Pixel driving circuit and display screen

Abstract

A pixel driving circuit and a display screen, for use in broadening the brightness display range of the display screen. The pixel driving circuit comprises a data writing branch, a first driving branch, a second driving branch and a compensation branch, wherein the data writing branch is connected to the first driving branch and the second driving branch, and writes a data signal to the connected driving branches; the compensation branch is connected to the first driving branch and the second driving branch to generate a first threshold voltage of the first driving branch and a second threshold voltage of the second driving branch; the first driving branch generates a first driving current on the basis of the data signal and the first threshold voltage, and outputs the first driving current to a driven device (LED); and the second driving branch generates a second driving current on the basis of the data signal and the second threshold voltage, and outputs the second driving current to the driven device (LED). Due to different width-to-length ratios of driving transistors in two driving branches, driving currents of different amplitudes are generated under the same data signal, so that different driving branches can be controlled to work on the basis of the brightness display requirements of the driven device (LED).

Description

Pixel driving circuit and display screen

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on March 29, 2024, with application number 202410386280.8 and application name "A pixel driving circuit and display screen", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of display technology, and in particular to a pixel driving circuit and a display screen. Background Art

[0004] Organic Light-Emitting Diode (OLED) displays have a prosperous future. Compared with liquid crystal displays, OLED displays have the characteristics of self-luminescence, large viewing angle, fast response speed, light weight, thin thickness, simple structure and low cost.

[0005] Active Matrix Organic Light Emitting Diode (AMOLED) is a type of OLED that features low driving current, luminescence throughout the entire cycle, and long lifespan. Therefore, AMOLED is more suitable for display drivers with high resolution, high refresh rate, and large screen sizes. As the demand for display brightness continues to increase, the display brightness range has increased from 2 nit to 3000 nit, or even to 5000 nit. The increase in display brightness range can be achieved by increasing the amplitude range of the data signal of the pixel drive circuit, or by increasing the mobility and aspect ratio of the drive transistor to increase the upper limit of the drive current, thereby meeting the brightness range of the existing display. However, a high aspect ratio drive transistor will also lead to an increase in the minimum brightness of the light-emitting diode, and an increase in the amplitude range of the data signal will also result in an increase in chip power consumption. Summary of the Invention

[0006] The present application provides a pixel driving circuit and a display screen, which are used to improve the display brightness range of the display screen.

[0007] In a first aspect, embodiments of the present application provide a pixel driver circuit that can be used in electronic devices equipped with display screens. The pixel driver circuit and a driven device (light source) can form a pixel, and the display screen includes a pixel array composed of multiple pixels. Specifically, the pixel driver circuit includes a data write branch, a first drive branch, a second drive branch, and a compensation branch.

[0008] The data write branch is connected to the first drive branch and the second drive branch, and is used to write a data signal into the first drive branch and the second drive branch; the compensation branch is connected to the first drive branch and the second drive branch, and is used to generate a first threshold voltage for the first drive branch and a second threshold voltage for the second drive branch; the first drive branch is used to generate a first drive current according to the data signal and the first threshold voltage, and output it to the driven device; the second drive branch is used to generate a second drive current according to the data signal and the second threshold voltage, and output it to the driven device; wherein the width-to-length ratios of the drive transistors in the first drive branch and the second drive branch are different.

[0009] Using the above architecture, the first and second drive branches are configured with drive transistors of different aspect ratios. When controlling the first and second drive branches to drive the driven device, different drive currents can be generated. The brightness values ​​of the driven device (light source) are different under different drive currents. Therefore, the drive current amplitudes output by the first and second drive branches can be controlled according to the display brightness requirements of the display to meet the brightness requirements of the display. In addition, a drive transistor with a small aspect ratio can be configured in one drive branch to reduce the minimum value of the display brightness range, thereby ensuring the expansion of grayscale at low brightness.

[0010] In a possible implementation, the first driving transistor may include a first driving transistor and a first switching transistor.

[0011] The first terminal of the first driver transistor is connected to the data writing branch, the second terminal of the first driver transistor is connected to the first terminal of the first switching transistor, and the control terminal of the first driver transistor is connected to the compensation branch. The second terminal of the first switching transistor is connected to the driven device, and the control terminal of the first switching transistor is used to receive a first drive signal, which is used to control the conduction of the first switching transistor. With this design, the control terminal voltage of the first driver transistor is provided by the compensation branch, and the conduction and shutdown of the first switching transistor are achieved by the first drive signal sent by the external control device. Therefore, when controlling the operation of the pixel driving circuit, the external control device can configure the corresponding first drive signal according to the brightness requirements of the display screen to select whether the first driver branch is to operate.

[0012] In a possible implementation, the second driving branch includes a second driving transistor and a second switching transistor.

[0013] The first terminal of the second driver transistor is connected to the data writing branch, the second terminal of the second driver transistor is connected to the first terminal of the second switch, and the control terminal of the second driver transistor is connected to the compensation branch. The second terminal of the second switch is connected to the driven device, and the control terminal of the second switch is used to receive a second drive signal, which is used to control the conduction of the second switch. With this design, the control terminal voltage of the second driver transistor is provided by the compensation module, and the conduction and shutdown of the second switch are achieved by the second drive signal sent by the external control device. Therefore, when controlling the operation of the pixel driver circuit, the external control device can configure the corresponding second drive signal according to the brightness requirements of the display screen to select whether the second driver branch is to operate.

[0014] In one possible implementation, the compensation branch includes a first capacitor and a third switching transistor. The first end of the first capacitor is connected to a power line, and the second end of the first capacitor is connected to the first end of the third switching transistor. The first end of the third switching transistor is connected to the control terminals of the driving transistors in the first and second driving branches, and the second end of the third switching transistor is connected to the driven device. With this design, the first capacitor can serve as the compensation capacitor for the first and second driving branches. When the first driving branch is operating, threshold compensation is performed on the driving transistor in the first driving branch. Similarly, when the second driving branch is operating, threshold compensation is performed on the driving transistor in the second driving branch.

[0015] In one possible implementation, the pixel driver circuit further includes a reset branch connected to the compensation branch for resetting the driven device and the compensation branch connected to the pixel driver circuit. With this design, the driven device and the compensation branch can be reset before each display phase of the display screen, i.e., the potentials of these devices are initialized, thereby ensuring the display results of the current display screen.

[0016] In one possible implementation, the reset branch includes a fourth switch and a fifth switch. A first end of the fourth switch is connected to the compensation branch, and a second end of the fourth switch is configured to receive a first reset voltage. A first end of the fifth switch is connected to the driven device, and a second end of the fifth switch is configured to receive a second reset voltage.

