CN116798345B - Pixel driving circuit, driving method and display device - Google Patents
Pixel driving circuit, driving method and display device Download PDFInfo
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- CN116798345B CN116798345B CN202310806172.7A CN202310806172A CN116798345B CN 116798345 B CN116798345 B CN 116798345B CN 202310806172 A CN202310806172 A CN 202310806172A CN 116798345 B CN116798345 B CN 116798345B
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Abstract
The invention discloses a pixel driving circuit, a driving method and a display device. A data write circuit that writes a voltage value at a data signal terminal to a first node; a control circuit for constant current leakage and gradually reducing the voltage value at the first node; a voltage control circuit that writes the voltage value at the first power supply output terminal to the second node when the voltage value at the first node decreases to the voltage value at the first power supply output terminal; when the voltage value of the second node is the voltage value at the output end of the first power supply, writing the voltage value at the negative end of the power supply into a switching circuit of the first node; and when the voltage value at the first node is lower than the voltage value at the first power supply output end, controlling the light-emitting circuit which does not work. The scheme provided by the invention can realize the length of the driving time according to the voltage, thereby realizing different gray scales.
Description
Technical Field
The present invention relates to the field of liquid crystal panels, and in particular, to a pixel driving circuit, a driving method, and a display device.
Background
Micro-LED display is considered as the next generation display technology following LCD, OLED, which has self-luminescence characteristics, does not require a backlight, is easier to debug in color than OLED, has higher resolution (1500 ppi), faster response speed (ns level), longer lifetime, and higher brightness.
At present, as shown in fig. 1, a pixel driving method adopted by a Micro-LED changes the change of a driving current flowing through an OLED of a light emitting device mainly through the change of a voltage Vdata at a data signal end, so as to further realize the change of the gray level of a pixel. And the magnitude of the driving current flowing through the light emitting device OLED affects the luminous efficiency and color coordinates of the pixel. For example, referring to fig. 2, when the driving currents of the OLEDs are different values, the corresponding luminous efficiencies and color coordinates are different. Therefore, the pixel driving method of the related art affects the luminous efficiency and color coordinates of the pixel.
Disclosure of Invention
In order to solve the technical problems of different driving currents, different luminous efficiencies and different color coordinates of Micro-LEDs in the driving aspect, the embodiment of the invention provides a pixel driving circuit, a driving method and a display device.
The technical scheme of the embodiment of the invention is realized as follows:
An embodiment of the present invention provides a pixel driving circuit, including: the data writing circuit is coupled with the first scanning signal end, the data signal end and the first node; the data writing circuit is configured to write a voltage value at the data signal terminal to the first node under control of a first scan signal received at the first scan signal terminal; the control circuit is coupled with the first node, the second scanning signal end and the power supply negative end; the control circuit is configured to control constant current leakage under the control of a second scanning signal received at the second scanning signal end, and gradually reduce the voltage value at the first node; the voltage control circuit is coupled with the first node, the third scanning signal end, the first power supply output end, the second node and the power supply negative end; the voltage control circuit is configured to write the voltage at the power supply negative terminal to the second node under control of a third scan signal received at the third scan signal terminal; and writing the voltage value at the first power supply output to the second node when the voltage value at the first node decreases to the voltage value at the first power supply output; the switch circuit is coupled with the first node, the second node and the power supply negative terminal; the switching circuit is configured to write the voltage value at the negative supply terminal to the first node when the voltage value of the second node is the voltage value at the first power supply output terminal; the light-emitting circuit is coupled with the first node, the first power supply output end and the second power supply output end; the light-emitting circuit is configured to drive the light-emitting device to work when the voltage value at the first node is higher than or equal to the voltage value at the first power supply output end; and controlling the light emitting device to be not operated when the voltage value at the first node is lower than the voltage value at the first power output terminal.
In one embodiment, the data write circuit includes: the grid electrode of the first active element is coupled with the first scanning signal end, the source electrode of the first active element is coupled with the first node, and the drain electrode of the first active element is coupled with the data signal end.
