LIGHT SOURCE SYSTEM AND METHOD FOR DRIVING LIGHT EMITTING DIODES

• US 20120119673A1
• Filed: 03/08/2011
• Published: 05/17/2012
• Est. Priority Date: 11/12/2010
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Wen, Chun-Kuei, Kuo, Shih-Chieh, Chen, Che-Hsien, Huang, Hung-Min
• Granted Patent: US 8,618,738 B2
• Time in Patent Office: Days
• US Class Current: 315/294
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines

Abstract

A light source system and a method for driving light emitting diodes (LEDs) are provided. The provided light source system includes: an LED module having a plurality of LED strings operated under a direct current (DC) output voltage; and a driving unit coupled to the LED module, and used for providing the DC output voltage by adopting a boost means and generating a plurality of pulsation current signals according to a setting signal so as to respectively drive the LED strings, in which the frequencies of the pulsation current signals are higher than a predetermined frequency.

Claims

1. A light source system, comprising:

a light emitting diode (LED) module, comprising a plurality of LED strings operated under a direct current (DC) output voltage; and

a driving unit, coupled to the LED module, and used for providing the DC output voltage by adopting a boost means and generating a plurality of pulsation current signals according to a setting signal so as to respectively drive the LED strings,

wherein frequencies of the pulsation current signals are higher than a predetermined frequency.

2. The light source system according to claim 1, wherein the driving unit comprises:

a boost circuit, used for receiving a DC input voltage and generating the DC output voltage after a boost processing of the DC input voltage; and

a driver, used for receiving and analyzing the setting signal to generate the pulsation current signals.

3. The light source system according to claim 2, wherein when the boost circuit is under an over voltage, the generation of the DC output voltage is stopped.

4. The light source system according to claim 2, wherein the driver further adjusts the strength of the pulsation current signals according to a current setting value.

5. The light source system according to claim 1, wherein the frequencies of the pulsation current signals are the same or different from each other.

6. The light source system according to claim 5, wherein the frequency of each pulsation current signal is in a multiple relation with the predetermined frequency.

7. The light source system according to claim 6, wherein the multiple relation is greater than or equal to an integral or a non-integral multiple of one.

8. The light source system according to claim 7, wherein the predetermined frequency is a highest audio frequency in an audible acoustic wave range.

9. The light source system according to claim 8, wherein duty cycles of the pulsation current signals are the same or different from each other.

10. The light source system according to claim 1, wherein the light source system is at least an LED backlight module.

11. A method for driving light emitting diodes (LEDs), applicable to driving a plurality of LED strings, the method comprising:

providing a direct current (DC) output voltage by adopting a boost means so as to enable the LED strings to be operated under the DC output voltage; and

generating a plurality of pulsation current signals according to a setting signal so as to respectively drive the LED strings,

wherein frequencies of the pulsation current signals are higher than a predetermined frequency.

12. The method according to claim 11, wherein the frequencies of the pulsation current signals are the same or different from each other.

13. The method according to claim 12, wherein the frequency of each pulsation current signal is in a multiple relation with the predetermined frequency.

14. The method according to claim 13, wherein the multiple relation is greater than or equal to an integral or a non-integral multiple of one.

15. The method according to claim 14, wherein the predetermined frequency is a highest audio frequency in an audible acoustic wave range.

16. The method according to claim 15, wherein duty cycles of the pulsation current signals are the same or different from each other.