US 9,660,518 B2Granted

Switching converter

AssigneeSemiconductor Energy Laboratory Co., Ltd.

InventorsMasumi Nomura, Kosei Noda

Life of this patent

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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.

Claims8

Dependent claims

A switching converter comprising:

a transformer electrically connected to a power supply portion;
a switch whose one of a source and a drain is 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, wherein a first terminal of the resistor is electrically connected to one of a source and a drain of the first transistor, and a second terminal of the resistor is electrically connected to a gate of the first transistor and one of a source and a drain of the second transistor;
a first rectifying and smoothing circuit whose first terminal is electrically connected to the transformer and whose second terminal is electrically connected to an output portion;
and
a second rectifying and smoothing circuit whose first terminal is electrically connected to the transformer and whose second terminal is electrically connected to the switching control circuit,
wherein the one of the source and the drain of the switch is electrically connected to the first terminal of the first rectifying and smoothing circuit,
wherein the other of the source and the drain of the second transistor is directly connected to a ground,
wherein the starter circuit further comprises a diode whose first terminal is electrically connected to the other of the source and the drain of the first transistor and whose second terminal is electrically connected to a first terminal of the control circuit,
wherein the one of a source and a drain of the first transistor and the first terminal of the resistor are electrically connected to the one of the source and the drain of the switch,
wherein a gate of the second transistor is electrically connected to a second terminal of the control circuit, and
wherein a gate of the switch is electrically connected to a third terminal of the control circuit.

15 more elements

A device comprising:

a transformer electrically connected to a power supply portion;
a switch whose one of a source and a drain is electrically connected to the transformer;
a switching control circuit electrically connected to the switch, the switching control circuit comprising:
a control circuit comprising an element that comprises a semiconductor different from an oxide semiconductor;
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, wherein a first terminal of the resistor is electrically connected to one of a source and a drain of the first transistor, and a second terminal of the resistor is electrically connected to a gate of the first transistor and one of a source and a drain of the second transistor;
a first rectifying and smoothing circuit whose first terminal is electrically connected to the transformer and whose second terminal is electrically connected to an output portion;
and
a second rectifying and smoothing circuit whose first terminal is electrically connected to the transformer and whose second terminal is electrically connected to the switching control circuit,
wherein the one of the source and the drain of the switch is electrically connected to the first terminal of the first rectifying and smoothing circuit,
wherein the other of the source and the drain of the second transistor is directly connected to a ground,
wherein the starter circuit further comprises a diode whose first terminal is electrically connected to the other of the source and the drain of the first transistor and whose second terminal is electrically connected to a first terminal of the control circuit,
wherein the one of a source and a drain of the first transistor and the first terminal of the resistor are electrically connected to the one of the source and the drain of the switch,
wherein a gate of the second transistor is electrically connected to a second terminal of the control circuit, and
wherein a gate of the switch is electrically connected to a third terminal of the control circuit.

15 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/875,415Filed 2 May 2013
Priority: JP 2012-1053592 May 2012
Published: US 2013/0294120 A17 Nov 2013
Granted: 23 May 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H02M 1/36
Details of apparatus for conversion: means for starting or stopping converters
H02M 1/0006
Details of control, feedback or regulation circuits: arrangements for supplying an adequate voltage to the control circuit of converters
H02M 3/335
Using devices of a triode or a transistor type requiring continuous application of a control signal: using semiconductor devices only
H02M 3/33507
Using semiconductor devices only: with automatic control of the output voltage or current, e.g. flyback converters