LED Backlight Driving Circuit, Backlight Module, and Liquid Crystal Display Device

• US 20140285748A1
• Filed: 03/28/2013
• Published: 09/25/2014
• Est. Priority Date: 03/19/2013
• Status: Active Grant

• Current Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Original Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Inventors: Zhang, Hua
• Granted Patent: US 9,024,528 B2
• Time in Patent Office: Days
• US Class Current: 349/61
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133612 Electrical details
• CPC Class Codes: H05B 31/50 specially adapted for ac
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 45/50 responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits

Abstract

The present invention provides a LED backlight driving circuit, a backlight module, and a liquid crystal display device, wherein, the LED backlight driving circuit comprises: a power module, a voltage converting module, a constant current driving IC module, and a boost module. The output terminal of the power module is connected with the power source of the constant current driving IC module through the voltage converting module; the output terminal of the power module is connected with the positive electrode of the LED strings through the boost module. The boost module is provided with an over voltage alarm unit used to warn that the voltage of the positive electrode of the LED strings is high. In the present invention, it can warn immediately and notice the failures when the output voltage of the LED backlight driving circuit is too high or the failure happens.

Claims

1. A LED backlight driving circuit, wherein it comprises:

a power module, a voltage converting module, a constant current driving IC module, and a boost module;

the output terminal of the power module being connected with the power source of the constant current driving IC module through the voltage converting module;

the output terminal of the power module being connected with the positive electrode of the LED strings through the boost module; and

the boost module being provided with an over voltage alarm unit used to warn that the voltage of the positive electrode of the LED strings being high.

2. The LED backlight driving circuit as claimed in claim 1, wherein the over voltage alarm unit is used to indicate whether the boost module fails or not.

3. The LED backlight driving circuit as claimed in claim 1, wherein it further comprises:

a power module failure alarm unit, which is used to indicate whether the power module fails or not.

4. The LED backlight driving circuit as claimed in claim 3, wherein it further comprises:

a constant current driving IC module failure alarm unit, which is used to indicate that whether the constant current driving IC module fails or not.

5. The LED backlight driving circuit as claimed in claim 1, wherein the boost module comprises an energy storage inductor, a rectifier diode, a MOSFET, and an output electrolytic capacitor;

the positive electrode of the rectifier diode is connected with the power module through the energy storage inductor, the negative electrode of which is connected with the LED strings;

one end of the output electrolytic capacitor is connected with the negative electrode of the rectifier diode, and the other end is connected to the ground;

the drain of the MOSFET is connected with the positive electrode of the rectifier diode, the source of which is connected to the ground, the gate of which is connected with a MOS driving signal output terminal of the constant current driving IC module;

the over voltage alarm unit is connected between the energy storage inductor and the positive electrode of the rectifier diode.

6. The LED backlight driving circuit as claimed in claim 3, wherein, when the LED driver circuit is working, the over voltage alarm unit lighting indicates that the positive electrode voltage of the LED strings is under high voltage.

7. The LED backlight driving circuit as claimed in claim 3, wherein the power module failure alarm unit is connected in series between the output terminal of the power module and the energy storage inductor of the boost module.

8. The LED backlight driving circuit as claimed in claim 4, wherein the constant current driving IC module failure alarm unit is connected in series between the power source of the constant current driving IC module and the voltage converting module.

9. The LED backlight driving circuit as claimed in claim 4, wherein the over voltage alarm unit, the power module failure alarm unit, and the constant current driving IC module failure alarm unit are LEDs.

10. The LED backlight driving circuit as claimed in claim 9, wherein, when the over voltage alarm unit stops flashing, it indicates that the boost module is failed;

when the power module failure alarm unit does not light, it indicates that the power module is failed;

when the constant current driving IC module failure alarm unit does not light, it indicates that the constant current driving IC module is failed.

