# US 7,612,506 B1 · Method for controlling light-emission of a light-emitting diode light source

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- Number: US 7,612,506 B1
- Document ID: US7612506B1
- Status: Granted
- Kind: B1
- Application number: 12/149,813
- Filed: 2008-05-08
- Published: 2009-11-12
- Granted: 2009-11-03
- Earliest claimed: 2008-05-08
- Assignees: National Central University
- Inventors: Tsung-Hsun Yang; Hung-Yu Chou
- Web page: https://patentgrep.com/patent/US7612506B1

## CPC

- H05B 45/14: using electrical feedback from LEDs or from LED modules
- H05B 45/56: involving measures to prevent abnormal temperature of the LEDs
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL

## Abstract

A method for controlling light-emission of a light-emitting diode (LED) light source whose heat is dissipated by a thermal module is provided. The method includes following steps: providing a constant current source to drive the LED light source and obtaining a reference voltage correspondingly; monitoring and obtaining a dynamic voltage of the LED light source; and comparing the dynamic voltage with the reference voltage and adjusting a heat-dissipating power of the thermal module in real time to make the dynamic voltage of the LED light source approach the reference voltage. By monitoring the dynamic voltage of the LED light source and adjusting the heat-dissipating power of the thermal module in real time, light power of the LED light source can be maintained.

## Claims

### Claim 1

A method for controlling light-emission of a light-emitting diode (LED) light source, the LED light source undergoing heat dissipation through a thermal module, the method comprising steps of:
providing a constant current source to drive the LED light source, and
obtaining a reference voltage corresponding to a drive current generated by the constant current source;
monitoring and obtaining a dynamic voltage across two electrodes of the LED light source; and
comparing the dynamic voltage with the reference voltage and adjusting a heat-dissipation power of the thermal module to make the dynamic voltage approach the reference voltage.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein the LED light source is a single LED or a combination of a plurality of LEDs.

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein the dynamic voltage is obtained via a voltage-sensing unit.

### Claim 4 (depends on 1)

The method as claimed in claim 1, wherein the dynamic voltage is a forward voltage of the LED light source, and the heat-dissipation power is decreased if the dynamic voltage is higher than the reference voltage, and increased if the dynamic voltage is lower than the reference voltage.