[0017] In a possible implementation, the first driving branch includes a third driving transistor, a first end of the third driving transistor is connected to the data writing branch, a second end of the third driving transistor is connected to the driven device, and a control end of the third driving transistor is connected to the compensation branch.

[0018] In a possible implementation, the second driving branch includes a fourth driving transistor, a first end of the fourth driving transistor is connected to the data writing branch, a second end of the fourth driving transistor is connected to the driven device, and a control end of the fourth driving transistor is connected to the compensation branch.

[0019] In a possible implementation, the compensation branch includes a second capacitor, a sixth switch tube, a third capacitor, and a seventh switch tube.

[0020] The first end of the second capacitor is connected to the power line, the second end of the second capacitor is connected to the reset branch and the first end of the sixth switch; the first end of the sixth switch is connected to the control terminal of the driving transistor in the first driving branch, and the second end of the sixth switch is connected to the driven device; the first end of the third capacitor is connected to the power line, the second end of the third capacitor is connected to the reset branch and the first end of the seventh switch; the first end of the seventh switch is connected to the control terminal of the driving transistor in the second driving branch, and the second end of the seventh switch is connected to the driven device. With the above design, the second capacitor serves as a compensation capacitor for the driving transistor in the first driving branch, and the third capacitor serves as a compensation capacitor for the driving transistor in the second driving branch. The sixth switch connected to the second capacitor can control the conduction and shutdown of the driving transistor in the first driving branch under the control of a control signal transmitted by an external control device, thereby controlling the operation of the first driving branch. Similarly, the seventh switch connected to the third capacitor can control the conduction and shutdown of the driving transistor in the second driving branch under the control of a control signal transmitted by the external control device, thereby controlling the operation of the second driving branch.

[0021] In one possible implementation, the reset branch includes an eighth switch and a ninth switch. The first end of the eighth switch is connected to the compensation branch, and the second end of the eighth switch is configured to receive a first reset voltage or a second reset voltage. The first end of the ninth switch is connected to the driven device, and the second end of the ninth switch is configured to receive a third reset voltage. With this design, the eighth switch can charge and reset the compensation capacitors of the two driver transistors based on the received first and second reset voltages.

[0022] In one possible implementation, the pixel driving circuit further includes a light-emitting control branch, which is connected to the first driving branch and the second driving branch, respectively. The light-emitting control branch is used to control the first driving branch and the second driving branch to be connected to the power supply and the driven device, respectively, when receiving a light-emitting control signal. At this time, the power supply forms a closed path with the driven device through the driving branch, and outputs different driving currents to the driven device according to the working conditions of the two driving branches, thereby driving the driven device to display different brightness.

[0023] In one possible implementation, the light-emitting control branch includes a tenth switching tube and an eleventh switching tube. A first end of the tenth switching tube is connected to a power line, and a second end of the tenth switching tube is connected to the first driving branch and the second driving branch; a second end of the eleventh switching tube is connected to the first driving branch and the second driving branch, and a second end of the eleventh switching tube is connected to the driven device.

[0024] In one possible implementation, the pixel driver circuit further includes a clearing branch, wherein the reset branch includes a twelfth switch transistor, a first terminal of the twelfth switch transistor being connected to the data writing branch, and a second terminal of the twelfth switch transistor being configured to receive a clearing voltage. With this design, when the pixel driver structure is used to drive a light-emitting diode to emit light, the twelfth switch transistor can be controlled to clear the charge at the connection point between the data writing branch and the driver module before the light-emission control phase, thereby eliminating the influence of the charge from the previous light-emission control process on the current control phase.

[0025] In one possible implementation, the data writing branch includes a thirteenth switch tube, the first end of the thirteenth switch tube is used to connect to the data line that outputs the data signal, and the second end of the thirteenth switch tube is respectively connected to the first driving branch, the second driving branch and the driven device.

[0026] In a second aspect, an embodiment of the present application provides a display screen, which is used in an electronic device with a display function. The display screen includes multiple pixel driving circuits provided in the first aspect of the embodiment of the present application and any possible design thereof, a light source connected to each pixel driving circuit, a power supply device and a control device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a first structural diagram of a pixel driving circuit provided in an embodiment of the present application;

[0028] FIG2 is a second structural diagram of a pixel driving circuit provided in an embodiment of the present application;

[0029] FIG3 is a third structural diagram of a pixel driving circuit provided in an embodiment of the present application;

[0030] FIG4 is a schematic structural diagram of a pixel driving circuit provided in Example 1 of the present application;

[0031] FIG5 is a schematic diagram of control signal waveforms of the pixel driving circuit provided in the first embodiment of the present application when operating in the first operating mode;

[0032] FIG6 is a schematic diagram of control signal waveforms of the pixel driving circuit provided in the first embodiment of the present application when operating in the second operating mode;

[0033] FIG7 is a first structural diagram of a display screen provided in an embodiment of the present application;

[0034] FIG8 is a first structural diagram of a pixel driving circuit provided in Example 2 of the present application;

[0035] FIG9 is a schematic diagram of control signal waveforms of the pixel driving circuit provided in the second embodiment of the present application when operating in the first operating mode;

[0036] FIG10 is a schematic diagram of control signal waveforms of the pixel driving circuit provided in the second embodiment of the present application when operating in the second operating mode;

[0037] FIG11 is a first schematic diagram of control signal waveforms when the pixel driving circuit provided in the second embodiment of the present application operates in the third operating mode;

[0038] FIG12 is a second structural diagram of a display screen provided in an embodiment of the present application;

[0039] FIG13 is a second structural diagram of a pixel driving circuit provided in the second embodiment of the present application;

[0040] FIG14 is a second schematic diagram of control signal waveforms when the pixel driving circuit provided in an embodiment of the present application operates in the third operating mode. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The specific operating methods in the method embodiments can also be applied to device embodiments or system embodiments. It should be noted that in the description of the present application, "at least one" refers to one or more, wherein "a plurality" refers to two or more. In view of this, "a plurality" can also be understood as "at least two" in the embodiments of the present application. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / ", unless otherwise specified, generally indicates that the previous and next associated objects are in an "or" relationship. In addition, it should be understood that in the description of the present application, words such as "first" and "second" are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order.

[0042] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The specific operating methods in the method embodiments can also be applied to device embodiments or system embodiments. It should be noted that in the description of the present application, "at least one" refers to one or more, wherein "a plurality" refers to two or more. In view of this, "a plurality" can also be understood as "at least two" in the embodiments of the present application. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / ", unless otherwise specified, generally indicates that the previous and next associated objects are in an "or" relationship. In addition, it should be understood that in the description of the present application, words such as "first" and "second" are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order.

