Drive circuit and display device

Abstract

The application provides a driving circuit and a display device. A control electrode voltage change of a switch tube does not couple a control electrode voltage of a driving tube, reduces a forward gamma voltage of a light emitting diode, enhances brightness of the light emitting diode, and further reduces power consumption of the driving circuit. The driving circuit can support image refresh frequencies of different grades at the same time, and realizes inductive switching before different image refresh frequencies. The driving circuit can include a storage capacitor, a driving tube, and a switch tube. The driving tube can be used to control a driving current of the light emitting diode, and the switch tube can control the control electrode voltage of the driving tube and compensate for a threshold voltage of the driving tube.

Description

Technical Field

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

[0002] With the rapid development of technology, semiconductor devices have been widely used in display devices (such as mobile phones and watches). Display devices can include multiple light-emitting devices (such as light-emitting diodes) and multiple driving circuits for driving the light-emitting diodes.

[0003] In the driving circuit provided by related technologies, the change in the control electrode voltage of the switching transistor (such as a transistor) will couple to the control electrode voltage of the driving transistor (such as a transistor), which will increase the forward gamma voltage of the light-emitting diode, that is, reduce the brightness of the light-emitting diode, resulting in greater power consumption of the driving circuit.

[0004] Therefore, there is an urgent need for a technical solution that can enhance the brightness of light-emitting diodes and reduce the power consumption of the driving circuit. Summary of the Invention

[0005] This application provides a driving circuit and a display device in which the change of the control electrode voltage of the switching transistor will not couple to the control electrode voltage of the driving transistor, thereby reducing the forward gamma voltage of the light-emitting diode, enhancing the brightness of the light-emitting diode, and thus reducing the power consumption of the driving circuit.

[0006] In a first aspect, this application provides a driving circuit that may include a first transistor (as a driving transistor), a second transistor (as a switching transistor), a third transistor (as a switching transistor), a fourth transistor (as a switching transistor), and a storage capacitor.

[0007] The first transistor can be electrically connected to the first power supply, the second power supply, the first node, and the third node. The second transistor can be electrically connected to the third node, the light-emitting control circuit, and the light-emitting diode. The third transistor can be electrically connected to the first node, the first control circuit, and the second node. The fourth transistor can be electrically connected to the second node, the second control circuit, and the third power supply. The storage capacitor can be electrically connected to the second power supply and the first node (that is, the storage capacitor can be electrically connected between the second power supply and the first node), and the second node is also used to be electrically connected to the third node. It is conceivable that the voltage of the second node can be equal to the voltage of the third node.

[0008] Based on the above electrical connection relationship, we can further conclude that:

[0009] The storage capacitor can be used to store a first voltage supplied by a first power source via a first transistor.

[0010] It should be noted that since the second voltage can be a DC voltage, and the storage capacitor has the function of blocking DC voltage, the second voltage is blocked by the storage capacitor during the process of driving the LED in the driving circuit, and the second voltage will not affect the voltage of the first node.

[0011] The first transistor can be used to control the voltage of the third node based on the first voltage stored in the storage capacitor and the second voltage provided by the second power supply.

[0012] The second transistor can be used to control the drive current of the light-emitting diode according to the light-emitting control signal provided by the light-emitting control circuit and the voltage of the third node.

[0013] The third transistor can be used to: control the control electrode voltage of the first transistor according to the first control signal provided by the first control circuit and the voltage of the second node. It can also be used to compensate the threshold voltage of the first transistor according to the first control signal and the first voltage provided by the first power supply.

[0014] The fourth transistor can be used to control the voltage of the second node according to the second control signal provided by the second control circuit and the third voltage provided by the third power supply.

[0015] In the driving circuit provided in this application, the control electrode of transistor T1, which serves as the driving transistor, is electrically connected to node N1, and the control electrode of transistor T3, which serves as the switching transistor, is connected to the first control circuit C1. Therefore, the change in the control electrode voltage of transistor T3 will not couple to the control electrode voltage of transistor T1, thereby reducing the forward gamma voltage of the light-emitting diode, enhancing the brightness of the light-emitting diode, and thus reducing the power consumption of the driving circuit.

[0016] In one example, within one image refresh cycle, the number of drive pulses in the first control signal is greater than or equal to the number of drive pulses in the second control signal.

[0017] In other words, within one image refresh cycle, the number of times the third transistor is turned on can be greater than or equal to the number of times the fourth transistor is turned on. If the number of times the third transistor is turned on is equal to the number of times the fourth transistor is turned on, the threshold voltage of the first transistor can be compensated as quickly as possible.

[0018] In another example, the number of driving pulses in the light emission control signal can be greater than or equal to 2 within one image refresh cycle.

[0019] In one possible implementation, the driving circuit provided in this application may further include a fifth transistor and a sixth transistor.

[0020] The first electrode of the fifth transistor can be used to connect to the second power supply, the control electrode of the fifth transistor can be used to connect to the light-emitting control circuit, and the second electrode of the fifth transistor can be used to connect to the fourth node.

[0021] The first terminal of the sixth transistor can be used to be electrically connected to the first power supply, the control terminal of the sixth transistor can be used to be electrically connected to the third control circuit, the second terminal of the sixth transistor can be used to be electrically connected to the fourth node, and the fourth node is also used to be electrically connected to the first transistor.

[0022] Based on the above electrical connection relationship, we can further conclude that:

[0023] The fifth transistor can be used to control the voltage of the fourth node based on the light emission control signal and the second voltage.

[0024] The sixth transistor can be used to control the voltage of the fourth node according to the third control signal provided by the third control circuit and the first voltage.

[0025] In some embodiments of this application, the frequency of the drive pulse in the third control signal can be equal to the image refresh frequency within one image refresh cycle.

[0026] Understandably, although both the fifth and sixth transistors control the voltage of the fourth node, they do not conduct simultaneously. When the fifth transistor is on, the voltage at the fourth node can be equal to the second voltage. When the sixth transistor is on, the voltage at the fourth node can be equal to the first voltage.

[0027] Therefore, the first transistor can be specifically used to control the voltage of the third node based on the voltage of the fourth node and the control electrode voltage of the first transistor.

[0028] Furthermore, the driving circuit provided in this application may also include a seventh transistor and an eighth transistor.

