Control circuit, pixel circuit, and display device

Abstract

The application discloses a control circuit, a pixel circuit and a display device. The control circuit is used for controlling a driving circuit to drive a light-emitting diode to emit light. The driving circuit is used for driving the light-emitting diode to work. The driving circuit comprises a reset voltage connection end. The reset voltage connection end is used for connecting a reset power supply. The reset power supply is used for providing a reset voltage to reset an anode voltage of the light-emitting diode. In the case that the driving circuit drives the light-emitting diode to switch from a first brightness mode to a second brightness mode, the control circuit is used for controlling the reset voltage connection end to be short-circuited with a cathode of the light-emitting diode according to a control mode, wherein the first brightness is greater than the second brightness. In this way, the control circuit makes the cathode voltage of the light-emitting diode follow the change of the reset voltage, so that the response time delay of the cathode voltage of the light-emitting diode and the reset voltage when switching from the first brightness mode to the second brightness mode can be eliminated or reduced, the light-emitting diode is prevented from flickering during the period, and the display effect of the display device is improved.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more specifically, to a control circuit, a pixel circuit, and a display device. Background Technology

[0002] In related technologies, OLED displays may need to switch from high brightness mode to low brightness mode. At this time, the reset voltage of the pixel driving circuit can respond immediately. However, the response of the cathode voltage of the pixel (light-emitting diode) needs to be triggered by electronic devices, which results in a time delay. This causes a large difference between the reset voltage and the cathode voltage of the pixel during this period, which in turn causes the pixel to flicker and affects the display effect. Summary of the Invention

[0003] The present invention provides a control circuit, a pixel circuit, and a display device.

[0004] The control circuit provided in this embodiment of the invention is used to control the driving circuit to drive the light-emitting diode to emit light. The driving circuit is used to drive the light-emitting diode to work. The driving circuit includes a reset voltage connection terminal, which is used to connect to a reset power supply. The reset power supply is used to provide a reset voltage to reset the anode voltage of the light-emitting diode. When the driving circuit drives the light-emitting diode to switch from a first brightness mode to a second brightness mode, the driving circuit is used to output a trigger signal to the control circuit. The control circuit is used to control the reset voltage connection terminal to be short-circuited with the cathode of the light-emitting diode according to the trigger signal, wherein the first brightness is greater than the second brightness.

[0005] In some embodiments, the control circuit is used to disconnect the reset voltage connection terminal from the cathode of the light-emitting diode after receiving the trigger signal for a first preset time. Specifically, when the light-emitting diode switches from the first brightness mode to the second brightness mode, the response time of the cathode voltage of the light-emitting diode is the first preset time.

[0006] In some embodiments, when the time after the driving circuit drives the light-emitting diode to switch from the first brightness mode to the second brightness mode reaches the first preset time, the cathode voltage of the light-emitting diode is greater than or equal to the first preset voltage. Specifically, when the light-emitting diode switches from the first brightness mode to the second brightness mode, the cathode voltage of the light-emitting diode is the first preset voltage after the response is completed.

[0007] In some embodiments, the driving circuit further includes a first switch, which is connected in series between the reset voltage connection terminal and the anode of the light-emitting diode; when the first switch is turned on, the driving circuit is used to output the trigger signal to the control circuit, and the control circuit is used to control the reset voltage connection terminal to be short-circuited with the cathode of the light-emitting diode according to the trigger signal.

[0008] In some implementations, when the first switch is open, the control circuit is used to control the reset voltage connection terminal to disconnect from the cathode of the light-emitting diode.

[0009] In some implementations, if a second preset time is reached after the first switch has been turned on, the first switch is turned off, and the control circuit is used to control the reset voltage connection terminal to disconnect from the cathode of the light-emitting diode.

[0010] In some embodiments, the control circuit includes a second switch, which is connected in series between the reset voltage connection terminal and the cathode of the light-emitting diode. The second switch closes according to the trigger signal to control the reset voltage connection terminal to be short-circuited with the cathode of the light-emitting diode.

[0011] In some embodiments, the second switch closes when the trigger signal output by the drive circuit is low.

[0012] In some embodiments, the control circuit further includes a drive transistor, which amplifies the trigger signal when the drive circuit outputs the trigger signal to drive the second switch to close.

[0013] In some embodiments, the driving circuit is connected to a fingerprint recognition module, which is used to recognize fingerprint information. When the fingerprint recognition module completes the recognition of the fingerprint information, the driving circuit drives the light-emitting diode to switch from the first brightness mode to the second brightness mode.

