US-12626637-B2 - Pixel driving circuit comprising a voltage-dividing transistor and mobile terminal

US12626637B2US 12626637 B2US12626637 B2US 12626637B2US-12626637-B2

Abstract

A pixel driving circuit and a mobile terminal are provided. The pixel driving circuit includes a switch thin film transistor, a storage circuit, and a light driving circuit. The switch thin film transistor receives data signal applied on the data line in response to scan signal applied on the scan line. The storage circuit is charged by the data signal. The light driving circuit emits light in response to the data signal. The light driving circuit includes a driving unit, light-emitting unit, a supply voltage end, a ground end, and a voltage-dividing transistor that is coupled between the driving unit and the ground end.

Inventors

Daobing HU

Assignees

TCL CHINA STAR OPTOELECTRONICS TECHNOLOGY CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20210810
Priority Date: 20210802

Claims (16)

1 . A pixel driving circuit used in a display panel having a scan line and a data line, the pixel driving circuit comprising: a switch thin film transistor, configured to receive data signal applied on the data line in response to scan signal applied on the scan line; a storage capacitor, electrically connected to the switch thin film transistor and configured to be charged by the data signal; and a light driving circuit, configured to emit light in response to the data signal, the light driving circuit having a driving unit, light-emitting unit, a supply voltage end, a ground end, and a voltage-dividing transistor that is coupled between the driving unit and the ground end, wherein the driving unit consisting of a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), the voltage-dividing transistor is configured to reduce a variation in a magnitude of a source-drain current of the MOSFET due to changes in the data signal, wherein one end of the storage capacitor is electrically connected to a gate of the MOSFET and a source of the switch thin film transistor, and another end of the storage capacitor is directly electrically connected to the ground end, wherein connection of the driving unit and the voltage-dividing transistor results in adjustment of a source-drain voltage of the voltage-dividing transistor to cause the voltage-dividing transistor to operate in a linear region or a saturation region.
2 . The pixel driving circuit as claimed in claim 1 , wherein a resistance of the voltage-dividing transistor is proportional to levels of grayscales of the display panel.
3 . The pixel driving circuit as claimed in claim 2 , wherein the voltage-dividing transistor is a voltage-dividing thin film transistor having a gate and a drain coupled thereto, and a ratio of a channel width and a channel length is proportional to levels of grayscales of the display panel.
4 . The pixel driving circuit as claimed in claim 3 , wherein the switch thin film transistor and the voltage-dividing thin film transistor are Amorphous silicon thin film transistors or indium gallium zinc oxide thin film transistors.
5 . The pixel driving circuit as claimed in claim 1 , wherein the voltage-dividing transistor is realized by transistors connected in series or in parallel.
6 . The pixel driving circuit as claimed in claim 1 , wherein the MOSFET comprises a gate coupled to the switch thin film transistor, a drain coupled to the supply voltage end, and a source coupled to the ground end.
7 . The pixel driving circuit as claimed in claim 1 , wherein the light-emitting unit is coupled between the supply voltage end and the driving unit or between the driving unit and the ground end.
8 . The pixel driving circuit as claimed in claim 1 , wherein a ratio of a supply voltage fed to the pixel driving circuit and a sum of a first resistance of the voltage-dividing transistor and a second resistance of the light-emitting unit is between values of a minimum driving current and a maximum driving current of the light-emitting unit.
9 . The pixel driving circuit as claimed in claim 1 , wherein the voltage-dividing transistor is a light emitting diode.
10 . A mobile terminal comprising: a display panel, having a scan line and a data line; a gate driver, connected to the scan line; a source driver, connected to the data line; a pixel driving circuit, configured to drive the display panel, the pixel driving circuit comprising: a switch thin film transistor, configured to receive data signal applied on the data line in response to scan signal applied on the scan line; a storage capacitor, electrically connected to the switch thin film transistor and configured to be charged by the data signal; and a light driving circuit, configured to emit light in response to the data signal, the light driving circuit having a driving unit, light-emitting unit, a supply voltage end, a ground end, and a voltage-dividing transistor that is coupled between the driving unit and the ground end, wherein the driving unit consisting of a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), the voltage-dividing transistor is configured to reduce a variation in a magnitude of a source-drain current of the MOSFET due to changes in the data signal wherein one end of the storage capacitor is electrically connected to a gate of the MOSFET and a source of the switch thin film transistor, and another end of the storage capacitor is directly electrically connected to the ground end, wherein connection of the driving unit and the voltage-dividing transistor results in adjustment of a source-drain voltage of the voltage-dividing transistor to cause the voltage-dividing transistor operate in a linear region or a saturation region.
11 . The mobile terminal as claimed in claim 10 , wherein a resistance of the voltage-dividing transistor is proportional to levels of grayscales of the display panel.
12 . The pixel driving circuit as claimed in claim 11 , wherein the voltage-dividing transistor is a voltage-dividing thin film transistor having a gate and a drain coupled thereto, and a ratio of a channel width and a channel length is proportional to levels of grayscales of the display panel.
13 . The pixel driving circuit as claimed in claim 12 , wherein the switch thin film transistor and the voltage-dividing thin film transistor are Amorphous silicon thin film transistors or indium gallium zinc oxide thin film transistors.
14 . The pixel driving circuit as claimed in claim 10 , wherein the MOSFET comprises a gate coupled to the switch thin film transistor, a drain coupled to the supply voltage end, and a source coupled to the ground end.
15 . The pixel driving circuit as claimed in claim 10 , wherein the light-emitting unit is coupled between the supply voltage end and the driving unit or between the driving unit and the ground end.
16 . The pixel driving circuit as claimed in claim 10 , wherein a ratio of a supply voltage fed to the pixel driving circuit and a sum of a first resistance of the voltage-dividing transistor and a second resistance of the light-emitting unit is between values of a minimum driving current and a maximum driving current of the light-emitting unit.

