# US 12,217,669 B2 · Pixel driving circuit, driving method thereof, and display device

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- Number: US 12,217,669 B2
- Document ID: US12217669B2
- Status: Granted
- Kind: B2
- Application number: 16/975,121
- Filed: 2020-06-15
- Published: 2023-04-20
- Granted: 2025-02-04
- Earliest claimed: 2020-04-29
- Assignees: Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
- Applicants: Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
- Inventors: Shiqiang Huang; Qi Cao; Zhengyue Chen; Xing Ming
- Web page: https://patentgrep.com/patent/US12217669B2

## CPC

- G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element
- G09G 3/3266: Details of drivers for scan electrodes
- G09G 3/3291: in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements
- G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing
- G09G 2300/0861: with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
- G09G 2310/0251: Precharge or discharge of pixel before applying new pixel voltage
- G09G 2310/0262: The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
- G09G 2320/0233: Improving the luminance or brightness uniformity across the screen
- G09G 2320/045: Compensation of drifts in the characteristics of light emitting or modulating elements
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)

## Abstract

The present disclosure provides a pixel driving circuit, a driving method thereof, and a display device. The pixel driving circuit includes a compensation unit, the compensation unit and a driving unit are coupled to a second node, and the compensation unit is connected to a first scanning signal; a light-emitting control unit is configured to receive a light-emitting signal, and the light-emitting control unit, the driving unit, and the compensation unit are coupled to a third node.

## Claims

### Claim 1

A pixel driving method based on a pixel driving circuit, wherein the pixel driving method comprises:
in a reset phase, writing a data voltage to a first node in response to control of a first scan signal by a data writing unit, and pulling down a voltage of a second node by a compensation unit and a light-emitting control unit;
in a compensation phase, charging the voltage of the second node to a first compensation voltage in response to the control of the first scan signal by both the data writing unit and the compensation unit;
wherein V1=Vdata+Vth, V1 represents the first compensation voltage, Vdata represents the data voltage, and Vth represents a threshold voltage of a driving transistor; and
in a light-emitting phase, inputting a first power supply voltage to the first node in response to control of a second scan signal by a first control unit;
wherein a driving unit outputs a driving current to a light-emitting device through the light-emitting control unit in response to control of the voltage of the second node to drive the light-emitting device to emit light; and
wherein the pixel driving circuit comprises:
the data writing unit connected to the data voltage and the first scan signal and configured to write the data voltage to the first node in the reset phase;
the first control unit connected to the first power supply voltage and the second scan signal, coupled to the first node with the driving unit and the data writing unit respectively, and configured to write the first power supply voltage to the first node during the light-emitting phase;
the driving unit connected to the first power supply voltage and configured to provide the driving current;
the compensation unit coupled to the second node with the driving unit, and connected to the first scan signal, wherein the data writing unit and the compensation unit are configured to charge the second node to the first compensation voltage during the compensation phase;
the light-emitting control unit configured to receive a light-emitting signal, coupled to a third node with the driving unit and the compensation unit, and configured to reset the light-emitting device and to control the driving current to transmit to the light-emitting device during the light-emitting phase; and
the light-emitting device, wherein a first electrode of the light-emitting device is connected to the light-emitting control unit, and a second electrode of the light-emitting device is configured to receive a second power supply voltage.

### Claim 2 (depends on 1)

The pixel driving method as claimed in claim 1, wherein the first control unit comprises a fourth transistor, a gate of the fourth transistor is connected to the second scan signal, a drain of the fourth transistor is connected to the first node, and a source of the fourth transistor is connected to the first power supply voltage.

### Claim 3 (depends on 2)

The pixel driving method as claimed in claim 2, wherein the driving unit comprises:
the driving transistor, wherein a gate of the driving transistor is connected to the second node, and a source of the driving transistor is respectively connected to the first node and the drain of the fourth transistor; and
a first capacitor, wherein one terminal of the first capacitor is connected to the first power supply voltage, and another terminal of the first capacitor is connected to the second node.

### Claim 4 (depends on 3)

The pixel driving method as claimed in claim 3, wherein the compensation unit comprises a third transistor, a gate of the third transistor is configured to receive the first scan signal, a source of the third transistor and a gate of the driving transistor are connected to another terminal of the first capacitor, and a drain of the third transistor is connected to the third node.