Display drive circuit and drive method thereof, and display device

Patent metadata

Field	Value
Publication number	US-11875742-B2
Application number	US-202117764163-A
Country	US
Kind code	B2
Filing date	May 19, 2021
Priority date	Jun 11, 2020
Publication date	Jan 16, 2024
Grant date	Jan 16, 2024

Abstract

A display drive circuit, a drive method thereof, and a display device are disclosed. The display drive circuit includes: a pixel circuit and a compensation circuit, the pixel circuit includes: a drive transistor, a light emitting device, a storage capacitor, and a gating sub-circuit configured to control connection and disconnection between the control electrode of the drive transistor and a control terminal of the compensation circuit and connection and disconnection between a second electrode of the light emitting device and a sensing terminal of the compensation circuit in response to a signal of a scanning line; the compensation circuit includes: a voltage generating sub-circuit configured to generate a sensing voltage according to the drive current and a target data voltage, and a voltage adjusting sub-circuit configured to adjust a voltage of the control terminal according to the sensing voltage and a voltage of a second power supply terminal.

First claim

What is claimed is:

1. A display drive circuit, comprising: a pixel circuit and a compensation circuit, wherein the pixel circuit comprises: a drive transistor, a light emitting device and a storage capacitor, two terminals of the storage capacitor are connected to a control electrode and a first electrode of the drive transistor, respectively, the first electrode of the drive transistor is connected to a first power supply terminal, a second electrode of the drive transistor is connected to a first electrode of the light emitting device, and the drive transistor is configured to provide a drive current to the light emitting device;
the pixel circuit further includes: a gating sub-circuit configured to control connection and disconnection between the control electrode of the drive transistor and a control terminal of the compensation circuit and control connection and disconnection between a second electrode of the light emitting device and a sensing terminal of the compensation circuit in response to a signal of a scanning line; and
the compensation circuit comprises:
a voltage generating sub-circuit configured to generate a sensing voltage positively correlated with the drive current according to the drive current flowing through the light emitting device and a target data voltage of a data receiving terminal; and
a voltage adjusting sub-circuit configured to adjust a voltage of the control terminal according to relationship of magnitude between the sensing voltage output by the voltage generating sub-circuit and a voltage of a second power supply terminal until the sensing voltage output by the voltage generating sub-circuit is equal to the voltage of the second power supply terminal,
wherein the voltage adjusting sub-circuit comprises: a comparison module, a first resistance module and a second resistance module,
the comparison module is connected to the voltage generating sub-circuit, the second power supply terminal and the second resistance module, the comparison module is configured to output a voltage to the second resistance module, and when the sensing voltage output by the voltage generating sub-circuit is greater than the voltage of the second power supply terminal, the output voltage is increased until the sensing voltage output by the voltage generating sub-circuit is equal to the voltage of the second power supply terminal; when the sensing voltage output by the voltage generating sub-circuit is less than the voltage of the second power supply terminal, the output voltage is decreased until the sensing voltage output by the voltage generating sub-circuit is equal to the voltage of the second power supply terminal; and
the first resistance module and the second resistance module are connected in series between the first power supply terminal and the second power supply terminal, a connecting node between the first resistance module and the second resistance module is the sensing terminal of the compensation circuit, the second resistance module has an adjustable resistance, and the resistance of the second resistance module is positively correlated with the output voltage of the comparison module.

2. The display drive circuit according to claim 1 , wherein the comparison module comprises an operational amplifier, a non-inverting input terminal of the operational amplifier is connected to the voltage generating sub-circuit, an inverting input terminal of the operational amplifier is connected to the second power supply terminal, and an output terminal of the operational amplifier is connected to the second resistance module.

3. The display drive circuit according to claim 1 , wherein the first resistance module comprises a first resistor, two terminals of the first resistor are connected to the first power supply terminal and the control terminal of the compensation circuit, respectively;
the second resistance module comprises: a second resistor, a third resistor and an adjustable resistance device;
a first terminal of the second resistor is connected to the control terminal of the compensation circuit, a second terminal of the second resistor is connected to a first electrode of the adjustable resistance device, a control electrode of the adjustable resistance device is connected to an output terminal of the comparison module, a second electrode of the adjustable resistance device is connected to the second power supply terminal, and a resistance between the first electrode and the second electrode of the adjustable resistance device is positively correlated with a voltage of the control electrode; and
two terminals of the third resistors are connected to the first power supply terminal and the second power supply terminal, respectively.

4. The display drive circuit according to claim 3 , wherein the adjustable resistance device comprises a triode, the control electrode of the adjustable resistance device is a base electrode of the triode, and one of the first electrode and the second electrode of the adjustable resistance device is an emitter electrode of the triode and the other one is a collector electrode of the triode.

5. The display drive circuit according to claim 1 , wherein the voltage generating sub-circuit comprises: a fourth resistor, and two terminals of the fourth resistor are connected to the sensing terminal of the compensation circuit and the data receiving terminal, respectively.

6. The display drive circuit according to claim 5 , wherein
the target data voltage P_Vdata satisfies: P_Vdata=Vss−I target ×r 4 ,
where Vss is the voltage of the second power supply terminal, I target is a target value of the drive current, and r 4 is a resistance value of the fourth resistor.

7. The display drive circuit according to claim 1 , wherein the gating sub-circuit comprises: a first gating transistor and a second gating transistor,
a control electrode of the first gating transistor is connected to the scanning line, a first electrode of the first gating transistor is connected to the control electrode of the drive transistor, and a second electrode of the first gating transistor is connected to the control terminal of the compensation circuit; and
a control electrode of the second gating transistor is connected to the scanning line, a first electrode of the second gating transistor is connected to the second electrode of the light emitting device, and a second electrode of the second gating transistor is connected to the sensing terminal of the compensation circuit.

8. The display drive circuit according to claim 1 , wherein the pixel circuit further comprises: a light emitting control module; and the light emitting control module is configured to control connection and disconnection between the second electrode of the light emitting device and the second power supply terminal in response to a signal of a light emitting control line.

9. The display drive circuit according to claim 8 , wherein the light emitting control module comprises: a light emitting control transistor, a control electrode of the light emitting control transistor is connected to the light emitting control line, a first electrode of the light emitting control transistor is connected to the second electrode of the light emitting device, and a second electrode of the light emitting control transistor is connected to the second power supply terminal.

10. A display device, comprising a display substrate, wherein the display substrate is provided thereon with a plurality of display drive circuits each being the display drive circuit according to claim 1 , the display substrate comprises pixels in a plurality of rows and a plurality of columns, each pixel is provided therein with the pixel circuit, and pixel circuits in a same column

Assignees

• Beijing Boe Display Tech Co
• Boe Technology Group Co Ltd

Inventors

• Xu Wenpeng
• Dong Dianzheng
• Zhang Qiang
• Wang Guangxing
• Huang Haiqin
• Lin Wan
• Wang Haixu
• Wang Leiyang

Classifications

• G09G3/3233 Primary

  with pixel circuitry controlling the current through the light-emitting element · CPC title

• G09G3/3291

  in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements · CPC title

• G09G2310/0291

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

• G09G2320/0233

  Improving the luminance or brightness uniformity across the screen · CPC title

• G09G3/3208 Primary

  organic, e.g. using organic light-emitting diodes [OLED] · CPC title