11. A backlight module, wherein it comprises a LED backlight driving circuit, which comprises:

a power module, a voltage converting module, a constant current driving IC module, and a boost module;

the output terminal of the power module being connected with the power source of the constant current driving IC module through the voltage converting module;

the output terminal of the power module being connected with the positive electrode of the LED strings through the boost module;

the boost module being provided with an over voltage alarm unit used to warn that the voltage of the positive electrode of the LED strings being high; and

the over voltage alarm unit being also used to indicate whether the boost module fails or not.

12. The backlight module as claimed in claim 11, wherein the LED backlight driving circuit further comprises:

a power module failure alarm unit, which is used to indicate whether the power module fails or not;

a constant current driving IC module failure alarm unit, which is used to indicate that whether the constant current driving IC module fails or not.

13. The backlight module as claimed in claim 12, wherein the boost module comprises an energy storage inductor, a rectifier diode, a MOSFET, and an output electrolytic capacitor;

the positive electrode of the rectifier diode is connected with the power module through the energy storage inductor, the negative electrode of which is connected with the LED strings;

one end of the output electrolytic capacitor is connected with the negative electrode of the rectifier diode, and the other end is connected to the ground;

the drain of the MOSFET is connected with the positive electrode of the rectifier diode, the source of which is connected to the ground, the gate of which is connected with a MOS driving signal output terminal of the constant current driving IC module;

the over voltage alarm unit is connected between the energy storage inductor and the positive electrode of the rectifier diode.

14. The backlight module as claimed in claim 13, wherein when the LED driver circuit is working, the over voltage alarm unit lighting indicates that the positive electrode voltage of the LED strings is under high voltage.

15. The backlight module as claimed in claim 14, wherein the power module failure alarm unit is connected in series between the output terminal of the power module and the energy storage inductor of the boost module;

the constant current driving IC module failure alarm unit is connected in series between the power source of the constant current driving IC module and the voltage converting module.

16. The backlight module as claimed in claim 15, wherein the over voltage alarm unit, the power module failure alarm unit, and the constant current driving IC module failure alarm unit are LEDs.

17. The backlight module as claimed in claim 16, wherein, when the over voltage alarm unit stops flashing, it indicates that the boost module is failed;

when the power module failure alarm unit does not light, it indicates that the power module is failed;

when the constant current driving IC module failure alarm unit does not light, it indicates that the constant current driving IC module is failed.

18. A liquid crystal display device, wherein it comprises a backlight module, the backlight module comprising a LED backlight driving circuit, the LED backlight driving circuit comprising:

a power module, a voltage converting module, a constant current driving IC module, and a boost module;

the output terminal of the power module being connected with the power source of the constant current driving IC module through the voltage converting module;

the output terminal of the power module being connected with the positive electrode of the LED strings through the boost module;

the boost module being provided with an over voltage alarm unit used to warn that the voltage of the positive electrode of the LED strings being high; and

the over voltage alarm unit being also used to indicate whether the boost module fails or not.

19. The liquid crystal display device as claimed in claim 18, wherein the LED backlight driving circuit further comprises:

a power module failure alarm unit, which is used to indicate whether the power module fails or not;

a constant current driving IC module failure alarm unit, which is used to indicate that whether the constant current driving IC module fails or not.

20. The liquid crystal display device as claimed in claim 19, wherein the boost module of the LED backlight driving circuit comprises an energy storage inductor, a rectifier diode, a MOSFET, and an output electrolytic capacitor;

the positive electrode of the rectifier diode is connected with the power module through the energy storage inductor, the negative electrode of which is connected with the LED strings;

one end of the output electrolytic capacitor is connected with the negative electrode of the rectifier diode, and the other end is connected to the ground;

the drain of the MOSFET is connected with the positive electrode of the rectifier diode, the source of which is connected to the ground, the gate of which is connected with a MOS driving signal output terminal of the constant current driving IC module;

the over voltage alarm unit is connected between the energy storage inductor and the positive electrode of the rectifier diode.