[0014] The present invention provides a pixel circuit, which includes a control circuit and a driving circuit according to any of the above embodiments.

[0015] The present invention provides a display device, which includes the pixel circuit of any of the above embodiments.

[0016] In some embodiments, the display device includes a fingerprint recognition module for collecting and recognizing fingerprint information; when the fingerprint recognition module collects the fingerprint information, the display device switches from the second brightness mode to the first brightness mode; when the fingerprint recognition module completes the recognition of the fingerprint information, the display device switches from the first brightness mode to the second brightness mode.

[0017] In the control circuit, pixel circuit, and display device of this invention, the control circuit controls the driving circuit to drive the light-emitting diode (LED) to emit light. The driving circuit drives the LED to operate. The driving circuit achieves brightness adjustment by driving the LED to emit light. When the driving circuit switches the LED from a first brightness mode to a second brightness mode, the driving circuit outputs a trigger signal to the control circuit. Based on the trigger signal, the control circuit can control the reset voltage connection terminal to be short-circuited with the cathode of the LED, so that the cathode voltage of the LED follows the reset voltage change. Therefore, the cathode voltage of the LED can quickly respond to the reset voltage change, eliminating or reducing the response delay between the cathode voltage and the reset voltage, preventing the LED from flickering during this period, and improving the display effect of the display device.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0020] Figure 1 This is a schematic diagram showing the connection between the control circuit and the drive circuit in an embodiment of the present invention;

[0021] Figure 2 This is a voltage variation diagram of the reset voltage and the cathode voltage of the light-emitting diode in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram showing the connection between the control circuit and the drive circuit in an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the control circuit according to an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the control circuit according to an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of a display device according to an embodiment of the present invention. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below, and these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0027] In related technologies, Organic Light-Emitting Diode (OLED) displays may need to switch from a high-brightness mode to a low-brightness mode. In this case, the reset voltage of the pixel driving circuit can respond immediately. However, the response of the pixel's (LED's) cathode voltage requires triggering by electronic devices, thus introducing a time delay. This causes a significant difference between the reset voltage and the pixel's cathode voltage during this period, leading to pixel flickering and affecting the display's performance.

[0028] OLEDs are current-driven organic light-emitting devices that emit light through carrier injection and recombination. The luminous intensity of an OLED is directly proportional to the injected current. Under the influence of an electric field, holes generated at the anode and electrons generated at the cathode move and are injected into the hole transport layer and electron transport layer, respectively, migrating to the emissive layer. When these holes and electrons meet in the emissive layer, they generate excitons, which excite the light-emitting molecules to produce visible light. This phenomenon is called electroluminescence. The greater the voltage difference between the anode and cathode of the light-emitting device, the greater the electroluminescent (EL) current, and the brighter the visible light emitted by the device.

[0029] With the expansion of OLED industry specifications and the increasing demands on products, the brightness of OLED displays in High Brightness Model (HBM) has now reached approximately 1800-2000 nits. At this display brightness value (DBV), to ensure sufficient EL current, the power supply voltage connected to the cathode (ELVSS) is reduced as much as possible while keeping the power supply voltage connected to the anode of the light-emitting diode constant (ELVDD). However, an excessively large voltage difference between the cathode and anode voltages can also affect some optical effects of the light-emitting diode, such as brightness uniformity and color uniformity. Currently, for ultra-high brightness HBM, the ELVSS voltage value is generally set at around -4.5V.

[0030] In pixel circuitry, during high-brightness mode, the reset voltage (Vint voltage) – ELVSS voltage of the light-emitting device's anode must be ≤0V. This means that in high-brightness mode, the Vint voltage needs to be more negative than the ELVSS voltage to prevent grayscale overexposure. In low-brightness mode, to ensure image quality in low-brightness, low-grayscale conditions, the Vin voltage is typically set positively, such as Vint – ELVSS = 0.5V. This means Vint is positively biased by 0.5V relative to ELVSS, thus improving low-grayscale image quality.