In one embodiment, the control circuit includes: the grid electrode of the second active element is coupled with the second scanning signal end, the source electrode of the second active element is coupled with the power supply negative end, and the drain electrode of the second active element is coupled with the first node and one end of the first capacitor; the other end of the first capacitor is coupled with the power supply negative terminal.
In one embodiment, the voltage control circuit includes: the grid electrode of the third active element is coupled with the first node, the source electrode of the third active element is coupled with the second node and the drain electrode of the fourth active element, and the drain electrode of the third active element is coupled with the first power supply output end; the grid electrode of the fourth active element is coupled with the third scanning signal end, and the source electrode of the fourth active element is coupled with the power supply negative end.
In one embodiment, the switching circuit includes: and a fifth active element, a gate of the fifth active element being coupled to the second node, a source of the fifth active element being coupled to the negative supply terminal, and a drain of the fifth active element being coupled to the first node.
In one embodiment, the light emitting circuit includes: the grid electrode of the sixth active element is coupled with the first node, the source electrode of the sixth active element is coupled with the anode of the light emitting device, the drain electrode of the sixth active element is coupled with the first power output end, and the cathode of the light emitting device is coupled with the second power output end.
In an embodiment, the voltage value at the data signal terminal is greater than the voltage value at the first power supply output terminal, which is greater than the voltage value of the supply negative terminal.
In one embodiment, the third active device is a P-channel mosfet.
The embodiment of the invention also provides a driving method of the pixel driving circuit according to any one of the above, which comprises the following steps: the data writing circuit writes a voltage value at the data signal end into the first node under the control of a first scanning signal received at the first scanning signal end; the control circuit is controlled by a second scanning signal received at the second scanning signal end to perform constant current leakage, and the voltage value at the first node is gradually reduced; the voltage control circuit writes the voltage at the power supply negative terminal into the second node under the control of a third scanning signal received at the third scanning signal terminal, and writes the voltage value at the first power supply output terminal into the second node when the voltage value at the first node is reduced to the voltage value at the first power supply output terminal; the switching circuit writes the voltage value at the power supply negative terminal into the first node when the voltage value of the second node is the voltage value at the first power supply output terminal; when the voltage value of the light-emitting circuit at the first node is higher than or equal to the voltage value at the output end of the first power supply, driving the light-emitting device to work; and controlling the light emitting device to be not operated when the voltage value at the first node is lower than the voltage value at the first power output terminal.
The embodiment of the invention also provides a display device which comprises the pixel driving circuit and a power supply module for supplying power to the pixel driving circuit.
The pixel driving circuit comprises a data writing circuit, a first scanning signal end, a data signal end and a first node, wherein the data writing circuit is connected with the first scanning signal end, the data signal end and the first node; the data writing circuit is configured to write a voltage value at the data signal terminal to the first node under control of a first scan signal received at the first scan signal terminal; the control circuit is coupled with the first node, the second scanning signal end and the power supply negative end; the control circuit is configured to control constant current leakage under the control of a second scanning signal received at the second scanning signal end, and gradually reduce the voltage value at the first node; the voltage control circuit is coupled with the first node, the third scanning signal end, the first power supply output end, the second node and the power supply negative end; the voltage control circuit is configured to write the voltage at the power supply negative terminal to the second node under control of a third scan signal received at the third scan signal terminal; and writing the voltage value at the first power supply output to the second node when the voltage value at the first node decreases to the voltage value at the first power supply output; the switch circuit is coupled with the first node, the second node and the power supply negative terminal; the switching circuit is configured to write the voltage value at the negative supply terminal to the first node when the voltage value of the second node is the voltage value at the first power supply output terminal; the light-emitting circuit is coupled with the first node, the first power supply output end and the second power supply output end; the light-emitting circuit is configured to drive the light-emitting device to work when the voltage value at the first node is higher than or equal to the voltage value at the first power supply output end; and controlling the light emitting device to be not operated when the voltage value at the first node is lower than the voltage value at the first power output terminal. The scheme provided by the application can change the time of constant current leakage of the control circuit by controlling the voltage value at the data signal end and/or the second scanning signal end, thereby realizing the voltage value change at the first node and realizing different gray scales of pixels. Since the driving current flowing through the light emitting device is constant in the present application, the change of the gray scale of the pixel is realized by the length of the display time, not by the magnitude of the driving current, so that the problems of different luminous efficiencies and different color coordinates are not generated in the present application.
