Pixel circuit and pixel circuit compensation method

Abstract

The application discloses a pixel circuit and a pixel circuit compensation method, and belongs to the technical field of display. The pixel circuit comprises a pixel driving module, a feedback module, a feedback delay compensation module and a data signal compensation module. The feedback delay compensation module comprises a compensation transistor. The gate of the compensation transistor is connected with the output end of the feedback module. The compensation transistor is used for providing gain to the part of the feedback signal output by the feedback module and having a frequency higher than a first threshold value. The data signal compensation module is used for determining and outputting a compensated target data signal. In this way, the gain is provided to the high-frequency part of the feedback signal to offset the attenuation effect of the feedback module wiring load on the high-frequency signal, the feedback signal delay is reduced, and the accuracy of the data signal compensation based on the feedback signal is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a pixel circuit and a pixel circuit compensation method. BACKGROUND

[0002] In the pixel circuit, the performance drift problem caused by the long-time load of the transistor is dynamic and difficult to predict, and the performance drift needs to be compensated according to the signal detected by the feedback module. However, there is a wiring load in the feedback module, which often leads to a delay in the output feedback signal, resulting in inaccurate compensation. SUMMARY

[0003] Embodiments of the present application provide a pixel circuit and a pixel circuit compensation method to solve the technical problem of low compensation accuracy of the pixel circuit.

[0004] According to an aspect of an embodiment of the present application, a pixel circuit is provided, comprising: a pixel driving module, a feedback module, a feedback delay compensation module, and a data signal compensation module.

[0005] The input end of the feedback module is connected with the output end of the pixel driving module.

[0006] The feedback delay compensation module comprises a compensation transistor, the gate of the compensation transistor is connected with the output end of the feedback module, and the compensation transistor is used to provide gain for the part of the feedback signal output by the feedback module with a frequency higher than a first threshold.

[0007] The input end of the data signal compensation module is connected with the drain of the compensation transistor, the output end of the data signal compensation module is connected with the data signal input end of the pixel driving module, and the data signal compensation module is used to determine and output a target data signal after compensation.

[0008] In a possible implementation, the feedback delay compensation module further comprises a first compensation resistor and a compensation capacitor, and the first compensation resistor and the compensation capacitor are connected in parallel between the source of the compensation transistor and the ground.

[0009] In a possible implementation, the feedback delay compensation module further comprises a second compensation resistor, and the second compensation resistor is connected with the drain of the compensation transistor.

[0010] In a possible implementation, the data signal compensation module comprises a driver, a memory, and a data driving chip.

[0011] The memory is connected with the positive input end of the driver, and is used to provide a preset signal corresponding to a current gray scale.

[0012] The negative input end of the driver is connected with the drain of the compensation transistor, and the output end of the driver is connected with the input end of the data driving chip; the driver is used for determining the difference between the preset signal voltage and the feedback signal voltage output by the compensation transistor;

[0013] The output end of the data driving chip is connected with the data signal input end of the pixel driving module, and is used for outputting the compensated data signal.

[0014] In a possible implementation, the data driving chip comprises a processing unit and a decoder.

[0015] The processing unit is connected with the output end of the driver and the decoder respectively, and is used for determining a second data code based on a first data code corresponding to an initial data signal and the difference output by the driver;

[0016] The decoder is connected with the data signal input end of the pixel driving module, and is used for decoding the second data code to obtain a target data signal and transmitting the target data signal to the pixel driving module.

[0017] According to another aspect of the embodiments of the present application, a pixel circuit compensation method is also provided, applied to the pixel circuit of any one of the first aspect, comprising:

[0018] The data signal compensation module outputs an initial data signal to the pixel driving module to start the pixel driving module.

[0019] The feedback delay compensation module provides gain to the part of the feedback signal output by the feedback module and having a frequency higher than a first threshold value.

[0020] The data signal compensation module compensates an initial data signal based on the feedback signal output by the feedback delay compensation module and having the gain, to obtain a target data signal, and outputs the target data signal to the pixel driving module.

[0021] In a possible implementation, the feedback delay compensation module further comprises a first compensation resistor, a compensation capacitor and a second compensation resistor; before the feedback delay compensation module provides gain to the part of the feedback signal output by the feedback module and having a frequency higher than a first threshold value, the method further comprises:

[0022] Based on the transconductance of the compensation transistor, the first compensation resistor, the compensation capacitor and the second compensation resistor, the first threshold value and the second threshold value of the gain of the feedback delay compensation module are determined; wherein the first threshold value is greater than the second threshold value.

[0023] In a possible implementation, the first compensation resistor is a variable resistor; and the method further includes:

[0024] determining a trace load of the feedback module;

[0025] adjusting the resistance value of the first compensation resistor based on the trace load, so as to adjust the gain multiple of the feedback delay compensation module.

[0026] In a possible implementation, the data signal compensation module includes a driver, a memory and a data driving chip.

