Pixel driving circuit and pixel driving system

Abstract

The present application relates to a pixel driving circuit and a pixel driving system. The circuit receives input signals, which comprise a slope signal, a grayscale voltage, a sampling signal and a reference signal. The circuit comprises: a first switch unit, which is configured to sample a grayscale voltage according to a sampling signal, and store the sampled grayscale voltage in a capacitor component; the capacitor component, which is configured to store the sampled grayscale voltage sampled by the first switch unit; a comparison component, which is configured to compare a slope signal with the sampled grayscale voltage, and generate a pulse width modulation signal according to a comparison result; and a display component, which adjusts light emission brightness on the basis of the pulse width modulation signal. Thus, the strict frequency and time sequence requirements of a control signal in a digital driving mode can be avoided, and the phenomena of pitting and non-uniformity in an analog driving mode can be solved.

Description

Pixel driving circuit and pixel driving system Technical Field

[0001] The present application relates to the field of micro-display technology, and in particular to a pixel driving circuit and a pixel driving system. Background Art

[0002] With the advancement of science and technology, display technology has been applied in various scenarios, and the demand for display technology is increasing, leading to the emergence of new display technologies. Microdisplays are display devices with miniature screen sizes, typically less than 1 inch (2.54 cm) in diagonal size. They are commonly used in head-mounted displays, AR (Augmented Reality) / VR (Virtual Reality) devices, automotive HUDs (Head-up Displays), and micro projectors. Microdisplay technology offers advantages such as low cost, small size, and low power consumption, and has excellent development prospects.

[0003] However, the two main methods of micro-display driving in traditional technologies both have certain disadvantages. One is analog driving technology, which converts grayscale data into driving electrical signals such as driving voltage or driving current through a digital-to-analog converter, and achieves different brightness by controlling the size of the driving voltage or current; its advantage is that the control method is simple, but it has the disadvantages of increasingly stringent requirements on the driving capability and bandwidth of the output buffer, and is susceptible to noise interference and pitting at low grayscales. The other is digital driving technology, which achieves different brightness by controlling the conduction time of the switch in the pixel while keeping the driving electrical signal unchanged. Its advantage is that the light-emitting device has high efficiency and good display uniformity, but its disadvantages include complex and stringent requirements on the system's interface circuit and timing, which will make it increasingly difficult for chips to support this driving mode.

[0004] Summary of the Invention

[0005] Based on this, it is necessary to provide a pixel driving circuit and a pixel driving system to address the above technical problems, which can avoid the pitting phenomenon during pixel display in a simpler control method.

[0006] In a first aspect, the present application provides a pixel driving circuit. The circuit receives an input signal, the input signal including a ramp signal, a grayscale voltage, and a sampling signal, and the circuit includes:

[0007] A first switch unit is configured to sample a grayscale voltage according to a sampling signal and store the sampled grayscale voltage in a capacitor component;

[0008] a capacitor component, configured to store a sampled grayscale voltage obtained by sampling the first switch unit;

[0009] A comparison component, used for comparing the ramp signal with the sampled grayscale voltage, and generating a pulse width modulation signal according to the comparison result;

[0010] Display components that adjust light brightness based on pulse width modulation signals.

[0011] In one embodiment, the first end of the first switch unit is connected to the grayscale voltage, the second end of the first switch unit is connected to the upper plate of the capacitor component and the first input end of the comparison component, and the control end of the first switch unit is connected to the sampling signal.

[0012] In one embodiment, the second input terminal of the comparison component receives the ramp signal, and the output terminal of the comparison component is connected to the display component.

[0013] In one embodiment, the brightness of the display device is proportional to the pulse width of the pulse width modulation signal.

[0014] In one embodiment, the display element includes LCOS or OLED; wherein, when the display element is LCOS, the pulse width modulation signal and the common electrode voltage are periodically flipped, and the difference is guaranteed to remain unchanged; when the display element is OLED, the pulse width modulation signal and the common electrode voltage remain unchanged.

[0015] In one embodiment, the circuit further includes a storage component, and the storage component includes a static random access memory.

[0016] In one embodiment, the circuit further includes a second switch unit and a reference source, where the reference source includes a reference voltage or a reference current.

[0017] In a second aspect, the present application further provides a pixel driving system. The system includes:

[0018] A pixel driving circuit as provided in any one embodiment of the first aspect;

[0019] A signal generating circuit, used for generating an input signal for a pixel driving circuit;

[0020] The common electrode voltage generating circuit is used to generate a common electrode voltage.

