Liquid crystal display with feedback circuit part

1. A liquid crystal display device, comprising:

a liquid crystal display panel including an array substrate on which a plurality of data lines and a plurality of scan lines are aligned, a common substrate having a common electrode, and liquid crystals interposed between the array substrate and the common substrate;

a power supply part for generating a power supply voltage, and for producing a common power supply voltage; and

a feedback circuit part connected between the power supply part and the common electrode of the common substrate;

wherein the feedback circuit part comprises a negative feedback part having a first input connected to the power supply part and having an output, a buffer part having an input connected to the output of the negative feedback part and having an output connected to the common electrode of the common substrate, a low-pass filter part connected to a junction between the output of the buffer part and the common electrode of the common substrate for receiving a third ripple voltage from the common electrode, a first impedance, and a second impedance;

said first impedance being connected between the output of the negative feedback part and a second input of the negative feedback part; and

said second impedance being connected directly between the output of the buffer part and the second input of the negative feedback part.

2. The liquid crystal display device according to claim 1 , wherein said negative feedback part produces a first ripple voltage which represents an inversion of the third ripple voltage due to feeding back of the third ripple voltage through the first and second impedances; and

wherein the buffer part receives the first ripple voltage of the negative feedback part, and produces a second ripple voltage through buffering.

3. The liquid crystal display device according to claim 2 , wherein the first ripple voltage, the second ripple voltage and the third ripple voltage are distortion components.

4. The liquid crystal display device according to claim 1 , wherein the first impedance is an alternating current network in which a third resistor and a second capacitor are connected in parallel.

5. The liquid crystal display device according to claim 4 , wherein the second impedance is an alternating current network comprising a first capacitor and a second resistor connected in series, and a first resistor connected in parallel with the first capacitor and the second resistor.

6. The liquid crystal display device according to claim 5 , wherein the low-pass filter part produces a compensation voltage by removing high frequency components of the third ripple voltage.

7. The liquid crystal display device according to claim 6 , wherein the negative feedback part comprises a first operation amplifier connected in series with the first impedance, and a common power supply electrode for receiving the common power supply voltage provided by the power supply part.

8. The liquid crystal display device according to claim 7 , wherein the buffer part includes a buffer amplifier comprising a second operational amplifier connected in series with the negative feedback part, and a fourth resistor connected in series with the buffer amplifier.

9. The liquid crystal display device according to claim 8 , wherein the low-pass filter part comprises a fifth resistor connected in series with the fourth resistor of the buffer part, a required electrode which is connected in series with the fifth resistor, a required voltage being supplied to the required electrode, the common electrode of the common substrate being connected in series with the fifth resistor, and a third capacitor being connected in parallel with the fifth resistor.

10. The liquid crystal display device according to claim 9 , wherein the required voltage is provided by the power supply part.

11. The liquid crystal display device according to claim 9 , wherein the compensation voltage is a voltage value that can be changed and controlled by adjusting at least one of the first resistor, the second resistor, the third resistor, the fourth resistor, the fifth resistor, the first capacitor, the second capacitor, the third capacitor and the common power supply voltage.

12. The liquid crystal display device according to claim 9 , wherein the common electrode comprises a ground electrode.

13. The liquid crystal display device according to claim 1 , wherein the liquid crystals are one of thermotropic liquid crystals and lyotropic liquid crystals.

14. A liquid crystal display device, comprising:

a liquid crystal display panel including an array substrate on which a plurality of data lines and a plurality of scan lines are aligned, a common substrate having a common electrode, and liquid crystals interposed between the array substrate and the common substrate;

a common power supply for generating a power supply voltage, and for producing a common power supply voltage; and

a feedback circuit part connected between the power supply part and the common electrode of the common substrate;

wherein the feedback circuit part comprises a negative feedback part having a first input connected to the power supply part and having an output, a buffer part having an input connected to the output of the negative feedback part and having an output connected to the common electrode of the common substrate, a low-pass filter part connected to a junction between the output of the buffer part and the common electrode of the common substrate for receiving a third ripple voltage from the common electrode, a first impedance, and a second impedance;

said first impedance being connected between the output of the negative feedback part and a second input of the negative feedback part; and

said second impedance being connected directly between the output of the buffer part and the second input of the negative feedback part.

15. The liquid crystal display device according to claim 14 , wherein the liquid crystals are one of thermotropic liquid crystals and lyotropic liquid crystals.

16. The liquid crystal display device according to claim 14 , wherein the first impedance is an alternating current network in which a third resistor and a second capacitor are connected in parallel.

17. The liquid crystal display device according to claim 14 , wherein the second impedance is an alternating current network comprising a first capacitor and a second resistor connected in series, and a first resistor connected in parallel with the first capacitor and the second resistor.

18. The liquid crystal display device according to claim 14 , wherein the low-pass filter part produces a compensation voltage by removing high frequency components of the third ripple voltage.

19. The liquid crystal display device according to claim 14 , wherein the negative feedback part comprises a first operation amplifier connected in series with the first impedance, and a common power supply electrode for receiving the common power supply voltage provided by the power supply part.

20. The liquid crystal display device according to claim 14 , wherein the negative feedback part produces a first ripple voltage which represents an inversion of the third ripple voltage by feeding back the third ripple voltage through the first and second impedances, and wherein the buffer part receives a first ripple voltage from the negative feedback part and produces a second ripple voltage through buffering, and the negative feedback part receives the common power supply voltage.

21. The liquid crystal display device according to claim 20 , wherein the first ripple voltage, the second ripple voltage and the third ripple voltage are distortion components.