[0043] It should be noted that in the embodiments of the present application, "coupling" can be understood as an electrical connection, and the coupling of two electrical components can be a direct or indirect coupling between the two electrical components. For example, the connection between A and B can be either direct coupling between A and B, or indirect coupling between A and B through one or more other electrical components, such as A and B coupling, or A and C direct coupling, C and B direct coupling, and A and B are coupled through C. In some scenarios, "coupling" can also be understood as connection. In short, the coupling between A and B enables the transmission of electrical energy between A and B.

[0044] To facilitate understanding of the technical solutions provided by the embodiments of the present application, the specific application scenarios are first described below. The pixel driving circuit provided by the embodiments of the present application can be applied to electronic devices with display screens, and the electronic devices can be common devices with camera functions such as mobile phones, tablet computers, and wearable electronic devices. Of course, the technical solutions claimed in this application can also be applied to other types of electronic devices with display functions.

[0045] The pixel driving circuit provided by the present application is described below with reference to the accompanying drawings. FIG1 is a schematic diagram of the structure of a pixel driving circuit provided by an embodiment of the present application. The pixel driving circuit can be applied to a display screen, wherein the display screen can include a pixel array consisting of a plurality of pixels. Each pixel in the pixel array can include a light source. Each light source can be connected to a pixel driving circuit and can emit light based on a driving current output by the pixel driving circuit, and can adjust the brightness according to the amplitude of the driving current. The light source can be, but is not limited to, a light-emitting diode (LED), an organic light-emitting diode (OLED), a cold cathode fluorescent lamp (CCFL), and a hot cathode fluorescent lamp (HCFL). The anode of each of the above light sources is connected to the driving circuit, and the cathode is connected to a fixed power line. To facilitate understanding of the present application, the following description uses an LED as an example of a light source.

[0046] FIG1 is a schematic diagram of a pixel driving circuit structure. Referring to FIG1 , the pixel driving circuit includes a data writing branch, a first driving branch, a second driving branch, and a compensation branch. The data writing branch is connected to the first driving branch and the second driving branch, respectively, and is configured to write a data signal Vdata into the first driving branch and the second driving branch. The compensation branch is connected to the first driving branch and the second driving branch, and is configured to generate a first threshold voltage for the first driving branch and a second threshold voltage for the second driving branch. The first driving branch is configured to generate a first driving current based on the data signal and the first threshold voltage, and output the first driving current to the driven device LED. The second driving branch is configured to generate a second driving current based on the data signal and the second threshold voltage, and output the second driving current to the driven device LED. The width-to-length ratios of the driving transistors in the first driving branch and the second driving branch are different.

[0047] In some embodiments, the display screen has different brightness requirements for the display screen during different display times. Therefore, the display screen has multiple display stages when working. In order to ensure that the output of each display stage can meet the brightness requirements, the pixel driving circuit also includes a reset circuit for resetting multiple branches. As shown in Figure 2, the reset circuit can be connected to the compensation branch and the driven device LED, and reset the driven device connected to the pixel driving circuit and the compensation branch before driving the driven device LED to emit light, thereby ensuring that the generated driving current meets the brightness requirements.

[0048] In some embodiments, before driving the driven device LED to emit light, in order to avoid the influence of other devices on the display brightness, the pixel driving circuit provided in the embodiment of the present application also includes a light-emitting control branch. As shown in Figure 3, the pixel driving circuit also includes a light-emitting control branch, and the light-emitting control branch is connected to the first driving branch and the second driving branch respectively. The light-emitting control branch is used to control the first driving branch and the second driving branch to be connected to the power supply Vdd and the driven device LED respectively when receiving the light-emitting control signal. At this time, the power supply forms a closed path between the driven device LED and the driving branch through the driving branch, and outputs different driving currents to the driven device LED according to the working conditions of the two driving branches, thereby realizing different brightness of the LED.

[0049] In the present application, in order to meet the display screen's selection of different display brightness, a first driving branch and a second driving branch are configured. As shown in Figures 1 to 3, the first driving branch and the second driving branch are directly connected to the driven device LED or connected to the driven device LED through other devices. Since the driving transistors in the first driving branch and the second driving branch are driving transistors with different aspect ratios, the first driving branch and the second driving branch can generate different driving currents when receiving the same data signal Vdata. According to the brightness requirements of the display screen, the corresponding driving branch can be controlled to work to meet the display screen's requirements for high and low brightness display.

[0050] As can be seen from the above description, the pixel driving circuit provided in the embodiments of the present application can have multiple operating modes, corresponding to different operating states of the driving branches within the pixel driving circuit. In other words, the driving branches in the pixel driving circuit provided in the embodiments of the present application have multiple operating states to achieve different brightness requirements of the display screen. Optionally, the driving branches can switch operating states under the control of signals sent by an external control device.

[0051] In actual use, the pixel driving circuit provided in the embodiments of the present application includes at least two operating modes. For example, when the pixel driving circuit is in a first operating mode, the first driving branch operates to generate a first driving current, and the pixel driving circuit drives the driven device LED to emit light based on the first driving current. When the pixel driving circuit is in a second operating mode, the second driving branch operates to generate a second driving current, and the pixel driving circuit drives the driven device LED to emit light based on the second driving current.

[0052] In one possible implementation, the pixel driving circuit provided in the embodiment of the present application may further include a third operating mode, that is, the first driving branch operates to generate a first driving current, and the second driving branch operates to generate a second driving current. The pixel driving circuit can jointly drive the driven device LED to emit light based on the first driving current and the second driving current, thereby further improving the brightness display range of the display screen.

[0053] In actual use, when a single driving branch is operating, the compensation branch only requires one compensation capacitor to initialize the control terminal voltage of the driving transistor in the driving branch. When two driving branches are operating simultaneously, two compensation capacitors must be provided in the compensation branch to initialize the control terminal voltages of the driving transistors in the two driving branches respectively. The following describes in detail the two structures of the pixel driving circuit and the process of generating the driving current, in conjunction with embodiments.

