SWITCHING CONVERTER

• US 20130294120A1
• Filed: 05/02/2013
• Published: 11/07/2013
• Est. Priority Date: 05/02/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Nomura, Masumi, Noda, Kosei
• Granted Patent: US 9,660,518 B2
• Time in Patent Office: Days
• US Class Current: 363/49
• CPC Class Codes: H02M 1/0006 Arrangements for supplying an adequate voltage to the control circuit of converters
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 3/335 using semiconductor devices only
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• 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 7/517 with special starting equipment

Abstract

A switching converter in which deterioration and breakage can be suppressed is provided. A switching converter whose area can be reduced is provided. The switching converter includes a switch connected to a power supply portion; a transformer connected to the power supply portion; a first rectifying and smoothing circuit and a second rectifying and smoothing circuit each connected to at least the transformer; and a switching control circuit which is connected to the first rectifying and smoothing circuit and the second rectifying and smoothing circuit and which controls operation of the switch. The switching control circuit includes a control circuit controlling on/off of the switch and operation of a starter circuit; and the starter circuit controlling startup of the control circuit. The starter circuit includes a transistor and a resistor each including a wide-gap semiconductor.

Claims

1. A switching converter comprising:

a transformer electrically connected to a power supply portion;

a switch electrically connected to the transformer;

a switching control circuit electrically connected to the switch, the switching control circuit comprising;

a control circuit; and

a starter circuit, the starter circuit comprising;

a first transistor and a second transistor each comprising an oxide semiconductor film in a channel region; and

a resistor comprising a film comprising an oxide semiconductor between a first terminal and a second terminal;

a first rectifying and smoothing circuit electrically connected to the transformer and an output portion; and

a second rectifying and smoothing circuit electrically connected to the transformer and the switching control circuit.

2. The switching converter according to claim 1,

wherein the switch comprises a gate, a source, and a drain,

wherein the starter circuit further comprises a diode,

wherein one of a source and a drain of the first transistor and the first terminal of the resistor are electrically connected to one of the source and the drain of the switch,

wherein a gate of the first transistor and the second terminal of the resistor are electrically connected to one of a source and a drain of the second transistor,

wherein the other of the source and the drain of the first transistor is electrically connected to a third terminal of the diode,

wherein a fourth terminal of the diode is electrically connected to a fifth terminal of the control circuit,

wherein the other of the source and the drain of the second transistor is grounded,

wherein a gate of the second transistor is electrically connected to a sixth terminal of the control circuit, and

wherein the gate of the switch is electrically connected to a seventh terminal of the control circuit.

3. The switching converter according to claim 2, wherein the other of the source and the drain of the switch is electrically connected to an eighth terminal of the output portion.

4. The switching converter according to claim 2, wherein the other of the source and the drain of the switch is electrically connected to a ninth terminal of the first rectifying and smoothing circuit and a tenth terminal of the transformer.

5. The switching converter according to claim 2, wherein the other of the source and the drain of the switch is grounded.

6. The switching converter according to claim 1,

wherein an element in the control circuit and the diode in the starter circuit are provided in a first element layer,

wherein the first transistor, the second transistor, and the resistor in the starter circuit are provided in a second element layer,

wherein the second element layer is provided over the first element layer,

wherein the first element layer comprises a semiconductor substrate,

wherein the semiconductor substrate in the first element layer is grounded, and

wherein an eleventh terminal of the second element layer is grounded through a conductive material.

7. A switching converter comprising:

a switch electrically connected to a power supply portion;

a transformer electrically connected to the switch;

a switching control circuit electrically connected to the power supply portion and the switch;

the switching control circuit comprising;

a control circuit; and

a starter circuit, the starter circuit comprising;

a first transistor and a second transistor each comprising an oxide semiconductor film in a channel region; and

a resistor comprising a film comprising an oxide semiconductor between a first terminal and a second terminal;

a first rectifying and smoothing circuit electrically connected to the switch, the transformer, and an output portion; and

a second rectifying and smoothing circuit electrically connected to the transformer and the switching control circuit.