[0029] Among them, the first terminal of the seventh transistor can be used to connect to the anode of the light-emitting diode, the second terminal of the seventh transistor can be used to connect to the fifth power supply, the first terminal of the eighth transistor can be used to connect to the third node, and the second terminal of the eighth transistor can be used to connect to the sixth power supply.

[0030] The control terminals of the seventh transistor and the eighth transistor can be electrically connected to the fourth control circuit, respectively; or, the control terminal of the seventh transistor can be electrically connected to the fifth control circuit, and the control terminal of the eighth transistor can be electrically connected to the fourth control circuit.

[0031] In other words, the control electrode of the seventh transistor and the control electrode of the eighth transistor can be used to be electrically connected to the same control circuit, or they can be connected to different control circuits respectively.

[0032] Based on the above electrical connection relationship, we can further conclude that:

[0033] The seventh transistor can be used to: control the anode voltage of the LED according to the fourth control signal provided by the fourth control circuit and the fifth voltage provided by the fifth power supply; or, control the anode voltage of the LED according to the fifth control signal and the fifth voltage provided by the fifth control circuit.

[0034] The eighth transistor can be used to control the voltage of the third node according to the fourth control signal and the sixth voltage provided by the sixth power supply.

[0035] As can be seen, the anode voltage of the LED can be controlled by the seventh transistor, which means the anode voltage of the LED can be reset. The voltage of the third node can be controlled by the eighth transistor, which means the voltage of the third node can be reset.

[0036] In this embodiment, when the eighth transistor is turned on, the voltage of the third node can be controlled by the sixth voltage, making the source and drain voltages of the first transistor controllable (or reset). This can enhance the negative bias temperature stress of the first transistor, that is, control the drift of the threshold voltage of the first transistor, avoid screen flickering during the switching of the display device between different image refresh frequencies, and avoid screen flickering at lower image refresh frequencies.

[0037] In one possible implementation, within one image refresh cycle, the number of driving pulses in the fourth control signal can be greater than or equal to the number of driving pulses in the light emission control signal, and the frequency of the driving pulses in the fifth control signal can be equal to the image refresh frequency.

[0038] It can be inferred that since the frequency of the drive pulse in the third control signal can be equal to the image refresh rate, the frequency of the drive pulse in the fifth control signal can be equal to the frequency of the drive pulse in the third control signal, and both are equal to the image refresh rate.

[0039] In some embodiments of this application, the frequency of the driving pulse in the fourth control signal can be N / 2 times the frequency of the driving pulse in the third control signal. Wherein, N≥2, and N is an integer.

[0040] For example, when the frequency of the driving pulse in the control signal S4n is 60Hz, the frequency of the driving pulse in the control signal S3n can be 60Hz, 40Hz, 30Hz, 24Hz, etc.

[0041] For example, when the frequency of the driving pulse in the control signal S4n is 120Hz, the frequency of the driving pulse in the control signal S3n can be 120Hz, 80Hz, 60Hz, etc.

[0042] It is conceivable that the fourth control signal and the third control signal can adopt different timing sequences. The driving pulse in the fourth control signal can be a higher frequency such as 360Hz. Since the frequency of the driving pulse in the third control signal can be the image refresh rate, different image refresh rates such as 120Hz, 90Hz, and 72Hz can be achieved. This not only enables dynamic switching between different image refresh rates, but also avoids screen flicker when switching between different image refresh rates or maintaining the image at a low refresh rate, thus improving the stability of the displayed image (screen).

[0043] In one possible implementation, the first transistor, the second transistor, the fifth transistor, and the sixth transistor can each be a low-temperature polycrystalline silicon thin-film transistor. The third transistor and the fourth transistor can each be an oxide thin-film transistor.

[0044] Furthermore, in one example, the seventh transistor and the eighth transistor can be low-temperature polycrystalline silicon thin-film transistors, respectively.

[0045] Therefore, the falling edge of the first drive pulse in the fourth control signal can be after the rising edge of the first drive pulse in the light emission control signal. The falling edge of the last drive pulse in the fourth control signal can be after the falling edge of the last drive pulse in the first control signal. The rising edge of the last drive pulse in the fourth control signal can be before the falling edge of the first drive pulse in the light emission control signal.

[0046] In some embodiments of this application, the falling edge of the drive pulse in the fifth control signal may precede the falling edge of the last drive pulse in the fourth control signal, and the rising edge of the drive pulse in the fifth control signal may follow the rising edge of the last drive pulse in the fourth control signal.

[0047] It is conceivable that the seventh and eighth transistors are low-temperature polycrystalline silicon thin-film transistors, therefore, the driving circuit provided in this application can be used in dynamic display devices with high image refresh rates, such as mobile phones and tablet computers.

[0048] In another example, the seventh and eighth transistors could be oxide thin-film transistors, respectively.

[0049] Therefore, the rising edge of the first drive pulse in the fourth control signal can be after the rising edge of the first drive pulse in the light emission control signal. The rising edge of the last drive pulse in the fourth control signal can be after the falling edge of the last drive pulse in the first control signal. The falling edge of the last drive pulse in the fourth control signal can be before the falling edge of the first drive pulse in the light emission control signal.

[0050] In some embodiments of this application, the rising edge of the drive pulse in the fifth control signal may precede the rising edge of the last drive pulse in the fourth control signal. The falling edge of the drive pulse in the fifth control signal may follow the falling edge of the last drive pulse in the fourth control signal.

[0051] It is conceivable that the seventh and eighth transistors are respectively oxide thin-film transistors, thus making them suitable for static display devices with low image refresh rates, such as watches and e-book readers.

[0052] This application can control the driving current of the light-emitting diode by using the control timing of the control signals in the two examples above, that is, to drive the light-emitting diode and make it emit light.

[0053] In one possible implementation, the rising edge of the drive pulse in the third control signal can precede the falling edge of the last drive pulse in the first control signal.

[0054] In some embodiments of this application, the number of driving pulses for the first control signal, the second control signal, the third control signal, and the fifth control signal are respectively during the high-level period of the first driving pulse of the light emission control signal.

[0055] Secondly, this application provides an electronic device that may include a first power supply, a second power supply, a third power supply, a light-emitting control circuit, a first control circuit, a second control circuit, a plurality of light-emitting diodes, and a plurality of driving circuits provided in the first aspect and its possible implementations.

