CN-122016068-A - Temperature sensing circuit and display device thereof

CN122016068ACN 122016068 ACN122016068 ACN 122016068ACN-122016068-A

Abstract

The invention discloses a temperature sensing circuit and a display device thereof. The temperature sensing circuit comprises a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a first capacitor and a second capacitor. The first capacitor is coupled between the control terminal of the first transistor and the first terminal of the second transistor. The third transistor has a first terminal coupled to the control terminal of the first transistor and a second terminal coupled to the second terminal of the first transistor. The fourth transistor has a first terminal coupled to the second terminal of the first transistor. The second capacitor is coupled between the control voltage and the control terminal of the first transistor. The fifth transistor has a first terminal coupled to the second terminal of the first transistor and a second terminal providing an output voltage.

Inventors

LIN ZHILONG
Wei Tingen
QIU YUZHANG
Qiu Zhongtian
GUO TINGWEI
DENG MINGYANG

Assignees

友达光电股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260320
Priority Date: 20251212

Claims (14)

1. A temperature sensing circuit, comprising: A first transistor having a first terminal for receiving a system high voltage, a control terminal, and a second terminal; a second transistor having a first end, a control end for receiving a first control voltage, and a second end for receiving a first signal voltage; A first capacitor coupled between the control terminal of the first transistor and the first terminal of the second transistor; a third transistor having a first end coupled to the control end of the first transistor, a control end receiving a second control voltage, and a second end coupled to the second end of the first transistor; A fourth transistor having a first end coupled to the second end of the first transistor, a control end receiving a third control voltage, and a second end receiving a system low voltage; A second capacitor coupled between a fourth control voltage and the control terminal of the first transistor, and A fifth transistor having a first terminal coupled to the second terminal of the first transistor, a control terminal for receiving a selection control voltage, and a second terminal for providing an output voltage.
2. The temperature sensing circuit of claim 1, wherein during a reset period, the second transistor, the third transistor, and the fourth transistor are turned on via the first control voltage, the second control voltage, and the third control voltage, In a compensation period, the second transistor and the third transistor are turned on via the first control voltage and the second control voltage, and During a sensing period, the second transistor, the third transistor and the fourth transistor are turned off by the first control voltage, the second control voltage and the third control voltage, and the first signal voltage is changed from a high voltage level to a low voltage level.
3. The temperature sensing circuit of claim 2, wherein a turn-on level of the fourth transistor is less than a turn-on level of the second transistor and the third transistor during the reset period.
4. The temperature sensing circuit of claim 1, wherein the first transistor, the second transistor, the third transistor, the fourth transistor, and the fifth transistor are each P-type transistors.
5. The temperature sensing circuit of claim 1, further comprising: A sixth transistor having a first end for receiving a second signal voltage, a control end for receiving the first control voltage, and a second end; A seventh transistor having a first end receiving a fourth control voltage, a control end receiving a fifth control voltage, and a second end coupled to the second end of the sixth transistor, and And a third capacitor coupled between the second end of the sixth transistor and the control end of the first transistor.
6. The temperature sensing circuit of claim 5, wherein during a reset period, the second transistor, the third transistor, the fourth transistor, and the sixth transistor are turned on via the first control voltage, the second control voltage, and the third control voltage, In a compensation period, the second transistor, the third transistor and the sixth transistor are turned on by the first control voltage and the second control voltage, In a coupling period, the fourth transistor and the seventh transistor are turned on via the third control voltage and the fifth control voltage, and In a sensing period, the second transistor, the third transistor, the sixth transistor and the seventh transistor are turned off by the first control voltage, the second control voltage and the fifth control voltage, and the first signal voltage is changed from a first high voltage level to a first low voltage level, and the second signal voltage is changed from a second low voltage level to a second high voltage level.
7. The temperature sensing circuit of claim 6, wherein a turn-on level of the fourth transistor is less than a turn-on level of the second transistor, the third transistor and the sixth transistor during the reset period.
8. The temperature sensing circuit of claim 5, wherein the second low voltage level is equal to the first high voltage level.
9. The temperature sensing circuit of claim 5, wherein the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, the sixth transistor, and the seventh transistor are each P-type transistors.
10. A display device, comprising: A plurality of pixel circuits; a plurality of temperature sensing circuits as recited in claim 1, each sensing one of the pixel circuits to provide one of a plurality of output voltages; an analog-to-digital converter circuit coupled to the temperature sensing circuits for providing a plurality of sensing output data based on the output voltages; a timing controller for receiving image data and coupled to the ADC circuit for receiving the sensing output data to provide a plurality of corrected data voltages based on the image data and the sensing output data, and And a source driver coupled to the timing controller and the pixel circuits for providing a plurality of pixel data voltages to the pixel circuits based on the corrected data voltages.
11. The display device of claim 10, further comprising a memory device storing a lookup table and coupled to the timing controller, wherein the timing controller performs a lookup table on the lookup table to output the corrected data voltages for the respective gray scales after temperature correction.
12. The display device of claim 10, further comprising a gate driver coupled to the pixel circuits for providing a plurality of gate signals to the pixel circuits.
13. The display device of claim 10, wherein the temperature sensing circuits and the pixel circuits are in one-to-one correspondence.
14. The display device of claim 10, wherein the temperature sensing circuits correspond to the pixel circuits in a one-to-many manner.