[0021] In one embodiment, the signal generating circuit includes:

[0022] A ramp signal generating circuit, connected to the pixel driving circuit, for generating a ramp signal;

[0023] The grayscale voltage generating circuit is connected to the pixel driving circuit and is used to generate a grayscale voltage.

[0024] In one embodiment, the signal generating circuit further includes a reference generating circuit connected to the pixel driving circuit and configured to generate a reference signal.

[0025] The above-mentioned pixel driving circuit and pixel driving system receive input signals, including a ramp signal, a grayscale voltage, and a sampling signal; a first switching unit for sampling the grayscale voltage according to the sampling signal and storing the sampled grayscale voltage in a capacitor component; a capacitor component for storing the sampled grayscale voltage obtained by sampling the first switching unit; a comparison component for comparing the ramp signal with the sampled grayscale voltage and generating a pulse width modulation signal based on the comparison result; and a display component for adjusting the luminous brightness based on the pulse width modulation signal. The pixel driving system includes a pixel driving circuit; a signal generation circuit for generating an input signal for the pixel driving circuit; and a common electrode voltage generation circuit for generating a common electrode voltage. The pixel driving circuit includes a grayscale voltage storage function, and the grayscale voltage generation circuit adopts an analog drive method, which has the advantage of a simple control method. At the same time, as screen resolution increases, the analog drive method can still meet the demand by increasing the driving capability and bandwidth of the output buffer, avoiding the strict frequency and timing requirements of the control signal in the digital drive method. Secondly, the pixel driving circuit converts its corresponding grayscale voltage into a PWM (Pulse Width Modulation) signal, realizing the conversion from analog driving mode to digital driving mode, avoiding the pitting and unevenness caused by leakage during pixel display in the analog driving mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic structural diagram of a pixel driving circuit in one embodiment;

[0027] FIG2 is a schematic structural diagram of a pixel driving system in one embodiment;

[0028] FIG3 is a schematic structural diagram of a pixel driving circuit in another embodiment;

[0029] FIG4 is a schematic structural diagram of a pixel driving system in another embodiment;

[0030] FIG5 is a line chart comparing the reference voltage, the common electrode voltage, the ramp signal, the grayscale voltage, and the pulse width modulation signal in one embodiment;

[0031] FIG6 is a schematic structural diagram of a pixel driving circuit in yet another embodiment;

[0032] FIG7 is a schematic structural diagram of a pixel driving system in yet another embodiment;

[0033] FIG8 is a line chart comparing the reference voltage, the common electrode voltage, the ramp signal, the grayscale voltage, and the pulse width modulation signal in another embodiment. DETAILED DESCRIPTION

[0034] With the development of science and technology, display technology has been applied in various scenarios, and the demand for display technology is increasing, with new display technologies emerging one after another. A microdisplay is a display device with a micro screen size, usually referring to a display with a diagonal size less than 1 inch (2.54 cm). It is often used in head-mounted displays, AR / VR devices, in-vehicle HUDs, micro projectors, etc. Microdisplay technology uses semiconductor processes to manufacture the driver panel on a silicon wafer. Then, the light-emitting device is injected between the CMOS (Complementary Metal Oxide Semiconductor) substrate and ITO (Indium Tin Oxide) conductive glass. Finally, the grayscale display of each pixel is achieved by controlling the driving electrical signal of the CMOS substrate and the ITO common electrode. Microdisplay technology has the advantages of low cost, small size, low power consumption, etc., and has excellent development prospects.

[0035] There are two main ways to drive micro displays in traditional technologies: analog drive and digital drive.

[0036] Analog drive technology converts grayscale data into an electrical drive signal via a digital-to-analog converter. Varying brightness levels are achieved by controlling the drive voltage or current. While its advantage lies in its simple control, it also has certain drawbacks. First, as screen resolution increases, the load increases, placing greater demands on the output buffer's drive capability and bandwidth. Second, at low grayscale levels, the drive signal amplitude is small, making it susceptible to noise interference. This results in poor brightness uniformity across the light-emitting device and a tendency for pitting.

[0037] Digital drive technology achieves varying brightness levels by controlling the on-time of pixel switches while maintaining a constant drive signal. Its advantages include high light-emitting device efficiency and improved display uniformity. However, because different grayscale levels within the same frame require different light-emitting times, frequency division is required to modulate the pixel switch on-time. This means that as the resolution and precision of the microdisplay increase, the frequency of the control signal output by the drive circuit increases exponentially, placing complex and stringent requirements on the system's interface circuitry and timing. This makes it increasingly difficult for chips to support this drive mode.