[0056] Among them, the first power supply, the second power supply, the third power supply, the light-emitting control circuit, the first control circuit, and the second control circuit can be used to electrically connect to each of the multiple driving circuits, and the multiple light-emitting diodes can be used to electrically connect to the multiple driving circuits one-to-one.

[0057] Therefore, each driving circuit can be used to control the driving current of the corresponding light-emitting diode, thereby driving the light-emitting diode.

[0058] It is conceivable that each driving circuit can compensate the threshold voltage of the first transistor according to the third transistor. Different driving circuits can eliminate the difference in the turn-on voltage of the corresponding light-emitting diodes, so that the display brightness of the display device is uniform, that is, the display brightness is as similar as possible.

[0059] It should be understood that the second aspect of this application is consistent with the technical solution of the first aspect of this application, and the beneficial effects achieved by each aspect and the corresponding feasible implementation are similar, so they will not be repeated here. Attached Figure Description

[0060] Figure 1 This is a schematic structural diagram of a display device in an embodiment of this application;

[0061] Figure 2 This is a schematic structural diagram of a driving circuit in an embodiment of this application;

[0062] Figure 3 This is a schematic structural diagram of a driving circuit in an embodiment of this application;

[0063] Figure 4 This is a schematic structural diagram of a driving circuit in an embodiment of this application;

[0064] Figure 5 This is a schematic timing diagram of the control signals in an embodiment of this application;

[0065] Figure 6 This is a schematic timing diagram of the control signals in an embodiment of this application;

[0066] Figure 7 This is a schematic timing diagram of the control signals in an embodiment of this application;

[0067] Figure 8 This is a schematic timing diagram of the control signals in an embodiment of this application;

[0068] Figure 9 This is a schematic timing diagram of the control signals in an embodiment of this application;

[0069] Figure 10 This is a schematic timing diagram of the control signals in an embodiment of this application. Detailed Implementation

[0070] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0071] The terms "first," "second," etc., used in the specification, embodiments, claims, and drawings of this application are for distinguishing purposes only and should not be construed as indicating or implying relative importance or order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as including a series of steps or units. A method, system, product, or apparatus is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0072] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0073] With the rapid development of technology, semiconductor devices (such as transistors) have been widely used in display devices. Based on their application scenarios, display devices can be divided into dynamic display devices (such as mobile phones, laptops, and tablets, which primarily display dynamic content) and static display devices (such as watches, e-book readers, electronic billboards, and wall-mounted windows, which primarily display static content). Comparatively, dynamic devices require a higher image refresh rate, while static devices require a lower one. The image refresh rate refers to the number of times the electron beam scans the image on the display screen. A higher refresh rate results in better image or screen stability.

[0074] To meet the image refresh rate requirements of different display devices, this application provides a display device, such as... Figure 1 As shown. The display device 1 may include a first power supply (PS) 1, a third power supply PS3, a second power supply PS2, a light-emitting control circuit CEM, a first control circuit C1, a second control circuit C2, N driving circuits, and N light-emitting diodes (LEDs), such as... Figure 1 As shown. The N driving circuits may include driving circuit 11, driving circuit 12, ..., driving circuit 1N. The N light-emitting diodes may include LED1, LED2, ..., LEDN.

[0075] Among them, N driving circuits can be electrically connected to N light-emitting diodes in a one-to-one correspondence.

[0076] For example, the driving circuit 11 can be electrically connected to the anode of LED1.

[0077] For example, the driving circuit 12 can be electrically connected to the anode of the LED2.

[0078] For example, the driving circuit 1N can be electrically connected to the anode of LEDN.

[0079] For example, the cathodes of LED1 to LEDN can be connected to a common ground terminal VSS.

[0080] In some embodiments of this application, power supplies PS1, PS2, and PS3, the light-emitting control circuit CEM, the control circuit C1, and the control circuit C2 can be respectively used to be electrically connected to each driving circuit. Figure 1 (Simplified illustration).

[0081] Based on the above electrical connection relationship, it can be determined that:

[0082] The first power supply PS1 can be used to: provide a first voltage V for each drive circuit. data (This can be understood as data voltage).

[0083] The second power supply PS2 can be used to: provide a second voltage V for each drive circuit. DD (This can be understood as the operating voltage).

[0084] The third power supply PS3 can be used to provide a third voltage V3 (which can be understood as an initialization voltage) for each drive circuit.

[0085] The light emission control circuit CEM can be used to: provide a light emission control signal EM (which can be represented by logic levels) for each driving circuit.

[0086] The first control circuit C1 can be used to provide a control signal S1n (which can be represented by logic levels) for each drive circuit.

[0087] The second control circuit C2 can be used to provide a control signal S2n (which can be represented by logic levels) for each drive circuit.

[0088] Therefore, the drive circuit 11 can be used to: based on the first voltage V data Second voltage V DD The third voltage V3, the light-emitting control signal EM, the control signal S1n, and the control signal S2n control the driving current of LED1, that is, drive LED1 to emit light.

[0089] Similarly, the drive circuit 12 can be used to: based on the first voltage V data Second voltage V DD The third voltage V3, the light emission control signal EM, the control signal S1n, and the control signal S2n control the driving current of LED2, that is, drive LED2 to emit light.

[0090] The drive circuit 1N can be used to: based on the first voltage V data Second voltage VDD The third voltage V3, the light-emitting control signal EM, the control signal S1n, and the control signal S2n control the driving current of LEDN, that is, drive LEDN to emit light.

[0091] Furthermore, such as Figure 2 As shown, each driving circuit (taking driving circuit 11 as an example) may include transistor T1 (i.e., the first transistor, as the driving transistor), transistor T2 (i.e., the second transistor, as the switching transistor), transistor T3 (i.e., the third transistor, as the switching transistor), transistor T4 (i.e., the fourth transistor, as the switching transistor) and storage capacitor Cst.

[0092] In some embodiments of this application, transistor T1 can be electrically connected to a first power supply PS1, a second power supply PS2, node N1 (i.e., the first node), and node N3 (i.e., the third node). Specifically, the first terminal (which can be the source) of transistor T1 can be electrically connected to the first power supply PS1, the control terminal (which can be the gate) of transistor T1 can be electrically connected to node N1 (the gate voltage of transistor T1 can be equal to the voltage of node N1), and the second terminal (which can be the drain) of transistor T1 can be electrically connected to node N3.