[0027] The compensation of the initial data signal by the data signal compensation module based on the gain feedback signal output by the feedback delay compensation module to obtain the target data signal includes:

[0028] determining a current gray scale corresponding to the pixel driving module;

[0029] obtaining a preset signal corresponding to the current gray scale stored in the memory;

[0030] determining, by the driver, a difference between a first voltage value of the preset signal and a second voltage value of the gain feedback signal output by the feedback delay compensation module;

[0031] sending the difference to the data driving chip;

[0032] compensating, by the data driving chip, the initial data signal based on the difference to obtain the target data signal.

[0033] In a possible implementation, the data driving chip includes a processing unit and a decoder.

[0034] The compensation of the initial data signal by the data driving chip based on the difference to obtain the target data signal includes:

[0035] determining, by the processing unit, a second data code based on a first data code corresponding to the initial data signal and the difference;

[0036] sending the second data code to the decoder;

[0037] outputting, by the decoder, a target data signal corresponding to the second data code.

[0038] The pixel circuit and the pixel circuit compensation method provided by the embodiment of the present application, the pixel circuit comprises a pixel driving module, a feedback module, a feedback delay compensation module and a data signal compensation module; the input end of the feedback module is connected with the output end of the pixel driving module; the feedback delay compensation module comprises a compensation transistor; the gate of the compensation transistor is connected with the output end of the feedback module; the compensation transistor is used for providing gain to the part of the feedback signal output by the feedback module and having a frequency higher than a first threshold value; the input end of the data signal compensation module is connected with the drain of the compensation transistor, and the output end of the data signal compensation module is connected with the data signal input end of the pixel driving module; the data signal compensation module is used for determining and outputting a target data signal after compensation. In this way, the feedback delay compensation module can provide gain to the high-frequency part of the feedback signal, thereby offsetting the high-frequency attenuation of the feedback signal caused by the wiring load in the feedback module, and further suppressing the delay of the feedback signal caused by the high-frequency attenuation, which is beneficial to more accurately combining the feedback signal for data voltage compensation. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings, which are included to provide a further understanding of the present application, constitute a part of the present application and illustrate the illustrative embodiments of the present application and their description serve to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0040] Figure 1 is a structural schematic diagram of a pixel circuit provided by the embodiment of the present application;

[0041] Figure 2 is a structural schematic diagram of a pixel driving module provided by the embodiment of the present application;

[0042] Figure 3 is a structural schematic diagram of a pixel circuit provided by the embodiment of the present application;

[0043] Figure 4 is a schematic diagram of a wiring load of a feedback module provided by the embodiment of the present application;

[0044] Figure 5 is a structural schematic diagram of a pixel circuit provided by the embodiment of the present application;

[0045] Figure 6 is a structural schematic diagram of a pixel circuit provided by the embodiment of the present application;

[0046] Figure 7 is a gain-frequency curve change diagram provided by the embodiment of the present application;

[0047] Figure 8 is a structural schematic diagram of a pixel circuit provided by the embodiment of the present application;

[0048] Figure 9 is a structural schematic diagram of a pixel circuit provided by an embodiment of the present application;

[0049] Figure 10 is a structural schematic diagram of a pixel circuit provided by an embodiment of the present application;

[0050] Figure 11 is a flowchart of a pixel compensation method provided by an embodiment of the present application;

[0051] Figure 12 is a structural schematic diagram of a pixel circuit provided by an embodiment of the present application.

[0052] Legend of Reference Signs

[0053] 1, pixel driving module; 2, feedback module; 3, feedback delay compensation module; 4, data signal compensation module; 31, compensation transistor; 32, first compensation resistor; 33, compensation capacitor; 34, second compensation resistor; 41, driver; 42, memory; 43, data driving chip; 431, processing unit; 432, decoder. DETAILED DESCRIPTION

[0054] In order to make the personnel in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person of ordinary skill in the art without making creative labor should belong to the protection scope of the present application. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0055] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, product or device including a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units not clearly listed or inherent to the process, method, product or device.

[0056] In the present embodiment, a pixel circuit is provided, Figure 1 is a structural schematic diagram of a pixel circuit provided by an embodiment of the present application. AsFigure 1 As shown, the pixel circuit may include: a pixel driving module 1, a feedback module 2, a feedback delay compensation module 3, and a data signal compensation module 4;

[0057] The input terminal of the feedback module 2 is connected to the output terminal of the pixel driving module 1;

[0058] The feedback delay compensation module 3 includes: a compensation transistor 31; the gate of the compensation transistor 31 is connected to the output terminal of the feedback module 2; the compensation transistor 31 is used to provide gain for the portion of the feedback signal output by the feedback module 2 with a frequency higher than a first threshold.

[0059] The input terminal of the data signal compensation module 4 is connected to the drain of the compensation transistor 31, and the output terminal of the data signal compensation module 4 is connected to the data signal input terminal of the pixel driving module 1; the data signal compensation module 4 is used to determine and output the compensated target data signal.