[0038] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0039] In one embodiment, as shown in FIG1 , a pixel driving circuit 100 is provided. The circuit receives an input signal, where the input signal includes a ramp signal, a grayscale voltage, and a sampling signal. The circuit includes:

[0040] The first switch unit 102 is configured to sample the grayscale voltage according to the sampling signal and store the sampled grayscale voltage in the capacitor component 104 .

[0041] The capacitor component 104 is configured to store the sampled grayscale voltage obtained by sampling the first switch unit.

[0042] The comparison component 106 is used to compare the ramp signal with the sampled grayscale voltage and generate a pulse width modulation signal according to the comparison result.

[0043] The display device 108 adjusts the light emission brightness based on the pulse width modulation signal.

[0044] In one embodiment, the pixel driving circuit input signals include a ramp signal Ramp, a grayscale voltage Vgray, and a sampling signal Sample. Furthermore, the first switching unit 102 samples the grayscale voltage Vgray according to the sampling signal Sample and stores the sampled grayscale voltage Vgray in the capacitor 104. The comparison component 106 compares the ramp signal Ramp with the sampled grayscale voltage Vgray to generate a PWM signal that controls the brightness of the display component 108.

[0045] In the aforementioned pixel drive circuit, the circuit receives input signals, including a ramp signal, a grayscale voltage, and a sampling signal. The circuit includes a first switching unit for sampling the grayscale voltage according to the sampling signal and storing the sampled grayscale voltage in a capacitor; a capacitor for storing the sampled grayscale voltage obtained by sampling the first switching unit; a comparison unit for comparing the ramp signal with the sampled grayscale voltage and generating a pulse-width modulation signal based on the comparison result; and a display unit for adjusting the luminous brightness based on the pulse-width modulation signal. The pixel drive circuit includes grayscale voltage storage and conversion functions for converting the grayscale voltage into a PWM signal. This conversion achieves a transition from analog to digital drive, avoiding the stringent frequency and timing requirements of the control signal in high-resolution digital drive, and also avoiding the pitting and unevenness caused by leakage during pixel display in analog drive.

[0046] In one embodiment, the first end of the first switch unit is connected to the grayscale voltage, the second end of the first switch unit is connected to the upper plate of the capacitor component and the first input end of the comparison component, and the control end of the first switch unit is connected to the sampling signal.

[0047] Specifically, the first end of the first switch unit is connected to the grayscale voltage, the second end of the first switch unit is connected to the upper plate of the capacitor component and the input end of the comparison component, and the control end of the first switch unit is connected to the sampling signal.

[0048] In this embodiment, the first end of the first switch unit is connected to the grayscale voltage, the second end of the first switch unit is connected to the upper plate of the capacitor component and the first input end of the comparison component, and the control end of the first switch unit is connected to the sampling signal. Through this connection method, the first switch unit, the capacitor component, and the comparison component are connected to the grayscale voltage and the sampling signal to form part of the pixel driving circuit structure. The grayscale voltage and the sampling signal are received and processed to prepare for obtaining the sampled grayscale voltage and the PWM signal.

[0049] In one embodiment, the second input terminal of the comparison component receives the ramp signal, and the output terminal of the comparison component is connected to the display component.

[0050] In this embodiment, the second input terminal of the comparison component receives the ramp signal, and the output terminal of the comparison component is connected to the display component, so that the comparison component, the display component and the ramp signal are connected to form a part of the pixel driving circuit structure.

[0051] In one embodiment, the brightness of the display device is proportional to the pulse width of the pulse width modulation signal.

[0052] Specifically, the wider the pulse width of the pulse width modulation signal, the brighter the brightness of the display component.

[0053] In this embodiment, a pulse width modulation signal is obtained by comparing the ramp signal with the sampled grayscale voltage, thereby controlling the display components.

[0054] In one embodiment, the display element includes LCOS (Liquid Crystal on Silicon) or OLED (Organic Light-Emitting Diode); wherein, when the display element is LCOS, the pulse width modulation signal and the common electrode voltage are periodically reversed, and the difference is ensured to remain unchanged; when the display element is OLED, the pulse width modulation signal and the common electrode voltage remain unchanged.

[0055] Specifically, the difference between LCOS and OLED is that LCOS requires periodic inversion of signals at both ends.

[0056] Furthermore, in the case where the display component is an LCOS, the method for achieving the periodic reversal of the pulse width modulation signal includes the ramp signal RAMP wave rising in one cycle and falling in one cycle.

[0057] In this embodiment, the pulse width modulation signal and the common electrode voltage are controlled according to the characteristics of different display components, so as to better realize the functions of the display components.