Drawings
FIG. 1 is a schematic diagram of a prior art pixel driving circuit;
FIG. 2 is a diagram showing the variation of different driving currents, luminous efficiency and color coordinates in the prior art;
FIG. 3 is a schematic diagram of a pixel driving circuit according to an embodiment of the invention;
FIG. 4 is a schematic diagram showing a driving circuit according to an embodiment of the invention;
FIG. 5 is a schematic diagram of a driving timing diagram according to an embodiment of the present invention;
fig. 6 is a flow chart of a driving method according to an embodiment of the invention.
The reference numerals are explained as follows:
101. A data writing circuit; 102. a control circuit; 103. a voltage control circuit; 104. a switching circuit; 105. a light emitting circuit; t1, a first active element; t2, a second active element; t3, a third active element; t4, a fourth active element; t5, a fifth active element; t6, a sixth active element; C. a first capacitor; micro-LED, light emitting device; n1, a first node; n2, a second node; gate, first scanning signal terminal; data and Data signal terminals; RET, second scanning signal end; VGL, negative terminal of power supply; reset, third scanning signal terminal; VDD, a first power supply output; VSS, a second power supply output terminal.
Detailed Description
In order to more clearly illustrate the technical solutions in the embodiments or exemplary techniques of the present application, the following description will explain specific embodiments of the present application with reference to the accompanying drawings. It is evident that the drawings in the following description are only examples of the application, from which other drawings and other embodiments can be obtained by a person skilled in the art without inventive effort.
For the sake of simplicity of the drawing, the parts relevant to the present application are shown only schematically in the figures, which do not represent the actual structure thereof as a product. In addition, in order to simplify the drawing for understanding, components having the same structure or function in some drawings are only schematically depicted, or only one of them is labeled. Herein, "a" means not only "only the one" but also "a plurality of" cases.
The present invention will be described in further detail with reference to the accompanying drawings and examples.
First embodiment:
referring to fig. 3, an embodiment of the present invention provides a pixel driving circuit including:
The Data writing circuit 101 is coupled to the first scan signal terminal Gate, the Data signal terminal Data and the first node N1; the Data writing circuit 101 is configured to write the voltage value at the Data signal terminal Data into the first node N1 under the control of the first scan signal received at the first scan signal terminal Gate;
the control circuit 102 is coupled to the first node N1, the second scan signal terminal RET, and the negative supply terminal VGL; the control circuit 102 is configured to gradually reduce the voltage value at the first node N1 under the control of the second scan signal received at the second scan signal terminal RET;
The voltage control circuit 103 is coupled to the first node N1, the third scanning signal terminal Reset, the first power output terminal VDD, the second node N2, and the negative power supply terminal VGL; the voltage control circuit 103 is configured to write the voltage at the negative supply terminal VGL to the second node N2 under the control of a third scan signal received at the third scan signal terminal Reset; and writing the voltage value at the first power output terminal VDD to the second node N2 when the voltage value at the first node N1 decreases to the voltage value at the first power output terminal VDD;
A switch circuit 104 coupled to the first node N1, the second node N2, and the negative supply terminal VGL; the switching circuit 104 is configured to write the voltage value at the supply negative terminal VGL to the first node N1 when the voltage value of the second node N2 is the voltage value at the first power supply output terminal VDD;
A light emitting circuit 105 coupled to the first node N1, the first power output terminal VDD, and the second power output terminal VSS; the light emitting circuit 105 is configured to drive the light emitting device to operate when the voltage value at the first node N1 is higher than or equal to the voltage value at the first power output terminal VDD; and controlling the light emitting device to be not operated when the voltage value at the first node N1 is lower than the voltage value at the first power output terminal VDD.
The pixel driving circuit provided in this embodiment may be applied to a liquid crystal display panel, where the time of constant current leakage of the control circuit 102 is changed by controlling the voltage value at the Data signal end Data and/or the voltage value at the second scanning signal end RET, so as to further realize the voltage value change at the first node N1, and realize different gray scales of pixels. Since the driving current flowing through the light emitting device is constant in the present application, the change of the gray scale of the pixel is realized by the length of the display time, not by the magnitude of the driving current, so that the problems of different luminous efficiencies and different color coordinates are not generated in the present application.
