# US 12,217,693 B2 · Pixel driving circuit and display panel > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,217,693 B2 - Document ID: US12217693B2 - Status: Granted - Kind: B2 - Application number: 17/623,433 - Filed: 2021-12-24 - Published: 2024-02-08 - Granted: 2025-02-04 - Earliest claimed: 2021-12-16 - Assignees: Tcl China Star Optoelectronics Technology Co., Ltd. - Applicants: Tcl China Star Optoelectronics Technology Co., Ltd. - Inventors: Xiaolong Chen - Web page: https://patentgrep.com/patent/US12217693B2 ## CPC - G09G 3/3258: with pixel circuitry controlling the voltage across the light-emitting element - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 3/3266: Details of drivers for scan electrodes - G09G 3/3275: Details of drivers for data 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 2300/043: Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver - 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 A pixel driving circuit and a display panel are provided by the present application. An electrical potential of a control terminal of a driving module can be kept stable through a detection module by connecting the detection module with a control terminal of the driving module when detecting a threshold voltage of the driving module. In this way, an obtained threshold voltage of the driving module is accurate, to make the threshold voltage of the driving module can be accurately compensated, and a display uniformity and a stability of the display panel are improved. ## Claims ### Claim 1 A pixel driving circuit, comprising: a driving module, a data writing module, an initialization module, a first capacitor, a detection module and a compensation module; wherein a control terminal of the driving module is connected to a first node, and wherein an input terminal of the driving module is connected to a constant voltage terminal of high electrical potential, and wherein an output terminal is connected to a second node, the driving module comprises a first thin film transistor; wherein a control terminal of the data writing module is connected to a first scan signal line, and wherein an input terminal of the data writing module is connected to a data signal line, and wherein an output terminal of the data writing module is connected to the first node; wherein a control terminal of the initialization module is connected to a second scan signal line, and wherein an input terminal of the initialization module is connected to a reset signal line, and wherein an output terminal of the initialization module is connected to the second node; wherein a first terminal of the first capacitor is connected to the first node, and wherein a second terminal of the first capacitor is connected to the second node; and wherein the detection module comprises an operational amplifier, a first switch, a second switch, and a second capacitor, the detection module is connected to the first node and is configured to control an electrical potential of the first node to obtain a threshold voltage of the driving module, wherein a first input terminal of the operational amplifier is connected to the first node through the first switch, and wherein a second input terminal of the operational amplifier is connected to a reference signal line, wherein the first switch is coupled between the first node and the first input terminal of the operational amplifier; and wherein the second switch and the second capacitor are coupled between the first input terminal of the operational amplifier and an output terminal of the operational amplifier; wherein the compensation module comprises an analog-to-digital converter, a control device, a digital-to-analog converter, and a third switch, an input terminal of the analog-to-digital converter is connected to the output terminal of the operational amplifier, the analog-to-digital converter is connected to the digital-to-analog converter through the control device, the control device is configured to superimpose a compensation voltage to a data signal from the data signal line, an output terminal of the digital-to-analog converter is connected to an input terminal of the data writing module through the third switch, wherein the third switch is configured to be turned on when the first switch and the second switch are turned off, such that an electrical potential difference between the first node and the second node is a sum of an electrical potential of the data signal and the threshold voltage, and the first thin film transistor is turned on, wherein the third switch is configured to be turned on when the first switch and the second switch are turned off, such that a current flowing through the first thin film transistor is not a function of the threshold voltage and is a function of only the data signal. ### Claim 2 (depends on 1) The pixel driving circuit according to claim 1, wherein a gate electrode of the first thin film transistor is connected to the first node, and wherein a source electrode of the first thin film transistor is connected to the second node, and wherein a drain electrode of the first thin film transistor is connected to the constant voltage terminal of high electrical potential. ### Claim 3 (depends on 1) The pixel driving circuit according to claim 1, wherein the data writing module comprises a second thin film transistor, and wherein a gate electrode of the second thin film transistor is connected to the first scan signal line, and wherein a source electrode of the second thin film transistor is connected to