[0093] Transistor T2 can be used to electrically connect to node N3, the light-emitting control circuit CEM, and LED1. Specifically, the first terminal (which can be the source) of transistor T2 can be electrically connected to node N3, and the control terminal (which can be the gate) of transistor T2 can be electrically connected to the light-emitting control circuit CEM. The second terminal (which can be the drain) of transistor T2 can be electrically connected to the anode of LED1, and the cathode of LED1 can be electrically connected to the common ground terminal VSS.

[0094] Transistor T3 can be electrically connected to node N1, the first control circuit C1, and node N2 (i.e., the second node). Specifically, the first terminal (which can be the drain) of transistor T3 can be electrically connected to node N1, the control terminal (which can be the gate) of transistor T2 can be electrically connected to the first control circuit C1, and the second terminal (which can be the source) of transistor T2 can be electrically connected to node N2.

[0095] Transistor T4 can be electrically connected to node N2, the second control circuit C2, and the third power supply PS3. Specifically, the first terminal (which can be the drain) of transistor T4 can be electrically connected to node N2, the control terminal (which can be the gate) of transistor T4 can be electrically connected to the second control circuit C2, and the second terminal (which can be the source) of transistor T4 can be electrically connected to the third power supply PS3.

[0096] The storage capacitor Cst can be used to electrically connect to the second power supply PS2 and node N1 (that is, the storage capacitor Cst can be electrically connected between the second power supply PS2 and node N1). Due to the second voltage V... DD The voltage can be DC, and the storage capacitor Cst has the function of blocking DC voltage. Therefore, during the process of driving LED1 by the driving circuit 11, the second voltage V DD Blocked by the storage capacitor Cst, the second voltage V DD It will not affect the voltage of node N1.

[0097] In some other embodiments, node N2 can also be electrically connected to node N3. In that case, the voltage of node N2 can be equal to the voltage of node N3.

[0098] For example, transistors T1, T2, T3 and T4 can be organic thin-film transistors and inorganic thin-film transistors, respectively.

[0099] In other embodiments, transistors T1 and T2 can be low-temperature polysilicon thin-film transistors (LTPSTFTs), or simply LTPS transistors. Of course, transistors T1 and T2 can also be other types of transistors, and this application does not limit the specific types.

[0100] Transistor T3 and transistor T4 can be oxide thin film transistors (oxide TFTs), respectively. Of course, transistors T3 and T4 can also be other types of transistors, which are not limited in the embodiments of this application.

[0101] Based on the above electrical connection relationship, we can further conclude that:

[0102] The storage capacitor Cst can be used to: store the first voltage V through transistor T1. data .

[0103] It is understandable that the storage capacitor Cst stores the first voltage V. data During the process, transistor T1 is in the on state.

[0104] Transistor T1 can be used to: store the first voltage V based on the storage capacitor Cst. data Second voltage V DD Control the voltage of node N3.

[0105] It is understandable that since transistor T1 is the driving transistor and transistor T2 is the switching transistor, and node N3 is electrically connected to both transistors T1 and T2, when transistor T2 is in the on state, transistor T1 controls the voltage at node N3, which in turn controls the anode voltage of LED1.

[0106] Transistor T2 can be used to control the drive current of LED1 based on the light emission control signal EM and the voltage of node N3.

[0107] It is understandable that, since transistor T2 can be an LTPS transistor, it is in the on state when the light-emitting control signal EM is low, and in the off state when EM is high. Therefore, when transistor T2 is on, the current between the drain and source of transistor T1 (which can be represented by I0)... ds (This can be represented as the driving current of LED1).

[0108] Transistor T4 can be used to control the voltage of node N2 according to the second control signal S2n and the third voltage V3.

[0109] It is understandable that, since transistor T4 can be an oxide thin-film transistor, transistor T4 is in the on state when the control signal S2n is high, and in the off state when the control signal S2n is low. Therefore, when transistor T4 is in the on state, the voltage at node N2 can be equal to the third voltage V3.

[0110] It is also understandable that since the voltage of node N2 can be equal to the voltage of node N3, and transistors T1 and T4 will not be in the conducting state at the same time, the voltage of node N2 can be controlled by either transistor T1 or transistor T4.

[0111] Transistor T3 can be used to: control the control electrode voltage (i.e., gate voltage, which can be expressed as V) of transistor T1 based on the control signal S1n and the voltage at node N2. g (Indicated), based on the control signal S1n and the first voltage V data The threshold voltage of transistor T1 is compensated by transistor T3 (the threshold voltage of transistor T1 compensated by transistor T3 can be expressed in V). th1 express).

[0112] Specifically, since transistor T3 can be an oxide thin-film transistor, it is in the on state when the control signal S1n is high and in the off state when the control signal S1n is low. When transistor T3 is on, the voltage at node N2 can be equal to the voltage at node N1. Therefore, the function of transistor T3 can be divided into the following two aspects:

[0113] On one hand, both transistors T3 and T4 are in the on state, and the voltage of node N1 can be controlled by the third voltage V3, which is to say, the control voltage V of transistor T1. g .

[0114] Therefore, the control voltage V of transistor T1 is controlled by transistors T3 and T4. g The process can be understood as the initialization stage t2 of the drive circuit 11 (see the following description).

[0115] It is understandable that only when the control electrode voltage V of the control transistor T1 is... g During this process, transistors T3 and T4 will be in the conducting state respectively.

[0116] On the other hand, when transistor T3 is in the on state and transistor T4 is in the off state, transistor T3 can adjust according to the first voltage V. data The threshold voltage of the compensation transistor T1.

[0117] In one example, the current I between the drain and source of transistor T1 ds It can be expressed by the following formula (1):

[0118] I ds =k(V gs -V th2 ) 2 Formula (1)

[0119] In formula (1), k is a coefficient, and V gs V represents the voltage between the drain and source of transistor T1. th2 This represents the threshold voltage of transistor T1 (i.e., the turn-on voltage of transistor T1).