[0054] Example 1: The pixel driving circuit includes two working modes

[0055] In some embodiments, as shown in FIG4 , the first driving branch includes a first driving transistor T1 and a first switching transistor T2, and the second driving branch includes a second driving transistor T3 and a second switching transistor T4. The first terminal of the first driving transistor T1 is connected to the data writing branch, the second terminal of the first driving transistor T1 is connected to the first terminal of the first switching transistor T2, and the control terminal of the first driving transistor T1 is connected to the compensation branch. The second terminal of the first switching transistor T2 is connected to the driven device LED via the light emission control branch, and the control terminal of the first switching transistor is configured to receive a first driving signal GD1, which is used to control the first switching transistor to conduct. The first terminal of the second driving transistor T3 is connected to the data writing branch, the second terminal of the second driving transistor T3 is connected to the first terminal of the second switching transistor T4, and the control terminal of the second driving transistor T3 is connected to the compensation branch. The second terminal of the second switching transistor T4 is connected to the driven device LED via the light emission control branch, and the control terminal of the second switching transistor T4 is configured to receive a second driving signal GD2, which is used to control the second switching transistor to conduct.

[0056] In actual use, the switching devices in the first driving branch and the second driving branch can be thin film transistors (TFTs), that is, the switching devices in the first driving branch and the second driving branch are both voltage-type driving switching devices. When the first driving transistor T1 and the second driving transistor T3 are turned on, the external control device can be directly connected to the control terminals of the first switching tube T2 and the second switching tube T4, and control the first driving branch to enter the first working mode and generate the first driving current I1 by sending a first driving signal GD1 to the control terminal of the first switching tube T1. The external control device can also control the second driving branch to enter the second working mode and generate the second driving current I2 by sending a second driving signal GD2 to the control terminal of the second switching tube T4. It should be noted that the device type of the driving switch tube in the above-mentioned driving branch is only an example. In actual use, the switching device of the driving switch tube can also be selected from other devices in the industry with the above-mentioned functions, and this application does not make specific limitations here.

[0057] In some embodiments, as shown in FIG4 , the control terminals of the first driver transistor T1 and the second driver transistor T3 are both connected to the compensation branch, that is, the control terminals of the first driver transistor and the second driver transistor are both connected to node N1. As shown in FIG2 , the compensation branch includes a first capacitor C1 and a third switch transistor T5. The first terminal of the first capacitor C1 is connected to the power supply line Vdd, and the second terminal of the first capacitor C1 is connected to the reset branch and the first terminal of the third switch transistor T5. The first terminal of the third switch transistor T5 is connected to the control terminals of the driver transistors in the first driver branch and the second driver branch, and the second terminal of the third switch transistor T5 is connected to the driven device LED via the light-emitting control branch.

[0058] As can be seen from the compensation branch structure shown in Figure 4, the first capacitor C1 in the compensation branch can constitute the compensation capacitor of the first driving transistor T1 and the second driving transistor T3, and is charged and reset according to the reset voltage provided by the reset branch connected to the compensation branch, thereby initializing the control terminal voltage of the first driving transistor and the second driving transistor.

[0059] In some embodiments, as shown in FIG2 , the reset branch includes a fourth switch transistor T6 and a fifth switch transistor T7. A first terminal of the fourth switch transistor T4 is connected to the compensation branch, and a second terminal of the fourth switch transistor T6 is configured to receive a first reset voltage Vref1 and use the received first reset voltage Vref1 to charge and reset the first capacitor C1. A first terminal of the fifth switch transistor T6 is connected to the anode of the driven device LED, and a second terminal of the fifth switch transistor T7 is configured to receive a second reset voltage Vref2 and use the received second reset voltage Vref2 to reset the anode of the driven device LED.

[0060] In some embodiments, the light-emitting control branch includes a tenth switch transistor T8 and an eleventh switch transistor T9. A first end of the tenth switch transistor T8 is connected to a power line Vdd, and a second end of the tenth switch transistor T8 is connected to the first drive branch and the second drive branch. A second end of the eleventh switch transistor T9 is connected to the first drive branch and the second drive branch, and a second end of the eleventh switch transistor T9 is connected to the anode of the driven device LED.

[0061] In some embodiments, the data writing branch includes a thirteenth switch tube T10, the first end of the thirteenth switch tube T10 is used to connect to the data line Vdata that outputs the data signal, and the second end of the thirteenth switch tube T10 is respectively connected to the first driving branch, the second driving branch and the light-emitting control branch.

[0062] 4 , the process of driving a light-emitting diode to emit light by the pixel driving circuit is described below, taking the case where the width-to-length ratio of the second driving transistor is N times the width-to-length ratio of the first driving transistor as an example, where N is a natural number greater than 1.

[0063] In the pixel driving circuit provided in the first embodiment of the present application, the working process of the pixel driving circuit is mainly divided into reset stage 1, data writing stage 2 and light emitting stage 3, and the switching of the above three stages is realized by the control signal sent by the external control device.

[0064] FIG5 is a schematic diagram illustrating the fluctuations of control signals sent by an external control device when the pixel drive circuit operates in the first operating mode. As shown in FIG3 , when the pixel drive circuit is in reset phase 1, the external control device sends a low-level first reset voltage Vref1 and a low-level second reset voltage Vref2 to the fourth switch transistor T6 and the fifth switch transistor T7, respectively, turning on the fourth and fifth switches T6 and T7. At this point, the anode of the driven device LED is reset, and the driven device LED stops emitting light. Simultaneously, the first node N1 at the second end of the first capacitor C1 is reset, and the voltages at the control terminals of the first and second drive transistors T1 and T3 connected to N1 are initialized. When the pixel driving circuit is in data writing phase 2, a low-level control signal PSn is sent to the control terminals of the third switch T5 and the thirteenth switch T10, and a low-level first drive signal GD1 is sent to the control terminal of the first switch T2. At this time, the third switch T5, the thirteenth switch T10, the first driver transistor T1, and the first switch T2 are all turned on. The data signal Vdata passes through the third switch T5, the thirteenth switch T10, and the first switch T2, generating a first drive current I1. When the pixel driving circuit is in light-emitting phase 3, a low-level EM is sent to the control terminals of the tenth switch T8 and the eleventh switch T9, turning them on. At this time, a closed path is formed between the first drive branch and the driven device LED, and the first drive current I1 generated by the first drive branch is transmitted to the driven device LED, driving the LED to emit light. At this time, the relationship between the first driving current I1 output by the pixel driving circuit and other parameters is I1=1 / 2*μ*W / L1*Cox1(Vdata-Vdd), where μ is the mobility of the first driving transistor, Cox1 is the capacitance of the dielectric layer of the first driving transistor, W / L1 is the width-to-length ratio of the first driving transistor, Vdata is the data signal received by the data writing circuit, and Vdd is the voltage of the power line.