the data signal line, and wherein a drain electrode of the second thin film transistor is connected to the first node. ### Claim 4 (depends on 1) The pixel drive circuit according to claim 1, characterized in that the initialization module comprises a third thin film transistor, wherein a gate electrode of the third thin film transistor is connected to the second scan signal line, and wherein a source electrode of the third thin film transistor is connected to the reset signal line, and wherein a drain electrode of the third thin film transistor is connected to the second node. ### Claim 5 (depends on 1) The pixel driving circuit according to claim 1, further comprising a threshold voltage detection stage, wherein the threshold voltage detection stage comprises a first period, a second period, and a third period; wherein in the first period, the first switch and the second switch are turned on, the third switch is turned off, the data writing module is turned off, and the initialization module and the driving module are turned on; wherein in the second period, the first switch and the second switch are turned on, the third switch is turned off, the data writing module and the initialization module are turned off, and the driving module changes from turned on to turned off; and wherein in the third period, the first switch is turned on, the second switch and the third switch are turned off, the data writing module and the driving module are turned off, and the initialization module is turned on. ### Claim 6 (depends on 5) The pixel driving circuit according to claim 5, wherein in the first period, an electrical potential of the first node is an electrical potential of the constant voltage terminal of high electrical potential VDD, and an electrical potential of the second node is an electrical potential Vini of the reference signal line; wherein in the second period, the electrical potential of the first node is the electrical potential Vref of the reference signal line, and the electrical potential of the second node is a difference between the electrical potential Vref of the reference signal line and a threshold voltage Vth of the driving module; wherein in the third period, the electrical potential of the first node is the electrical potential Vref of the reference signal line, and the electrical potential of the second node is the electrical potential Vini of the reference signal line. ### Claim 7 (depends on 1) The pixel driving circuit according to claim 1, further comprising a display compensation stage, wherein the display compensation stage comprises a fourth period and a fifth period; wherein in the fourth period, the first switch and the second switch are turned off, the third switch is turned on, the data writing module and the initialization module are turned on, and the driving module changes from turned off to turned on; wherein in the fifth period, the first switch and the second switch are turned off, the third switch is turned on, the driving module is turned on, and the data writing module and the initialization module are turned off. ### Claim 8 (depends on 7) The pixel driving circuit according to claim 7, wherein in the fourth period and the fifth period, the electrical potential of the first node is a sum of an electrical potential Vdata of the data signal line, the threshold voltage Vth of the driving module, and the electrical potential Vini of the reset signal line, and wherein the electrical potential of the second node is the electrical potential Vini of the reference signal line. ### Claim 9 A display panel, further comprising an organic light emitting diode and a pixel driving circuit, the pixel driving circuit comprising: a driving module, a data writing module, an initialization module, a first capacitor, a detection module and a compensation module; wherein a control terminal of the driving module is connected to a first node, and wherein an input terminal of the driving module is connected to a constant voltage terminal of high electrical potential, and wherein an output terminal is connected to a second node, the driving module comprises a first thin film transistor; wherein a control terminal of the data writing module is connected to a first scan signal line, and wherein an input terminal of the data writing module is connected to a data signal line, and wherein an output terminal of the data writing module is connected to the first node; wherein a control terminal of the initialization module is connected to a second scan signal line, and wherein an input terminal of the initialization module is connected to a reset signal line, and wherein an output terminal of the initialization module is connected to the second node; wherein a first terminal of the first capacitor is connected to the first node, and wherein a second terminal of the first capacitor is connected to the second node; and wherein the detection module comprises an operational amplifier, a first switch, a second switch, and a second capacitor, the detection module is connected to the first node and is configured to control an electrical potential of the first node to obtain a threshold voltage of the driving module, wherein a first input terminal of the operational amplifier is connected to the first node through the first switch, and wherein a second input terminal of the operational amplifier is connected to a reference signal line, wherein the first switch is coupled between the first node and the first input terminal of the operational amplifier; and wherein the