[0120] Due to V gs =V g -V s And V g =V data +V th1 Therefore, we can have the following formula (2):

[0121] I ds =k(V gs -Vth2 ) 2 =k(V data +V th1 -V DD -V th2 ) 2 Formula (2)

[0122] Furthermore, due to the threshold voltage V of transistor T1 compensated by transistor T3... th1 It can be related to the turn-on voltage V of transistor T1 th2 Therefore, we can have the following formula (3):

[0123] I ds =k(V data -V DD ) 2 Formula (3)

[0124] As can be seen from formula (3), the turn-on voltage V of transistor T1 is... th2 There is no current I between the drain and source of transistor T1. d This has an impact. In other words, the turn-on voltage V of transistor T1... th2 It did not affect the driving current of LED1.

[0125] As can be seen from the function of transistor T3, each driving circuit can compensate the threshold voltage of internal transistor T1 according to internal transistor T3. Different driving circuits can eliminate the difference in the turn-on voltage of the corresponding LEDs, so that the display brightness of the display device is uniform, that is, the display brightness is as similar as possible.

[0126] In the driving circuit provided in this application, the control electrode of transistor T1, which serves as the driving transistor, is electrically connected to node N1, and the control electrode of transistor T3, which serves as the switching transistor, is connected to the first control circuit C1. Therefore, the change in the control electrode voltage of transistor T3 will not couple to the control electrode voltage of transistor T1, thereby reducing the forward gamma voltage of the light-emitting diode, enhancing the brightness of the light-emitting diode, and thus reducing the power consumption of the driving circuit.

[0127] In addition, since oxide thin film transistors have low leakage current and LTPS transistors have high electron mobility, the driving circuit provided in this application combines oxide thin film transistors and LTPS transistors, which can support more image refresh rates at the same time and realize seamless switching between different image refresh rates.

[0128] In one possible implementation, such as Figure 3 As shown, the driving circuit 11 may also include transistor T5 (i.e., the fifth transistor, which acts as a switch) and transistor T6 (i.e., the sixth transistor, which acts as a switch).

[0129] In some embodiments of this application, the first electrode (which can be the source electrode) of transistor T5 can be electrically connected to the second power supply PS2, the control electrode (which can be the gate electrode) of transistor T5 can be electrically connected to the light-emitting control circuit CEM, and the second electrode (which can be the drain electrode) of transistor T5 can be electrically connected to node N4 (i.e., the fourth node).

[0130] The first terminal (which can be the source) of transistor T6 can be electrically connected to the first power supply PS1. The control terminal of transistor T6 can be electrically connected to the third control circuit C3. The second terminal (which can be the drain) of transistor T6 can be electrically connected to node N4. Node N4 can also be electrically connected to the first terminal of transistor T1.

[0131] from Figure 3 It can be seen that transistors T5, T6, and T1 are electrically connected to node N4. Alternatively, it can be said that transistor T5 is electrically connected to transistor T1 through node N4, and similarly, transistor T6 is also electrically connected to transistor T1 through node N4.

[0132] In other embodiments of this application, transistor T5 and transistor T6 may also be organic thin-film transistor and inorganic thin-film transistor, respectively.

[0133] Furthermore, transistors T5 and T6 can be LTPS transistors, respectively. Of course, transistors T5 and T6 can also be other types of transistors, which are not limited in the embodiments of this application.

[0134] Based on the above electrical connection relationship, we can further conclude that:

[0135] Transistor T5 can be used to: control the light emission signal EM and the second voltage V DD The voltage at node N4 is controlled. That is, when thyristor T5 is in the ON state according to the light emission control signal EM, the voltage at node N4 can be equal to the second voltage V. DD .

[0136] Transistor T6 can be used to: respond to the third control signal S3n provided by the third control circuit C3 and the first voltage V data The voltage of node N4 is controlled. That is, when thyristor T6 is in the on state according to the third control signal S3n, the voltage of node N4 can be equal to the first voltage Vdata.

[0137] Understandably, since transistors T5 and T6 can both be LTPS transistors, transistor T5 can be in the on state when the light emission control signal EM is low, and in the off state when the light emission control signal EM is high. Similarly, transistor T6 can be in the on state when the third control signal is low, and in the off state when the third control signal is high.

[0138] As described above, transistor T3 can adjust according to the first voltage V. data The threshold voltage of transistor T1 is compensated. Therefore, during the threshold voltage compensation phase of transistor T3 (which can be called the threshold compensation phase, see below), transistors T3 and T6 can both be in the on state. It should be noted that thyristor T6 will also be in the on state during the threshold compensation phase.

[0139] According to formula (3) above, the driving current of LED1 can be related to the second voltage V. DD Related. Since LED1 only emits light under the influence of driving current, during the light-emitting phase of LED1, transistors T1 and T2 can be in the on state, and transistor T5 can also be in the on state. Therefore, the voltage at node N4 can be equal to the second voltage V. DD Furthermore, transistor T1 can control the voltage of node N3 based on the voltage of node N4 and the control electrode voltage of transistor T1.

[0140] Therefore, it's understandable that although both transistors T5 and T6 control the voltage at node N4, they will not conduct simultaneously. When transistor T5 is on, the voltage at node N4 can be equal to the second voltage V. DD When transistor T6 is in the ON state, the voltage at node N4 can be equal to the first voltage V. data .

[0141] Furthermore, the drive circuit 11 may also include transistor T7 (i.e., the seventh transistor, which acts as a switch) and transistor T8 (i.e., the eighth transistor, which acts as a switch).

[0142] In some embodiments of this application, the first terminal (which can be the source) of transistor T7 is electrically connected to the anode of LED1, and the second terminal (which can be the drain) of transistor T7 is electrically connected to the fifth power supply PS5. The first terminal (which can be the drain) of transistor T8 is electrically connected to the sixth power supply PS6, and the second terminal (which can be the source) of transistor T8 is electrically connected to node N3.

[0143] In the first example, such as Figure 3 As shown, the control terminals of transistors T7 and T8 are respectively electrically connected to the fourth control circuit C4. That is, the control terminals of transistors T7 and T8 are each connected to the same control circuit (i.e., the fourth control circuit C4).

[0144] In some embodiments of this application, transistor T7 and transistor T8 may be LTPS transistors, or both may be oxide thin-film transistors. Of course, transistors T7 and T8 may also be other types of transistors, and this application does not limit the types of transistors.