[0031] When the driving circuit for the light-emitting device switches from a high-brightness mode to a low-brightness mode, the response times of the Vint voltage and the ELVSS voltage are inconsistent. After the brightness mode switch, the Vint voltage is pulled high immediately upon response. However, the response of the ELVSS voltage requires the display driver chip to output a corresponding square wave (swire) signal, and then the corresponding power supply chip to switch the ELVSS voltage. Therefore, there is a certain time delay between the ELVSS voltage and the Vint voltage, approximately 0.5 to 1 frame. When Vint has changed, ELVSS may not have changed or may still be on its rising edge. This can cause a large difference between the Vint and ELVSS voltages during this period, resulting in pixel flickering and affecting the display effect. It is even possible that the light-emitting device will light up due to the Vint voltage connected to the anode when the power supply voltage of the display device is turned off and the driving circuit no longer provides ELVDD voltage to the light-emitting device.

[0032] Please see Figure 1 This invention provides a control circuit 100. The control circuit 100 controls a driving circuit 200 to drive a light-emitting diode (LED) D1 to emit light. The driving circuit 200 includes a reset voltage connection terminal 210, which is connected to a reset power supply. The reset power supply provides a reset voltage to reset the anode voltage of the LED D1. When the driving circuit 200 drives the LED D1 to switch from a first brightness mode to a second brightness mode, the driving circuit 200 outputs a trigger signal to the control circuit 100. The control circuit 100 then controls the reset voltage connection terminal 210 to short-circuit with the cathode of the LED D1 according to the trigger signal, wherein the first brightness mode is greater than the second brightness mode.

[0033] Specifically, the light-emitting diode D1 is a current-driven device, which may include a micro light-emitting diode (Micro LED), a mini light-emitting diode (Mini LED), an organic light-emitting diode (OLED), or a quantum light-emitting diode (QLED). The driving circuit 200 controls the optical effect of the light-emitting diode D1 by generating a voltage difference between the anode and cathode voltages of the light-emitting device, resulting in a corresponding EL current.

[0034] The driving circuit 200 includes an initialization phase before driving the light-emitting diode D1 to emit light. During the initialization phase, the reset voltage source connected to the reset voltage connection terminal 210 outputs a corresponding reset voltage to the anode of the light-emitting diode D1 under the influence of the reset control signal, so as to reset the anode voltage of the light-emitting diode D1.

[0035] When LED D1 is operating in high-brightness mode, the Vint voltage connected to the reset voltage connection terminal 210 is set to be more negative than the ELVSS voltage connected to the cathode of LED D1. Driving LED D1 includes a first brightness mode and a second brightness mode. In the first brightness mode, LED D1 emits a light with a first brightness level, and in the second brightness mode, it emits a light with a second brightness level, where the first brightness level is greater than the second brightness level. When the driving circuit 200 switches LED D1 from the first brightness mode to the second brightness mode, the brightness of LED D1 decreases.

[0036] When the driving circuit 200 drives the light-emitting diode D1 to switch from the first brightness mode to the second brightness mode, while outputting a corresponding driving signal to the light-emitting diode D1, the driving circuit 200 also outputs a corresponding trigger signal to the control circuit 100. The trigger signal causes the control circuit 100 to short-circuit the reset voltage connection terminal 210 and the cathode of the light-emitting diode D1. After the reset voltage connection terminal 210 and the cathode of the light-emitting diode D1 are short-circuited, the ELVSS voltage responds together with the Vint voltage, and the magnitude of the ELVSS voltage changes with the magnitude of the Vint voltage.

[0037] The changes in ELVSS voltage and Vint voltage can be referenced. Figure 2 ,exist Figure 2The ELVSS and Vint voltage values ​​begin to change at time T1. Time T1 can be the time during which the driving circuit 200 switches the LED D1 from the first brightness mode to the second brightness mode. Furthermore, between time T1 and time T2, the magnitudes of the ELVSS and Vint voltage values ​​remain consistent, with no voltage difference between them.

[0038] Thus, when the driving circuit 200 drives the light-emitting diode D1 to switch from the first brightness mode to the second brightness mode, by controlling the reset voltage connection terminal 210 to short-circuit the cathode of the light-emitting diode D1, the cathode voltage of the light-emitting diode D1 can follow the switch of the reset voltage response mode. This can eliminate or reduce the response delay of the cathode voltage and reset voltage of the light-emitting diode D1, avoid the diode flickering during this period, and improve the display effect of the display device.

[0039] In some embodiments, the control circuit 100 is used to disconnect the reset voltage connection terminal 210 from the cathode of the light-emitting diode D1 after receiving a trigger signal for a first preset time. Specifically, when the light-emitting diode D1 switches from a first brightness mode to a second brightness mode, the response time of the cathode voltage of the light-emitting diode D1 is the first preset time.

