Pixel driver of a display device and pulse width modulation circuit thereof

Abstract

The utility model provides a kind of pixel driver of display device and its pulse width modulation circuit.The pixel driver of display device is suitable for driving the light-emitting component of display device, and include: constant current generating circuit, the output end of constant current generating circuit is connected light-emitting component and is configured to supply a light-emitting drive current to light-emitting component;And pulse width modulation circuit, include: pulse width modulation transistor, the first end of pulse width modulation transistor is connected the control end of constant current generating circuit, the second end of pulse width modulation transistor is coupled a reference potential, the control end of pulse width modulation transistor is connected to a charging node;And drive circuit, connected to charging node, configured to charge charging node according to a pulse width modulation signal and a scanning charging signal;Wherein, when pulse width modulation transistor opens, the control end of constant current generating circuit is coupled to reference potential by pulse width modulation transistor, so that constant current generating circuit stops supplying light-emitting drive current.

Description

Technical Field

[0001] This utility model relates to a driver, and more particularly to a pixel driver for a display device and its pulse width modulation circuit. Background Technology

[0002] With the development of micro-LED (Micro-LED) array drivers, improvements to backplane circuitry are becoming increasingly important. Currently, there is a need to develop a pixel driver capable of providing a stable driving current based on variations in the luminous current caused by factors such as process variations or operating time. This ensures consistent image quality across all locations on the panel and maintains a good current error rate at both high and low temperatures. Utility Model Content

[0003] To address the shortcomings of existing technologies, this utility model provides a pixel driver for a display device. The pixel driver is suitable for driving the light-emitting components of a display device and includes: a constant current generation circuit, the output of which is connected to the light-emitting component and configured to supply a light-emitting driving current to the component; and a pulse width modulation circuit, including: a pulse width modulation transistor, a first terminal of which is connected to the control terminal of the constant current generation circuit, a second terminal of which is coupled to a reference potential, and the control terminal of which is connected to a charging node; and a driving circuit connected to the charging node, configured to charge the charging node according to a pulse width modulation signal and a scanning charging signal; wherein, when the pulse width modulation transistor is turned on, the control terminal of the constant current generation circuit is coupled to the reference potential through the pulse width modulation transistor, causing the constant current generation circuit to stop supplying the light-emitting driving current.

[0004] Furthermore, the light-emitting component includes at least one light-emitting diode.

[0005] Furthermore, the driving circuit first charges the voltage of the charging node to an initial voltage according to the pulse width modulation signal, and then charges the voltage of the charging node from the initial voltage according to the scan charging signal.

[0006] Furthermore, the driving circuit includes: a pulse width modulation driving circuit connected to the charging node, configured to output a pulse charging signal to the charging node according to a pulse width modulation signal, so as to charge the voltage of the charging node to an initial voltage; and a scan driving circuit connected to the charging node, configured to output a scan charging signal to the charging node according to a scan signal, so as to charge the voltage of the charging node from the initial voltage.

[0007] Furthermore, the pulse width modulation driving circuit includes a pulse driving transistor, and the scan driving circuit includes a scan driving transistor; wherein the first terminal of the pulse driving transistor receives the pulse width modulation signal from an external circuit, the second terminal of the pulse driving transistor is connected to the charging node, and the control terminal of the pulse driving transistor is coupled to a modulation start voltage; wherein the first terminal of the scan driving transistor is connected to the charging node, the second terminal of the scan driving transistor receives the scan signal from the external circuit, and the control terminal of the scan driving transistor is coupled to a light emission control voltage.

[0008] Furthermore, the pulse width modulation circuit further includes: a pulse width modulation compensation circuit, connected to the first terminal of the pulse width modulation transistor and the control terminal, configured to compensate the voltage of the first terminal of the pulse width modulation transistor and the control terminal.

[0009] Furthermore, the pulse width modulation compensation circuit includes: a pulse coupling capacitor, the first end of which is connected to the second end of the pulse driving transistor and the first end of the scan driving transistor, and the second end of which is connected to the charging node.

[0010] Furthermore, the pulse width modulation compensation circuit includes: a reference modulation transistor, a first terminal of which is coupled to a compensation potential, a second terminal of which is connected to the charging node, and a control terminal of which is coupled to a first control voltage.

[0011] Furthermore, the pulse width modulation compensation circuit further includes: a pulse width modulation compensation transistor, a first terminal of which is connected to the second terminal of the reference modulation transistor, a second terminal of which is connected to the first terminal of the pulse width modulation transistor, and a control terminal of which is coupled to a second control voltage.

[0012] Furthermore, the pixel driver of the display device further includes: a bridge circuit connecting the first terminal of the pulse width modulation transistor and the control terminal of the constant current generation circuit, configured to connect the first terminal of the pulse width modulation transistor to the control terminal of the constant current generation circuit when turned on.