[0145] Based on the above electrical connection relationship, we can further conclude that:

[0146] Transistor T7 can be used to control the anode voltage of LED1 according to the fourth control signal S4n provided by the fourth control circuit C4 and the fifth voltage V5 provided by the fifth power supply PS5. That is, when transistor T7 is in the on state according to the fourth control signal S4n, the anode voltage of LED1 can be equal to the fifth voltage V5.

[0147] Transistor T8 can be used to control the voltage of node N3 according to the fourth control signal C4 and the sixth voltage V6 provided by the sixth power supply PS6. That is, when transistor T8 is in the on state according to the fourth control signal S4n, the voltage of node N3 can be equal to the sixth voltage V6.

[0148] In some embodiments of this application, a second example of the driving circuit 11 is provided (e.g., Figure 4 (As shown). With Figure 3 The difference is, Figure 4 The gate electrode of transistor T7 can be electrically connected to the fifth control circuit C5, and the gate electrode of transistor T8 can be electrically connected to the fourth control circuit C4. In other words, the gate electrodes of transistors T7 and T8 can be connected to different control circuits.

[0149] Therefore, transistor T7 can be used to control the anode voltage of LED1 according to the fifth control signal S5n provided by the fifth control circuit C5 and the fifth voltage V5 provided by the fifth power supply PS5. That is, when transistor T7 is in the on state according to the fifth control signal S5n, the anode voltage of LED1 can be equal to the fifth voltage V5.

[0150] In other embodiments of this application, transistor T8 can also be used to control the voltage of node N3 according to the fourth control signal C4 and the sixth voltage V6 provided by the sixth power supply PS6. That is, when transistor T8 is in the on state according to the fourth control signal S4n, the voltage of node N3 can be equal to the sixth voltage V6.

[0151] In this embodiment, when transistor T8 is turned on, the voltage of node N3 can be controlled by the sixth voltage V6, making the source voltage (i.e., the voltage of node N4, which can be the sixth voltage V6) and drain voltage (i.e., the voltage of node N3) of transistor T1 controllable (or reset). This can enhance the positive bias temperature stress (PBTS) of transistor T1, that is, control the drift of the threshold voltage of transistor T1, avoid screen flickering during the switching of the display device between different image refresh frequencies, and avoid screen flickering at lower image refresh frequencies.

[0152] In addition, transistors T7 and T8 in this embodiment are respectively oxide thin film transistors. During the control of the anode voltage of LED1 and the source voltage of transistor T1, the leakage current of transistors T7 and T8 is reduced, so that the driving circuit 11 can support a lower image refresh rate (such as 1 / 60Hz). In other words, the driving circuit 11 can be used in scenarios with a lower image refresh rate.

[0153] In one example, based on transistors T1, T2, T5, and T6 being LTPS transistors and transistors T3 and T4 being oxide thin-film transistors, this embodiment of the present application is described using transistors T7 and T8 being LTPS transistors as an example. Figure 3 The control timing of the provided drive circuit 11.

[0154] Understandably, since transistors T7 and T8 can both be LTPS transistors, therefore... Figure 3 When the fourth control signal S4n is low, transistors T7 and T8 can be in the on state; when the fourth control signal S4n is high, transistors T7 and T8 can be in the off state.

[0155] Similarly, targeting Figure 4 When the fourth control signal S4n is low, transistor T8 can be in the on state; when the fourth control signal S4n is high, transistor T8 can be in the off state. When the fifth control signal S5n is low, transistor T7 can be in the on state; when the fifth control signal S5n is high, transistor T7 can be in the off state.

[0156] In one possible implementation, for Figure 3The entire light-emitting process of the driving circuit 11 driving LED1 (that is, the driving circuit 11 controlling the driving current of LED1) can be divided into the first initialization stage t1, the second initialization stage t2, the threshold compensation stage t3, the third initialization stage t4, and the light-emitting stage t5 (only a part of the light-emitting stage t5 is shown). The specific timing diagram can be seen as follows: Figure 5 As shown.

[0157] (1) In the first initialization phase t1, the light emission control signal EM and the control signal S3n are both at high levels, so transistors T2, T5, and T6 are turned off. The control signals S1n and S2n are both at low levels, so transistors T3 and T4 are turned off. The control signal S4n changes from high to low and then from low to high. As a result, transistors T7 and T8 change from off to on and then from on to off.

[0158] It can be seen that in the first initialization stage t1, transistors T7 and T8 are turned on, realizing the control of the voltage of node N3 (making the voltage of node N3 the sixth voltage V6) and the control of the anode voltage of LED1 (making the anode voltage of LED1 the fifth voltage V5), that is, realizing the reset of the voltage of node N3 and the anode voltage of LED1.

[0159] (2) In the second initialization phase t2, control signals S1n and S2n change from low to high and then back to low, respectively. Consequently, transistors T3 and T4 change from off to on and then back to off, respectively. The light emission control signal EM, control signal S3n, and control signal S4n remain high, thus transistors T2, T5, T6, T7, and T8 are turned off.

[0160] It can be seen that in the second initialization phase t2, transistors T1, T3, and T4 are turned on, realizing voltage control of node N2 and node N1. Since transistors T3 and T4 act as switches, node N1 is electrically connected to the control electrode of transistor T1, and node N2 is electrically connected to node N3. Therefore, voltage control of transistor T1, node N1, node N2, and node N3 is achieved (making the control electrode voltage of transistor T1, the voltage of node N1, the voltage of node N2, and the voltage of node N3 the third voltage V3). In other words, the control electrode voltage of transistor T1, the voltage of node N1, the voltage of node N2, and the voltage of node N3 are reset respectively.

[0161] (3) During the threshold compensation stage t3, the control signal S1n changes from low to high and then back to low. Consequently, transistor T3 changes from off to on and then back to off. The control signal S3n changes from high to low and then back to high. Consequently, transistor T6 changes from on to off and then back to on. The light emission control signal EM and control signal S4n remain high, while control signal S2n remains low. Consequently, transistors T2, T4, T5, T7, and T8 are turned off.