[0058] In one embodiment, the circuit further includes a storage component, and the storage component includes a static random access memory.

[0059] Optionally, the pixel driving circuit further includes a storage component, which includes a static random access memory, i.e., an SRAM (Static Random-Access Memory) unit, for storing a PWM signal generated by the comparison component comparing the ramp signal Ramp with the sampled grayscale voltage Vgray.

[0060] Optionally, the input end of the SRAM unit is connected to the output end of the comparison component, and the output end of the SRAM unit is connected to the display component.

[0061] In this embodiment, by adding an SRAM unit to the pixel driving circuit, the PWM signal can be stored therein, thereby improving the stability of the pixel driving circuit.

[0062] In one embodiment, the circuit further includes a second switch unit and a reference source, where the reference source includes a reference voltage or a reference current.

[0063] Specifically, when the pixel driving circuit includes a second switching unit and a reference source, the second switching unit adjusts the on-time of the second switching unit based on a pulse width modulation signal. Furthermore, a second input terminal of the comparison component receives a ramp signal, and an output terminal of the comparison component is connected to a control terminal of the second switching unit; the control terminal of the second switching unit is connected to the output terminal of the comparison component, a first terminal of the second switching unit is connected to the reference source, and a second terminal of the second switching unit is connected to the output terminal of the pixel driving circuit.

[0064] Specifically, when the pixel driving circuit includes a second switching unit and a reference source, the input signal includes a reference signal. The reference source replicates the reference signal in the input signal to obtain a reference voltage or a reference current, which is then used to provide a driving electrical signal when the second switching unit is turned on. Furthermore, the reference source adjusts the driving amplitude based on the reference signal.

[0065] Optionally, when the pixel driving circuit includes a second switching unit and a reference source, and the input signal includes a reference signal, when the reference signal is a reference voltage, the display element is an LCOS, the reference signal and the common electrode voltage are periodically reversed, and the difference is ensured to remain unchanged. When the reference signal is a reference current, the display element is an OLED, and both the reference signal and the common electrode voltage remain unchanged.

[0066] Optionally, when the pixel driving circuit includes a second switching unit and a reference source, the brightness of the display element is proportional to the conduction time of the second switching unit.

[0067] In this embodiment, the pixel drive circuit may also optionally include a second switching unit and a reference source. After the comparison component compares the ramp signal with the sampled grayscale voltage and generates a pulse-width modulation signal based on the comparison result, the second switching unit adjusts the on-time based on the pulse-width modulation signal. The reference source replicates the reference signal generated in the pixel drive system to provide the second switching unit with a driving electrical signal for on-time. The effective duration of the reference signal is the on-time of the second switching unit, thereby further controlling the brightness of the display component.

[0068] In one embodiment, as shown in FIG2 , a pixel driving system is provided, the system comprising:

[0069] Pixel driving circuit 100;

[0070] The signal generating circuit 202 is used to generate an input signal for the pixel driving circuit 100;

[0071] The common electrode voltage generating circuit 204 is configured to generate a common electrode voltage.

[0072] Specifically, the signal generating circuit 202 is connected to the pixel driving circuit 100 and is used to generate an input signal for the pixel driving circuit 100. The common electrode voltage generating circuit 204 is used to generate a common electrode voltage Vcom, which is used to provide a voltage difference for the display element 108 to ensure that the display element 108 emits light normally.

[0073] In this embodiment, a pixel drive system is provided. The system includes a pixel drive circuit, a signal generation circuit, and a common electrode voltage generation circuit. The signal generation circuit is used to generate an input signal for the pixel drive circuit; the common electrode voltage generation circuit is used to generate a common electrode voltage, forming the pixel drive system. The signal generation circuit employs an analog drive method, which provides simple control. Furthermore, as screen resolution increases, the analog drive method can still meet demand by increasing the drive capability and bandwidth of the output buffer, avoiding the stringent frequency and timing requirements of the control signal in the digital drive method.

[0074] In one embodiment, the signal generating circuit includes: a ramp signal generating circuit connected to the pixel driving circuit and configured to generate a ramp signal; and a grayscale voltage generating circuit connected to the pixel driving circuit and configured to generate a grayscale voltage.

[0075] Specifically, the ramp signal generating circuit is used to generate the ramp signal Ramp; the grayscale voltage generating circuit is used to generate the grayscale voltages Vgray1 to Vgray X .

[0076] In this embodiment, the ramp signal generating circuit and the grayscale voltage generating circuit are connected to the pixel driving circuit to generate an input signal for the pixel driving circuit.