Specifically, referring to fig. 4, a schematic diagram of another pixel driving circuit according to the present application is shown. The pixel driving circuit includes:
The Data writing circuit 101 is coupled to the first scan signal terminal Gate, the Data signal terminal Data and the first node N1; the Data writing circuit 101 is configured to write the voltage value at the Data signal terminal Data into the first node N1 under the control of the first scan signal received at the first scan signal terminal Gate;
the control circuit 102 is coupled to the first node N1, the second scan signal terminal RET, and the negative supply terminal VGL; the control circuit 102 is configured to gradually reduce the voltage value at the first node N1 under the control of the second scan signal received at the second scan signal terminal RET;
The voltage control circuit 103 is coupled to the first node N1, the third scanning signal terminal Reset, the first power output terminal VDD, the second node N2, and the negative power supply terminal VGL; the voltage control circuit 103 is configured to write the voltage at the negative supply terminal VGL to the second node N2 under the control of a third scan signal received at the third scan signal terminal Reset; and writing the voltage value at the first power output terminal VDD to the second node N2 when the voltage value at the first node N1 decreases to the voltage value at the first power output terminal VDD;
A switch circuit 104 coupled to the first node N1, the second node N2, and the negative supply terminal VGL; the switching circuit 104 is configured to write the voltage value at the supply negative terminal VGL to the first node N1 when the voltage value of the second node N2 is the voltage value at the first power supply output terminal VDD;
A light emitting circuit 105 coupled to the first node N1, the first power output terminal VDD, and the second power output terminal VSS; the light emitting circuit 105 is configured to drive the light emitting device Micro-LED to operate when the voltage value at the first node N1 is higher than or equal to the voltage value at the first power output terminal VDD; and controlling the light emitting device Micro-LED to be not operated when the voltage value at the first node N1 is lower than the voltage value at the first power output terminal VDD.
Wherein the data writing circuit 101 includes: the Gate of the first active element T1 is coupled to the first scan signal terminal Gate, the source of the first active element T1 is coupled to the first node N1, and the drain of the first active element T1 is coupled to the Data signal terminal Data.
The control circuit 102 includes: a second active element T2 and a first capacitor C, wherein a gate of the second active element T2 is coupled to the second scan signal terminal RET, a source of the second active element T2 is coupled to the negative supply terminal VGL, and a drain of the second active element T2 is coupled to the first node N1 and one end of the first capacitor C; the other end of the first capacitor C is coupled with the power supply negative end VGL.
The voltage control circuit 103 includes: a gate of the third active element T3 is coupled to the first node N1, a source of the third active element T3 is coupled to the second node N2 and a drain of the fourth active element T4, and a drain of the third active element T3 is coupled to the first power output terminal VDD; the gate of the fourth active element T4 is coupled to the third scan signal terminal Reset, and the source of the fourth active element T4 is coupled to the negative supply terminal VGL.
The switching circuit 104 includes: a fifth active element T5, the gate of the fifth active element T5 is coupled to the second node N2, the source of the fifth active element T5 is coupled to the negative supply terminal VGL, and the drain of the fifth active element T5 is coupled to the first node N1.
The light emitting circuit 105 includes: the light emitting device comprises a sixth active element T6 and a light emitting device Micro-LED, wherein a grid electrode of the sixth active element T6 is coupled with the first node N1, a source electrode of the sixth active element T6 is coupled with an anode of the light emitting device Micro-LED, a drain electrode of the sixth active element T6 is coupled with a first power output end VDD, and a cathode of the light emitting device Micro-LED is coupled with a second power output end VSS.
Here, it should be noted that, in the present embodiment, the voltage value at the Data signal terminal Data is greater than the voltage value at the first power output terminal VDD, and the voltage value at the first power output terminal VDD is greater than the voltage value of the negative supply terminal VGL.