[0013] Furthermore, the constant current generating circuit includes: a current control transistor, the first terminal of which serves as the control terminal of the constant current generating circuit, the control terminal of which is coupled to a light emission control voltage; and a light emission current generating circuit, connected to the second terminal of the current control transistor and the light emission component, configured to output the light emission driving current to the light emission component based on the voltage of the second terminal of the current control transistor.

[0014] Furthermore, the light-emitting current generating circuit includes: a power input transistor, the first terminal of which is coupled to a common voltage, and the control terminal of which is coupled to a power input control voltage; and a constant current output transistor, the first terminal of which is connected to the second terminal of the power input transistor, the second terminal of which is connected to the light-emitting component, and the control terminal of which is connected to the second terminal of the current control transistor.

[0015] Furthermore, the light-emitting current generating circuit includes: a constant current starting transistor, the first terminal of which is connected to the first terminal of the constant current output transistor, the second terminal of which is connected to the control terminal of the constant current output transistor, and the control terminal of which is coupled to a first control voltage.

[0016] Furthermore, the constant current generation circuit also includes: a current modulation transistor, the first terminal of which is connected to the second terminal of the constant current output transistor, the second terminal of which is coupled to the reference potential, and the control terminal of which is coupled to a modulation start-up voltage.

[0017] Furthermore, the constant current generation circuit also includes a constant current compensation circuit connected to the control terminal of the constant current output transistor, configured to compensate the voltage of the control terminal of the constant current output transistor.

[0018] Furthermore, the constant current compensation circuit includes: a first current compensation transistor, the first terminal of which receives a pulse amplitude modulation signal from an external circuit, and the control terminal of the first current compensation transistor is coupled to a first control voltage; and a second current compensation transistor, the first terminal of which is connected to the second terminal of the first current compensation transistor, the second terminal of which is coupled to a compensation potential, and the control terminal of the second current compensation transistor is coupled to a second control voltage.

[0019] Furthermore, the constant current compensation circuit also includes: a compensation coupling capacitor, the first end of which is connected to the first end of the second current compensation transistor, and the second end of which is connected to the control terminal of the constant current output transistor.

[0020] Furthermore, the pixel driver of the display device further includes: a light-emitting input circuit connected to the output terminal of the constant current generating circuit and the light-emitting component, configured to transmit the light-emitting driving current supplied by the constant current generating circuit to the light-emitting component when turned on.

[0021] In addition, this utility model provides a pulse width modulation circuit for a pixel driver, which is suitable for driving the light-emitting components of a display device, and includes: a pulse width modulation transistor, a first terminal of which is connected to the control terminal of a constant current generation circuit, a second terminal of which is coupled to a reference potential, and the control terminal of which is connected to a charging node; and a driving circuit connected to the charging node, configured to charge the charging node according to a pulse width modulation signal and a scanning charging signal; wherein the constant current generation circuit supplies a light-emitting driving current to the light-emitting component; wherein when the pulse width modulation transistor is turned on, the control terminal of the constant current generation circuit is coupled to the reference potential through the pulse width modulation transistor, so that the constant current generation circuit stops supplying the light-emitting driving current.

[0022] Furthermore, the driving circuit includes: a pulse driving transistor, the first terminal of which receives the pulse width modulation signal from an external circuit, the second terminal of which is connected to the charging node, and the control terminal of which is coupled to a modulation start-up voltage; and a scan driving transistor, the first terminal of which is connected to the charging node, the second terminal of which receives a scan signal from the external circuit, and the control terminal of which is coupled to a light emission control voltage.

[0023] As described above, this invention provides a pixel driver for a display device and its pulse width modulation circuit. By charging the control terminal of the pulse width modulation transistor with a pulse width modulation signal and a scan charging signal, the voltage of the control terminal of the pulse width modulation transistor is controlled, thereby controlling the speed at which the pulse width modulation transistor switches from the off state to the on state. This achieves the effect of controlling or modulating the duration of light emission from the light-emitting component to the point where it stops emitting light. After testing, the pixel driver of this invention exhibits good output simulation results under high temperature and high leakage current conditions, indicating that it has good leakage current protection capabilities.

[0024] To further understand the features and technical content of this utility model, please refer to the following detailed description and drawings of this utility model. However, the drawings provided are for reference and illustration only and are not intended to limit this utility model. Attached Figure Description

[0025] Figure 1 This is a circuit diagram of the pixel driver and pulse width modulation circuit of the display device according to the first embodiment of the present invention.

[0026] Figure 2 This is a circuit diagram of the pixel driver and pulse width modulation circuit of the display device according to the second embodiment of the present invention.

[0027] Figure 3 This is a circuit diagram of the pixel driver and pulse width modulation circuit of the display device according to the third embodiment of the present invention.

[0028] Figure 4 This is a circuit diagram of the pixel driver and pulse width modulation circuit of the display device according to the fourth embodiment of the present invention.