[0077] In one embodiment, the signal generating circuit further includes a reference generating circuit connected to the pixel driving circuit and configured to generate a reference signal.

[0078] Specifically, the reference generation circuit BG is used to generate a reference signal for the pixel driving circuit, wherein the reference signal includes a reference voltage Vref and a reference current Iref.

[0079] In this embodiment, when the pixel driving circuit includes a second switching unit and a reference source, the signal generating circuit includes a reference generating circuit for generating a reference signal to provide a driving electrical signal for the second switching unit when the second switching unit is turned on.

[0080] In one embodiment, a pixel driving circuit is provided. The circuit receives an input signal, where the input signal includes a ramp signal, a grayscale voltage, a sampling signal, and a reference signal. The circuit includes:

[0081] The first switch unit is configured to sample the grayscale voltage according to the sampling signal and store the sampled grayscale voltage in the capacitor component.

[0082] The capacitor component is used to store the sampled grayscale voltage obtained by sampling the first switch unit.

[0083] The comparison component is used to compare the ramp signal with the sampled grayscale voltage and generate a pulse width modulation signal according to the comparison result.

[0084] The second switch unit adjusts the on-time of the second switch unit based on the pulse width modulation signal.

[0085] The reference source is used to replicate the reference signal and provide a driving electrical signal when the second switch unit is turned on.

[0086] Display components that adjust light brightness based on pulse width modulation signals.

[0087] Specifically, the first end of the first switch unit is connected to the grayscale voltage, the second end of the first switch unit is connected to the upper plate of the capacitor component and the inverting input end of the comparison component, and the control end of the first switch unit is connected to the sampling signal.

[0088] Specifically, the non-inverting input terminal of the comparison component is connected to the ramp signal, and the output terminal of the comparison component is connected to the control terminal of the second switch unit.

[0089] Specifically, the control end of the second switch unit is connected to the output end of the comparison component, the first end of the second switch unit is connected to the reference source, the reference source receives a reference signal, and the second end of the second switch unit serves as the output end of the pixel driving circuit to output the copied reference signal, wherein the effective time of the reference signal is the conduction time of the second switch unit.

[0090] Specifically, the display component is connected to the second end of the second switch unit, ie, the output end of the pixel driving circuit.

[0091] Specifically, in this embodiment, a reference voltage is selected as the reference signal Vref.

[0092] In this embodiment, a first switching unit is connected to a grayscale voltage at its first terminal, a second switching unit is connected to the upper plate of a capacitor and a first input terminal of a comparison component, and a control terminal of the first switching unit is connected to a sampling signal. The grayscale voltage and the sampling signal are received and processed to prepare for obtaining a sampled grayscale voltage and a PWM signal. A ramp signal is received at the second input terminal of the comparison component, a control terminal of the second switching unit is connected to the output terminal of the comparison component, a first terminal of the second switching unit is connected to a reference source, and a second terminal of the second switching unit is connected to the output terminal of a pixel driving circuit. The second switching unit, the comparison component, and the reference source are connected, and the display component is connected to the second terminal of the second switching unit, i.e., the output terminal of the pixel driving circuit. The replicated reference signal is output as a control variable for the brightness of the display component, thereby improving display accuracy in the pixel driving system. The effective duration of the reference signal is the on-time of the second switching unit. Specifically, the PWM signal controls the conduction of the second switching unit. When the second switching unit is in the on state, a reference signal Vref replicated from the reference source is output through the output terminal to control the brightness of the display component.

[0093] In this embodiment, a reference voltage is selected as the reference signal Vref. Therefore, the second terminal of the first switch unit is connected to the upper plate of the capacitor component and the inverting input terminal of the comparator component, while the non-inverting input terminal of the comparator component is connected to the ramp signal. The PWM signal controls the conduction of the second switch unit, and the reference source replicates the reference signal to provide the driving signal when the second switch unit is turned on.

[0094] In another embodiment, as shown in FIG3 , a pixel driving circuit is provided. The circuit receives an input signal, wherein the input signal includes a ramp signal Ramp, a grayscale voltage Vgray, a sampling signal Sample, and a reference signal Vref. The circuit includes:

[0095] The first switch unit 302 is configured to sample the grayscale voltage Vgray according to the sampling signal Sample, and store the sampled grayscale voltage Vgray in the capacitor component 304 .

[0096] The capacitor component 304 is configured to store the sampled grayscale voltage Vgray obtained by sampling through the first switch unit 302 .

