# US 2017/0257916 A1 · Lighting device

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- Number: US 2017/0257916 A1
- Document ID: US20170257916A1
- Status: Published application
- Kind: A1
- Application number: 15/506,568
- Filed: 2015-06-18
- Published: 2017-09-07
- Earliest claimed: 2014-08-27
- Assignees: Sharp Kabushiki Kaisha
- Applicants: Sharp Kabushiki Kaisha
- Inventors: Ken SUMITANI
- Web page: https://patentgrep.com/patent/US20170257916A1

## CPC

- H05B 45/20: Controlling the colour of the light
- H05B 45/37: Converter circuits
- H05B 45/46: having LEDs disposed in parallel lines
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL

## Abstract

A lighting device includes a plurality of light sources, a power supply circuit that generates a power supply voltage on the basis of a voltage which is output from an external power supply, and a control circuit that is driven by the power supply voltage. The control circuit detects a drop in the power supply voltage and controls lighting states of the plurality of light sources on the basis of the detection. The power supply voltage is supplied to all or a portion of the plurality of light sources.

## Claims

### Claim at position 1

1-5. (canceled)

### Claim 6

A lighting device comprising:
a plurality of light sources that have different characteristics of emitted light;
a power supply circuit that generates a power supply voltage on the basis of a voltage which is output from an external power supply; and
a control circuit that is driven by the power supply voltage,
wherein the control circuit includes a detection unit that detects a drop in the power supply voltage, and a voltage generation unit that generates a power supply voltage for the detection unit for driving the detection unit on the basis of the power supply voltage,
wherein the voltage generation unit includes a voltage dropping unit and a voltage holding unit,
wherein the control circuit detects a drop in the power supply voltage by the detection unit and controls lighting states of the plurality of light sources on the basis of the detection,
wherein the control circuit is operable by only the power supply voltage for the detection unit, and has a function of performing setting to an initial selection state by a drop in the power supply voltage, and
wherein the power supply voltage is supplied to all or a portion of the plurality of light sources.

### Claim 7 (depends on 6)

The lighting device according to claim 6,
wherein the voltage generation unit has a capacity as the voltage holding unit, and
wherein a time period for which the control circuit is capable of being driven with the capacity is longer than a time period for which the detection unit detects a drop in the power supply voltage.

### Claim 8 (depends on 6)

The lighting device according to claim 6,
wherein the control circuit sets selection states of the plurality of light sources to be a first selection state in an initial state, makes the selection states of the plurality of light sources transition to another selection state when a first time period elapses after a drop in the power supply voltage is detected, and sets the selection states of the plurality of light sources to be the first selection state when a second time period longer than the first time period elapses after a drop in the power supply voltage is detected or when the control circuit is reset by a drop in the power supply voltage for the detection unit.

### Claim 9 (depends on 6)

The lighting device according to claim 6,
wherein the power supply circuit adjusts a value of an output current in accordance with a light control signal.

### Claim 10 (depends on 9)

The lighting device according to claim 9,
wherein the control circuit generates the light control signal.