[0040] Specifically, after the reset voltage connection terminal 210 and the cathode of LED D1 are shorted, the ELVSS voltage responds along with the Vint voltage, and the magnitude of the ELVSS voltage changes with the magnitude of the Vint voltage. When the driving circuit 200 drives LED D1 to operate in the second brightness mode, the Vint voltage needs to be forward biased relative to the ELVSS voltage. When LED D1 operates in the second brightness mode, forward bias of the Vint voltage relative to the ELVSS voltage is beneficial for improving low grayscale image quality. However, if the ELVSS voltage and the Vint voltage are the same, it cannot meet the requirements for LED D1 to operate in the second brightness mode. Therefore, after the response delay of the ELVSS voltage relative to the Vint voltage is reduced or eliminated, the voltage difference between the ELVSS voltage and the Vint voltage will not cause LED D1 to flicker. It is necessary to again disconnect the reset voltage connection terminal 210 and the cathode of LED D1 so that the Vint voltage can be forward biased relative to the ELVSS voltage.

[0041] After the time elapsed after LED D1 switches from the first brightness mode to the second brightness mode reaches the first preset time, it can be considered that the ELVSS voltage value has completed its response. The response delay of the cathode voltage and reset voltage of LED D1 is eliminated, and there is no longer a large voltage difference between the ELVSS voltage value and the Vint voltage value that would cause LED D1 to flicker.

[0042] For details on the voltage changes of Vint and ELVSS, please refer to... Figure 2 Time T1 can be the time it takes for the driving circuit 200 to switch the LED D1 from the first brightness mode to the second brightness mode. The time from T1 to T2 can be the first preset time after the driving circuit 200 switches the LED D1 from the first brightness mode to the second brightness mode. During the time from T1 to T2, the reset voltage connection terminal 210 and the cathode of the LED D1 are short-circuited, and the magnitudes of the ELVSS voltage and Vint voltage remain consistent, with no voltage difference between them. After time T2, the reset voltage connection terminal 210 and the cathode of the LED D1 are disconnected, the ELVSS voltage no longer increases, and the Vint voltage continues to increase. The ELVSS voltage no longer increases after time T2. The Vint voltage no longer increases after time T3, and finally, the Vint voltage is forward biased relative to the ELVSS voltage.

[0043] Thus, after the time it takes for LED D1 to switch from the first brightness mode to the second brightness mode reaches the first preset time, it can be determined that the response delay of the cathode voltage and reset voltage of LED D1 has been eliminated or reduced. By controlling the reset voltage connection terminal 210 to be disconnected from the cathode of LED D1, the Vint voltage can be forward biased relative to the ELVSS voltage, which is beneficial to improving the low grayscale image quality of LED D1 in the second brightness mode.

[0044] In some embodiments, when the time after the driving circuit 200 drives the light-emitting diode D1 to switch from the first brightness mode to the second brightness mode reaches a first preset time, the cathode voltage of the light-emitting diode D1 is greater than or equal to the first preset voltage. In the case of the light-emitting diode D1 switching from the first brightness mode to the second brightness mode, the cathode voltage of the light-emitting diode D1 is the first preset voltage after the response is completed.

[0045] Specifically, when LED D1 switches from the first brightness mode to the second brightness mode, the ELVSS and Vint voltage values ​​change with a rising edge after the initial response. The ELVSS voltage rises to a maximum value and then remains stable, as does the Vint voltage rise to another maximum value and then remain stable. The final Vint voltage value is forward biased relative to the ELVSS voltage value. The ELVSS voltage value reflects the response delay of the ELVSS voltage. When the ELVSS voltage reaches the first preset voltage, the response can be considered complete. The response delay of the cathode voltage and reset voltage of LED D1 is eliminated, and there is no longer a large voltage difference between the ELVSS and Vint voltage values ​​that would cause LED D1 to flicker.