[0060] In this embodiment, the pixel driving module 1 may include a first transistor T1, a second transistor T2, and a driving capacitor C. ST The structure of the 2T1C pixel driver module 1, such as Figure 2 As shown, or alternatively, it may include other forms of pixel driving module structures to drive the light-emitting elements corresponding to the pixels to emit light. Here, the light-emitting element can be an organic light-emitting diode (OLED), etc. The transistor can be a thin-film transistor (TFT), etc. DD This is the operating voltage, input to the source of the OLED and T1, controlled by the gate voltage of T1, used to drive the OLED to emit light, and the brightness of the OLED is controlled by this operating voltage.

[0061] In one embodiment, the OLED can be disposed at the source of T1 or at the drain of T1, for example, connected between the drain of T1 and the feedback module 2.

[0062] In one embodiment, such as Figure 3 As shown, feedback module 2 may include a third transistor T3, and may also include a grounded resistor R. F The input terminal of feedback module 2 is connected to the output terminal of pixel driving module 1. This means the source of T3 is connected to the drain of T1, and the output signal from the drain of T1 enters the source of T3, thus allowing the output signal of pixel driving module 1 to be input to feedback module 2. The trace load in feedback module 2, i.e., the resistor-capacitor RC load, can be handled as follows: Figure 4 As shown, R FP and C FPThese are the resistive load and capacitive load corresponding to the feedback module 2, respectively.

[0063] In one embodiment, the source of T2 can serve as a data signal input terminal, used to connect to a data line to input a data signal. The gates of T3 and T2 can be connected to a scan line.

[0064] In one embodiment, the compensation transistor 31 in the feedback delay compensation module 3 can be an N-type metal-oxide-semiconductor (NMOS). The gate of the compensation transistor 31 can be connected to the output terminal of the feedback module 2, for example, to the drain of T3, to receive the feedback signal output by the feedback module 2.

[0065] In one embodiment, the feedback delay compensation module 3 may further include: a first compensation resistor 32 and a compensation capacitor 33. Wherein, as... Figure 5 As shown, the first compensation resistor 32 and the compensation capacitor 33 are connected in parallel between the source of the compensation transistor 31 and ground. By setting the first compensation resistor 32 and the compensation capacitor 33, the transfer function of the circuit containing the compensation transistor is optimized, which allows for more precise control of the gain effect on the high-frequency signal portion and reduces the impact on the low-frequency signal portion.

[0066] In some embodiments, the first compensation resistor 32 can be a variable resistor. Here, adjusting the value of the first compensation resistor 32 can control the gain factor to adapt to different trace loads.

[0067] In one embodiment, the first compensation resistor 32 is a variable resistor, and the maximum and minimum resistance values ​​are determined based on the wiring load of the feedback module 2.

[0068] In this way, different trace loads can be generated for the feedback module 2, and the first compensation resistor 32 can be adjusted to flexibly control the gain of the feedback signal, thereby better eliminating the high-frequency attenuation effect of the trace load on the feedback signal.

[0069] In one embodiment, the feedback delay compensation module 3 may further include: a second compensation resistor 34; the second compensation resistor 34 is connected to the drain of the compensation transistor 31. For example, as shown... Figure 6 As shown, the second compensation resistor 34 can be connected to V DD Between the drain of the compensation transistor 31 and the drain of the compensation transistor 31, it can act as a voltage divider resistor to prevent the feedback signal voltage from being too high.

[0070] In one embodiment, the second compensation resistance 34 can be a variable resistance, which can be adjusted according to the wiring load of the feedback module 2, or also according to the working voltage V DD The adjustment can be made so as to flexibly control the voltage dividing capability.

[0071] In this way, by setting the second compensation resistance 34, the voltage dividing effect in the feedback delay compensation module 3 can be provided, so as to avoid the feedback signal voltage being too high.

[0072] In one embodiment, the transfer function H(s) of the feedback delay compensation module 3 is determined according to the transconductance g m of the compensation transistor 31, S the first compensation resistance 32 R S , the compensation capacitance 33 C L and the second compensation resistance 34 R

[0073]

[0074] Here, / / represents the parallel operation of impedance.

[0075] In one embodiment, the feedback delay compensation module 3 can be used to provide gain to the feedback signal, wherein a first gain provided to a part of the feedback signal with a frequency higher than a first threshold is greater than a second gain provided to a part of the feedback signal with a frequency lower than a second threshold. In this way, the gain of the high-frequency signal is better, and on the basis of offsetting the high-frequency attenuation caused by the wiring load, the gain of the low-frequency signal is not too large, so as to avoid the feedback signal generating another error.

[0076] In one embodiment, the zero point corresponding to the transfer function of the feedback delay compensation module 3 is

[0077]

[0078] In one embodiment, the pole corresponding to the transfer function of the feedback delay compensation module 3 is

[0079]

[0080] In one embodiment, the high-frequency gain multiple of the feedback delay compensation module 3 is Obviously, the high-frequency gain multiple is greater than 1, that is, the gain of the high-frequency part is greater than the gain of the low-frequency part.

