Planar type transformer and switching power supply circuit

Patent metadata

Field	Value
Publication number	US-9472333-B2
Application number	US-201514661717-A
Country	US
Kind code	B2
Filing date	Mar 18, 2015
Priority date	Apr 22, 2014
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

A planar type transformer includes: a multilayer substrate including a primary main winding pattern and a secondary main winding pattern that perform first power transmission, the primary main winding pattern and the secondary main winding pattern being stacked with an insulating layer interposed between the primary main winding pattern and the secondary main winding pattern; and an auxiliary winding that is disposed outside the multilayer substrate and performs second power transmission between the auxiliary winding and the primary main winding pattern or the secondary main winding pattern.

First claim

What is claimed is:

1. A planar type transformer comprising:
a multilayer substrate including a primary main winding pattern and a secondary main winding pattern that perform first power transmission, the primary main winding pattern and the secondary main winding pattern being stacked with an insulating layer interposed between the primary main winding pattern and the secondary main winding pattern; and
an auxiliary winding that is disposed outside the multilayer substrate and performs second power transmission between the auxiliary winding and the primary main winding pattern or the secondary main winding pattern.

2. The planar type transformer according to claim 1 ,
wherein main winding patterns including the primary main winding pattern and the secondary main winding pattern are formed over an even number of layers with the insulating layer interposed between the primary main winding pattern and the secondary main winding pattern.

3. The planar type transformer according to claim 1 ,
wherein part of the auxiliary winding is disposed at a lateral wall of a through hole that is formed in the multilayer substrate for insertion of a core.

4. The planar type transformer according to claim 1 , further comprising
a core that is inserted into a through hole formed in the multilayer substrate and covers part of the multilayer substrate,
wherein the core has a groove that allows at least part of the auxiliary winding to pass through the groove.

5. A switching power supply circuit comprising:
a planar type transformer;
a rectifier circuit that rectifies an input signal;
a switch element that switches to determine whether or not a switching current based on the rectified input signal is supplied to the planar type transformer; and
a control circuit that controls an operation of the switch element,
wherein the planar type transformer includes
a multilayer substrate having the primary main winding pattern and the secondary main winding pattern that perform first power transmission, the primary main winding pattern and the secondary main winding pattern being stacked with an insulating layer interposed between the primary main winding pattern and the secondary main winding pattern, and
an auxiliary winding that is disposed outside the multilayer substrate, performs second power transmission between the auxiliary winding and the primary main winding pattern or the secondary main winding pattern, and supplies power to the control circuit.

Assignees

• Fujitsu Ltd

Inventors

• Yonezawa Yu
• Nakao Hiroshi
• Nakashima Yoshiyasu

Classifications

• H01F27/2804 Primary

  Printed windings · CPC title

• H01F2027/2809

  on stacked layers · CPC title

• H01F2027/2819

  Planar transformers with printed windings, e.g. surrounded by two cores and to be mounted on printed circuit · CPC title

• H02M3/28

  using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC · CPC title