Common voltage adjustment circuit for display panel and display apparatus

Patent metadata

Field	Value
Publication number	US-9715856-B2
Application number	US-201414408080-A
Country	US
Kind code	B2
Filing date	May 20, 2014
Priority date	Dec 24, 2013
Publication date	Jul 25, 2017
Grant date	Jul 25, 2017

Abstract

Provided are a common voltage adjustment circuit for a display panel and a display apparatus. The adjustment circuit comprises: a filter unit ( 101 ) configured to filter a PWM signal provided externally and provide a DC voltage signal obtained through the filtering to a first voltage clamp unit; a first voltage clamp unit ( 102 ) configured to adjust the DC voltage signal to obtain a first adjusted signal and provide the first adjusted signal to a feedback amplification unit; a feedback amplification unit ( 103 ) configured to amplify the first adjusted signal to obtain a first amplified signal and provide the first amplified signal to a second voltage clamp unit; and a second voltage clamp unit ( 104 ) configured to adjust the first amplified signal to output a second adjusted signal and provide the voltage value of the second adjusted signal to the display panel. The adjustment circuit can rapidly and precisely adjust the common voltage of the display panel to reduce the flicker phenomenon during the displaying of the display panel.

First claim

What is claimed is:

1. A common voltage adjustment circuit for a display panel, comprising:
a filter unit configured to filter a pulse width modulation (PWM) signal provided externally and provide a DC voltage signal obtained through the filtering to a first voltage clamp unit;
a first voltage clamp unit configured to adjust the DC voltage signal to obtain a first adjusted signal and provide the first adjusted signal to a feedback amplification unit;
a feedback amplification unit configured to amplify the first adjusted signal to obtain a first amplified signal and provide the first amplified signal to a second voltage clamp unit; and
a second voltage clamp unit configured to adjust the first amplified signal to output a second adjusted signal and provide a voltage value of the second adjusted signal to the display panel.

2. The adjustment circuit according to claim 1 , wherein the filter unit comprises a first resistor, a second resistor, a first capacitor and a second capacitor;
a first terminal of the first resistor is connected to a first terminal of the first capacitor as an input terminal of the filter unit, a second terminal of the first resistor is connected to a first terminal of the second resistor and a first terminal of the second capacitor respectively, a second terminal of the second resistor is taken as an output terminal of the filter unit, and both a second terminal of the first capacitor and a second terminal of the second capacitor are connected to a reference ground; and
the output terminal of the filter unit provides the DC voltage signal to the first voltage clamp unit.

3. The adjustment circuit according to claim 2 , wherein the first voltage clamp unit comprises a third resistor and a fourth resistor;
a first terminal of the third resistor is connected to a DC power supply, a second terminal of the third resistor and a first terminal of the fourth resistor is connected to a first pull-down node, a second terminal of the fourth resistor is connected to a reference ground; and
the first voltage clamp unit provides the first adjusted signal to the feedback amplification unit through the first pull-down node.

4. The adjustment circuit according to claim 3 , wherein the feedback amplification unit comprises an amplifier, a fifth resistor, a sixth resistor and a seventh resistor;
the amplifier comprises a positive input terminal, a negative input terminal and an output terminal;
a first terminal of the fifth resistor is connected to the positive terminal of the amplifier;
both a first terminal of the sixth resistor and a first terminal of the seventh resistor are connected to the negative terminal of the amplifier;
a second terminal of the fifth resistor, a second terminal of the sixth resistor and the output terminal of the amplifier are connected as an output terminal of the feedback amplification unit;
a second terminal of the seventh resistor is connected to a reference ground; and
the output terminal of the feedback amplification unit provides the first amplified signal to the second voltage clamp unit.

5. The adjustment circuit according to claim 4 , wherein the amplifier further comprises a reference ground input terminal and a power supply input terminal.