[0162] It can be seen that during the threshold compensation stage t3, transistors T6, T3, and T1 are turned on, thereby converting the first voltage V... data The voltage is stored in the storage capacitor Cst, which also compensates for the threshold voltage of transistor T1. The threshold voltage compensation process of transistor T1 can be considered as the process of transistor T1 changing from the on state to the off state.

[0163] (4) In the third initialization stage t4, the control signal S4n changes from high level to low level and then from low level to high level. Therefore, transistors T7 and T8 change from off to on and then from on to off, respectively. The light emission control signal EM and control signal S3n remain high, while control signals S1n and S2n remain low. Therefore, transistors T1, T2, T3, T4, T5, and T6 are off.

[0164] It can be seen that in the third initialization stage t4, transistors T7 and T8 are turned on respectively, realizing the voltage control of node N3 (making the voltage of node N3 the sixth voltage V6) and the anode voltage control of LED1 (making the anode voltage of LED1 the fifth voltage V5), that is, realizing the reset of the voltage of node N3 and the anode voltage of LED1.

[0165] (5) During the light-emitting stage t5, the light-emitting control signal EM changes from high level to low level, and transistors T2 and T5 are turned on respectively. Control signals S1n and S2n are low level respectively, and transistors T3 and T4 are turned off respectively. Control signals S3n and S4n are high level respectively, and transistors T6, T7 and T8 are turned off respectively.

[0166] It can be seen that during the light-emitting stage t5, transistors T5, T1, and T2 are turned on respectively, realizing the control of the driving current of LED1, that is, realizing the driving of LED1 and making LED1 light up.

[0167] from Figure 5Understandably, during the entire driving process of LED1, transistor T3 is turned on twice (meaning there are 2 driving pulses in control signal S1n), and transistor T4 is turned on once (meaning there is 1 driving pulse in control signal S2n). Therefore, it can be inferred that within one image refresh cycle (which is the reciprocal of the image refresh frequency, for example, the image refresh cycle corresponding to an image refresh frequency of 120Hz), the number of driving pulses in control signal S1n can be greater than the number of driving pulses in control signal S2n.

[0168] from Figure 5 It can also be seen that during the entire driving process, the control signal S3n can have one driving pulse, and due to the first voltage V data Since it can be the data voltage, it can be assumed that within one image refresh cycle, the frequency of the drive pulse in the control signal S3n can be equal to the image refresh frequency.

[0169] In some embodiments of this application, during the entire driving process, the control signal S4n may have two driving pulses, and the control signal S3n may have one driving pulse. Therefore, it is conceivable that the frequency of the driving pulse in the control signal S4n can be twice the frequency of the driving pulse in the control signal S3n.

[0170] In one embodiment, when the frequency of the driving pulse in the control signal S4n is 60Hz, the frequency of the driving pulse in the control signal S3n can be 60Hz, 40Hz, 30Hz, 24Hz, etc.

[0171] In another embodiment, when the frequency of the driving pulse in the control signal S4n is 120Hz, the frequency of the driving pulse in the control signal S3n can be 120Hz, 80Hz, 60Hz, etc.

[0172] In another embodiment, when the frequency of the driving pulse in the control signal S4n is 180Hz, the frequency of the driving pulse in the control signal S3n can be 120Hz, 90Hz, 72Hz, etc.

[0173] In another embodiment, when the frequency of the driving pulse in the control signal S4n is 240Hz, the frequency of the driving pulse in the control signal S3n can be 120Hz, 96Hz, 80Hz, etc.

[0174] In another embodiment, when the frequency of the driving pulse in the control signal S4n is 360Hz, the frequency of the driving pulse in the control signal S3n can be 144Hz, 120Hz, 102.86Hz, 90Hz, 80Hz, etc.

[0175] As can be seen from the above example, the frequency of the driving pulse in the control signal S4n can be N / 2 times the frequency of the driving pulse in the control signal S3n; where N≥2 and N is an integer.

[0176] In this embodiment, the control signals S4n and S3n can use different timing sequences. The driving pulse in the control signal S4n can be a higher frequency such as 360Hz. Since the frequency of the driving pulse in the control signal S3n can be the image refresh rate, different image refresh rates such as 120Hz, 90Hz, and 72Hz can be achieved. This not only enables dynamic switching between different image refresh rates, but also avoids screen flicker when switching between different image refresh rates or maintaining the image at a low refresh rate, thus improving the stability of the displayed image (screen).

[0177] It can be inferred that, during the entire driving process, the light-emitting control signal EM can contain 2, 4, or other driving pulses (see the description below). Except for transistor T8, which will operate during the light-emitting phase (i.e., change its state, meaning that the control signal S4n will have driving pulses during the light-emitting phase), other transistors will not change their state during the light-emitting phase (meaning that the control signals S1n, S2n, and S3n will not have driving pulses during the light-emitting phase).

[0178] Therefore, from Figure 5 It can be seen that the falling edge of the first driving pulse in the control signal S4n can occur after the rising edge of the first driving pulse in the light emission control signal EM. That is to say, during the image refresh cycle, transistors T2 and T7 are turned off only after transistors T7 and T8 are turned on.

[0179] The falling edge of the second drive pulse (i.e., the last drive pulse in the driving process) in control signal S4n can occur after the falling edge of the second drive pulse (i.e., the last drive pulse) in control signal S1n. In other words, within the image refresh cycle, transistors T7 and T8 only turn on after transistor T3 is turned off for the second time.

[0180] The rising edge of the second drive pulse in the control signal S4n can precede the falling edge of the first drive pulse in the light emission control signal EM. That is, during the image refresh cycle, transistors T2 and T7 only turn on for the first time after transistors T7 and T8 are turned off respectively.

[0181] from Figure 5It can also be seen that the rising edge of the drive pulse in control signal S3n can precede the falling edge of the second drive pulse in control signal S1n. That is to say, during the image refresh cycle, transistor T3 is turned off only after transistor T6 is turned off.

[0182] The number of driving pulses for control signals S1n, S2n, and S3n occurs during the high-level period of the first driving pulse of the light emission control signal EM. In other words, within one image refresh cycle, the state switching of transistors T3, T4, T6, T7, and T8 occurs when transistors T5 and T2 are in the off state.