[0081] In one embodiment, the gain-frequency diagram of the feedback delay compensation module 3 can be as shown in Figure 7 For a part of the signal with a frequency higher than or equal to the first threshold, it can be considered as a high-frequency part, and for a part of the signal with a frequency lower than or equal to the second threshold, it can be considered as a low-frequency part. The zero point W ZThe second gain is provided for the low frequency part, and the frequency value corresponding to the point can be the second threshold value; the pole W P The first gain is provided for the high frequency part, and the frequency value corresponding to the point can be the first threshold value.

[0082] In an embodiment, the input end of the data signal compensation module 4 is connected with the drain of the compensation transistor 31, and receives the gain feedback signal. The data signal compensation module 4 is used to determine the compensated target data signal based on the gain feedback signal. The output end of the data signal compensation module 4 can be connected with the data signal input end of the pixel driving module 1, i.e., the source of T2, for outputting the compensated target data signal to the pixel driving module 1.

[0083] In an embodiment, the data signal compensation module 4 can include a data driving chip 43 for determining the compensated target data signal, which can refer to compensating the voltage of the initial data signal to obtain the target data signal. The compensation amount for compensating the voltage of the initial data signal can be determined according to the gain feedback signal.

[0084] In this way, the feedback delay compensation module 3 provides gain for the high frequency part in the feedback signal, thereby offsetting the high frequency attenuation of the feedback signal caused by the wiring load in the feedback module 2, and further suppressing the delay of the feedback signal caused by the high frequency attenuation. The precise compensation of the data signal can be realized in combination with the feedback signal, and the pixel control accuracy can be improved.

[0085] As shown in Figure 8 The data signal compensation module 4 in the above pixel circuit can include a driver 41, a memory 42, and a data driving chip 43.

[0086] The memory 42 is connected with the positive input end of the driver 41, and is used to provide a preset signal corresponding to a current gray scale;

[0087] The negative input end of the driver 41 is connected with the drain of the compensation transistor 31, and the output end of the driver 41 is connected with the input end of the data driving chip 43. The driver 41 is used to determine the difference between the preset signal voltage and the feedback signal voltage output by the compensation transistor 31.

[0088] The output end of the data driving chip 43 is connected with the data signal input end of the pixel driving module 1, and is used to output the compensated data signal.

[0089] In this embodiment, the driver 41 includes a positive input terminal, a negative input terminal, and an output terminal. The positive input terminal is connected to the memory 42 and is used to acquire a preset signal or preset signal voltage value corresponding to the current grayscale stored in the memory 42. The negative input terminal is connected to the output terminal of the feedback delay compensation module 3, i.e., the drain of the compensation transistor 31, and is used to receive the feedback signal after being amplified by the feedback delay compensation module 3. The driver 41 is used to determine the difference between the preset signal voltage and the feedback signal voltage output by the compensation transistor 31, and outputs the difference to the data driver integrated circuit 43 through the output terminal.

[0090] In one embodiment, the driver 41 may further include a grayscale determination unit, which is used to determine the current grayscale corresponding to the pixel driving module 1, and obtain the preset signal or preset signal voltage value corresponding to the current grayscale from the memory 42 according to the current grayscale.

[0091] In one embodiment, the data driver chip 43 is used to compensate the data signal voltage based on the difference determined by the driver 41, and outputs the compensated data signal to the pixel driver module 1. For example, the output terminal of the data driver chip 43 is connected to the source of T2, and by outputting the compensated data signal to T2, it controls T1 to turn on and simultaneously to C. ST Charge.

[0092] In one embodiment, the memory 42 may store preset signals corresponding to all gray levels, or it may store preset signal voltage values ​​corresponding to all gray levels.

[0093] In one embodiment, the driver 41 can amplify the difference by a predetermined ratio and output it to the data driver chip 43. The data driver chip 43 is used to compensate the data signal voltage based on the amplified difference and output the compensated data signal to the pixel driver module 1. For example, as Figure 9 As shown, a first resistor R1 can be connected in series between the positive input terminal of driver 41 and memory 42, and a second resistor R2 grounded can also be connected to the positive input terminal. A third resistor R3 can be connected in series between the negative input terminal of driver 41 and the drain of compensation transistor 31, and the negative input terminal can also be connected to the input terminal of data driver chip 43 through a fourth resistor R4.

[0094] In one embodiment, R1=R3, R2=R4. For example, the signal voltage output by the pixel driving module 1 is VF1, the feedback signal voltage output by the feedback module 2 is VF2, the gain feedback signal voltage output by the feedback delay compensation module 3 is VF3, and the preset signal voltage corresponding to the current gray scale obtained by the driver 41 from the memory 42 is Vdref. The output difference can be (Vdref-VF3)R2 / R1, so as to realize the amplification of the difference (Vdref-VF3) between the preset signal voltage and the gain feedback signal voltage output by the compensation transistor 31, and the predetermined amplification ratio is R2 / R1.

[0095] In one embodiment, at least one of R1, R3, R2 and R4 can be a variable resistance, which can be adjusted according to the preset signal voltage corresponding to the current gray scale and / or the gain feedback signal voltage. In this way, the amplification of the difference between the preset signal voltage and the gain feedback signal voltage output by the compensation transistor 31 is realized by setting the resistances R1, R3, R2 and R4, so as to avoid that the small difference signal is difficult to be recognized by the data driver chip 43 after the subtraction, and further improve the signal compensation accuracy.