[0029] Figure 5 The above are signal waveform diagrams of the pixel driver and pulse width modulation circuit of the display device according to the first to fourth embodiments of this utility model. Detailed Implementation

[0030] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can understand the advantages and effects of this utility model from the content disclosed in this specification. This utility model can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of this utility model. Furthermore, the accompanying drawings of this utility model are for simple illustrative purposes only and are not depictions of actual dimensions, as stated in advance. The following embodiments will further describe the relevant technical content of this utility model in detail, but the disclosed content is not intended to limit the scope of protection of this utility model. Additionally, the term "or" as used herein may, depending on the actual situation, include any combination of one or more of the associated listed items.

[0031] Please see Figure 1 and Figure 5 ,in Figure 1 This is a circuit diagram of the pixel driver and pulse width modulation circuit of the display device according to the first embodiment of the present invention. Figure 5 The above are signal waveform diagrams of the pixel drivers of the display devices according to the first to fourth embodiments of this utility model.

[0032] The pixel driver of this invention is applicable to display devices, such as micro-light-emitting diode (Micro-LED) display devices. In the display panel of the display device, multiple pixels are arranged in a matrix, and each of the multiple pixels includes multiple sub-pixels. Each of the multiple sub-pixels includes the pixel driver of this invention and a light-emitting component LED1 (e.g., a micro-light-emitting diode), wherein the light-emitting component LED1 emits light based on a driving current provided from the pixel driver of this invention.

[0033] This utility model pixel driver includes, for example, Figure 1 The pulse width modulation circuit 100 and constant current generation circuit 200 are shown. The pulse width modulation circuit 100 includes a pulse width modulation transistor Tm and a driving circuit 110, wherein the driving circuit 110 may include a pulse width modulation driving circuit 111 and a scanning driving circuit 112.

[0034] Pulse width modulation (PWM) driving circuit 111 and scan driving circuit 112 are connected to a charging node Nm. PWM driving circuit 111 receives a pulse width modulation signal (PWM) from a connected external circuit, while scan driving circuit 112 receives a scan signal (VSWEEP) from a connected external circuit. It should be understood that the external device described herein is a circuit other than the pixel driver of this invention, and may be other circuits in the display device.

[0035] The control terminal of the pulse width modulation transistor Tm is connected to a charging node Nm. The first terminal of the pulse width modulation transistor Tm is connected to the control terminal of the constant current generation circuit 200. The second terminal of the pulse width modulation transistor Tm is coupled to a reference potential VSS.

[0036] The output of the constant current generating circuit 200 is connected to the first terminal (e.g., anode) of the light-emitting component LED1. The second terminal (e.g., cathode) of the light-emitting component LED1 is coupled to a reference potential VSS.

[0037] When the pulse width modulation transistor Tm is turned off, the constant current generation circuit 200 generates a light-emitting driving current and supplies this light-emitting driving current to the anode of the light-emitting component LED1 so that the light-emitting component LED1 emits light.

[0038] The pulse width modulation (PWM) drive circuit 111 outputs a pulse charging signal to the charging node Nm based on a PWM signal, thereby charging the voltage of the charging node Nm to an initial voltage. Then, the scan drive circuit 112 outputs a scan charging signal to the charging node Nm based on a scan signal VSWEEP, thereby starting the charging of the charging node Nm from this initial voltage and gradually increasing the voltage of the charging node Nm from this initial voltage.

[0039] When the voltage at charging node Nm increases to the point where the pulse width modulation transistor Tm is turned on, the control terminal of the constant current generation circuit 200 is coupled to a low reference potential VSS through the pulse width modulation transistor Tm, thus turning off the constant current generation circuit 200 and stopping the supply of a light-emitting driving current to the light-emitting component LED1. At this time, the light-emitting component LED1 stops emitting light.

[0040] In other words, the pixel driver of this invention first uses a pulse width modulation signal (PWM) and then a scan signal (VSWEEP) to charge the voltage at the control terminal of the pulse width modulation transistor Tm. For example... Figure 5 As shown, during the working time interval t5, the voltage of the scan signal VSWEEP gradually increases, causing the voltage at the control terminal of the pulse width modulation transistor Tm to gradually increase accordingly. Until the pulse width modulation transistor Tm is turned on, the pixel driver of this invention stops supplying power to the light-emitting component LED1, causing LED1 to stop emitting light.

[0041] Therefore, the lower the voltage of the pulse width modulation signal (PWM) and the slower the voltage of the scan signal (VSWEEP) increases, the longer it takes for the voltage at the control terminal of the pulse width modulation transistor (Tm) to increase until Tm is turned on, and the longer the LED1 emits light. Conversely, the higher the voltage of the PWM signal and the faster the voltage of the scan signal (VSWEEP) increases, the shorter the time it takes for the voltage at the control terminal of the pulse width modulation transistor (Tm) to increase until Tm is turned on, and the shorter the LED1 emits light.