[0046] The voltage variations of Vint and ELVSS can be referenced. Figure 2 During the time interval T1 to T2, the reset voltage connection terminal 210 and the cathode of LED D1 are shorted, and the rising edges of the ELVSS and Vint voltage values ​​change, with the magnitudes of the ELVSS and Vint voltage values ​​remaining consistent. During this time interval, both the ELVSS and Vint voltage values ​​begin to rise from voltage V0. Voltage V1 can be a first preset voltage. During time interval T2, both the ELVSS and Vint voltage values ​​rise to voltage V1, at which point the reset voltage connection terminal 210 and the cathode of LED D1 are disconnected. After time T2, the ELVSS voltage value stops rising, while the Vint voltage value continues to rise. The Vint voltage value rises to voltage V2 at time T3, and voltage V2 is forward biased relative to voltage V1. The Vint voltage value remains stable after time T3, and ultimately, the Vint voltage is forward biased relative to the ELVSS voltage.

[0047] Thus, after LED D1 switches from the first brightness mode to the second brightness mode, if the ELVSS voltage reaches the first preset voltage, the response delay of the cathode voltage and reset voltage of LED D1 can be eliminated or reduced. By controlling the reset voltage connection terminal 210 to be disconnected from the cathode of LED D1, the Vint voltage can be forward biased relative to the ELVSS voltage, which is beneficial to improving the low grayscale image quality of LED D1 in the second brightness mode.

[0048] In some embodiments, the driving circuit 200 further includes a first switch, which is connected in series between the reset voltage connection terminal 210 and the anode of the light-emitting diode D1. When the first switch is turned on, the driving circuit 200 outputs a trigger signal to the control circuit 100, and the control circuit 100 controls the reset voltage connection terminal 210 to be short-circuited with the cathode of the light-emitting diode D1 according to the trigger signal.

[0049] Specifically, the first switch can be Figure 3 In the circuit, switch Q1 is connected in series between the reset voltage connection terminal 210 and the anode of LED D1. When the first switch is open, the reset voltage connection terminal 210 is disconnected from the anode of LED D1. When the first switch is closed, the reset voltage connection terminal 210 is connected to the anode of LED D1. When the brightness mode of LED D1 is changed by the driving circuit 200, the gate of switch Q1 is charged, causing switch Q1 to close. When switch Q1 is closed, the reset voltage connection terminal 210 is connected to the anode of LED D1, resulting in the Vint voltage being applied to the anode of LED D1. When the light-emitting device switches from the first brightness mode to the second brightness mode, the Vint voltage and the ELVSS voltage differ significantly for a period of time. Since the Vint voltage is applied to the anode of LED D1, this causes LED D1 to flicker during this period.

[0050] With the first switch closed, LED D1 can be considered to have switched from the first brightness mode to the second brightness mode. At this time, the driving circuit 200 outputs a corresponding driving signal to LED D1 and a corresponding trigger signal to the control circuit 100. The trigger signal causes the control circuit 100 to short-circuit the reset voltage connection terminal 210 and the cathode of LED D1, causing the ELVSS voltage to change with the Vint voltage. After the reset voltage connection terminal 210 and the cathode of LED D1 are short-circuited, the ELVSS voltage responds along with the Vint voltage, and the magnitude of the ELVSS voltage changes with the magnitude of the Vint voltage.

[0051] The voltage variations of Vint and ELVSS can be referenced. Figure 2 ,exist Figure 2 The ELVSS and Vint voltage values ​​begin to change at time T1. Time T1 can be the time when the first switch just begins to close. Furthermore, between time T1 and T2, the magnitudes of the ELVSS and Vint voltage values ​​remain consistent, with no voltage difference between them.

[0052] Thus, when the first switch is closed, by shorting the reset voltage connection terminal 210 to the cathode of the LED D1, the cathode voltage of the LED D1 can follow the switching of the reset voltage response mode. This eliminates or reduces the response delay between the cathode voltage and the reset voltage of the LED D1, preventing the diode from flickering during this period and improving the display effect of the display device.

[0053] In some embodiments, when the first switch is open, the control circuit 100 controls the reset voltage connection terminal 210 to disconnect from the cathode of the light-emitting diode D1.

[0054] Specifically, when the first switch is open, the reset voltage connection terminal 210 is disconnected from the anode of LED D1, and the Vint voltage is not connected to the anode of LED D1. When the light-emitting device switches from the first brightness mode to the second brightness mode, even if the Vint voltage and the ELVSS voltage differ significantly, the Vint voltage will not cause the LED to flicker because it is not connected to the anode of LED D1. At this time, the control circuit 100 can control the reset voltage connection terminal 210 to disconnect from the cathode of LED D1, so that the Vint voltage can ultimately be forward biased relative to the ELVSS voltage. The second brightness mode is the low brightness mode of LED D1, and the forward bias of the Vint voltage relative to the ELVSS voltage is beneficial to improving the low grayscale image quality of LED D1 in the low brightness mode.

