# US 10,482,815 B2 · Pixel driving circuit and display panel

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- Number: US 10,482,815 B2
- Document ID: US10482815B2
- Status: Granted
- Kind: B2
- Application number: 15/744,082
- Filed: 2017-11-30
- Published: 2018-12-27
- Granted: 2019-11-19
- Earliest claimed: 2017-04-28
- Assignees: Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
- Applicants: Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
- Inventors: Xiaolong Chen; Yi-Chien Wen; Ming-Jong Jou
- Web page: https://patentgrep.com/patent/US10482815B2

## CPC

- G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element
- G09G 2230/00: Details of flat display driving waveforms
- G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing
- G09G 2300/0852: being a dynamic memory with more than one capacitor
- G09G 2310/0216: Interleaved control phases for different scan lines in the same sub-field, e.g. initialization, addressing and sustaining in plasma displays that are not simultaneous for all scan lines
- G09G 2310/0251: Precharge or discharge of pixel before applying new pixel voltage
- G09G 2320/0233: Improving the luminance or brightness uniformity across the screen
- 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 application provides a pixel driving circuit, which comprises a driving transistor which comprises a gate terminal, a source terminal, and a drain terminal. The first switch is connected between the gate terminal and the drain terminal. The gate terminal is connected with the reset-voltage-signal terminal via the second switch. The source terminal is respectively connected with the driving-voltage-signal terminal and the data-voltage-signal terminal via the third switch and the fourth switch. The first capacitor is connected between the gate terminal and the charge-voltage terminal. The charge-voltage terminal is connected with a control terminal of the first switch. The second capacitor is connected between the gate terminal and the driving-voltage-signal terminal. The present application further provides a display panel.

## Claims

### Claim 1

A pixel driving circuit, comprising a driving transistor, a first switch, a second switch, a third switch, a fourth switch, a first capacitor, a second capacitor, a charge-voltage terminal, a reset-voltage-signal terminal, a data-voltage-signal terminal, and a driving-voltage-signal terminal; wherein the driving transistor comprises a gate terminal, a source terminal, and a drain terminal;
the first switch is disposed between the gate terminal and the drain terminal, the gate terminal is connected with the reset-voltage-signal terminal via the second switch; the source terminal is respectively connected with the driving-voltage-signal terminal and the data-voltage-signal terminal via the third switch and the fourth switch;
the first capacitor is connected between the gate terminal and the charge-voltage terminal; the charge-voltage terminal is connected with a control terminal of the first switch, the second capacitor is connected between the gate terminal and the driving-voltage-signal terminal;
the pixel driving circuit further comprising:
a first control-signal terminal, wherein the first control-signal terminal is connected with the charge-voltage terminal, the control terminal of the first switch, a control terminal of the third switch, and a control terminal of the fourth switch, so as to control on/off of the first switch, the third switch, and the fourth switch;
a second control-signal terminal, wherein the second control-signal terminal is connected with a control terminal of the second switch, so as to control on/off of the second switch;
a fifth switch, a light-emitting diode and a negative voltage-signal terminal; wherein the light-emitting diode comprises a positive terminal and a negative terminal; the fifth switch is connected between the drain terminal and the positive terminal, so as to control on/off of the driving transistor and the light-emitting diode, and the negative terminal is connected with the negative voltage-signal terminal;
a third control-signal terminal, wherein the third control-signal terminal is connected with a control terminal of the fifth switch, so as to control on/off of the fifth switch;
wherein when the first control-signal terminal and the third control-signal terminal are loaded with a high-level signal, and the second control-signal terminal is loaded with a low-level signal, the potential of the charge-voltage terminal is at a high level, the second switch and the third switch are turned on, and the first switch, the fourth switch, and the fifth switch are turned off; and the gate terminal is connected with the reset-voltage-signal terminal via the second switch, the source terminal is connected with the driving-voltage-signal terminal via the third switch, so as to reset a potential of the gate terminal and a potential of the source terminal.

### Claim 2 (depends on 1)

The pixel driving circuit according to claim 1, wherein when the first control-signal terminal is loaded with a low-level signal, and the second control-signal terminal and the third control-signal terminal are loaded with a high-level signal, the potential of the charge-voltage terminal is at a low level, the first switch and the fourth switch are turned on, and the second switch, the third switch, and the fifth switch are turned off; and the source terminal is connected with the data-voltage-signal terminal via the fourth switch, so that the gate terminal is charged by the data-voltage-signal terminal via the fourth switch, the driving transistor, and the first switch until a potential difference between the source terminal and the gate terminal is a threshold voltage of the driving transistor.

### Claim 3 (depends on 2)

The pixel driving circuit according to claim 2, wherein when the first control-signal terminal and the second control-signal terminal are loaded with a high-level signal, and the third control-signal terminal is loaded with a low-level signal, the third switch and the fifth switch are turned on, and the second switch, the first switch, and the fourth switch are turned off; the source terminal is connected with the driving-voltage-signal terminal via the third switch, the potential of the charge-voltage terminal is at a high level and the potential of the gate terminal is changed, so that a driving current of the driving transistor is dependent of the threshold voltage; the third switch, the driving transistor, and the fifth switch are turned on, to make the driving-voltage-signal terminal and the negative voltage-signal terminal are conducted to drive the light-emitting diode to light.

### Claim 4 (depends on 3)

The pixel driving circuit according to claim 3, wherein a capacitance of the second capacitor is larger than a capacitance of the first capacitor.