[0042] Therefore, the pulse width modulation circuit 100 of the pixel driver of this invention can supply a stable driving current and accurately control and modulate the light-emitting time of the light-emitting components LED1 of the sub-pixels of the display device. Multiple pixel drivers of this invention can be set in the display device to control multiple light-emitting components LED1 of multiple sub-pixels, thereby controlling the grayscale level of the pixels on the display panel and preventing color shift.

[0043] Please see Figure 2 and Figure 5 ,in Figure 2 This is a circuit diagram of the pixel driver and pulse width modulation circuit of the display device according to the second embodiment of the present invention. Figure 5 The above are signal waveform diagrams of the pixel drivers of the display devices according to the first to fourth embodiments of this utility model.

[0044] The second embodiment of this utility model is the same as the first embodiment, and will not be repeated in this article.

[0045] like Figure 2As shown, in the second embodiment, the pulse width modulation driving circuit 111 may include a transistor as a pulse driving transistor Tp1, and the scan driving circuit 112 may include a transistor as a scan driving transistor Tp2.

[0046] The first terminal of the pulse-driven transistor Tp1 receives a pulse width modulation (PWM) signal from a connected external circuit. The second terminal of the pulse-driven transistor Tp1 is connected to a charging node Nm. The control terminal of the pulse-driven transistor Tp1 is coupled to or receives a modulation start-up voltage ST from an external circuit.

[0047] The second terminal of the scan driver transistor Tp2 receives a scan signal VSWEEP from an external circuit. The first terminal of the scan driver transistor Tp2 is connected to a charging node Nm. The control terminal of the scan driver transistor Tp2 is coupled to or receives a light emission control voltage EM from an external circuit.

[0048] For example, the constant current generating circuit 200 includes a constant current output circuit 210, wherein the constant current output circuit 210 may include a current control transistor Tr and a light emission current generating circuit 211.

[0049] The first terminal of the current-controlled transistor Tr serves as the control terminal of the constant current generation circuit 200 and is connected to the first terminal of the pulse width modulation transistor Tm. The control terminal of the current-controlled transistor Tr is coupled to a light-emitting control voltage EM.

[0050] The light-emitting current generating circuit 211 is connected to the second terminal of the current-controlling transistor Tr. The light-emitting current generating circuit 211 is configured to output a light-emitting driving current to the anode of the light-emitting component LED1 based on the voltage at the second terminal of the current-controlling transistor Tr. For example, this light-emitting current generating circuit 211 may include one or more transistors, such as, but not limited to, those shown below. Figure 2 The power input transistor Tc1 and the constant current output transistor Tc2 are shown.

[0051] The first terminal of the power input transistor Tc1 is coupled to a common voltage VDD. The control terminal of the power input transistor Tc1 is coupled to a power input control voltage SC.

[0052] The first terminal (e.g., drain) of the constant current output transistor Tc2 is connected to the second terminal of the power input transistor Tc1. The second terminal (e.g., source) of the constant current output transistor Tc2 is connected to the anode of the light-emitting component LED1. The control terminal (e.g., gate) of the constant current output transistor Tc2 is connected to the second terminal of the current control transistor Tr.

[0053] like Figure 5As shown, during the working time interval t1 to t3, the modulation start voltage ST received by the control terminal of the pulse drive transistor Tp1 is at a high potential, which turns on the pulse drive transistor Tp1. The voltage of the pulse width modulation signal PWM is input to the first terminal of the pulse drive transistor Tp1, so that the second terminal of the pulse drive transistor Tp1 outputs a pulse charging signal to the charging node Nm, so as to charge the voltage of the control terminal of the pulse width modulation transistor Tm to an initial voltage.

[0054] After the modulation start-up voltage ST transitions from a high potential to a low potential, within the working time interval t5, the light emission control voltage EM transitions from a low potential to a high potential, turning on the scan drive transistor Tp2. At this time, the voltage of the scan signal VSWEEP is input to the second terminal of the scan drive transistor Tp2, causing the first terminal of the scan drive transistor Tp2 to output a scan charging signal through the charging node Nm, thereby gradually increasing the voltage at the control terminal of the pulse width modulation transistor Tm from the initial voltage.

[0055] During the working time interval t5, the power input control voltage SC coupled to the control terminal of the power input transistor Tc1 is at a high potential, which turns on the power input transistor Tc1. This allows the power supply current supplied by the common voltage VDD to flow sequentially through the power input transistor Tc1 and the constant current output transistor Tc2 to the light-emitting component LED1, causing the light-emitting component LED1 to emit light.

