# US 7,746,049 B2 · Power supply device and recording apparatus

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- Number: US 7,746,049 B2
- Document ID: US7746049B2
- Status: Granted
- Kind: B2
- Application number: 12/056,114
- Filed: 2008-03-26
- Published: 2008-10-02
- Granted: 2010-06-29
- Earliest claimed: 2007-03-30
- Assignees: Canon Kabushiki Kaisha
- Inventors: Takashi Sato
- Web page: https://patentgrep.com/patent/US7746049B2

## CPC

- H02M 3/158: including plural semiconductor devices as final control devices for a single load
- H02M 1/322: {Means for rapidly discharging a capacitor of the converter for protecting electrical components or for preventing electrical shock}
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)

## Abstract

A power supply device includes a DC-DC converter configured to regulate an output voltage based on an externally input instruction, and a discharge circuit connected to an output capacitor of the DC-DC converter, wherein the discharge circuit includes a switch element configured to switch between a conductive state and a nonconductive state according to an instruction, and a capacitor-resistor (C-R) circuit configured to charge electric charge accumulated in the output capacitor of the DC-DC converter when the switch element is conductive and to discharge the electric charge to ground when the switch element is nonconductive.

## Claims

### Claim 1

A power supply device comprising:
a DC-DC converter configured to regulate an output voltage based on an externally input instruction; and
a discharge circuit connected to an output capacitor of the DC-DC converter, wherein the discharge circuit includes,
a switch element configured to switch between a conductive state and a nonconductive state according to an instruction; and
a capacitor-resistor (C-R) circuit configured to charge electric charge accumulated in the output capacitor of the DC-DC converter when the switch element is conductive and to discharge the electric charge to ground while the switch element is nonconductive.

### Claim 2 (depends on 1)

The power supply device according to claim 1, wherein one end of the switch element is connected to an output voltage line of the DC-DC converter via a first resistor and the other end of the switch element is connected to the C-R circuit.

### Claim 3 (depends on 2)

The power supply device according to claim 2, wherein the C-R circuit includes a resistor and a capacitor connected in series between the other end of the switch element and the ground.

### Claim 4 (depends on 1)

The power supply device according to claim 1, wherein one end of the switch element is connected to an output voltage line of the DC-DC converter and the other end of the switch element is connected to the C-R circuit.

### Claim 5 (depends on 4)

The power supply device according to claim 4, wherein the C-R circuit includes a resistor and a capacitor connected in series between the other end of the switch element and the ground.

### Claim 6 (depends on 2)

The power supply device according to claim 2, wherein a time constant of the C-R circuit is smaller than an interval of conduction timing of the switch element.

### Claim 7

A power supply device comprising:
a DC-DC converter configured to regulate an output voltage based on an externally input instruction; and
a discharge circuit connected to an output line of the DC-DC converter, wherein the discharge circuit includes,
a switch element configured to switch between a conductive state and a nonconductive state according to an instruction; and
a capacitor-resistor (C-R) circuit configured to charge electric charge of an output capacitor of the DC-DC converter when the switch element is conductive and to discharge the electric charge to ground when the switch element is nonconductive.

### Claim 8

A recording apparatus comprising:
a power supply device including,
a DC-DC converter configured to regulate an output voltage based on an externally input instruction; and
a discharge circuit connected to an output capacitor of the DC-DC converter, wherein the discharge circuit includes,
a switch element configured to switch between a conductive state and a nonconductive state according to an instruction; and
a capacitor-resistor (C-R) circuit configured to charge electric charge accumulated in the output capacitor of the DC-DC converter when the switch element is conductive and to discharge the electric charge to ground while the switch element is nonconductive; and
a control unit configured to control an operation of the recording apparatus, wherein the control unit outputs an instruction for changing the output voltage to the DC-DC converter and the discharge circuit.

### Claim 9

A recording apparatus comprising:
a power supply device including,
a DC-DC converter configured to regulate an output voltage based on an externally input instruction; and
a discharge circuit connected to an output capacitor of the DC-DC converter,
wherein the discharge circuit includes,
a switch element configured to switch between a conductive state and a nonconductive state according to an instruction; and
a capacitor-resistor (C-R) circuit configured to charge electric charge accumulated in the output capacitor of the DC-DC converter when the switch element is conductive and to discharge the electric charge to ground while the switch element is nonconductive; and
a control unit configured to control an operation of the recording apparatus, wherein the control unit outputs an instruction to the switch element such that a nonconduction period of the switch element becomes longer than a conduction period of the switch element.

### Claim 10

A recording apparatus comprising:
a power supply device including,
a DC-DC converter configured to regulate an output voltage based on an externally input instruction; and
a discharge circuit connected to an output line of the DC-DC converter, wherein the discharge circuit includes,
a switch element configured to switch between a conductive state and a nonconductive state according to an instruction; and
a capacitor-resistor (C-R) circuit configured to charge electric charge of an output capacitor of the DC-DC converter when the switch element is conductive and to discharge the electric charge to ground when the switch element is nonconductive; and
a control unit configured to control an operation of the recording apparatus, wherein the control unit outputs an instruction for changing the output voltage to the DC-DC converter and the discharge circuit.