[0065] FIG6 is a schematic diagram illustrating the fluctuations of control signals sent by an external control device when the pixel drive circuit operates in the second operating mode. As shown in FIG6 , when the pixel drive circuit is in reset phase 1, the external control device sends a low-level first reset voltage Vref1 and a low-level second reset voltage Vref2 to the fourth switch transistor T6 and the fifth switch transistor T7, respectively, turning on the fourth and fifth switches T6 and T7. At this point, the anode of the driven device LED is reset, and the LED stops emitting light. Simultaneously, the first node N1 at the second end of the first capacitor C1 is reset, and the voltages at the control terminals of the first and second drive transistors T1 and T3 connected to N1 are initialized. When the pixel driving circuit is in data writing phase 2, a low-level control signal PSn is sent to the control terminals of the third switch transistor T5 and the thirteenth switch transistor T10, and a low-level second drive signal GD2 is sent to the control terminal of the second switch transistor T4. At this time, the third switch transistor T5, the thirteenth switch transistor T10, the second drive transistor T3, and the second switch transistor T4 are all turned on. The data signal Vdata passes through the third switch transistor T5, the thirteenth switch transistor T10, and the second switch transistor T4 to generate a second drive current I2. When the pixel driving circuit is in light-emitting phase 3, a low-level EM is sent to the control terminals of the tenth switch transistor T8 and the eleventh switch transistor T9, turning on the tenth switch transistor T8 and the eleventh switch transistor T9. At this time, a closed path is formed between the second drive branch and the driven device LED, and the second drive current I2 generated by the second drive branch is transmitted to the driven device LED, driving the LED to emit light. At this time, the relationship between the first driving current I2 output by the pixel driving circuit and other parameters is I2=1 / 2*μ*W / L2*Cox2(Vdata-Vdd), where μ is the mobility of the second driving transistor, Cox2 is the capacitance of the dielectric layer of the second driving transistor, and W / L2 is the width-to-length ratio of the second driving transistor.

[0066] In conjunction with the above description, when the pixel driving circuit operates in the first operating mode, the first driving transistor T1 is turned on to generate a driving current I1, and when the pixel driving circuit operates in the second operating mode, the second driving transistor T3 is turned on to generate a driving current I2. During the operation of the pixel driving circuit, the driving current amplitude output to the driven device LED varies when the pixel driving circuit operates in different operating modes. Accordingly, the luminous brightness of the driven device LED connected to the pixel driving circuit varies. In actual use, the aspect ratio of the first driving transistor T1 and the second driving transistor T3 can be set according to the brightness requirements of the display screen to which they belong, which will not be further described in this application.

[0067] In actual use, when the pixel driver circuit provided by the embodiments of the present application is applied to a display screen, the structure of the display screen can be seen in FIG7 , where multiple pixels Px in the display screen are arranged in a pixel array structure. Each pixel Px includes at least one pixel driver circuit and a driven device LED connected to the pixel driver circuit. During operation of each pixel driver circuit, the signals required by the internal switching devices can be provided by a control device installed in the display screen. To facilitate the circuit layout of the display screen, the signal transmission lines between the control device and the pixels can be arranged between adjacent pixel rows or between adjacent pixel columns.

[0068] Embodiment 2: The pixel driving circuit includes three working modes

[0069] In some embodiments, as shown in FIG8 , the first driving branch includes a third driving transistor T1, and the second driving branch includes a fourth driving transistor T2. The first end of the third driving transistor T1 is connected to the data writing branch, the second end of the third driving transistor T1 is connected to the light emission control branch, and the control end of the third driving transistor T1 is connected to the compensation branch. The first end of the fourth driving transistor T2 is connected to the data writing branch, the second end of the fourth driving transistor T2 is connected to the driven device LED via the light emission control branch, and the control end of the fourth driving transistor T2 is connected to the compensation branch.

[0070] In some embodiments, as shown in FIG8 , the compensation branch includes a second capacitor C1, a sixth switch transistor T3, a third capacitor C2, and a seventh switch transistor T4. The second capacitor constitutes a compensation capacitor for the third driving transistor T1. The first end of the second capacitor C1 is connected to the power line Vdd, and the second end of the second capacitor C1 is connected to the reset branch and the first end of the sixth switch transistor T3. The first end of the sixth switch transistor T3 is connected to the control terminal of the driving transistor in the first driving branch, and the second end of the sixth switch transistor T3 is connected to the light control branch. The third capacitor C2 constitutes a compensation capacitor for the fourth driving transistor T2. The first end of the third capacitor C2 is connected to the power line Vdd, and the second end of the third capacitor C2 is connected to the reset control and the first end of the seventh switch transistor T4. The first end of the seventh switch transistor T4 is connected to the control terminal of the driving transistor in the second driving branch, and the second end of the seventh switch transistor T4 is connected to the driven device LED via the light control branch.

[0071] Referring to the compensation branch structure shown in FIG8 , it can be seen that the second capacitor C1 constitutes the compensation capacitor of the third driving transistor T1, and the third capacitor C2 constitutes the compensation capacitor of the fourth driving transistor T2. The sixth switching transistor T3 and the seventh switching transistor T4 are both voltage-type control switching devices. An external control device can be connected to the control terminals of the sixth switching transistor T3 and the seventh switching transistor T4, respectively. When receiving a low-level reset voltage received by the reset branch, if it is necessary to control the third driving transistor T1 to be turned on, the external control device can control the sixth switching transistor T3 to be turned on, thereby charging and resetting the compensation capacitor of the third driving transistor T1 and initializing the voltage at the control terminal of the third driving transistor T1. Similarly, when receiving a low-level reset voltage received by the reset branch, if it is necessary to control the fourth driving transistor T2 to be turned on, the external control device can control the seventh switching transistor T4 to be turned on, thereby charging and resetting the compensation capacitor of the fourth driving transistor T2 and initializing the voltage at the control terminal of the fourth driving transistor T2.

[0072] In some embodiments, the reset branch includes an eighth switch transistor T5 and a ninth switch transistor T6. A first terminal of the eighth switch transistor T5 is connected to the compensation branch, and a second terminal of the eighth switch transistor T5 is configured to receive a first reset voltage Vref1 or a second reset voltage Vref2, and to charge and reset the two compensation capacitors using the first reset voltage Vref1 and the second reset voltage Vref2. A first terminal of the ninth switch transistor T6 is connected to an anode of an LED, a driven device, connected to the pixel driving circuit, and a second terminal of the ninth switch transistor T6 is configured to receive a third reset voltage Vref3, and to reset the anode of the driven device, the LED, using the third reset voltage Vref3.