[0056] It is worth noting that during the operating time interval t5, when the light-emitting component LED1 emits light, the scan signal VSWEEP continuously charges the control terminal of the pulse width modulation transistor Tm through the scan drive transistor Tp2. Until the pulse width modulation transistor Tm is turned on, the control terminal of the constant current output transistor Tc2, coupled to a low-level reference potential VSS through the current control transistor Tr and the pulse width modulation transistor Tm, turns off the constant current output transistor Tc2. At this time, the constant current output transistor Tc2 stops supplying a light-emitting drive current to the light-emitting component LED1. Therefore, the light-emitting component LED1 stops emitting light.

[0057] Please see Figure 3 This is a circuit diagram of the pixel driver and pulse width modulation circuit of the display device according to the third embodiment of the present invention.

[0058] The third embodiment of this utility model is the same as the first and second embodiments, and will not be repeated herein. The difference between the third embodiment and the second embodiment lies in that, as... Figure 3 As shown, the pixel driver of the third embodiment of the present invention further includes a bridging circuit 300.

[0059] The bridging circuit 300 connects the first terminal of the pulse width modulation transistor Tm and the first terminal of the current control transistor Tr (i.e., the control terminal of the constant current generation circuit 200), and is coupled to a light emission control voltage EM or receives this light emission control voltage EM from an external circuit.

[0060] For example, the bridging circuit 300 includes a switching component, such as, but not limited to, a switching component. Figure 3 The diagram shows a bridging transistor Tb. The first terminal of the bridging transistor Tb is connected to the first terminal of a pulse width modulation transistor Tm. The second terminal of the bridging transistor Tb is connected to the first terminal of a current control transistor Tr. The control terminal of the bridging transistor Tb is coupled to a light-emitting control voltage EM.

[0061] When the bridging transistor Tb receives a light-emitting control voltage EM, such as Figure 5 As shown, during the operating time interval t1 to t4, when there is a shutdown potential (e.g., a low potential), the bridge transistor Tb is turned off. At this time, the first terminal of the pulse width modulation transistor Tm is not connected to the first terminal of the current control transistor Tr through the bridge transistor Tb.

[0062] Conversely, when the light-emitting control voltage EM is as follows Figure 5 As shown, when a turn-on potential (e.g., a high potential) is reached within the operating time interval t5, the first terminal of the pulse width modulation transistor Tm is connected to the first terminal of the current control transistor Tr through the bridge transistor Tb.

[0063] The control terminal of the scan drive transistor Tp2 also receives a light emission control voltage EM. Therefore, the scan drive transistor Tp2 and the bridge transistor Tb will be turned on or off simultaneously. Before the scan signal VSWEEP charges the charging node Nm through the turned-on scan drive transistor Tp2, the bridge transistor Tb prevents the control terminal of the constant current output transistor Tc2 from being affected by the voltage at the first terminal of the pulse width modulation transistor Tm.

[0064] Please see Figure 4 and Figure 5 ,in Figure 4 This is a circuit diagram of the pixel driver and pulse width modulation circuit of the display device according to the fourth embodiment of the present invention. Figure 5 The above are signal waveform diagrams of the pixel drivers of the display devices according to the first to fourth embodiments of this utility model.

[0065] The fourth embodiment of this utility model is the same as the first to third embodiments, and will not be repeated in this article.

[0066] like Figure 4As shown, the pixel driver of this utility model includes a pulse width modulation circuit 100, a constant current generation circuit 200, and a bridge circuit 300, as well as a light emission input circuit 400. The pulse width modulation circuit 100 includes a driving circuit 110 and a pulse width modulation compensation circuit 120, and the constant current generation circuit 200 includes a constant current output circuit 210 and a constant current compensation circuit 220.

[0067] If needed, such as Figures 1 to 3 The pulse width modulation circuit 100 shown may also include, for example, Figure 4 The pulse width modulation compensation circuit 120 shown, or as... Figures 1 to 3 The constant current generating circuit 200 shown may also include, for example: Figure 4 The constant current compensation circuit 220 shown is illustrated.

[0068] like Figure 4 As shown, the pulse width modulation compensation circuit 120 connects the first terminal and the control terminal of the pulse width modulation transistor Tm. The pulse width modulation compensation circuit 120 is configured to compensate for the voltage at the first terminal and the control terminal of the pulse width modulation transistor Tm.

[0069] For example, the pulse width modulation compensation circuit 120 may include a pulse coupling capacitor Cw, a reference modulation transistor Tw1, a pulse width modulation compensation transistor Tw2, or any combination thereof.

[0070] The first terminal of the pulse coupling capacitor Cw is connected to the node between the second terminal of the pulse driving transistor Tp1 and the first terminal of the scan driving transistor Tp2. The second terminal of the pulse coupling capacitor Cw is connected to a charging node Nm.

[0071] The control terminal of the reference modulation transistor Tw1 is coupled to a first control voltage SF. The first terminal of the reference modulation transistor Tw1 is coupled to a compensation potential VREF. The second terminal of the reference modulation transistor Tw1 is connected to a charging node Nm.