[0096] Based on the above circuit, the preset signal corresponding to the full gray scale is stored in the memory 42, so that when the gray scale corresponding to the pixel driven by the pixel driving circuit changes, the corresponding preset signal can be flexibly selected to determine the difference, so as to accurately compensate the data signal.

[0097] As shown in Figure 10 the data driver chip 43 in the above pixel circuit can include a processing unit 431 and a decoder 432;

[0098] The processing unit 431 is connected with the output end of the driver 41 and the decoder 432 respectively, and is used to determine a second data code based on a first data code corresponding to an initial data signal and the difference value output by the driver 41.

[0099] The decoder 432 is connected with the data signal input end of the pixel driving module 1, and is used to decode the second data code to obtain a target data signal and transmit the target data signal to the pixel driving module 1.

[0100] In the embodiment, the processing unit 431 can also be connected with the memory 42, and is used to obtain the initial data signal stored in the memory 42 or the first data code corresponding to the initial data signal.

[0101] In one embodiment, the processing unit 431 is connected with the decoder 432, which can include a first channel for transmitting the first data code and a second channel for transmitting the second data code. After the initial data signal is output by the decoder 432 to the pixel driving module 1 through the first channel for transmitting the first data code, the processing unit 431 determines the gain according to the difference between the feedback signal and the preset signal, and determines the second data code, and then controls the first channel for transmitting the first data code to the decoder 432 to be disconnected, and outputs the second data code to the decoder 432 through the second channel, and the target data signal is output by the decoder 432.

[0102] In one embodiment, the first channel can include a switch unit, and the processing unit 431 controls the first channel for transmitting the first data code to the decoder 432 to be disconnected through the switch unit.

[0103] In this way, the data driving chip 43 can complete the compensation of the initial data signal based on the difference between the preset signal and the feedback signal, and the processing efficiency of the data signal compensation can be improved based on the conversion output after the calculation of the data code and the difference.

[0104] As shown in Figure 11 , a pixel circuit compensation method is provided, which is applied to the pixel circuit in any of the foregoing embodiments, and includes:

[0105] S10: Control the data signal compensation module 4 to output the initial data signal to the pixel driving module 1 to start the pixel driving module 1.

[0106] S20: The feedback signal output by the feedback module 2 is provided with gain by the feedback delay compensation module 3 for the part with a frequency higher than the first threshold value.

[0107] S30: The initial data signal is compensated by the data signal compensation module 4 to obtain the target data signal based on the feedback signal output by the feedback delay compensation module 3 after the gain, and the target data signal is output to the pixel driving module 1.

[0108] In this embodiment, before step S10, it can also include controlling the scanning line connected with the pixel driving module 1 to output high level. At this time, T2 and T3 are opened, and the data signal compensation module 4 is controlled to output the initial data signal to the pixel driving module 1, which can include controlling the processing unit 431 to output the first data code to the decoder 432, and the decoder 432 outputs the initial data signal to the source electrode of T2, i.e. the data signal input end of the pixel driving module 1, through the data signal line Data line.

[0109] At this time, T1 is also opened for C ST charging. After T1 is opened, the current controlled by the gate-source voltage of T1 flows through OLED, and OLED emits brightness controlled by the size of the current.

[0110] In one embodiment, step S20 can include: providing, by the feedback delay compensation module 3, a first gain to a part of the feedback signal output by the feedback module 2 with a frequency higher than or equal to a first threshold, and providing a second gain to a part of the feedback signal with a frequency lower than or equal to a second threshold. Wherein the first gain is greater than the second gain, so that the gain of the high-frequency signal is better, and the low-frequency signal does not produce a larger gain on the basis of offsetting the high-frequency attenuation caused by the wiring load, avoiding the generation of another error of the feedback signal.

[0111] In one embodiment, providing, by the feedback delay compensation module 3, a gain to a part of the feedback signal output by the feedback module 2 with a frequency higher than the first threshold can refer to providing a gain to a part of the feedback signal output by the feedback module 2 with a frequency higher than the first threshold based on the transfer function of the feedback delay compensation module 3.

[0112] In one embodiment, compensating, in step S30, the initial data signal based on the feedback signal after the gain output by the feedback delay compensation module 3 to obtain the target data signal can include: obtaining a preset signal corresponding to the current gray scale of the pixel driving module 1; determining the difference between the preset signal voltage and the feedback signal voltage after the gain; compensating the initial data signal based on the difference to obtain the target data signal.

[0113] In one embodiment, when the data signal compensation module 4 includes the aforementioned resistors R1, R2, R3 and R4, compensating the initial data signal based on the difference to obtain the target data signal can include: amplifying the difference based on a predetermined ratio; compensating the initial data signal based on the amplified difference to obtain the target data signal.