[0055] Thus, when the first switch is off, the Vint voltage will not cause the diode to flicker. By controlling the reset voltage connection 210 to disconnect from the cathode of the LED D1, the Vint voltage can be forward biased relative to the ELVSS voltage. This is beneficial for improving the low grayscale image quality of the LED D1 in low-brightness mode.

[0056] In some embodiments, when the time after the first switch is turned on reaches a second preset time, the first switch is turned off, and the control circuit 100 is used to control the reset voltage connection terminal 210 to disconnect from the cathode of the light-emitting diode D1.

[0057] Specifically, when LED D1 switches from the first brightness mode to the second brightness mode, the gate terminal of the first switch is charged, causing the first switch to conduct. When the brightness mode of LED D1 is no longer switching, the gate terminal of the first switch stops charging, and the first switch is turned off.

[0058] After the first switch closes, a second preset time is elapsed, at which point the Gate terminal of the first switch is considered to be no longer charging. The first switch then opens, at which point the control reset voltage connection 210 and the cathode of the LED D1 are disconnected. For details, please refer to... Figure 2Time T1 can be the time the first switch closes, and the time from T1 to T2 can be a second preset time after the first switch closes. During the time from T1 to T2, the reset voltage connection terminal 210 and the cathode of LED D1 are short-circuited, and the magnitudes of the ELVSS voltage and Vint voltage remain consistent, with no voltage difference between them. After time T2, the reset voltage connection terminal 210 and the cathode of LED D1 are disconnected, the ELVSS voltage no longer increases, and the Vint voltage continues to increase. The Vint voltage no longer increases after time T3, and finally, the Vint voltage is forward biased relative to the ELVSS voltage.

[0059] Thus, after the first switch is closed, once the first preset time has elapsed, it can be determined that the Gate terminal of the first switch will no longer be charged, and the first switch will be opened. By controlling the reset voltage connection terminal 210 to disconnect from the cathode of the light-emitting diode D1, the Vint voltage can be forward biased relative to the ELVSS voltage, which is beneficial to improving the low grayscale image quality of the light-emitting diode D1 in low brightness mode.

[0060] Reference Figure 4 In some embodiments, the control circuit 100 includes a second switch, which is connected in series between the reset voltage connection terminal 210 and the cathode of the light-emitting diode D1. The second switch closes according to a trigger signal to control the reset voltage connection terminal 210 to be short-circuited with the cathode of the light-emitting diode D1.

[0061] Specifically, the second switch can be Figure 4 The second switch, Q2, can be a PMOS transistor or other electronic switching transistor. The trigger signal is a control signal used to close the second switch. When the second switch is closed, the reset voltage connection terminal 210 is shorted to the cathode of the light-emitting diode D1, making the ELVSS voltage consistent with the Vint voltage. When the driving circuit 200 drives the light-emitting diode D1 to switch from the first brightness mode to the second brightness mode, the driving circuit 200 can simultaneously output the corresponding trigger signal to control the second switch to close.

[0062] In some implementations, the second switch closes when the trigger signal output by the drive circuit 200 is low.

[0063] Specifically, the trigger signal can be a low-level signal, and the corresponding driver chip in the driver circuit 200 outputs the corresponding trigger signal through a general-purpose input / output (GPIO) interface. In the pixel circuit voltage settings, the reset voltage connected to the reset voltage terminal 210 and the voltage at the negative terminal of the LED D1 are both negative potentials. The voltage value of Vint is approximately -1.5V, and the voltage value of ELVSS is approximately -4.5V. For logic control switches, a high level is easier to identify. If a high level is used to control the closing of switch Q2, zero potential can also be a high potential, which can close switch Q2, resulting in poor anti-interference capability of the circuit.

[0064] Therefore, using a low-level signal as a trigger signal to control the closing of the second switch can improve the circuit's anti-interference capability.

[0065] Reference Figure 4 In some embodiments, the control circuit 100 further includes a drive transistor. When the drive circuit 200 outputs a trigger signal, the drive transistor is used to amplify the trigger signal to drive the second switch to close.