[0097] The comparison component 306 is used to compare the ramp signal Ramp with the sampled grayscale voltage Vgray, and generate a pulse width modulation signal according to the comparison result.

[0098] The second switch unit 308 adjusts the on-time of the second switch unit 308 based on the pulse width modulation signal.

[0099] The reference source 310 is used to replicate the reference signal and provide a driving electrical signal when the second switch unit 308 is turned on.

[0100] The storage component 312 is used to store the pulse width modulation signal.

[0101] The display device 314 adjusts the light luminance based on the pulse width modulation signal.

[0102] The first terminal of the first switch unit 302 is connected to the grayscale voltage Vgray. The second terminal of the first switch unit 302 is connected to the upper plate of the capacitor element 304 and the inverting input terminal of the comparison element 306. The control terminal of the first switch unit 302 is connected to the sampling signal Sample. The non-inverting input terminal of the comparison element 306 is connected to the ramp signal Ramp. The output terminal of the comparison element 306 is connected to the input terminal of the storage element 312. The output terminal of the storage element 312 is connected to the control terminal of the second switch unit 308. The first terminal of the second switch unit 308 is connected to the reference source 310. The second terminal of the second switch unit 308 is connected to the display element 314. The capacitor element 304 can be represented by C, the storage element 312 can be represented by SRAM, and the pulse width modulation signal can be represented by PWM. The brightness of the display element 314 is proportional to the conduction time of the second switch unit 308.

[0103] Specifically, the display component 314 is LCOS.

[0104] Accordingly, in one embodiment, as shown in FIG4 , a pixel driving system 400 is provided, the system comprising:

[0105] Pixel driving circuit 300;

[0106] The signal generating circuit 402 is used to generate an input signal for the pixel driving circuit 300;

[0107] The common electrode voltage generating circuit 404 is configured to generate a common electrode voltage.

[0108] Specifically, the signal generating circuit 402 includes: a ramp signal generating circuit 406 for generating a ramp signal Ramp; a grayscale voltage generating circuit 408 for generating grayscale voltages Vgray1 to Vgray2; X The reference generation circuit 410 is used to generate a reference signal for the pixel driving circuit 300, wherein the reference signal is a reference voltage Vref.

[0109] Specifically, the pixel driving circuit 300 compares the ramp signal Ramp with the grayscale voltage Vgray to generate a PWM signal to control the on-time of the second switch unit 308. The brightness of the display element 314 is proportional to the on-time of the second switch unit 308.

[0110] Furthermore, as shown in FIG5 , the reference voltage Vref and the common electrode voltage Vcom in the pixel driving system 400 need to be periodically reversed, and the difference between the two needs to remain unchanged; the ramp signal Ramp output by the ramp signal generating circuit 406 is compared with the multiple sets of grayscale voltages Vgray output by the grayscale voltage generating circuit 408 through the comparing component 306 to output multiple sets of PWM signals, and the multiple sets of PWM signals control the conduction time of the second switch unit 308 in the corresponding pixel driving circuit 300, and the brightness of the display component 314 is proportional to the conduction time of the second switch unit 308.

[0111] Specifically, the ramp signal Ramp output by the ramp signal generating circuit 406 is compared with Vgray1 and Vgray2 output by the grayscale voltage generating circuit 408 through the comparing element 306 to output the PWM1 signal and the PWM2 signal.

[0112] In this embodiment, when the reference signal is a reference voltage, LCOS is selected as the display component. To prevent the LCOS from becoming inert and stagnant, dynamic voltage control is required for the liquid crystal. That is, based on the characteristics of the LCOS, the reference voltage and the common electrode voltage in the pixel drive system are periodically reversed, and the difference between the two is maintained constant to ensure that the LCOS emits light normally, thereby ensuring the normal operation of the pixel drive circuit and the pixel drive system.

[0113] In one embodiment, a pixel driving circuit is provided. The circuit receives an input signal, where the input signal includes a ramp signal, a grayscale voltage, a sampling signal, and a reference signal. The circuit includes:

[0114] The first switch unit is configured to sample the grayscale voltage according to the sampling signal and store the sampled grayscale voltage in the capacitor component.

[0115] The capacitor component is used to store the sampled grayscale voltage obtained by sampling the first switch unit.

[0116] The comparison component is used to compare the ramp signal with the sampled grayscale voltage and generate a pulse width modulation signal according to the comparison result.

[0117] Display components that adjust light brightness based on pulse width modulation signals.

[0118] The second switch unit adjusts the on-time of the second switch unit based on the pulse width modulation signal.

[0119] The reference source is used to replicate the reference signal and provide a driving electrical signal when the second switch unit is turned on.