[0073] In some embodiments, as shown in FIG6 , the light-emitting control branch includes a tenth switch transistor T7 and an eleventh switch transistor T8 . A first end of the tenth switch transistor T7 is connected to a power line Vdd, and a second end of the tenth switch transistor T7 is connected to the first drive branch and the second drive branch. A second end of the eleventh switch transistor T8 is connected to the first drive branch and the second drive branch, and a second end of the eleventh switch transistor T8 is connected to the anode of a driven device LED connected to the pixel driving circuit.

[0074] In some embodiments, the data writing branch includes a thirteenth switch tube T9, the first end of the thirteenth switch tube T9 is used to connect to the data line Vdata that outputs the data signal, and the second end of the thirteenth switch tube T9 is respectively connected to the first driving branch, the second driving branch and the light-emitting control branch.

[0075] 8 , the process of driving an LED to emit light using a pixel driving circuit is described below, taking the case where the width-to-length ratio of the second driving transistor is M times the width-to-length ratio of the first driving transistor as an example, where M is a natural number greater than 1.

[0076] In the pixel driving circuit provided in the first embodiment of the present application, the working process of the pixel driving circuit is mainly divided into reset stage 1, data writing stage 2 and light emitting stage 3, and the switching of the above three stages is realized by the control signal sent by the external control device.

[0077] FIG9 is a schematic diagram illustrating fluctuations in control signals sent by an external control device when the pixel driving circuit operates in the first operating mode. As shown in FIG9 , when the pixel driving circuit is in reset phase 1, since only the third driving transistor T1 is required to operate, not only the compensation capacitor C1 of the third driving transistor T1 needs to be charged and reset during the reset phase, but also the compensation capacitor C1 of the fourth driving transistor T2 needs to be charged and reset to prevent the fourth driving transistor T2 from being mis-turned on. Specifically, the external control device sends a low-level third reset voltage Vref3 and a low-level PSn-1 to the ninth switching transistor T6 to turn on the ninth switching transistor T6, thereby resetting the anode of the driven device LED and causing the LED to stop emitting light. First, the compensation capacitor of the driver transistor that needs to be turned on is charged and reset. The external control device sends a low-level first reset voltage Vref1 and a low-level PS3n to the eighth switch transistor T5, and sends a low-level PS1n to the sixth switch transistor T3. The eighth switch transistor T5 and the sixth switch transistor T3 are now turned on, charging and resetting the second capacitor C1, and setting the control terminal voltage of the third driver transistor T1 to a low level, turning off the sixth switch transistor T3. Then, the compensation capacitor of the driver transistor that does not need to be turned on is set to a high level. The high-level second reset voltage Vref2 is sent to the eighth switch transistor T5, and the low-level PS2n is sent to the seventh switch transistor T4. The eighth switch transistor T5 and the seventh switch transistor T4 are now turned on, charging and resetting the third capacitor C2, and setting the control terminal voltage of the fourth driver transistor T2 to a high level. Finally, the high-level PS3n is sent to the eighth switch transistor T5, turning off the eighth switch transistor T5. When the pixel driving circuit is in data writing phase 2, a low-level signal PS1n is sent to the control terminal of the sixth switch transistor T3, a low-level signal PS2n is sent to the control terminal of the seventh switch transistor T4, and a low-level control signal PSn is sent to the control terminal of the thirteenth switch transistor T9. At this time, since the control terminal voltage of the fourth drive transistor T2 is high and the device is turned off, the sixth switch transistor T3, the third drive transistor T1, and the thirteenth switch transistor T9 are all turned on. The data signal Vdata passes through the thirteenth switch transistor T9 and the third drive transistor T1 to generate a first drive current I1. When the pixel driving circuit is in light-emitting phase 3, a low-level signal EM is sent to the control terminals of the tenth switch transistor T7 and the eleventh switch transistor T8, turning them on. At this time, a closed path is formed between the first drive branch and the driven device LED, and the first drive current I1 generated by the first drive branch is sent to the driven device LED, driving the LED to emit light.At this time, the relationship between the first driving current I1 output by the pixel driving circuit and other parameters is I1=1 / 2*μ*W / L1*Cox1(Vdata-Vdd), where μ is the mobility of the third driving transistor, Cox1 is the capacitance of the dielectric layer of the third driving transistor, W / L1 is the width-to-length ratio of the third driving transistor, Vdata is the data signal received by the data writing circuit, and Vdd is the voltage of the power line.

[0078] FIG10 is a schematic diagram illustrating fluctuations in control signals sent by an external control device when the pixel driving circuit operates in the second operating mode. As shown in FIG8 , when the pixel driving circuit is in reset phase 1, since only the fourth driving transistor T2 is required to operate, during the reset phase, not only is it necessary to perform a low-level charging reset on the compensation capacitor C2 of the fourth driving transistor T2 , but it is also necessary to perform a high-level charging reset on the compensation capacitor of the third driving transistor T1 to prevent the third driving transistor T1 from being mis-turned on. Specifically, the external control device sends a low-level third reset voltage Vref3 and a low-level PSn-1 to the ninth switching transistor T6 to turn on the ninth switching transistor T6, thereby resetting the anode of the driven device LED and causing the driven device LED to stop emitting light. First, the compensation capacitor C2 of the fourth driver transistor T2, which needs to be turned on, is charged and reset at a low level. The external control device sends a low-level first reset voltage Vref1 and a low-level PS3n to the eighth switch T5, and sends a low-level PS2n to the seventh switch T4. The eighth and seventh switches T5 and T4 are now turned on, charging and resetting the third capacitor C2 at a low level, and turning off the seventh switch T4. Then, the compensation capacitor of the third driver transistor T1, which does not need to be turned on, is placed in a high-level state. The high-level second reset voltage Vref1 is sent to the eighth switch T5, and a low-level PS1n is sent to the sixth switch T3. The eighth and sixth switches T5 and T3 are now turned on, charging and resetting the third capacitor C2 at a high level, and then sending a high-level PS3n to the eighth switch T5, turning off the eighth switch T5. When the pixel driving circuit is in data writing phase 2, a low-level signal PS1n is sent to the control terminal of the sixth switch transistor T3, a low-level signal PS2n is sent to the control terminal of the seventh switch transistor T4, and a low-level control signal PSn is sent to the control terminal of the thirteenth switch transistor T9. At this time, since the control terminal voltage of the third drive transistor T1 is high and the device is turned off, the seventh switch transistor T4, the fourth drive transistor T2, and the thirteenth switch transistor T9 are all turned on. The data signal Vdata generates a second drive current I2 through the thirteenth switch transistor T9 and the fourth drive transistor T2. When the pixel driving circuit is in light-emitting phase 3, a low-level signal EM is sent to the control terminals of the tenth switch transistor T7 and the eleventh switch transistor T8, turning them on. At this time, a closed path is formed between the second drive branch and the driven device LED, and the first drive current I1 generated by the second drive branch is sent to the driven device LED, driving the LED to emit light. At this time, the relationship between the second driving current I2 output by the pixel driving circuit and other parameters is I2=1 / 2*μ*W / L2*Cox2(Vdata-Vdd), where μ is the mobility of the fourth driving transistor, Cox2 is the capacitance of the dielectric layer of the fourth driving transistor, and W / L2 is the width-to-length ratio of the third driving transistor.