[0066] Specifically, the driver transistor is used to amplify the trigger signal to drive the second switch to close when the driving capability of the trigger signal is insufficient. The driver transistor can be... Figure 4 Transistor Q3 in the circuit is a PNP transistor. The base of the transistor is used to receive the trigger signal output from the driver circuit 200, and the collector is used to receive either the AVEE voltage or the VGL voltage. Both AVEE and VGL voltages are low-potential voltages provided by the power supply chip. The emitter of the transistor is connected to ground via a current-limiting resistor R0. When the driver circuit 200 outputs the trigger signal, the transistor conducts, causing the AVEE voltage or VGL voltage to be applied to the gate of the second switch, thus closing the second switch.

[0067] If the trigger signal output by the driver circuit 200 is sufficient to close the second switch, a driver transistor is not required. See [reference needed] for details. Figure 5 The corresponding driver chip in the driver circuit 200 is directly connected to the gate of Q2 through the GPIO interface. When the driver circuit 200 outputs a trigger signal, the trigger signal is connected to the gate of Q2 and can control Q2 to close.

[0068] In some embodiments, the driving circuit 200 is connected to the fingerprint recognition module, which is used to recognize fingerprint information. When the fingerprint recognition module completes the recognition of the fingerprint information, the driving circuit 200 drives the light-emitting diode D1 to switch from a first brightness mode to a second brightness mode.

[0069] Specifically, the driving circuit 200 and the control circuit 100 can be applied in a fingerprint recognition device. When the fingerprint recognition module completes the recognition of fingerprint information, the driving circuit 200 drives the light-emitting diode D1 to switch from the first brightness mode to the second brightness mode.

[0070] The present invention provides a pixel circuit, which includes a control circuit 100 and a driving circuit 200 as described in any of the above embodiments.

[0071] Specifically, the implementation of the control circuit 100 and the drive circuit 200 can refer to the above-described implementation. Since the pixel circuit includes the control circuit 100 and the drive circuit 200 of any of the above-described implementations, the beneficial effects of the pixel circuit include all the beneficial effects of the control circuit 100 and the drive circuit 200, which will not be elaborated here.

[0072] The present invention provides a display device, which includes the pixel circuit of any of the above embodiments.

[0073] Specifically, the display device can be any device that displays text or images, whether moving (e.g., video) or stationary (e.g., still images). More specifically, the display device can be one of a variety of electronic devices, and embodiments can be implemented in or associated with a variety of electronic devices. These electronic devices include, but are not limited to, mobile phones, wireless devices, personal data assistants (PS1), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, camcorders, game consoles, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controllers and / or displays, camera view displays (e.g., displays of rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging and aesthetic structures (e.g., displays of images of a piece of jewelry), etc. The embodiments of this disclosure do not impose any particular limitation on the specific form of the aforementioned display device.

[0074] The pixel circuit includes a control circuit 100 and a driving circuit 200. The implementation of the control circuit 100 and the driving circuit 200 can refer to the above implementation. The beneficial effects of the display device include all the beneficial effects of the control circuit 100 and the driving circuit 200, which will not be described in detail here.

[0075] Reference Figure 6In some embodiments, the display device 1000 includes a fingerprint recognition module 300, which is used to collect and recognize fingerprint information. When the fingerprint recognition module 300 collects fingerprint information, the display device 1000 switches from a second brightness mode to a first brightness mode. When the fingerprint recognition module 300 completes the recognition of the fingerprint information, the display device 1000 switches from the first brightness mode to a second brightness mode.

[0076] Specifically, in the display device 1000 with fingerprint recognition function, when the fingerprint recognition module 300 collects fingerprint information, the display device 1000 switches to a first brightness mode. In the first brightness mode, the fingerprint recognition module 300 can recognize fingerprint information more accurately. After the fingerprint recognition module 300 completes the fingerprint recognition, the display device 1000 switches from the first brightness mode to a second brightness mode.

[0077] In the control circuit 100, pixel circuit, and display device 1000 of this embodiment of the invention, the control circuit 100 controls the driving circuit 200 to drive the light-emitting diode D1 to emit light. The driving circuit 200 drives the light-emitting diode D1 to operate, and the driving circuit 200 achieves brightness adjustment function by driving the light-emitting diode D1 to emit light. When the driving circuit 200 drives the light-emitting diode D1 to switch from the first brightness mode to the second brightness mode, the driving circuit 200 outputs a trigger signal to the control circuit 100. According to the trigger signal, the control circuit 100 can control the reset voltage connection terminal 210 to be short-circuited with the cathode of the light-emitting diode D1, so that the cathode voltage of the light-emitting diode D1 follows the change of the reset voltage. Therefore, when the driving circuit 200 drives the light-emitting diode D1 to switch from the first brightness mode to the second brightness mode, the cathode voltage of the light-emitting diode D1 can follow the switch of the reset voltage response mode, eliminating or reducing the response delay between the cathode voltage and the reset voltage of the light-emitting diode D1, avoiding flickering of the light-emitting diode D1 during this period, thereby improving the display effect of the display device.