8. The switching converter according to claim 7,

wherein the switch comprises a gate, a source, and a drain,

wherein the starter circuit further comprises a diode,

wherein one of a source and a drain of the first transistor and the first terminal of the resistor are electrically connected to one of the source and the drain of the switch,

wherein a gate of the first transistor and the second terminal of the resistor are electrically connected to one of a source and a drain of the second transistor,

wherein the other of the source and the drain of the first transistor is electrically connected to a third terminal of the diode,

wherein a fourth terminal of the diode is electrically connected to a fifth terminal of the control circuit,

wherein the other of the source and the drain of the second transistor is grounded,

wherein a gate of the second transistor is electrically connected to a sixth terminal of the control circuit, and

wherein the gate of the switch is electrically connected to a seventh terminal of the control circuit.

9. The switching converter according to claim 8, wherein the other of the source and the drain of the switch is electrically connected to an eighth terminal of the output portion.

10. The switching converter according to claim 8, wherein the other of the source and the drain of the switch is electrically connected to a ninth terminal of the first rectifying and smoothing circuit and a tenth terminal of the transformer.

11. The switching converter according to claim 8, wherein the other of the source and the drain of the switch is grounded.

12. The switching converter according to claim 7,

wherein an element in the control circuit and the diode in the starter circuit are provided in a first element layer,

wherein the first transistor, the second transistor, and the resistor in the starter circuit are provided in a second element layer,

wherein the second element layer is provided over the first element layer,

wherein the first element layer comprises a semiconductor substrate,

wherein the semiconductor substrate in the first element layer is grounded, and

wherein an eleventh terminal of the second element layer is grounded through a conductive material.

13. A switching converter comprising:

a first transformer and a second transformer each electrically connected to a power supply portion;

a switch connected to the first transformer and the second transformer;

a switching control circuit connected to the switch;

the switching control circuit comprising;

a control circuit; and

a starter circuit, the starter circuit comprising;

a first transistor and a second transistor each comprising an oxide semiconductor film in a channel region; and

a resistor comprising a film comprising an oxide semiconductor between a first terminal and a second terminal;

a first rectifying and smoothing circuit electrically connected to the first transformer and an output portion; and

a second rectifying and smoothing circuit electrically connected to the second transformer and the switching control circuit.

14. The switching converter according to claim 13,

wherein the switch comprises a gate, a source, and a drain,

wherein the starter circuit further comprises a diode,

wherein one of a source and a drain of the first transistor and the first terminal of the resistor are electrically connected to one of the source and the drain of the switch,

wherein a gate of the first transistor and the second terminal of the resistor are electrically connected to one of a source and a drain of the second transistor,

wherein the other of the source and the drain of the first transistor is electrically connected to a third terminal of the diode,

wherein a fourth terminal of the diode is electrically connected to a fifth terminal of the control circuit,

wherein the other of the source and the drain of the second transistor is grounded,

wherein a gate of the second transistor is electrically connected to a sixth terminal of the control circuit, and

wherein the gate of the switch is electrically connected to a seventh terminal of the control circuit.

15. The switching converter according to claim 14, wherein the other of the source and the drain of the switch is electrically connected to an eighth terminal in the output portion.

16. The switching converter according to claim 14, wherein the other of the source and the drain of the switch is electrically connected to a ninth terminal of the first rectifying and smoothing circuit and a tenth terminal of the transformer.

17. The switching converter according to claim 14, wherein the other of the source and the drain of the switch is grounded.

18. The switching converter according to claim 13,

wherein an element in the control circuit and the diode in the starter circuit are provided in a first element layer,

wherein the first transistor, the second transistor, and the resistor in the starter circuit are provided in a second element layer,

wherein the second element layer is provided over the first element layer,

wherein the first element layer comprises a semiconductor substrate,

wherein the semiconductor substrate in the first element layer is grounded, and

wherein an eleventh terminal of the second element layer is grounded through a conductive material.

19. The switching converter according to claim 13, wherein the oxide semiconductor film of at least one of the first transistor and the second transistor comprises at least one of In and Zn.

20. The switching converter according to claim 13, wherein the oxide semiconductor comprises at least one of In and Zn.