[0114] In this way, by providing a gain to the high-frequency part of the feedback signal through the feedback delay compensation module 3, the high-frequency attenuation of the feedback signal caused by the wiring load in the feedback module 2 is offset, and the delay of the feedback signal caused by the high-frequency attenuation is suppressed, which can realize accurate compensation of the data signal in combination with the feedback signal, and improve the pixel control accuracy.

[0115] In some embodiments, the feedback delay compensation module 3 further includes: a first compensation resistor 32, a compensation capacitor 33, and a second compensation resistor 34; before step S20, the method can further include:

[0116] Based on the transconductance of the compensation transistor 31, the first compensation resistor 32, the compensation capacitor 33, and the second compensation resistor 34, the first threshold and the second threshold of the gain of the feedback delay compensation module 3 are determined; wherein the first threshold is greater than the second threshold.

[0117] In the embodiment, the transfer function H(s) of the feedback delay compensation module 3 is determined according to the transconductance g m of the compensation transistor 31 S , the compensation capacitance 33 C S , and the compensation resistance 34 R L .

[0118]

[0119] Here, / / represents the parallel operation of impedance.

[0120] In one embodiment, the feedback delay compensation module 3 provides a first gain to the part of the feedback signal output by the feedback module 2 with a frequency higher than or equal to a first threshold value, and provides a second gain to the part of the feedback signal with a frequency lower than or equal to a second threshold value.

[0121] In one embodiment, the zero point corresponding to the transfer function of the feedback delay compensation module 3, i.e. the second gain, is

[0122] In one embodiment, the pole corresponding to the transfer function of the feedback delay compensation module 3, i.e. the first gain, is

[0123] In this way, the gain of the high-frequency signal is better, and on the basis of offsetting the high-frequency attenuation caused by the wiring load, the low-frequency signal does not produce a large gain, avoiding the generation of another error in the feedback signal.

[0124] In some embodiments, the first compensation resistance 32 is a variable resistance; before step S20, the method can further include:

[0125] determining the wiring load of the feedback module 2;

[0126] adjusting the resistance value of the first compensation resistance 32 based on the wiring load, so as to adjust the gain multiple of the feedback delay compensation module 3.

[0127] In the embodiment, adjusting the gain multiple of the feedback delay compensation module 3 can refer to adjusting the first gain multiple provided by the feedback delay compensation module 3 to the part of the feedback signal with a frequency higher than or equal to the first threshold value, and / or the second gain multiple provided to the part of the feedback signal with a frequency lower than or equal to the second threshold value.

[0128] In one embodiment, the first compensation resistance 32 is a variable resistance, and the maximum resistance value and the minimum resistance value are determined according to the wiring load of the feedback module 2.

[0129] In this way, different wiring load can be generated for the feedback module 2, the first compensation resistor 32 is adjusted to flexibly control the gain multiple of the feedback signal, and thus the high-frequency attenuation influence of the wiring load on the feedback signal can be better eliminated.

[0130] In some embodiments, the data signal compensation module 4 comprises a driver 41, a memory 42, and a data driving chip 43.

[0131] The step S30 can comprise:

[0132] Determining a current gray scale corresponding to the pixel driving module 1;

[0133] Obtaining a preset signal corresponding to the current gray scale stored in the memory 42;

[0134] Determining, by the driver 41, a difference between a first voltage value of the preset signal and a second voltage value of the gain feedback signal output by the feedback delay compensation module 3;

[0135] Sending the difference to the data driving chip 43;

[0136] Compensating, by the data driving chip 43, an initial data signal based on the difference to obtain a target data signal.

[0137] In this embodiment, the current gray scale corresponding to the pixel driving module 1 can refer to a gray scale currently corresponding to a pixel driven by the pixel driving module 1, or can also refer to a gray scale currently corresponding to a row in which the pixel is located. For example, the current gray scale can be determined according to the current light-emitting state of the pixel or the row in which the pixel is located. Obtaining the preset signal corresponding to the current gray scale stored in the memory 42 can refer to searching for the corresponding preset signal in the memory 42 according to the current gray scale, or searching for the first voltage value of the corresponding preset signal.

[0138] In one embodiment, sending the difference to the data driving chip 43 can comprise amplifying the difference by a predetermined ratio and then sending the amplified difference to the data driving chip 43. The predetermined ratio can refer to R2 / R1, and the data signal compensation module 4 comprises the aforementioned resistors R1, R2, R3, and R4.

[0139] In this way, the preset signals corresponding to all gray scales are stored in the memory 42, so that when the gray scale corresponding to the pixel driven by the pixel driving circuit changes, the corresponding preset signal can be flexibly selected for difference determination, and thus the data signal can be accurately compensated.

[0140] In some embodiments, the data driving chip 43 comprises a processing unit 431 and a decoder 432.

[0141] The target data signal is obtained by compensating the initial data signal based on the difference value by the data driving chip 43, and the compensation includes:

[0142] The second data code is determined based on the first data code corresponding to the initial data signal and the difference value by the processing unit 431.

[0143] The second data code is sent to the decoder 432.

[0144] The target data signal corresponding to the second data code is output by the decoder 432.

