Backlight driving circuit, liquid crystal display device and drive method

1. A backlight drive circuit, comprising:

an error amplification unit configured to receive a feedback voltage from a backlight, and used for comparing the feedback voltage with a basis voltage, adjusting the amplification coefficient and amplification speed for the comparison result based on the magnitude of the comparison result, and outputting the amplification result as a control signal; and

a drive control unit, which receives the control signal from the error amplification unit, and outputs, according to the control signal, a pulse width modulation dimming signal with a corresponding duty cycle to modulate a voltage signal output to the backlight from a power supply.

2. The backlight drive circuit of claim 1 , wherein,

the error amplification unit includes a plurality of error amplifiers, the comparison terminals of which are mutually coupled to receive the feedback voltage, the reference terminals of which receive different reference voltages, and the output terminals of which are mutually coupled to output the control signal, wherein the reference voltages each are a multiple of the basis voltage.

3. The backlight drive circuit of claim 2 , wherein,

the error amplifiers are distributed in a mirroring manner.

4. The backlight drive circuit of claim 3 , wherein further comprising:

a reference voltage generating unit, which is coupled to the error amplification unit and supplies the reference voltages to the error amplification unit.

5. The backlight drive circuit of claim 2 , wherein,

the error amplifiers are current amplifiers.

6. The backlight drive circuit of claim 5 , wherein further comprising:

a reference voltage generating unit, which is coupled to the error amplification unit and supplies the reference voltages to the error amplification unit.

7. The backlight drive circuit of claim 2 , wherein further comprising:

a reference voltage generating unit, which is coupled to the error amplification unit and supplies the reference voltages to the error amplification unit.

8. The backlight drive circuit of claim 2 , wherein,

the error amplification unit includes error amplifiers OP i , wherein i=−N . . . +N, and N is an integer greater or equal to 1,

and wherein the reference voltage V REFi of the i th amplifier satisfies the following relationship with the basis voltage V REF0 :

V REFi =(1+ pxi ) V REF0 ,

wherein p is an adjustment parameter greater than zero.

9. The backlight drive circuit of claim 8 , wherein,

the error amplifiers are distributed in a mirroring manner.

10. The backlight drive circuit of claim 9 , wherein further comprising:

a reference voltage generating unit, which is coupled to the error amplification unit and supplies the reference voltages to the error amplification unit.

11. The backlight drive circuit of claim 8 , wherein further comprising:

a reference voltage generating unit, which is coupled to the error amplification unit and supplies the reference voltages to the error amplification unit.

12. The backlight drive circuit of claim 8 , wherein,

the adjustment parameter p is equal to 0.1.

13. The backlight drive circuit of claim 12 , wherein,

the error amplifiers are distributed in a mirroring manner.

14. A liquid crystal display device including a display panel and a backlight module, wherein the backlight module includes a backlight drive circuit comprising:

an error amplification unit configured to receive a feedback voltage from a backlight, and used for comparing the feedback voltage with a basis voltage, adjusting the amplification coefficient and amplification speed for the comparison result based on the magnitude of the comparison result, and outputting the amplification result as a control signal; and

a drive control unit, which receives the control signal from the error amplification unit, and outputs, according to the control signal, a pulse width modulation dimming signal with a corresponding duty cycle to modulate a voltage signal output to the backlight from a power supply.

15. The liquid crystal display device of claim 14 , wherein,

the error amplification unit includes a plurality of error amplifiers, the comparison terminals of which are mutually coupled to receive the feedback voltage, the reference terminals of which receive different reference voltages, and the output terminals of which are mutually coupled to output the control signal, wherein the reference voltages each are a multiple of the basis voltage.

16. The liquid crystal display device of claim 15 , wherein,

the error amplification unit includes error amplifiers OP i , wherein i=−N . . . +N, and N is an integer greater or equal to 1, wherein the reference voltage V RERi of the i th amplifier satisfies the following relationship with the basis voltage V REF0 :

V REFi =(1+ pxi ) V REF0 ,

wherein p is an adjustment parameter greater than zero.

17. The liquid crystal display device of claim 15 , wherein,

the error amplifiers are distributed in a mirroring manner.

18. A backlight drive method, comprising steps of:

a collection step of collecting a backlight feedback voltage;

a comparison step of comparing the backlight feedback voltage with a basis voltage;

an amplification step of adjusting the amplification coefficient and the amplification speed for the comparison result based on to the magnitude of the comparison result and outputting an amplification result as a control signal; and

an output step of outputting, according to the control signal, a pulse width modulation dimming signal with a corresponding duty cycle to modulate a voltage signal output to the backlight from a power supply.

19. The backlight drive method of claim 18 , wherein,

in the amplification step, the amplifiers in corresponding quantity with corresponding gains are triggered according to the magnitude of the comparison result, so as to amplify the comparison result with different amplification coefficients and at different amplification speeds.