[0072] The first terminal of the pulse width modulation compensation transistor Tw2 is connected to the second terminal of the reference modulation transistor Tw1. The second terminal of the pulse width modulation compensation transistor Tw2 is connected to the first terminal of the pulse width modulation transistor Tm. The control terminal of the pulse width modulation compensation transistor Tw2 is coupled to the second control voltage SK.

[0073] For example, the constant current compensation circuit 220 may include a first current compensation transistor Ts1, a second current compensation transistor Ts2, a compensation coupling capacitor Cs, or any combination thereof, while the constant current output circuit 210 may include a constant current start-up transistor Td, a current control transistor Tr, and a light-emitting current generation circuit 211. The light-emitting current generation circuit 211 may include a power input transistor Tc1 and a constant current output transistor Tc2.

[0074] The first terminal of the constant current start-up transistor Td is connected to the node between the second terminal of the power input transistor Tc1 and the first terminal of the constant current output transistor Tc2. The second terminal of the constant current start-up transistor Td is connected to the control terminal of the constant current output transistor Tc2. The control terminal of the constant current start-up transistor Td is coupled to the first control voltage SF.

[0075] The first terminal of the first current compensation transistor Ts1 receives a pulse amplitude modulation signal PAM from an external circuit. The control terminal of the first current compensation transistor Ts1 is coupled to a first control voltage SF.

[0076] The first terminal of the second current compensation transistor Ts2 is connected to the second terminal of the first current compensation transistor Ts1. The second terminal of the second current compensation transistor Ts2 is coupled to a compensation potential VREF. The control terminal of the second current compensation transistor Ts2 is coupled to a second control voltage SK.

[0077] The first terminal of the compensation coupling capacitor Cs is connected to the node between the first terminal of the second current compensation transistor Ts2 and the second terminal of the first current compensation transistor Ts1. The second terminal of the compensation coupling capacitor Cs is connected to the control terminal of the constant current output transistor Tc2.

[0078] like Figure 5 As shown, during the working time interval t1 to t2, the first control voltage SF is at a high potential, which turns on the first current compensation transistor Ts1. This allows the pulse amplitude modulation signal PAM to pass through the first current compensation transistor Ts1 and the compensation coupling capacitor Cs to compensate the voltage at the control terminal of the constant current output transistor Tc2.

[0079] Next, during the working time interval t3 to t4, the second control voltage SK is at a high potential, which turns on the second current compensation transistor Ts2. This causes the compensation potential VREF to pass through the second current compensation transistor Ts2 and the compensation coupling capacitor Cs to compensate the voltage at the control terminal of the constant current output transistor Tc2.

[0080] It is worth noting that the pixel driver of this invention can include a second current compensation transistor Ts2 that can resist changes in carrier mobility. Therefore, compared with conventional drivers, when using the pixel driver of this invention to drive a display device, it can prevent uneven bright and dark spots (MURA) from appearing on the display screen, achieve more uniform brightness, and reduce integrated circuit traces, thereby reducing the layout area.

[0081] It should be understood that in the pixel driver of the fourth embodiment of this utility model, compensation for the pulse width modulation transistor Tm is achieved through the diode-connected structure of the pulse width modulation compensation transistor Tw2, and compensation for the constant current output transistor Tc2 is achieved through the second current compensation transistor Ts2, which has a smaller carrier mobility. Thus, the pixel driver of this utility model can stably maintain a constant driving current, improving the luminous stability of the light-emitting component LED1. When multiple pixel drivers of this utility model are used in a display device to control multiple light-emitting components LED1 of multiple sub-pixels respectively, it can ensure that the image quality is the same at each position on the display panel of the display device.

[0082] If necessary, the second terminal of the constant current output transistor Tc2 can be connected to the first terminal of the current modulation transistor Tk. The second terminal of the current modulation transistor Tk is coupled to a reference potential VSS. The control terminal of the current modulation transistor Tk is coupled to a modulation start-up voltage ST. When the current modulation transistor Tk is turned on, the second terminal of the constant current output transistor Tc2 can discharge to the reference potential VSS, thereby reducing the voltage at the second terminal of the constant current output transistor Tc2.

[0083] If necessary, a light-emitting input circuit 400 can be provided between the output terminal of the constant current generating circuit 200 and the anode of the light-emitting component LED1.

[0084] For example, the light-emitting input circuit 400 may include a light-emitting input transistor Tu. The first terminal of the light-emitting input transistor Tu is connected to the second terminal of the constant current output transistor Tc2 (i.e., the output terminal of the constant current generation circuit 200). The second terminal of the light-emitting input transistor Tu is connected to the anode of the light-emitting component LED1. The control terminal of the light-emitting input transistor Tu is coupled to a light-emitting control voltage EM.