[0120] Specifically, the first end of the first switch unit is connected to the grayscale voltage Vgray, the second end of the first switch unit is connected to the upper plate of the capacitor component and the non-inverting input end of the comparison component, and the control end of the first switch unit is connected to the sampling signal.

[0121] Specifically, the inverting input terminal of the comparison component is connected to the ramp signal, and the output terminal of the comparison component is connected to the control terminal of the second switch unit.

[0122] Specifically, the control end of the second switch unit is connected to the output end of the comparison component, the first end of the second switch unit is connected to the reference source, the reference source receives a reference signal, and the second end of the second switch unit serves as the output end of the pixel driving circuit to output the copied reference signal, wherein the effective time of the reference signal is the conduction time of the second switch unit.

[0123] Specifically, the display component is connected to the second end of the second switch unit, that is, the output end of the pixel driving circuit.

[0124] Specifically, in this embodiment, a reference current is selected as the reference signal Iref.

[0125] In this embodiment, a first terminal of a first switch unit is connected to a grayscale voltage, a second terminal of the first switch unit is connected to the upper plate of a capacitor element and the first input terminal of a comparison element, and a control terminal of the first switch unit is connected to a sampling signal. The first switch unit, the capacitor element, and the comparison element are connected to the grayscale voltage and the sampling signal. The second input terminal of the comparison element receives a ramp signal. The output terminal of the comparison element is connected to the control terminal of a second switch unit, so that the comparison element and the second switch unit are connected to the ramp signal. The control terminal of the second switch unit is connected to the output terminal of the comparison element. The first terminal of the second switch unit is connected to a reference source, the second terminal of the second switch unit is connected to the output terminal of the pixel driving circuit, and the display element is connected to the output terminal of the pixel driving circuit. The second switch unit, the comparison element, and the reference source are connected to form part of the pixel driving circuit structure. The pixel driving circuit outputs the replicated reference signal Iref as a control variable in the pixel driving system, where the effective time of Iref is the conduction time of the second switch unit.

[0126] In this embodiment, a reference current is selected as the reference signal Iref. Therefore, the second terminal of the first switch unit is connected to the upper plate of the capacitor element and the non-inverting input terminal of the comparator element, while the inverting input terminal of the comparator element is connected to the ramp signal. A PWM signal controls the conduction of the second switch unit, and a reference source replicates the reference signal to provide the driving signal when the second switch unit is on. Specifically, when the second switch unit is in the on state, the reference signal Iref replicated by the reference source is output through the output terminal, and the PWM signal serves as the control variable to control the brightness of the display element.

[0127] In another embodiment, as shown in FIG6 , a pixel driving circuit is provided. The circuit receives an input signal, wherein the input signal includes a ramp signal Ramp, a grayscale voltage Vgray, a sampling signal Sample, and a reference signal Iref. The circuit includes:

[0128] The first switch unit 602 is configured to sample the grayscale voltage Vgray according to the sampling signal Sample, and store the sampled grayscale voltage Vgray in the capacitor component 604 .

[0129] The capacitor component 604 is configured to store the sampled grayscale voltage Vgray obtained by sampling through the first switch unit 602 .

[0130] The comparison component 606 is used to compare the ramp signal Ramp with the sampled grayscale voltage Vgray, and generate a pulse width modulation signal according to the comparison result.

[0131] The second switch unit 608 adjusts the on-time of the second switch unit 608 based on the pulse width modulation signal.

[0132] The reference source 610 is used to replicate the reference signal and provide a driving electrical signal when the second switch unit 608 is turned on.

[0133] The storage component 612 is used to store the PWM signal.

[0134] The display device 614 adjusts the light luminance based on the pulse width modulation signal.

[0135] The first end of the first switch unit 602 is connected to the grayscale voltage Vgray, the second end of the first switch unit 602 is connected to the upper plate of the capacitor element 604 and the non-inverting input end of the comparison element 606, and the control end of the first switch unit 602 is connected to the sampling signal Sample. The inverting input end of the comparison element 606 is connected to the ramp signal Ramp, and the output end of the comparison element 606 is connected to the input end of the storage element 612. The output end of the storage element 612 is connected to the control end of the second switch unit 608, the first end of the second switch unit 608 is connected to the reference source 610, and the second end of the second switch unit 608 serves as the output end of the pixel driving circuit and is connected to the display element 614. The capacitor element 604 can be represented by C, the storage element 612 can be represented by SRAM, and the pulse width modulation signal can be represented by PWM.