[0078] In the description of this specification, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with an embodiment or example that are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0079] Furthermore, the term "connection" should be interpreted broadly. For example, it can include fixed connections, detachable connections, or integral connections; it can include direct connections or indirect connections through an intermediate medium; and it can also include internal communication between two elements. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0081] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain.

[0082] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A control circuit for controlling a drive circuit to drive a light emitting diode to emit light, characterized by, The driving circuit is used to drive the light-emitting diode to work. The driving circuit includes a reset voltage connection terminal, which is used to connect to a reset power supply. The reset power supply is used to provide a reset voltage to reset the anode voltage of the light-emitting diode. When the driving circuit drives the light-emitting diode to switch from a first brightness mode to a second brightness mode, the driving circuit is used to output a trigger signal to the control circuit, and the control circuit is used to control the reset voltage connection terminal to be short-circuited with the cathode of the light-emitting diode according to the trigger signal, wherein the first brightness is greater than the second brightness; The control circuit includes a second switch, which is connected in series between the reset voltage connection terminal and the cathode of the light-emitting diode. The second switch closes according to the trigger signal to control the reset voltage connection terminal to be short-circuited with the cathode of the light-emitting diode.

2. The control circuit of claim 1, wherein, The control circuit is used to control the reset voltage connection terminal to disconnect from the cathode of the light-emitting diode after receiving the trigger signal for a first preset time, wherein when the light-emitting diode switches from the first brightness mode to the second brightness mode, the response time of the cathode voltage of the light-emitting diode is the first preset time.

3. The control circuit according to claim 2, characterized in that, When the time after the driving circuit drives the light-emitting diode to switch from the first brightness mode to the second brightness mode reaches the first preset time, the cathode voltage of the light-emitting diode is greater than or equal to the first preset voltage, wherein when the light-emitting diode switches from the first brightness mode to the second brightness mode, the cathode voltage of the light-emitting diode is the first preset voltage after the response is completed.

4. The control circuit according to claim 1, characterized in that, The driving circuit also includes a first switch, which is connected in series between the reset voltage connection terminal and the anode of the light-emitting diode; When the first switch is turned on, the driving circuit outputs the trigger signal to the control circuit, and the control circuit controls the reset voltage connection terminal to be short-circuited with the cathode of the light-emitting diode according to the trigger signal.

5. The control circuit according to claim 4, characterized in that, When the first switch is open, the control circuit is used to control the reset voltage connection terminal to disconnect from the cathode of the light-emitting diode.

6. The control circuit according to claim 5, characterized in that, If the time after the first switch is turned on reaches a second preset time, the first switch is turned off, and the control circuit is used to control the reset voltage connection terminal to disconnect from the cathode of the light-emitting diode.

7. The control circuit according to claim 1, characterized in that, When the trigger signal output by the drive circuit is low, the second switch closes.

8. The control circuit according to claim 1, characterized in that, The control circuit also includes a drive transistor, which amplifies the trigger signal when the drive circuit outputs the trigger signal to drive the second switch to close.

9. The control circuit according to claim 1, characterized in that, The driving circuit is connected to the fingerprint recognition module, which is used to recognize fingerprint information. When the fingerprint recognition module completes the recognition of the fingerprint information, the driving circuit drives the light-emitting diode to switch from the first brightness mode to the second brightness mode.

10. A pixel circuit, characterized in that, The pixel circuit includes the control circuit as described in any one of claims 1-9 and the driving circuit.

11. A display device, characterized in that, The display device includes the control circuit according to any one of claims 1-9 or the pixel circuit according to claim 10.

12. The display device according to claim 11, characterized in that, The display device includes a fingerprint recognition module, which is used to collect and recognize fingerprint information; When the fingerprint recognition module collects the fingerprint information, the display device switches from the second brightness mode to the first brightness mode. When the fingerprint recognition module completes the recognition of the fingerprint information, the display device switches from the first brightness mode to the second brightness mode.

Images