Backlight module driving circuit

Abstract

A backlight driver circuit has a transformer, a switching circuit and a plurality of switch devices. The switching circuit couples a DC voltage to a primary side of the transformer and alternates polarities thereof so that an AC voltage is generated on a secondary side of the transformer to turn on the backlight blocks. The switch devices are respectively connected between one of the backlight blocks and the transformer, and the AC voltage turns the backlight blocks on when the switch devices are turned on.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims and accompanying drawings, where:

FIG. 1 shows the framework of a conventional LCD;

FIG. 2 shows the framework of the backlight module driver circuit used in the conventional LCD;

FIG. 3A shows the framework of a backlight module driver circuit according to one embodiment;

FIG. 3B shows the circuit diagram of the backlight module driver circuit;

FIG. 4 shows the framework of a backlight module driver circuit according to another embodiment; and

FIG. 5 shows the framework of a backlight module driver circuit according to another embodiment.

Claims

1. A backlight module driver circuit used to turn on a plurality of backlight blocks in a backlight module, the backlight driver circuit comprising: a transformer;a switching circuit coupling a DC voltage to a primary side of the transformer and alternating polarities thereof so that an AC voltage is generated on a secondary side of the transformer to turn on the backlight blocks; anda plurality of switch devices respectively connected between one of the backlight blocks and the transformer, and the AC voltage turns the backlight blocks on when the switch devices are turned on.

2. The backlight module driver circuit as claimed in claim 1, wherein the switch devices are not turned on and off at the same time.

3. The backlight module driver circuit as claimed in claim 1, wherein the switching circuit comprises two sets of inverting switches, and the polarities of the DC voltage are alternated by alternately switching between the two sets of inverting switches.

4. The backlight module driver circuit as claimed in claim 3, wherein the two sets of inverting switches comprise a plurality of MOSFETs.

5. The backlight module driver circuit as claimed in claim 1, wherein the switch devices are triacs.

6. The backlight module driver circuit as claimed in claim 1, further comprising a plurality of capacitors respectively disposed on the primary side and the secondary side of the transformer, wherein the capacitors are used to block the DC portion of the AC voltage.

7. A backlight module driver circuit used to turn on a plurality of backlight blocks in a backlight module, the backlight driver circuit comprising: a plurality of transformers;a switching circuit coupling a DC voltage to primary sides of the transformers and alternating polarities thereof so that an AC voltage is generated on secondary sides of the transformers to turn on the backlight blocks; anda plurality of switch devices respectively connected to the transformers, and the switch devices are used to determine whether the backlight blocks are turned on,wherein when one of the switch devices is turned on, the transformer connected to the turned-on switch device outputs the AC voltage to turn on one of the backlight blocks.

8. The backlight module driver circuit as claimed in claim 7, wherein the switch devices are respectively disposed between the switching circuit and one of the transformers, when the switch devices are turned on, the transformers are enabled to output the AC voltage to turn on the backlight blocks.

9. The backlight module driver circuit as claimed in claim 7, wherein the switch devices are respectively disposed between one of the transformers and one of the backlight blocks, when the switch devices are turned on, the transformers output the AC voltage to turn on the backlight blocks.

10. The backlight module driver circuit as claimed in claim 7, wherein the switch devices are not turned on and off at the same time.

11. The backlight module driver circuit as claimed in claim 7, wherein the switching circuit comprises two sets of inverting switches, and the polarities of the DC voltage are alternated by alternately switching the two sets of inverting switches.

12. The backlight module driver circuit as claimed in claim 11, wherein the two sets of inverting switches comprise a plurality of MOSFETs.

13. The backlight module driver circuit as claimed in claim 7, wherein the switch devices are triacs.

14. The backlight module driver circuit as claimed in claim 7, further comprising a plurality of capacitors respectively disposed at the primary side and the secondary side of the transformers, wherein the capacitors are used to block the DC portion of the AC voltage.

15. A flat display panel, comprising: a pixel array comprising a plurality of display blocks;a backlight module comprising a plurality of backlight blocks, wherein the backlight blocks correspond the display blocks in position; anda backlight module driver circuit used to turn on the backlight blocks, the backlight module driver circuit comprising: a transformer;a switching circuit coupling a DC voltage to a primary side of the transformer and alternating polarities thereof so that an AC voltage is generated on a secondary side of the transformer to turn on the backlight blocks; anda plurality of switch devices respectively connected between one of the backlight blocks and the transformer, and the switch devices are used to determine whether the backlight blocks are turned on, wherein when one of the switch devices is turned on, the backlight block connected to the turned-on switch device is turned on by the AC voltage.

16. The flat display panel as claimed in claim 15, wherein the switch devices are not turned on and off at the same time.

17. The flat display panel as claimed in claim 15, wherein the switching circuit comprises two sets of inverting switches, and the polarities of the DC voltage are alternated by alternately switching the two sets of inverting switches.

18. The flat display panel as claimed in claim 17, wherein the two sets of inverting switches comprise a plurality of MOSFETs.

19. The flat display panel as claimed in claim 15, wherein the switch devices are triacs.

20. The flat display panel as claimed in claim 15, further comprising a plurality of capacitors respectively disposed on the primary side and the secondary side of the transformer, wherein the capacitors are used to block the DC portion of the AC voltage.