[0145] In the embodiment, the first data code corresponding to the initial data signal can be obtained by the processing unit 431, for example, obtained from the memory 42 or obtained from the initial data signal generating circuit. The second data code is determined based on the first data code corresponding to the initial data signal and the difference value, which can include: determining a target gain of the initial data signal based on the difference value; and determining the second data code based on the first data code corresponding to the initial data signal and the target gain.

[0146] In one embodiment, outputting the target data signal corresponding to the second data code can mean outputting the target data signal corresponding to the second data code to the data signal input end of the pixel driving module 1. For example, the data signal input end is the source electrode of T2.

[0147] In this way, the data driving chip 43 can complete the compensation of the initial data signal based on the difference between the preset signal and the feedback signal, and the conversion output based on the calculation of the data code and the difference value can improve the processing efficiency of the data signal compensation.

[0148] As a possible implementation, a pixel circuit is provided, as shown in Figure 12 A pixel circuit compensation method applied to the pixel circuit is provided, and specifically includes:

[0149] First, the scan line Scan line outputs a high level, T2 and T3 are turned on, the original data code, i.e., the first data code, in the data driving chip 43 Data Driver IC is normally output to the decoder 432, the initial data signal is output to the data signal line Data line, T1 is turned on at the same time, and C ST is charged. After T1 is turned on, the current controlled by the gate-source voltage of T1 flows through OLED, and OLED emits brightness controlled by the current size. Figure 11 In the embodiment, I O is the current direction in the pixel driving module.

[0150] Due to the threshold voltage drift phenomenon of TFT, the current flowing through OLED at this time will be less than the expected current, and the brightness of OLED will be lower than the preset value. By adjusting the voltage of the data signal line Data line, the current flowing through OLED can be adjusted to the expected current, and the brightness of OLED can be adjusted to the preset value.F The current signal is converted into a voltage signal. Since T3 is open, the signal enters the feedback module, and the signal delay caused by the RC load on the feedback module can cause poor compensation effect. The delay compensation link is set based on the feedback delay compensation module, the high frequency gain of the feedback signal is improved, and the feedback signal delay is suppressed.

[0151] The subsequent compensated feedback signal enters the difference calculation link, the preset signal voltage Vdref in the memory is subtracted from the feedback signal voltage and amplified by a certain proportion, and then finally fed back to the internal of the Data Driver IC, enters the gain calculation link, which calculates the new data code according to the difference value of the feedback and the original data code. This link will control the original data code output to the channel of the decoder to be disconnected, and output the new data code, i.e. the second data code, to the decoder. The decoder outputs the new target data signal into the Data line to control the gate-source voltage of T1, so as to ensure that the current flowing through the OLED meets the preset value. Subsequently, the Scanline outputs low level, T2 and T3 are disconnected, and the charging time of this row is ended. In this way, the monitoring and compensation of the TFT threshold voltage drift phenomenon are realized within the charging time of a row.

[0152] The feedback delay compensation link adopts source negative feedback. The AC signal model and the corresponding transfer function of the circuit of this link are given below, wherein, g m is the transconductance of NMOS tube M1.

[0153] Transfer function

[0154] Zero point:

[0155] Pole:

[0156] High frequency gain multiple:

[0157] The root cause of the waveform delay caused by the original RC wiring load is that the high frequency component of the transmission signal is attenuated, and the low frequency part changes little. However, this circuit can make gain compensation for the high frequency component with a frequency greater than W P to cope with the signal delay caused by R FP &C FP , and adjusting the size of R S can control the gain multiple to adapt to different wiring loads and suppress the occurrence of overcompensation.

[0158] In the difference calculation link, R1=R3, R2=R4, and the output signal is:

[0159]

[0160] In this way, the feedback signal VF3 is compared with the feedback signal preset in the memory corresponding to each gray scale, and the subsequent compensation amount corresponding to the result is calculated to compensate the brightness change caused by the TFT threshold voltage drift at each gray scale.

[0161] In this way, in order to ensure the synchronization and accuracy of monitoring and compensation of the TFT threshold voltage drift phenomenon, to overcome the influence of the parasitic capacitance and the wire impedance of the in-plane array on the feedback signal, and to avoid the phenomenon of overcompensation, a feedback delay compensation circuit is arranged at the receiving end of the external compensation circuit to strengthen the high-frequency gain of the feedback signal. At the same time, an external difference calculation link is arranged to calculate the difference between the feedback signal and the reference signal in the memory and then feedback to the Data Driver IC for processing, so that the influence of the TFT threshold voltage drift can be suppressed in real time when each row is charged.

[0162] From the above description of the embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be realized by means of software and necessary general hardware platforms, and of course, it can also be realized by hardware, but in many cases, the former is a better embodiment. Based on this understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a plurality of instructions for making a terminal device (which can be a mobile phone, computer, server, or network device, etc.) execute the method described in each embodiment of the present application.