The first active device T1 in the present embodiment includes a thin film field effect transistor or a metal-oxide semiconductor field effect transistor; the second active device T2 includes a thin film field effect transistor or a metal-oxide semiconductor field effect transistor; the third active device T3 includes a thin film field effect transistor or a metal-oxide semiconductor field effect transistor; the fourth active device T4 includes a thin film field effect transistor or a metal-oxide semiconductor field effect transistor; the fifth active device T5 includes a thin film field effect transistor or a metal-oxide semiconductor field effect transistor. The sixth active element T6 comprises a thin film field effect transistor or a metal-oxide semiconductor field effect transistor. The third active device T3 may be a PMOS.
Here, referring to fig. 5, a schematic diagram of a change of voltage values at the first scan signal terminal Gate, the second scan signal terminal RET, and the third scan signal terminal Reset according to an embodiment of the present invention is shown. Based on the pixel driving circuit of the present embodiment shown in fig. 5, at the beginning of a frame, the third scanning signal terminal Reset outputs a high voltage level, the fourth active element T4 is turned on, and the second node N2 writes a low voltage value of the negative supply terminal VGL. Then, the third scan signal terminal Reset outputs a low voltage level, a frame starts to scan, the first scan signal terminal Gate outputs a high voltage level, the first active device T1 is turned on, the first node N1 writes a high voltage value at the Data signal terminal Data, the second scan signal terminal RET is at the low voltage level, and the second active device T2 is turned off. The second scan signal terminal RET is at a high voltage level, and the second active device T2 is turned on. Since the thin film transistor of the second active device T2 is generally smaller, the second active device T2 starts to leak current. That is, as the turn-on time of the second active device T2 increases, the leakage time increases, and the voltage value at the first node N1 gradually decreases with time. The voltage value at the first node N1 varies in proportion to the capacitance value of the first capacitor C. The specific formula is as follows: q=c×Δv=ion×t. Wherein, C is the capacitance value of the first capacitor C, which is generally larger, ion is the on-current of the second active device T2, i.e. the thin film transistor, whose magnitude is related to the voltage value at the second scanning signal terminal RET, T is the leakage time, and Δv is the variation of the voltage value at the first node N1. Since the second active element T2 is turned on, the voltage of the first node N1 drops immediately, the third active element T3 is turned on when the voltage of the first node N1 is smaller than the voltage value at the first power output terminal VDD, here, the third active element T3 is a PMOS, the third active element T3 is turned on when the voltage at the gate of the third active element T3 (i.e., the first node N1) is smaller than the voltage value at the first power output terminal VDD, the second node N2 is at a high voltage, the fifth active element T5 is turned on, the first node N1 is written with a low voltage at the power supply negative terminal VGL, the sixth active element T6 is turned off, the light emitting device Micro-LED does not pass current, and the pixel does not emit light.
What needs to be specifically stated is: the sixth active element T6 in the present embodiment operates in the linear region. That is, the driving current of the sixth active device T6 is not changed by the gate voltage of the sixth active device T6, so as to ensure that the working current of the sixth active device T6 is not changed. The gate voltage of the sixth active element T6 is required to be higher than the voltage at the first power output terminal VDD. However, when the sixth active element T6 is turned on, the anode of the light emitting device Micro-LED is always at the voltage value at the first power output terminal VDD.
The pixel driving circuit provided by the embodiment can improve the luminous efficiency and the change of color coordinates caused by different current driving. The pixel driving circuit converts the analog signal into the equivalent change in time, and adjusts and controls the light-emitting time according to the voltage of the analog signal, so as to realize the change of different gray scales. Since the driving current flowing through the light emitting device is constant in the present application, the change of the gray scale of the pixel is realized by the length of the display time, not by the magnitude of the driving current, so that the problems of different luminous efficiencies and different color coordinates are not generated in the present application.
The embodiment not only can realize the length of the driving time through the voltage at the data signal end, but also can realize different gray scales; meanwhile, the voltage change of the first node can be controlled through the voltage at the second scanning signal end, so that adjustment of different gray scales can be realized.