Description

CROSS REFERENCE This application is a US national phase application based upon an International Application No. PCT/CN2021/111781, filed on Aug. 10, 2021, which claims the priority of Chinese Patent Application No. 202110882071.9, entitled “Pixel Driving Circuit and Mobile Terminal”, filed on Aug. 2, 2021, the disclosure of which is incorporated herein by reference in its entirety. FIELD OF THE INVENTION The present disclosure relates to a field of a display panel, more particularly, to a pixel driving circuit and a mobile terminal. BACKGROUND In contrast to conventional backlight, using Mini-LEDs as backlight sources shows better contrast. Currently, two transistors and one capacitor (2T1C) drive architecture is mostly used in the current Mini-LED display panel, and a light-emitting diode (LED) is a current drive device. Under this technology, the stability requirements of thin film transistor (TFT) devices are very high, especially the stability and uniformity of driving thin film transistors used to drive light emitting diodes will directly affect the brightness of light emitting diodes. Conventionally, a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), hereinafter referred to as a MOS transistor, is used as a driving transistor of a pixel driving circuit. However, since MOSFET is mainly operated in a saturation region, a few change in data voltage applied on a gate of the MOSFET induces a great change in current flowing through a drain of the MOSFET. Therefore, a pixel driving circuit using the MOSFETs may not output exact current corresponding to high grey scales. SUMMARY Technical Problem The present disclosure proposes a pixel driving circuit and a mobile terminal, effectively solving the problem that the pixel driving circuit using the MOSFETs may not output exact current corresponding to high grey scales. Technical Solution According to a first aspect of the present disclosure, a pixel driving circuit used in a display panel having a scan line and a data line is provided. The pixel driving circuit includes a switch thin film transistor, a storage circuit, and a light driving circuit. The switch thin film transistor is configured to receive data signal applied on the data line in response to scan signal applied on the scan line. The storage circuit, electrically connected to the switch transistor, is configured to be charged by the data signal. The light driving circuit is configured to emit light in response to the data signal. The light driving circuit has a driving unit, light-emitting unit, a supply voltage end, a ground end, and a voltage-dividing transistor that is coupled between the driving unit and the ground end. Preferably, a resistance of the voltage-dividing transistor is proportional to levels of grayscales of the display panel. Preferably, the voltage-dividing transistor is a voltage-dividing thin film transistor having a gate and a drain coupled thereto, and a ratio of a channel and a channel length is proportional to levels of grayscales of the display panel. Preferably, the pixel driving circuit further comprises a control module, configured to adjust supply voltage fed into the pixel driving circuit to make the voltage-dividing thin film transistor operate in a linear region or a saturation region. Preferably, the switch thin film transistor and the voltage-dividing thin film transistor are Amorphous silicon thin film transistors or indium gallium zinc oxide thin film transistors. Preferably, the voltage-dividing transistor is realized by transistors connected in series or in parallel. Preferably, the storage circuit comprises a capacitor connected between the light driving circuit and the ground end. Preferably, the driving unit is a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) that comprises a gate coupled to the switch thin film transistor, a drain coupled to the supply voltage end, and a source coupled to the ground end. Preferably, the light-emitting unit is coupled between the supply voltage end and the driving unit or between the driving unit and the ground end. Preferably, a ratio of a supply voltage fed to the pixel driving circuit and a sum of a first resistance of the voltage-dividing transistor and a second resistance of the light-emitting unit is between values of a minimum driving current and a maximum driving current of the light-emitting unit. Preferably, the voltage-dividing transistor is a light emitting diode. According to a second aspect of the present disclosure, a mobile terminal includes a pixel driving circuit, a gate driver, and a source driver. The pixel driving circuit includes a switch thin film transistor, a storage circuit, and a light driving circuit. The switch thin film transistor is configured to receive data signal applied on the data line in response to scan signal applied on the scan line. The storage circuit, electrically connected to the switch transistor, is configured to be charged by the data signal. The light driv