[0136] Specifically, the display element 614 is an OLED.

[0137] Accordingly, in one embodiment, as shown in FIG7 , a pixel driving system 700 is provided, the system comprising:

[0138] Pixel driving circuit 600;

[0139] The signal generating circuit 702 is used to generate an input signal for the pixel driving circuit 600;

[0140] The common electrode voltage generating circuit 704 is configured to generate a common electrode voltage.

[0141] Specifically, the signal generating circuit 702 includes: a ramp signal generating circuit 706 for generating a ramp signal Ramp; a grayscale voltage generating circuit 708 for generating grayscale voltages Vgray1 to Vgray2; X The reference generating circuit 710 is used to generate a reference signal for the pixel driving circuit 600, wherein the reference signal is a reference current Iref.

[0142] Specifically, the pixel driving circuit 600 compares the ramp signal Ramp with the grayscale voltage Vgray to generate a PWM signal to control the on-time of the second switch unit 608 .

[0143] Furthermore, as shown in FIG8 , the reference current Iref and the common electrode voltage Vcom in the pixel driving system 600 remain unchanged; the ramp signal Ramp output by the ramp signal generating circuit 706 is compared with the multiple sets of grayscale voltages Vgray output by the grayscale voltage generating circuit 708 through the comparing component 606 to output multiple sets of PWM signals, and the multiple sets of PWM signals control the conduction time of the second switching unit 608 in the corresponding pixel driving circuit 600, and the brightness of the display component 614 OLED is proportional to the conduction time of the second switching unit 608.

[0144] Specifically, the ramp signal Ramp output by the ramp signal generating circuit 706 is compared with Vgray1 and Vgray2 output by the grayscale voltage generating circuit 708 through the comparing element 606 to output the PWM1 signal and the PWM2 signal.

[0145] In this embodiment, when the reference signal is a reference current, an OLED is selected as the display component. Since the OLED is an active light-emitting device, according to the characteristics of the OLED, the reference current and common electrode voltage in the pixel drive system remain unchanged, ensuring that the OLED can emit light normally, thereby ensuring the normal operation of the pixel drive circuit and pixel drive system.

[0146] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0147] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0148] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of relevant countries and regions.

[0149] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0150] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A pixel driving circuit, characterized in that: The circuit receives an input signal, wherein the input signal includes a ramp signal, a grayscale voltage, and a sampling signal. The circuit includes: A first switch unit, configured to sample the grayscale voltage according to the sampling signal, and store the sampled grayscale voltage in a capacitor component; A capacitor component, used for storing a sampled grayscale voltage obtained by sampling the first switch unit; A comparison component, used for comparing the ramp signal with the sampled grayscale voltage, and generating a pulse width modulation signal according to the comparison result; The display component adjusts the light emitting brightness based on the pulse width modulation signal.

2. The circuit according to claim 1, characterized in that The first end of the first switch unit is connected to the grayscale voltage, the second end of the first switch unit is connected to the upper plate of the capacitor component and the first input end of the comparison component, and the control end of the first switch unit is connected to the sampling signal.

3. The circuit according to claim 1, characterized in that The second input terminal of the comparison component receives the ramp signal, and the output terminal of the comparison component is connected to the display component.

4. The circuit according to claim 1, characterized in that The brightness of the display element is proportional to the pulse width of the pulse width modulation signal.

5. The circuit according to claim 1, characterized in that The display element includes LCOS or OLED; wherein, when the display element is LCOS, the pulse width modulation signal and the common electrode voltage are periodically flipped and the difference is kept unchanged; when the display element is OLED, the pulse width modulation signal and the common electrode voltage remain unchanged.

6. The circuit according to claim 1, characterized in that The circuit also includes a storage component, and the storage component includes a static random access memory.

7. The circuit according to claim 1, characterized in that The circuit further includes a second switch unit and a reference source, wherein the reference source includes a reference voltage or a reference current.

8. A pixel driving system, characterized in that: The system comprises: The pixel driving circuit according to any one of claims 1 to 7; A signal generating circuit, used for generating an input signal of the pixel driving circuit; The common electrode voltage generating circuit is used to generate a common electrode voltage.

9. The system according to claim 8, characterized in that The signal generating circuit comprises: A ramp signal generating circuit, connected to the pixel driving circuit, and configured to generate a ramp signal; The grayscale voltage generating circuit is connected to the pixel driving circuit and is used to generate a grayscale voltage.

10. The system according to claim 9, characterized in that The signal generating circuit further includes a reference generating circuit connected to the pixel driving circuit and configured to generate a reference signal.

Images