The pixel driving circuit provided by the embodiment of the application comprises a data writing circuit, a first scanning signal terminal, a data signal terminal and a first node, wherein the data writing circuit is connected with the first scanning signal terminal, the data signal terminal and the first node; the data writing circuit is configured to write a voltage value at the data signal terminal to the first node under control of a first scan signal received at the first scan signal terminal; the control circuit is coupled with the first node, the second scanning signal end and the power supply negative end; the control circuit is configured to control constant current leakage under the control of a second scanning signal received at the second scanning signal end, and gradually reduce the voltage value at the first node; the voltage control circuit is coupled with the first node, the third scanning signal end, the first power supply output end, the second node and the power supply negative end; the voltage control circuit is configured to write the voltage at the power supply negative terminal to the second node under control of a third scan signal received at the third scan signal terminal; and writing the voltage value at the first power supply output to the second node when the voltage value at the first node decreases to the voltage value at the first power supply output; the switch circuit is coupled with the first node, the second node and the power supply negative terminal; the switching circuit is configured to write the voltage value at the negative supply terminal to the first node when the voltage value of the second node is the voltage value at the first power supply output terminal; the light-emitting circuit is coupled with the first node, the first power supply output end and the second power supply output end; the light-emitting circuit is configured to drive the light-emitting device to work when the voltage value at the first node is higher than or equal to the voltage value at the first power supply output end; and controlling the light emitting device to be not operated when the voltage value at the first node is lower than the voltage value at the first power output terminal. The scheme provided by the application can change the time of constant current leakage of the control circuit by controlling the voltage value at the data signal end and/or the second scanning signal end, thereby realizing the voltage value change at the first node and realizing different gray scales of pixels. Since the driving current flowing through the light emitting device is constant in the present application, the change of the gray scale of the pixel is realized by the length of the display time, not by the magnitude of the driving current, so that the problems of different luminous efficiencies and different color coordinates are not generated in the present application.
Second embodiment:
Referring to fig. 6, an embodiment of the present invention further provides a driving method of the pixel driving circuit according to any one of the above, including:
Step 401: the data writing circuit writes a voltage value at the data signal end into the first node under the control of a first scanning signal received at the first scanning signal end;
Step 402: the control circuit is controlled by a second scanning signal received at the second scanning signal end to perform constant current leakage, and the voltage value at the first node is gradually reduced;
Step 403: the voltage control circuit writes the voltage at the power supply negative terminal into the second node under the control of a third scanning signal received at the third scanning signal terminal, and writes the voltage value at the first power supply output terminal into the second node when the voltage value at the first node is reduced to the voltage value at the first power supply output terminal;
Step 404: the switching circuit writes the voltage value at the power supply negative terminal into the first node when the voltage value of the second node is the voltage value at the first power supply output terminal;
Step 405: when the voltage value of the light-emitting circuit at the first node is higher than or equal to the voltage value at the output end of the first power supply, driving the light-emitting device to work; and controlling the light emitting device to be not operated when the voltage value at the first node is lower than the voltage value at the first power output terminal.
Specifically, referring to fig. 5, a schematic diagram of a change of voltage values at the first scanning signal terminal, the second scanning signal terminal, and the third scanning signal terminal according to an embodiment of the present invention is shown. Based on the pixel driving circuit of the present embodiment shown in fig. 5, at the beginning of a frame, the third scan signal terminal outputs a high voltage level, the fourth active element T4 is turned on, and the second node writes a low voltage value of the negative supply terminal. Then, the third scan signal terminal outputs a low voltage level, a frame starts to scan, the first scan signal terminal outputs a high voltage level, the first active device T1 is turned on, the first node writes a high voltage value at the data signal terminal, the second scan signal terminal is at the low voltage level, and the second active device T2 is turned off. The second scan signal terminal is then at a high voltage level, and the second active device T2 is turned on. Since the thin film transistor of the second active device T2 is generally smaller, the second active device T2 starts to leak current. That is, as the turn-on time of the second active device T2 increases, the leakage time increases, and the voltage value at the first node gradually decreases with time. The voltage value at the first node varies in proportion to the capacitance value of the first capacitor. The specific formula is as follows: q=c×Δv=ion×t. Wherein, C is the capacitance value of the first capacitor, which is generally larger, ion is the on-current of the second active device T2, i.e. the thin film transistor, whose magnitude is related to the voltage value at the second scanning signal terminal, T is the length of the leakage time, and Δv is the variation of the voltage value at the first node. Since the second active element T2 is turned on, the voltage of the first node drops immediately, when the voltage of the first node is smaller than the voltage value at the first power output terminal, the third active element T3 is turned on, here, the third active element T3 is a PMOS, when the voltage at the gate (i.e., the first node) of the third active element T3 is smaller than the voltage value at the first power output terminal, the third active element T3 is turned on, the second node is a high voltage, the fifth active element T5 is turned on, the first node writes a low voltage at the power supply negative terminal, the sixth active element T6 is turned off, the light emitting device Micro-LED does not pass through, and the pixel does not emit light.