Description

Temperature sensing circuit and display device thereof Technical Field The present invention relates to a sensing circuit, and more particularly to a temperature sensing circuit and a display device thereof. Background With the development of display technology, flat panel display technology is gradually maturing. Advantages of flat panel display technology mainly include thinner design, space saving, lower power consumption, better image quality and wider viewing angle, so flat panel display is already the current main display mode. However, due to the physical reaction of the display element, the display brightness of the display element may change along with the temperature change, so when the ambient temperature changes, the display brightness of the display element needs to be compensated for the ambient temperature to offset the brightness drift caused by the temperature change, so as to adapt the display panel to different ambient temperatures. In order to compensate the temperature of the display panel, it is necessary to dispose a temperature sensor on the side of the display panel or to dispose a temperature sensing circuit directly on the display panel. If the temperature sensing circuit is formed by using the N-type transistor and the P-type transistor, the N-type transistor and the P-type transistor are utilized to perform charge-discharge and leakage operations, but the N-type transistor and the P-type transistor are utilized to be mixed, the complexity of the manufacturing process is increased, and the N-type transistor and the P-type transistor are disadvantageously integrated in the pixel circuit. Moreover, if the temperature sensing circuit only uses parasitic capacitance to store potential, the temperature sensing circuit is easily affected by an external load effect (loading effect) when the temperature sensing circuit is integrated in the pixel circuit. Disclosure of Invention The invention provides a temperature sensing circuit and a display device thereof, which can distinguish the temperature difference between 25 degrees and 85 degrees for every 10 degrees, and can compensate the threshold voltage variation of a driving transistor so as to output a sensing curve positively correlated with the temperature. The temperature sensing circuit comprises a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a first capacitor and a second capacitor. The first transistor has a first terminal for receiving a system high voltage, a control terminal, and a second terminal. The second transistor has a first terminal, a control terminal receiving a first control voltage, and a second terminal receiving a first signal voltage. The first capacitor is coupled between the control terminal of the first transistor and the first terminal of the second transistor. The third transistor has a first terminal coupled to the control terminal of the first transistor, a control terminal for receiving a second control voltage, and a second terminal coupled to the second terminal of the first transistor. The fourth transistor has a first terminal coupled to the second terminal of the first transistor, a control terminal receiving the third control voltage, and a second terminal receiving the system low voltage. The second capacitor is coupled between the fourth control voltage and the control terminal of the first transistor. The fifth transistor has a first terminal coupled to the second terminal of the first transistor, a control terminal receiving the selection control voltage, and a second terminal providing the output voltage. The display device of the present invention includes a plurality of pixel circuits, a plurality of temperature sensing circuits as described above, an analog-to-digital converter circuit, a timing controller, and a source driver. The temperature sensing circuit individually senses one of the pixel circuits to provide one of a plurality of output voltages. The analog-to-digital converter circuit is coupled to the temperature sensing circuits to provide a plurality of sensing output data based on the output voltages. The timing controller receives the image data and is coupled to the analog-to-digital converter circuit to receive the sensing output data to provide a plurality of corrected data voltages based on the image data and the sensing output data. The source driver is coupled to the timing controller and the pixel circuits for providing a plurality of pixel data voltages to the pixel circuits based on the corrected data voltages. Based on the above, in the temperature sensing circuit and the display device thereof according to the embodiments of the present invention, the gate voltage of the first transistor leaks electricity through the second transistor to the first capacitor, and then the gate voltage of the first transistor is reduced through the coupling effect of the first capacitor. Therefore, besides the temperature of 25-85 d