[0079] FIG11 is a schematic diagram illustrating the fluctuations of control signals sent by an external control device when the pixel driving circuit operates in the third operating mode. As shown in FIG11 , when the pixel driving circuit is in reset phase 1, both driving branches must be active. Therefore, during the reset phase, the compensation capacitors of both driving transistors must be charged and reset at a low level. Specifically, the external control device sends a low-level third reset voltage Vref3 and a low-level signal PSn-1 to the ninth switching transistor T6 to turn on the ninth switching transistor T6, thereby resetting the anode of the driven device LED and stopping the driven device LED from emitting light. First, the external control device sends a low-level first reset voltage Vref1 and a low-level signal PS3n to the eighth switching transistor T5, and sends a low-level signal PS1n to the sixth switching transistor T3. At this point, the eighth switching transistor T5 and the sixth switching transistor T3 are turned on, charging and resetting the second capacitor C1. Furthermore, the voltage at the control terminal of the third driving transistor T1 is set to a low level, turning off the sixth switching transistor T3. Then, a low-level first reset voltage Vref1 is sent to the eighth switch transistor T5, and a low-level signal PS2n is sent to the seventh switch transistor T4. At this time, the eighth and seventh switches T5 and T4 are turned on, charging and resetting the third capacitor C2, and setting the control terminal voltage of the fourth drive transistor T2 to a low level. Then, a high-level signal PS3n is sent to the eighth switch transistor T5 to turn off the eighth switch transistor T5. When the pixel drive circuit is in data writing phase 2, a low-level signal PS1n is sent to the control terminal of the sixth switch transistor T3, a low-level signal PS2n is sent to the control terminal of the seventh switch transistor T4, and a low-level control signal PSn is sent to the control terminal of the thirteenth switch transistor T9. At this time, both drive transistors with low-level control terminal voltages are turned on, and the sixth and thirteenth switches T3 and T9 are also turned on. The data signal Vdata passes through the thirteenth switch transistor T9 and the third drive transistor T1 to generate a first drive current I1, and the data signal Vdata passes through the thirteenth switch transistor T9 and the fourth drive transistor T2 to generate a first drive current I2. When the pixel driving circuit is in the light-emitting stage 3, a low-level EM is sent to the control terminals of the tenth switch tube T7 and the eleventh switch tube T8, and the tenth switch tube T7 and the eleventh switch tube T8 are turned on. At this time, a closed path is formed between the first driving branch and the driven device LED, and the first driving current I1 generated by the first driving branch is sent to the driven device LED to drive the LED to emit light. A closed path is formed between the second driving branch and the driven device LED, and the second driving current I2 generated by the first driving branch is sent to the driven device LED to drive the LED to emit light.At this time, the total driving current output by the pixel driving circuit is I3. The relationship between the driving current I3 and other parameters is I3 = 1 / 2*μ*(W / L1+W / L2)*Cox1(Vdata-Vdd), where μ is the mobility of the third driving transistor, Cox1 is the capacitance of the dielectric layer of the third driving transistor, W / L1 is the width-to-length ratio of the third driving transistor, Vdata is the data signal received by the data writing circuit, and Vdd is the voltage of the power line. It should be noted that the calculation formula for the driving current in the above embodiment of the present application is described using the example of the same mobility of the two driving transistors. In practical applications, the mobility of the two driving transistors can be the same or different.

[0080] It should be noted that, in the introduction to the working mode of the pixel driving circuit provided in the above embodiment, the compensation capacitor of the turned-on driving transistor is charged first as an example. In actual use, the charging and resetting order of the compensation capacitors of the two driving transistors is not limited.

[0081] In actual use, when the pixel driver circuit provided by the embodiments of the present application is applied to a display screen, the structure of the display screen can be seen in FIG10 , wherein a plurality of pixels Px in the display screen are arranged in a pixel array structure, each pixel Px including at least one pixel driver circuit and a driven device connected to the pixel driver circuit. During operation of each pixel driver circuit, the signals required by the internal switching devices can be provided by a control device installed in the display screen. To facilitate the circuit layout of the display screen, the signal transmission lines between the control device and the pixels can be arranged between adjacent pixel rows or between adjacent pixel columns.

[0082] In some embodiments, if the sixth switch tube T3, the seventh switch tube T4, and the eighth switch tube T8 are devices of the type of thin film field effect transistor, in order to avoid the low frame rate flicker problem of the display screen caused by the use of the above devices, as shown in FIG12, the pixel driving circuit also includes a clearing branch, which is connected between the data writing branch and the driving branch. As shown in FIG13, the clearing branch includes a twelfth switch tube T10, the first end of the twelfth switch tube T10 is connected to the data writing branch, and the second end of the twelfth switch tube T10 is used to receive a fourth reset voltage. Since the twelfth switch tube T10 is connected between the data writing branch and the driving branch, when the above pixel driving structure is used to drive the LED to emit light, the twelfth switch tube T10 can be controlled to clear the charge at the above position before the light-emitting control stage, thereby eliminating the influence of the charge in the previous control process of the light-emitting diode on the current control.

[0083] In a specific embodiment, the clearing process of the data writing branch by the added twelfth switch tube T10 can be located at any time before the light-emitting control stage. For example, the clearing process of the data writing branch by the twelfth switch tube T10 can be located before the data writing stage 2 and the light-emitting stage 3. Taking the pixel driving circuit operating in the third operating mode as an example, the control signal waveform received by the pixel driving circuit in the third operating mode can be shown in Figure 14.

[0084] Based on the same concept, an embodiment of the present application also provides a display screen, which includes multiple pixel driving circuits and a light-emitting diode connected to each pixel driving circuit. Each pixel driving circuit and the connected light-emitting diode can serve as a pixel, and multiple pixels can form a pixel array. The display screen also includes a power supply device and a control device. The power supply device can supply power to the pixel driving circuit, and the control device can provide control signals to the pixel driving circuit to control the operation of the pixel driving circuit.