The pixel driving circuit provided by the embodiment can improve the luminous efficiency and the change of color coordinates caused by different current driving. The pixel driving circuit converts the analog signal into the equivalent change in time, and adjusts and controls the light-emitting time according to the voltage of the analog signal, so as to realize the change of different gray scales. Since the driving current flowing through the light emitting device is constant in the present application, the change of the gray scale of the pixel is realized by the length of the display time, not by the magnitude of the driving current, so that the problems of different luminous efficiencies and different color coordinates are not generated in the present application.
The embodiment not only can realize the length of the driving time through the voltage at the data signal end, but also can realize different gray scales; meanwhile, the voltage change of the first node can be controlled through the voltage at the second scanning signal end, so that adjustment of different gray scales can be realized.
According to the driving method of the pixel driving circuit, the data writing circuit writes the voltage value at the data signal end into the first node under the control of the first scanning signal received at the first scanning signal end; the control circuit is controlled by a second scanning signal received at the second scanning signal end to perform constant current leakage, and the voltage value at the first node is gradually reduced; the voltage control circuit writes the voltage at the power supply negative terminal into the second node under the control of a third scanning signal received at the third scanning signal terminal, and writes the voltage value at the first power supply output terminal into the second node when the voltage value at the first node is reduced to the voltage value at the first power supply output terminal; the switching circuit writes the voltage value at the power supply negative terminal into the first node when the voltage value of the second node is the voltage value at the first power supply output terminal; when the voltage value of the light-emitting circuit at the first node is higher than or equal to the voltage value at the output end of the first power supply, driving the light-emitting device to work; and controlling the light emitting device to be not operated when the voltage value at the first node is lower than the voltage value at the first power output terminal. The scheme provided by the application can change the time of constant current leakage of the control circuit by controlling the voltage value at the data signal end and/or the second scanning signal end, thereby realizing the voltage value change at the first node and realizing different gray scales of pixels. Since the driving current flowing through the light emitting device is constant in the present application, the change of the gray scale of the pixel is realized by the length of the display time, not by the magnitude of the driving current, so that the problems of different luminous efficiencies and different color coordinates are not generated in the present application.
Third embodiment:
The embodiment of the invention also provides a display device which comprises the pixel driving circuit and a power supply module for supplying power to the pixel driving circuit.
The display device provided by the embodiment can improve the luminous efficiency and the change of color coordinates caused by different current driving. The analog signal is converted into equivalent change in time, and the light-emitting time is regulated and controlled according to the voltage of the analog signal, so that the change of different gray scales is realized. Since the driving current flowing through the light emitting device is constant in the present application, the change of the gray scale of the pixel is realized by the length of the display time, not by the magnitude of the driving current, so that the problems of different luminous efficiencies and different color coordinates are not generated in the present application.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element.
The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and variations of the present application will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the application are to be included in the scope of the claims of the present application.