[0163] The above only describes the preferred embodiments of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0164] The above only describes the specific embodiments of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A pixel circuit, characterized in that, include: Pixel driving module, feedback module, feedback delay compensation module and data signal compensation module; The input terminal of the feedback module is connected to the output terminal of the pixel driving module; The feedback delay compensation module includes: a compensation transistor; the gate of the compensation transistor is connected to the output terminal of the feedback module; the compensation transistor is used to provide gain for the portion of the feedback signal output by the feedback module whose frequency is higher than a first threshold, wherein the first threshold is the frequency value corresponding to the pole of the transfer function of the feedback delay compensation module; The input terminal of the data signal compensation module is connected to the drain of the compensation transistor, and the output terminal of the data signal compensation module is connected to the data signal input terminal of the pixel driving module; the data signal compensation module is used to determine and output the compensated target data signal; the feedback delay compensation module further includes: a first compensation resistor and a compensation capacitor; the first compensation resistor and the compensation capacitor are connected in parallel between the source of the compensation transistor and ground; The poles of the transfer function are: Among them, W p R is the pole. S For the first compensation resistor, g m C is the transconductance of the compensation transistor; S For compensation capacitors.

2. The pixel circuit according to claim 1, characterized in that, The feedback delay compensation module further includes: a second compensation resistor; the second compensation resistor is connected to the drain of the compensation transistor.

3. The pixel circuit according to claim 1, characterized in that, The data signal compensation module includes: a driver, a memory, and a data driver chip; The memory is connected to the positive input terminal of the driver and is used to provide a preset signal corresponding to the current gray level; The negative input terminal of the driver is connected to the drain of the compensation transistor, and the output terminal of the driver is connected to the input terminal of the data driver chip; the driver is used to determine the difference between the preset signal voltage and the feedback signal voltage output by the compensation transistor. The output terminal of the data driver chip is connected to the data signal input terminal of the pixel driver module, and is used to output the compensated data signal.

4. The pixel circuit according to claim 3, characterized in that, The data driver chip includes: a processing unit and a decoder; The processing unit is connected to the output of the driver and the decoder respectively, and is used to determine the second data code based on the difference between the first data code corresponding to the initial data signal and the output of the driver. The decoder is connected to the data signal input terminal of the pixel driving module and is used to decode the second data code to obtain the target data signal and transmit it to the pixel driving module.

5. A pixel circuit compensation method, applied to the pixel circuit according to any one of claims 1 to 4, characterized in that, The method includes: The control data signal compensation module outputs an initial data signal to the pixel driving module to start the pixel driving module; The feedback delay compensation module provides gain to the portion of the feedback signal output by the feedback module whose frequency is higher than a first threshold, wherein the first threshold is the frequency value corresponding to the pole of the transfer function of the feedback delay compensation module. The data signal compensation module compensates the initial data signal based on the feedback signal after gain output by the feedback delay compensation module to obtain the target data signal, and outputs the target data signal to the pixel driving module; the feedback delay compensation module further includes: a first compensation resistor and a compensation capacitor; the first compensation resistor and the compensation capacitor are connected in parallel between the source of the compensation transistor and ground; The poles of the transfer function are: Among them, W p R is the pole. S For the first compensation resistor, g m C is the transconductance of the compensation transistor; S For compensation capacitors.

6. The pixel circuit compensation method according to claim 5, characterized in that, The feedback delay compensation module further includes: a second compensation resistor; before providing gain to the portion of the feedback signal output by the feedback module with a frequency higher than a first threshold through the feedback delay compensation module, the method further includes: Based on the transconductance of the compensation transistor, the first compensation resistor, the compensation capacitor, and the second compensation resistor, a first threshold and a second threshold for the gain of the feedback delay compensation module are determined; wherein the first threshold is greater than the second threshold.

7. The pixel circuit compensation method according to claim 6, characterized in that, The first compensation resistor is a variable resistor; before providing gain to the portion of the feedback signal output by the feedback module with a frequency higher than a first threshold through the feedback delay compensation module, the method further includes: Determine the wiring load of the feedback module; The resistance value of the first compensation resistor is adjusted based on the trace load to adjust the gain of the feedback delay compensation module.

8. The pixel circuit compensation method according to claim 5, characterized in that, The data signal compensation module includes: a driver, a memory, and a data driver chip; The step of compensating the initial data signal to obtain the target data signal by means of the data signal compensation module based on the feedback signal after gain output by the feedback delay compensation module includes: Determine the current grayscale corresponding to the pixel driving module; Obtain the preset signal corresponding to the current gray level stored in the memory; The difference between the first voltage value of the preset signal and the second voltage value of the feedback signal after gain output by the feedback delay compensation module is determined by the driver. The difference is sent to the data driver chip; The target data signal is obtained by the data driver chip compensating the initial data signal based on the difference.

9. The pixel circuit compensation method according to claim 8, characterized in that, The data driver chip includes: a processing unit and a decoder; The step of obtaining the target data signal by compensating the initial data signal based on the difference using the data driving chip includes: The processing unit determines the second data code based on the first data code corresponding to the initial data signal and the difference; The second data code is sent to the decoder; The decoder outputs the target data signal corresponding to the second data code.

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