[0085] The above describes the process of driving a light-emitting diode to emit light from the perspective of a pixel driving circuit as a separate device. Those skilled in the art will appreciate that the pixel driving circuit provided in the embodiments of the present application may also be implemented in the form of a fully hardware embodiment, a fully software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may be implemented in the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0086] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the present application. It should be understood that each flow and / or box in the flow chart and / or block diagram, as well as the combination of the flow chart and / or box in the flow chart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more flow charts and / or one or more boxes in the block diagram.

[0087] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0088] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0089] Obviously, those skilled in the art may make various modifications and variations to this application without departing from the scope of protection of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A pixel driving circuit, characterized in that: include: A data writing branch, a first driving branch, a second driving branch and a compensation branch; The data writing branch is connected to the first driving branch and the second driving branch, and is used to write a data signal into the first driving branch and the second driving branch; The compensation branch is connected to the first driving branch and the second driving branch, and is used to generate a first threshold voltage of the first driving branch and a second threshold voltage of the second driving branch; The first driving branch is configured to generate a first driving current according to the data signal and the first threshold voltage, and output the first driving current to the driven device; The second driving branch is used to generate a second driving current according to the data signal and the second threshold voltage, and output the second driving current to the driven device; wherein the width-to-length ratios of the driving transistors in the first driving branch and the second driving branch are different.

2. The pixel driving circuit according to claim 1, wherein: The first driving branch includes: a first driving transistor and a first switching tube; The first end of the first driving transistor is connected to the data writing branch, the second end of the first driving transistor is connected to the first end of the first switching transistor, and the control end of the first driving transistor is connected to the compensation branch; The second end of the first switching tube is connected to the driven device. The control end of the first switching tube is used to receive a first driving signal. The first driving signal is used to control the first switching tube to be turned on.

3. The pixel driving circuit according to claim 1 or 2, wherein: The second driving branch includes a second driving transistor and a second switching tube; The first end of the second driving transistor is connected to the data writing branch, the second end of the second driving transistor is connected to the first end of the second switch tube, and the control end of the second driving transistor is connected to the compensation branch; The second end of the second switch tube is connected to the driven device, and the control end of the second switch tube is used to receive a second drive signal, and the second drive signal is used to control the second switch tube to be turned on.

4. The pixel driving circuit according to claim 2 or 3, wherein: The compensation branch includes: a first capacitor and a third switch tube; The first end of the first capacitor is used to be connected to the power line, and the second end of the first capacitor is connected to the first end of the third switch tube; A first end of the third switch tube is connected to the control ends of the drive transistors in the first drive branch and the second drive branch, and a second end of the third switch tube is connected to the driven device.

5. The pixel driving circuit according to any one of claims 2 to 4, wherein: The pixel driving circuit further includes a reset branch, which is connected to the compensation branch and is used to reset the driven device connected to the pixel driving circuit and the compensation branch.

6. The pixel driving circuit according to claim 5, wherein: The reset branch includes: a fourth switch tube and a fifth switch tube; A first end of the fourth switch tube is connected to the compensation branch, and a second end of the fourth switch tube is used to receive a first reset voltage; A first end of the fifth switch tube is connected to the driven device, and a second end of the fifth switch tube is used to receive a second reset voltage.

7. The pixel driving circuit according to claim 1, wherein: The first driving branch includes a third driving transistor, a first end of the third driving transistor is connected to the data writing branch, a second end of the third driving transistor is connected to the driven device, and a control end of the third driving transistor is connected to the compensation branch.

8. The pixel driving circuit according to claim 1 or 7, wherein: The second driving branch includes a fourth driving transistor, a first terminal of the fourth driving transistor is connected to the data writing branch, a second terminal of the fourth driving transistor is connected to the driven device, and a control terminal of the fourth driving transistor is connected to the compensation branch.

9. The pixel driving circuit according to claim 6 or 7, wherein: The compensation branch includes: a second capacitor, a sixth switch tube, a third capacitor and a seventh switch tube; The first end of the second capacitor is used to be connected to the power line, and the second end of the second capacitor is connected to the reset branch and the first end of the sixth switch tube; A first end of the sixth switch tube is connected to the control end of the driving transistor in the first driving branch, and a second end of the sixth switch tube is connected to the driven device; The first end of the third capacitor is used to be connected to the power line, and the second end of the third capacitor is connected to the reset branch and the first end of the seventh switch tube; A first end of the seventh switch tube is connected to the control end of the driving transistor in the second driving branch, and a second end of the seventh switch tube is connected to the driven device.

10. The pixel driving circuit according to claim 9, wherein: The reset branch includes an eighth switch tube and a ninth switch tube; A first end of the eighth switch tube is connected to the compensation branch, and a second end of the eighth switch tube is used to receive a first reset voltage or a second reset voltage; A first end of the ninth switch tube is connected to the driven device, and a second end of the ninth switch tube is used to receive a third reset voltage.

11. The pixel driving circuit according to any one of claims 1 to 10, wherein: The pixel driving circuit also includes a light-emitting control branch, which is connected to the first driving branch and the second driving branch respectively. The light-emitting control branch is used to control the first driving branch and the second driving branch to be connected to the power supply and the driven device respectively when receiving a light-emitting control signal.

12. The pixel driving circuit according to claim 11, wherein: The light emitting control branch includes: a tenth switch tube and an eleventh switch tube; The first end of the tenth switch tube is used to be connected to the power line, and the second end of the tenth switch tube is connected to the first driving branch and the second driving branch; The second end of the eleventh switching tube is connected to the first driving branch and the second driving branch, and the second end of the eleventh switching tube is used to be connected to the driven device.

13. The pixel driving circuit according to claim 9, wherein: The pixel driving circuit further includes a clearing branch, the reset branch includes a twelfth switch tube, a first end of the twelfth switch tube is connected to the data writing branch, and a second end of the twelfth switch tube is used to receive a clearing voltage.

14. The pixel driving circuit according to any one of claims 1 to 11, wherein: The data writing branch includes a thirteenth switch tube, a first end of the thirteenth switch tube is used to connect to the data line outputting the data signal, and a second end of the thirteenth switch tube is respectively connected to the first driving branch, the second driving branch and the driven device.

15. A display screen, characterized in that: The device comprises a plurality of pixel driving circuits according to any one of claims 1 to 14, a light source connected to each pixel driving circuit, a power supply device and a control device.

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