Claims (10)
1. A pixel driving circuit, the pixel driving circuit comprising:
The data writing circuit is coupled with the first scanning signal end, the data signal end and the first node; the data writing circuit is configured to write a voltage value at the data signal terminal to the first node under control of a first scan signal received at the first scan signal terminal;
The control circuit is coupled with the first node, the second scanning signal end and the power supply negative end; the control circuit is configured to control constant current leakage under the control of a second scanning signal received at the second scanning signal end, and gradually reduce the voltage value at the first node;
the voltage control circuit is coupled with the first node, the third scanning signal end, the first power supply output end, the second node and the power supply negative end; the voltage control circuit is configured to write the voltage at the power supply negative terminal to the second node under control of a third scan signal received at the third scan signal terminal; and writing the voltage value at the first power supply output to the second node when the voltage value at the first node decreases to the voltage value at the first power supply output;
The switch circuit is coupled with the first node, the second node and the power supply negative terminal; the switching circuit is configured to write the voltage value at the negative supply terminal to the first node when the voltage value of the second node is the voltage value at the first power supply output terminal;
The light-emitting circuit is coupled with the first node, the first power supply output end and the second power supply output end; the light-emitting circuit is configured to drive the light-emitting device to work when the voltage value at the first node is higher than or equal to the voltage value at the first power output end; and controlling the light emitting device to be not operated when the voltage value at the first node is lower than the voltage value at the first power output terminal.
2. The pixel driving circuit according to claim 1, wherein the data writing circuit comprises:
The grid electrode of the first active element is coupled with the first scanning signal end, the source electrode of the first active element is coupled with the first node, and the drain electrode of the first active element is coupled with the data signal end.
3. The pixel driving circuit according to claim 1, wherein the control circuit includes:
The grid electrode of the second active element is coupled with the second scanning signal end, the source electrode of the second active element is coupled with the power supply negative end, and the drain electrode of the second active element is coupled with the first node and one end of the first capacitor; the other end of the first capacitor is coupled with the power supply negative terminal.
4. The pixel driving circuit according to claim 1, wherein the voltage control circuit comprises:
The grid electrode of the third active element is coupled with the first node, the source electrode of the third active element is coupled with the second node and the drain electrode of the fourth active element, and the drain electrode of the third active element is coupled with the first power supply output end; the grid electrode of the fourth active element is coupled with the third scanning signal end, the
The source of the fourth active element is coupled to the negative supply terminal.
5. The pixel driving circuit according to claim 1, wherein the switching circuit includes:
and a fifth active element, a gate of the fifth active element being coupled to the second node, a source of the fifth active element being coupled to the negative supply terminal, and a drain of the fifth active element being coupled to the first node.
6. The pixel driving circuit according to claim 1, wherein the light emitting circuit includes:
The grid electrode of the sixth active element is coupled with the first node, the source electrode of the sixth active element is coupled with the anode of the light emitting device, the drain electrode of the sixth active element is coupled with the first power output end, and the cathode of the light emitting device is coupled with the second power output end.
7. The pixel drive circuit of claim 1, wherein the voltage value at the data signal terminal is greater than the voltage value at the first power supply output terminal, the voltage value at the first power supply output terminal being greater than the voltage value of the supply negative terminal.
8. The pixel driving circuit according to claim 4, wherein the third active element is a P-channel mosfet.
9. A driving method of the pixel driving circuit according to any one of claims 1 to 7, comprising:
The data writing circuit writes a voltage value at the data signal end into the first node under the control of a first scanning signal received at the first scanning signal end;
the control circuit is controlled by a second scanning signal received at the second scanning signal end to perform constant current leakage, and the voltage value at the first node is gradually reduced;
The voltage control circuit writes the voltage at the power supply negative terminal into the second node under the control of a third scanning signal received at the third scanning signal terminal, and writes the voltage value at the first power supply output terminal into the second node when the voltage value at the first node is reduced to the voltage value at the first power supply output terminal;
the switching circuit writes the voltage value at the power supply negative terminal into the first node when the voltage value of the second node is the voltage value at the first power supply output terminal;
when the voltage value of the light-emitting circuit at the first node is higher than or equal to the voltage value at the output end of the first power supply, driving the light-emitting device to work; and controlling the light emitting device to be not operated when the voltage value at the first node is lower than the voltage value at the first power output terminal.
10. A display device comprising the pixel driving circuit according to any one of claims 1 to 7, and a power supply module for supplying power to the pixel driving circuit.
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| CN202310806172.7A CN116798345B (en) | 2023-06-30 | 2023-06-30 | Pixel driving circuit, driving method and display device |
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| CN116798345A (en) | 2023-09-22 |
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