6. The adjustment circuit according to claim 2 , wherein the feedback amplification unit comprises an amplifier, a fifth resistor, a sixth resistor and a seventh resistor;
the amplifier comprises a positive input terminal, a negative input terminal and an output terminal;
a first terminal of the fifth resistor is connected to the positive terminal of the amplifier;
both a first terminal of the sixth resistor and a first terminal of the seventh resistor are connected to the negative terminal of the amplifier;
a second terminal of the fifth resistor, a second terminal of the sixth resistor and the output terminal of the amplifier are connected as an output terminal of the feedback amplification unit;
a second terminal of the seventh resistor is connected to a reference ground; and
the output terminal of the feedback amplification unit provides the first amplified signal to the second voltage clamp unit.

7. The adjustment circuit according to claim 6 , wherein the amplifier further comprises a reference ground input terminal and a power supply input terminal.

8. The adjustment circuit according to claim 2 , wherein the second voltage clamp unit comprises an eighth resistor and ninth resistor;
a first terminal of the eighth resistor is connected to a DC power supply;
both a second terminal of the eighth resistor and a first terminal of the ninth resistor are connected to a second pull-down node;
a second terminal of the ninth resistor is connected to a reference ground; and
the second voltage clamp unit provides the voltage value of the second adjusted signal to the display panel through the second pull-down node.

9. The adjustment circuit according to claim 2 , further comprises:
a signal receiving unit whose output terminal is connected to an input terminal of the filter unit;
wherein the signal receiving unit is configured to receive a control signal based on which the PWM signal is generated and provide the PWM signal to the filter unit; and
the control signal carries instruction information and adjustment parameters for adjusting the common voltage of the display panel.

10. The adjustment circuit according to claim 1 , wherein the first voltage clamp unit comprises a third resistor and a fourth resistor;
a first terminal of the third resistor is connected to a DC power supply, a second terminal of the third resistor and a first terminal of the fourth resistor is connected to a first pull-down node, a second terminal of the fourth resistor is connected to a reference ground; and
the first voltage clamp unit provides the first adjusted signal to the feedback amplification unit through the first pull-down node.

11. The adjustment circuit according to claim 10 , wherein the feedback amplification unit comprises an amplifier, a fifth resistor, a sixth resistor and a seventh resistor;
the amplifier comprises a positive input terminal, a negative input terminal and an output terminal;
a first terminal of the fifth resistor is connected to the positive terminal of the amplifier;
both a first terminal of the sixth resistor and a first terminal of the seventh resistor are connected to the negative terminal of the amplifier;
a second terminal of the fifth resistor, a second terminal of the sixth resistor and the output terminal of the amplifier are connected as an output terminal of the feedback amplification unit;
a second terminal of the seventh resistor is connected to a reference ground; and
the output terminal of the feedback amplification unit provides the first amplified signal to the second voltage clamp unit.

12. The adjustment circuit according to claim 11 , wherein the amplifier further comprises a reference ground input terminal and a power supply input terminal.

13. The adjustment circuit according to claim 10 , wherein the second voltage clamp unit comprises an eighth resistor and ninth resistor;
a first terminal of the eighth resistor is connected to the DC power supply;
both a second terminal of the eighth resistor and a first terminal of the ninth resistor are connected to a second pull-down node;
a second terminal of the ninth resistor is connected to a reference ground; and
the second voltage clamp unit provides the voltage value of the second adjusted signal to the display panel through the second pull-down node.

14. The adjustment circuit according to claim 10 , further comprises:
a signal re

Assignees

• Boe Technology Group Co Ltd
• Beijing Boe Vision-Electronic Tech Co Ltd

Inventors

• Wang Jianting
• Tan Qin

Classifications

• G09G2310/0291

  Details of output amplifiers or buffers arranged for use in a driving circuit · CPC title

• G09G2320/0247

  Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes · CPC title

• G09G2320/0204

  Compensation of DC component across the pixels in flat panels · CPC title

• G09G3/3655 Primary

  Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors · CPC title

• G09G3/3696

  Generation of voltages supplied to electrode drivers · CPC title