second switch and the second capacitor are coupled between the first input terminal of the operational amplifier and an output terminal of the operational amplifier; wherein the compensation module comprises an analog-to-digital converter, a control device, a digital-to-analog converter, and a third switch, an input terminal of the analog-to-digital converter is connected to the output terminal of the operational amplifier, the analog-to-digital converter is connected to the digital-to-analog converter through the control device, the control device is configured to superimpose a compensation voltage to a data signal from the data signal line, an output terminal of the digital-to-analog converter is connected to an input terminal of the data writing module through the third switch, wherein the third switch is configured to be turned on when the first switch and the second switch are turned off, such that an electrical potential difference between the first node and the second node is a sum of an electrical potential of the data signal and the threshold voltage, and the first thin film transistor is turned on, wherein the third switch is configured to be turned on when the first switch and the second switch are turned off, such that a current flowing through the first thin film transistor is not a function of the threshold voltage and is a function of only the data signal; wherein the organic light emitting diode is coupled between the output terminal of the driving module of the pixel driving circuit and the constant voltage terminal of low electrical potential, to make the pixel driving circuit configured to drive the organic light emitting diode to emit light. ### Claim 10 (depends on 9) The display panel according to claim 9, wherein a gate electrode of the first thin film transistor is connected to the first node, and wherein a source electrode of the first thin film transistor is connected to the second node, and wherein a drain electrode of the first thin film transistor is connected to the constant voltage terminal of high electrical potential. ### Claim 11 (depends on 9) The display panel according to claim 9, wherein the data writing module comprises a second thin film transistor, and wherein a gate electrode of the second thin film transistor is connected to the first scan signal line, and wherein a source electrode of the second thin film transistor is connected to the data signal line, and wherein a drain electrode of the second thin film transistor is connected to the first node. ### Claim 12 (depends on 9) The display panel according to claim 9, wherein the pixel driving circuit further comprises a threshold voltage detection stage, wherein the threshold voltage detection stage comprises a first period, a second period, and a third period; wherein in the first period, the first switch and the second switch are turned on, the third switch is turned off, the data writing module is turned off, and the initialization module and the driving module are turned on; wherein in the second period, the first switch and the second switch are turned on, the third switch is turned off, the data writing module and the initialization module are turned off, and the driving module changes from turned on to turned off; and wherein in the third period, the first switch is turned on, the second switch and the third switch are turned off, the data writing module and the driving module are turned off, and the initialization module is turned on. ### Claim 13 (depends on 12) The display panel according to claim 12, wherein in the first period, an electrical potential of the first node is an electrical potential of the constant voltage terminal of high electrical potential VDD, and an electrical potential of the second node is an electrical potential Vini of the reference signal line; wherein in the second period, the electrical potential of the first node is the electrical potential Vref of the reference signal line, and the electrical potential of the second node is a difference between the electrical potential Vref of the reference signal line and a threshold voltage Vth of the driving module; wherein in the third period, the electrical potential of the first node is the electrical potential Vref of the reference signal line, and the electrical potential of the second node is the electrical potential Vini of the reference signal line. ### Claim 14 (depends on 9) The display panel according to claim 9, wherein the pixel driving circuit further comprises a display compensation stage, wherein the display compensation stage comprises a fourth period and a fifth period; wherein in the fourth period, the first switch and the second switch are turned off, the third switch is turned on, the data writing module and the initialization module are turned on, and the driving module changes from turned off to turned on; wherein in the fifth period, the first switch and the second switch are turned off, the third switch is turned on, the driving module is turned on, and the data writing module and the initialization module are turned off. ### Claim 15 (depends on 14) The display panel according to claim 14, wherein in the fourth period and the fifth period, the electrical potential of the first node is a sum of an electrical potential Vdata of the data signal line, the threshold voltage Vth of the driving module, and the electrical potential Vini of the reset signal line, and wherein the electrical potential of the second node is the electrical potential Vini of the reference signal line.