[0085] When the light-emitting control voltage EM reaches a turn-on potential (e.g., a high potential), a light-emitting driving current output from the second terminal of the constant current output transistor Tc2 flows through the light-emitting input circuit 400 (the light-emitting input transistor Tu) to the anode of the light-emitting component LED1, causing the light-emitting component LED1 to emit light.

[0086] In summary, this utility model provides a pixel driver for a display device and its pulse width modulation circuit. Its main technical feature lies in controlling the speed at which the pulse width modulation transistor switches from a cutoff state to a conduction state by charging the voltage of the control terminal of the pulse width modulation transistor with a pulse width modulation signal and a scan charging signal. This controls the duration of light emission from emission to cessation of light emission by the light-emitting component. After testing, the pixel driver of this utility model exhibits good output simulation results under high temperature and high leakage current conditions, indicating that it possesses good leakage current protection capabilities.

[0087] The above-disclosed content is only a preferred and feasible embodiment of the present utility model, and is not intended to limit the claims of the present utility model. Therefore, all equivalent technical changes made based on the content of the present utility model specification and drawings are included in the claims of the present utility model.

Claims

1. A pixel driver for a display device, characterized in that, The pixel driver of the display device is adapted to drive the light-emitting components of the display device and includes: A constant current generating circuit, wherein the output terminal of the constant current generating circuit is connected to the light-emitting component and configured to supply a light-emitting driving current to the light-emitting component; and Pulse width modulation circuit, comprising: A pulse width modulation transistor, wherein the first terminal of the pulse width modulation transistor is connected to the control terminal of the constant current generation circuit, the second terminal of the pulse width modulation transistor is coupled to a reference potential, and the control terminal of the pulse width modulation transistor is connected to a charging node. and A driving circuit, connected to the charging node, is configured to charge the charging node according to a pulse width modulation signal and a scan charging signal; When the pulse width modulation transistor is turned on, the control terminal of the constant current generation circuit is coupled to the reference potential through the pulse width modulation transistor, so that the constant current generation circuit stops supplying the light-emitting driving current.

2. The pixel driver of the display device according to claim 1, characterized in that, The light-emitting component includes at least one light-emitting diode.

3. The pixel driver of the display device according to claim 1, characterized in that, The driving circuit first charges the voltage of the charging node to an initial voltage according to the pulse width modulation signal, and then charges the voltage of the charging node from the initial voltage according to the scan charging signal.

4. The pixel driver of the display device according to claim 1, characterized in that, The driving circuit includes: A pulse width modulation drive circuit, connected to the charging node, is configured to output a pulse charging signal to the charging node according to a pulse width modulation signal, so as to charge the voltage of the charging node to an initial voltage. as well as A scan drive circuit, connected to the charging node, is configured to output a scan charging signal to the charging node based on a scan signal, so as to charge the voltage of the charging node from the initial voltage.

5. The pixel driver of the display device according to claim 4, characterized in that, The pulse width modulation driving circuit includes a pulse driving transistor, and the scan driving circuit includes a scan driving transistor. The first terminal of the pulse driving transistor receives the pulse width modulation signal from an external circuit, the second terminal of the pulse driving transistor is connected to the charging node, and the control terminal of the pulse driving transistor is coupled to a modulation start-up voltage. The first terminal of the scan driving transistor is connected to the charging node, the second terminal of the scan driving transistor receives the scan signal from the external circuit, and the control terminal of the scan driving transistor is coupled to a light emission control voltage.

6. The pixel driver of the display device according to claim 5, characterized in that, The pulse width modulation circuit further includes: A pulse width modulation compensation circuit is connected to the first terminal and the control terminal of the pulse width modulation transistor, and is configured to compensate the voltage of the first terminal and the control terminal of the pulse width modulation transistor.

7. The pixel driver of the display device according to claim 6, characterized in that, The pulse width modulation compensation circuit includes: A pulse coupling capacitor, wherein the first end of the pulse coupling capacitor is connected to the second end of the pulse driving transistor and the first end of the scan driving transistor, and the second end of the pulse coupling capacitor is connected to the charging node.

8. The pixel driver of the display device according to claim 6, characterized in that, The pulse width modulation compensation circuit includes: A reference modulation transistor, wherein a first terminal of the reference modulation transistor is coupled to a compensation potential, a second terminal of the reference modulation transistor is connected to the charging node, and a control terminal of the reference modulation transistor is coupled to a first control voltage.

9. The pixel driver of the display device according to claim 8, characterized in that, The pulse width modulation compensation circuit further includes: A pulse width modulation compensation transistor, wherein the first terminal of the pulse width modulation compensation transistor is connected to the second terminal of the reference modulation transistor, the second terminal of the pulse width modulation compensation transistor is connected to the first terminal of the pulse width modulation transistor, and the control terminal of the pulse width modulation compensation transistor is coupled to a second control voltage.

