Switching power supply unit

Patent metadata

Field	Value
Publication number	US-9787197-B2
Application number	US-201615295429-A
Country	US
Kind code	B2
Filing date	Oct 17, 2016
Priority date	Oct 29, 2015
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

A switching power supply unit includes input terminals, output terminals, first to third primary windings and first to third secondary windings, a switching circuit, a rectifying smoothing circuit, and a driver. In the switching circuit, first and second switching devices, third and fourth switching devices, and first and second capacitors, coupled in series to one another, are disposed in parallel between the input terminals. In the rectifying smoothing circuit, first to third arms, each having two of rectifying devices disposed in series, are disposed in parallel between the output terminals, the first secondary winding is coupled between the first and the second arms to form an H-bridge coupling, the second and the third secondary windings are coupled between the second and the third arms to form an H-bridge coupling, and a choke coil is disposed between the first to the third arms and an output capacitor.

First claim

What is claimed is:

1. A switching power supply unit comprising:
a pair of input terminals that receives an input voltage;
a pair of output terminals that outputs an output voltage;
first to third primary windings and first to third secondary windings that form three transformers;
a switching circuit disposed between the pair of input terminals and the first to the third primary windings, and including first to fourth switching devices and first and second capacitors;
a rectifying smoothing circuit provided between the pair of output terminals and the first to the third secondary windings, and including six rectifying devices, a choke coil, and an output capacitor that is disposed between the pair of output terminals; and
a driver that performs a switching drive that controls operation of the first to the fourth switching devices, wherein
in the switching circuit,
the first and the second switching devices are coupled in series to one another through a first connection point, the third and the fourth switching devices are coupled in series to one another through a second connection point, the first and the second capacitors are coupled in series to one another through a third connection point, and the coupled first and second switching devices, the coupled third and fourth switching devices and the coupled first and second capacitors are disposed in parallel to one another between the pair of input terminals,
the first primary winding is inserted between the first and the third connection points,
the second primary winding is inserted between the second and the third connection points, and
the third primary winding is inserted between the first and the second connection points, and
in the rectifying smoothing circuit,
first to third arms are disposed in parallel to one another between the pair of output terminals, the first to the third arms each having two of the rectifying devices disposed in series to one another in a same orientation,
the first secondary winding is coupled between the first and the second arms to form an H-bridge coupling,
the second and the third secondary windings coupled in series to one another are coupled between the second and the third arms to form an H-bridge coupling, and
the choke coil is disposed between the first to the third arms and the output capacitor.

2. The switching power supply unit according to claim 1 , wherein the transformers includes:
a first transformer that includes the first primary winding and the first secondary winding that are magnetically coupled to one another;
a second transformer that includes the second primary winding and the second secondary winding that are magnetically coupled to one another; and
a third transformer that includes the third primary winding and the third secondary winding that are magnetically coupled to one another.

3. The switching power supply unit according to claim 2 , wherein
a turn ratio of the first primary winding to the first secondary winding in the first transformer defined by the number of winding turns of the first primary winding/the number of winding turns of the first secondary winding is equal to a turn ratio of the second primary winding to the second secondary winding in the second transformer defined by the number of winding turns of the second primary winding/the number of winding turns of the second secondary winding, and
a voltage range upon voltage conversion from the input voltage to the output voltage changes depending on magnitude of a turn ratio of the third primary winding to the third secondary winding in the third transformer defined by the number of winding turns of the third primary winding/the number of winding turns of the third secondary winding.

4. The switching power supply unit according to claim 1 , wherein, between the second and the third arms,
the second secondary winding is disposed on side on which the second arm is provided, and
the third secondary winding is disposed on side on which the third arm is provided.

5. The switching power supply unit according to claim 1 , wherein, in the rectifying smoothing circuit,
a fourth arm is further disposed in parallel to the first to the third arms, the fourth arm having two other rectifying devices that are disposed in series to one another in a same orientation as an orientation in which the six rectifying devices are disposed, and
the two other rectifying devices are coupled together at a connection point between the second and the third secondary windings.

6. The switching power supply unit according to claim 5 , further comprising a resonance inductor coupled in series to one of the second primary winding and the third primary winding, and provided between a connection point of phase-shift-side switching devices of the first and the second connection points and one of the third connection point and a connection point of phase-locked-side switching devices.

7. The switching power supply unit according to claim 1 , further comprising a resonance inductor coupled in series to one of the first primary winding and the second primary winding, and provided between a connection point of phase-locked-side switching devices of the first and the second connection points and the third connection point.

8. The switching power supply unit according to claim 1 , wherein
the choke coil is inserted between a connection point of first ends of the first to the third arms and a first end of the output capacitor, between a connection point of second ends of the first to the third arms and a second end of the output capacitor, or both.

9. The switching power supply unit according to claim 8 , wherein, in each of the first to the third arms,
a cathode of corresponding one of the rectifying devices is disposed on side on which corresponding one of the first ends is provided, and
an anode of the corresponding one of the rectifying devices is disposed on side on which corresponding one of the second ends is provided.

10. The switching power supply unit according to claim 1 , wherein the rectifying devices each comprise a parasitic diode of a field effect transistor.

11. The switching power supply unit according to claim 1 , wherein the driver performs the switching drive to cause a connection state of the first to the third secondary windings to be switched.

12. The switching power supply unit according to claim 11 , wherein the driver performs the switching drive to cause the connection state of the first to the third secondary windings to be switched between a three serial connection state and a two parallel connection state or between the three serial connection state and a three parallel connection state.

13. The switching power supply unit according to claim 1 , wherein the switching circuit includes:
a first half-bridge circuit including the first and the second switching devices and the first and the second capacitors;
a second half-bridge circuit including the third and the fourth switching devices and the first and the second capacitors; and
a full-bridge circuit including the first to the fourth switching devices.

14. The switching power supply unit according to claim 13 , wherein the driver performs the switching drive to cause the first and the second half-bridge circuits to operate with a phase difference, and to cause phase control of the full-bridge circuit to be performed.

15. The switching power supply unit according to claim 14 , wherein the driver performs the switching drive to cause durations of on-duty periods of the first to the fourth switching devices to be substantially a maximum, in each of the first and the s

Assignees

• Tdk Corp

Inventors

• Nakahori Wataru

Classifications

• H02M3/3376 Primary

  with automatic control of output voltage or current · CPC title

• H02M3/33507 Primary

  with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence) · CPC title

• H02M2001/0048

  Electricity · mapped topic

• H02M2001/0058

  Electricity · mapped topic

• H02M1/0048

  Circuits or arrangements for reducing losses (using snubbers H02M1/34) · CPC title