/06/2011
• Est. Priority Date: 03/30/2007
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Nakahori, Wataru
• Primary Examiner(s): Enad, Elvin G
• Assistant Examiner(s): Hinson, Ronald
• Application Number:
  US12/047,770
• Publication Number:
  US 20080239759A1
• Time in Patent Office: 1,363 Days
• Field of Search: 336/200, 336220-223, 336/232, 363/15, 363/20, 363/34, 363/171
• US Class Current: 336/200
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 27/2847 Sheets; Strips H01F27/2866 takes precedence
• CPC Class Codes: H01F 27/2871 Pancake coils
• CPC Class Codes: H01F 27/2876 Cooling cooling transformers and inductances in general H01F27/08
• CPC Class Codes: H01F 27/343 Preventing or reducing surge voltages; oscillations
• 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 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/337 in push-pull configuration H02M3/33576 takes precedence; with self-oscillating arrangements H02M3/3382, H02M3/3385
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections

Abstract

Primary and secondary coils are provided in the first through section and a coil group is also provided in the second through section. Hence, the surface area over which the coil group extends within a plane which is perpendicular to the through sections is greater than in the case where all of the coils are provided in a single through section. The surface area which is not covered by the magnetic body cores of the platelike members increases. In cases where the surface area of the members is large, the heat radiation characteristic is enhanced. Hence, the cooling efficiency of the transformer improves. In cases where there is a plurality of coil groups which are magnetically coupled to one another in particular, because it is difficult to move the heat produced in the plurality of coil groups through heat conduction, heat transfer, or heat radiation, a heat radiation structure of this kind is effective.

Claims

1. A switching supply comprising:

an inverter circuit which is connected to a primary coil group of a transformer; and

a rectification/smoothing circuit which is connected to a secondary coil group of the transformer, wherein

the transformer comprises a core having a first through section and a second through section, which is spatially separate from the first through section and constitutes a magnetic circuit together with the first through section,

the first through section passes through the inside of at least one coil of the primary coil group and at least one coil of the secondary coil group,

the second through section passes through the inside of the remaining coils of the primary and secondary coil groups,

following one loop direction of the magnetic circuit, a first coil group has a primary coil and a secondary coil that are magnetically coupled and, subsequently to the first coil group, a second coil group has a primary coil and a secondary coil that are magnetically coupled,

the secondary coil group includes secondary coils, the secondary coils of the secondary coil group being constituted by first and second platelike members,

the first platelike member of the secondary coils has first and second openings and first and second slits,

the first through section is arranged in the first opening,

the second through section is arranged in the second opening,

the first slit is continued to the first opening,

the second slit is continued to the second opening;

the first and second slits extend from the first and second openings in mutually opposite directions,

the second platelike member of the secondary coils has third and fourth openings and third and fourth slits,

the first through section is arranged in the third opening,

the second through section is arranged in the fourth opening,

the third slit is continued to the third opening,

the fourth slit is continued to the fourth opening,

the third and fourth slits extend from the third and fourth openings in mutually opposite directions, and

the first and third slits extend from the first and third openings in mutually opposite directions.

2. The switching supply according to claim 1, wherein the coils of the first or second coil group are arranged in one loop direction of the magnetic circuit in the following order:

secondary coil, primary coil and secondary coil, or primary coil, secondary coil and primary coil.

3. The switching supply according to claim 1, wherein

the primary coil of the first coil group and the primary coil of the second coil group are connected in series, and

the AC resistance of the primary coil of the first coil group and the AC resistance of the primary coil of the second coil group are set such that one is alternately higher than the other in sync with the switching of the inverter circuit.

4. The switching supply according to claim 1, wherein said switching supply is a DC/DC converter.

5. The switching supply according to claim 1, wherein

the mutually opposite directions of the first and second slits allow a current to flow in a rotary direction in the first platelike member of the secondary coils, and

the mutually opposite directions of the third and fourth slits allow a current to flow in a rotary direction in the second platelike member of the secondary coils.