10. The pixel driver of the display device according to claim 9, characterized in that, The pixel driver of the display device further includes: A bridging circuit is provided to connect the first terminal of the pulse width modulation transistor and the control terminal of the constant current generation circuit, and is configured to connect the first terminal of the pulse width modulation transistor to the control terminal of the constant current generation circuit when the circuit is turned on.

11. The pixel driver of the display device according to claim 1, characterized in that, The constant current generating circuit includes: A current-controlled transistor, wherein the first terminal of the current-controlled transistor serves as the control terminal of the constant current generation circuit, and the control terminal of the current-controlled transistor is coupled to a light-emitting control voltage; and A light-emitting current generating circuit is connected to the second terminal of the current-controlled transistor and the light-emitting component, and is configured to output the light-emitting driving current to the light-emitting component based on the voltage of the second terminal of the current-controlled transistor.

12. The pixel driver of the display device according to claim 11, characterized in that, The light-emitting current generating circuit includes: A power input transistor, wherein the first terminal of the power input transistor is coupled to a common voltage, and the control terminal of the power input transistor is coupled to a power input control voltage; as well as A constant current output transistor, wherein the first terminal of the constant current output transistor is connected to the second terminal of the power input transistor, the second terminal of the constant current output transistor is connected to the light-emitting component, and the control terminal of the constant current output transistor is connected to the second terminal of the current control transistor.

13. The pixel driver of the display device according to claim 12, characterized in that, The light-emitting current generating circuit includes: A constant current start-up transistor, wherein the first terminal of the constant current start-up transistor is connected to the first terminal of the constant current output transistor, the second terminal of the constant current start-up transistor is connected to the control terminal of the constant current output transistor, and the control terminal of the constant current start-up transistor is coupled to a first control voltage.

14. The pixel driver of the display device according to claim 12, characterized in that, The constant current generating circuit further includes: A current modulation transistor, wherein the first terminal of the current modulation transistor is connected to the second terminal of the constant current output transistor, the second terminal of the current modulation transistor is coupled to the reference potential, and the control terminal of the current modulation transistor is coupled to a modulation start-up voltage.

15. The pixel driver of the display device according to claim 12, characterized in that, The constant current generating circuit further includes: A constant current compensation circuit is connected to the control terminal of the constant current output transistor and configured to compensate the voltage at the control terminal of the constant current output transistor.

16. The pixel driver of the display device according to claim 15, characterized in that, The constant current compensation circuit includes: A first current compensation transistor, the first terminal of the first current compensation transistor receives a pulse amplitude modulation signal from an external circuit, and the control terminal of the first current compensation transistor is coupled to a first control voltage. as well as A second current compensation transistor has a first terminal connected to the second terminal of the first current compensation transistor, a second terminal of the second current compensation transistor coupled to a compensation potential, and a control terminal of the second current compensation transistor coupled to a second control voltage.

17. The pixel driver of the display device according to claim 16, characterized in that, The constant current compensation circuit further includes: A compensation coupling capacitor is provided, wherein the first end of the compensation coupling capacitor is connected to the first end of the second current compensation transistor, and the second end of the compensation coupling capacitor is connected to the control terminal of the constant current output transistor.

18. The pixel driver of the display device according to claim 1, characterized in that, The pixel driver of the display device further includes: A light-emitting input circuit is connected to the output terminal of the constant current generating circuit and the light-emitting component. When turned on, it is configured to transmit the light-emitting driving current supplied by the constant current generating circuit to the light-emitting component.

19. A pulse width modulation circuit for a pixel driver, characterized in that, The pulse width modulation circuit of the pixel driver is suitable for driving the light-emitting components of a display device, and includes: A pulse width modulation transistor, wherein the first terminal of the pulse width modulation transistor is connected to the control terminal of a certain current generation circuit, the second terminal of the pulse width modulation transistor is coupled to a reference potential, and the control terminal of the pulse width modulation transistor is connected to a charging node. as well as A driving circuit, connected to the charging node, is configured to charge the charging node according to a pulse width modulation signal and a scan charging signal; The constant current generating circuit supplies a light-emitting driving current to the light-emitting component; When the pulse width modulation transistor is turned on, the control terminal of the constant current generation circuit is coupled to the reference potential through the pulse width modulation transistor, so that the constant current generation circuit stops supplying the light-emitting driving current.

20. The pulse width modulation circuit of the pixel driver according to claim 19, characterized in that, The driving circuit includes: A pulse-driven transistor, wherein a first terminal of the pulse-driven transistor receives the pulse width modulation signal from an external circuit, a second terminal of the pulse-driven transistor is connected to the charging node, and a control terminal of the pulse-driven transistor is coupled to a modulation start-up voltage; as well as A scan driving transistor, wherein a first terminal of the scan driving transistor is connected to the charging node, a second terminal of the scan driving transistor receives a scan signal from the external circuit, and a control terminal of the scan driving transistor is coupled to a light emission control voltage.

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