[0183] In some embodiments of this application, within one image refresh cycle, the driving pulses of the emission control signal EM can be two or more. For example... Figure 6 As shown, the light emission control signal EM can have 4 driving pulses within one image refresh cycle (this embodiment of the application takes the example of the light emission control signal EM having 4 driving pulses in the image refresh cycle T corresponding to an image refresh frequency of 120Hz for illustration).

[0184] Figure 6 In the image refresh cycle, the first drive pulse of the emission control signal EM corresponds to the five stages of the driving process, and the second to fourth drive pulses of the emission control signal EM correspond to the emission maintenance stage. The control signal S4n has two drive pulses during the high-level period of the first drive pulse of the emission control signal EM, and one drive pulse during the high-level period of the third drive pulse of the emission control signal EM. That is, within one image refresh cycle, the control signal S4n can have three drive pulses.

[0185] It needs to be explained that, Figure 6 t in a This represents the duration of the first two drive pulses in the control signal S4n during the low-level period (corresponding to the conduction duration of transistors T7 and T8), t b This indicates the duration of the driving pulse in the light emission control signal EM during the low-level period (corresponding to the conduction duration of transistors T2 and T5).

[0186] from Figure 6 It can also be seen that the pulse widths of the first two drive pulses in the control signal S4n can be the same, and the pulse width of the third drive pulse can be greater than the pulse widths of the first two drive pulses.

[0187] In another embodiment, for Figure 4 ,and Figure 5Similarly, the entire light-emitting process of driving LED1 by driving circuit 11 can also be divided into the first initialization stage t1, the second initialization stage t2, the threshold compensation stage t3, the third initialization stage t4, and the light-emitting stage t5 (only a portion of the light-emitting stage t5 is shown). A detailed timing diagram can be found as follows: Figure 7 As shown.

[0188] In other embodiments of this application, during the threshold compensation stage t3, the falling edge of the drive pulse in control signal S5n can precede the falling edge of the second drive pulse in control signal S4n. The rising edge of the drive pulse in control signal S5n can follow the rising edge of the second drive pulse in control signal S4n. That is, after transistor T7 is turned on, transistor T8 can be turned on a second time. And after transistor T8 is turned off a second time, transistor T7 can be turned off.

[0189] It should be noted that, Figure 7 The timing sequence of each of the following control signals: EM, S1n, S2n, S3n, and S4n Figure 5 The timing sequence of the light emission control signal EM, control signal S1n, control signal S2n, control signal S3n, and control signal S4n is the same, and will not be repeated in the embodiments of this application.

[0190] It should also be noted that, Figures 5 to 7 In the driving circuit corresponding to the timing diagram shown, transistors T7 and T8 are LTPS transistors, which can therefore be used in dynamic display devices with high image refresh rates, such as mobile phones and tablets.

[0191] In another example, based on transistors T1, T2, T5, and T6 being LTPS transistors and transistors T3 and T4 being oxide thin-film transistors, this embodiment of the present application is described using transistors T7 and T8 being oxide thin-film transistors as an example. Figure 3 The control timing of the provided drive circuit 11.

[0192] Understandably, since transistors T7 and T8 can both be oxide thin-film transistors, therefore... Figure 3 When the fourth control signal S4n is low, transistors T7 and T8 can be in the off state; when the fourth control signal S4n is high, transistors T7 and T8 can be in the on state.

[0193] Similarly, targeting Figure 4When the fourth control signal S4n is low, transistor T8 can be in the off state; when the fourth control signal S4n is high, transistor T8 can be in the on state. When the fifth control signal S5n is low, transistor T7 can be in the off state; when the fifth control signal S5n is high, transistor T7 can be in the on state.

[0194] In one possible implementation, for Figure 3 ,and Figure 5 and Figure 7 Similarly, the entire light-emitting process of driving LED1 by driving circuit 11 can also be divided into the first initialization stage t1, the second initialization stage t2, the threshold compensation stage t3, the third initialization stage t4, and the light-emitting stage t5 (only a portion of the light-emitting stage t5 is shown). A detailed timing diagram can be found as follows: Figure 8 As shown.

[0195] and Figure 5 The difference is, Figure 8 In the timing diagram shown, during the first initialization phase t1 and the third initialization phase t4, the control signal S4n changes from low to high and then from high to low, respectively. However, because transistors T7 and T8 are oxide thin-film transistors, and... Figure 5 Since they are the same, transistors T7 and T8 change from off to on and then from on to off again during the first initialization phase t1 and the third initialization phase t4, respectively. Therefore, Figure 7 The timing diagram shown can also be used to reset the voltage of node N3 and the anode voltage of LED1.

[0196] from Figure 8 It can be seen that the rising edge of the first driving pulse in the control signal S4n can be after the rising edge of the first driving pulse in the light emission control signal EM. That is to say, within one image refresh cycle, after transistors T2 and T5 are turned off, transistors T7 and T8 can be turned on.

[0197] The rising edge of the second drive pulse in control signal S4n can occur after the falling edge of the second drive pulse in control signal S1n. That is, within one image refresh cycle, after transistor T3 is turned off for the second time, transistors T7 and T8 can be turned on respectively.

[0198] The falling edge of the second drive pulse in the control signal S4n can precede the falling edge of the first drive pulse in the control signal EM. That is, within one image refresh cycle, after transistors T7 and T8 are turned off for the second time, transistors T2 and T5 can be turned on respectively.

[0199] from Figure 8 It can also be seen that the rising edge of the drive pulse in control signal S3n can precede the falling edge of the second drive pulse in control signal S1n. That is to say, within the image refresh cycle, transistor T6 is turned off before transistor T3 is turned off.

[0200] The number of driving pulses for control signals S1n, S2n, and S3n occurs during the high-level period of the first driving pulse of the light emission control signal EM. In other words, within one image refresh cycle, the state switching of transistors T3, T4, T6, T7, and T8 occurs when transistors T5 and T2 are in the off state.

[0201] It should be noted that, Figure 8 The timing of the light emission control signals EM, S1n, S2n, and S3n is as follows: Figure 5 and Figure 6 The timing sequence of the light emission control signal EM, control signal S1n, control signal S2n, and control signal S3n is the same, and will not be repeated in the embodiments of this application.

[0202] In another possible implementation, targeting Figure 4 ,and Figure 8 Similarly, the entire light-emitting process of driving LED1 by driving circuit 11 can also be divided into the first initialization stage t1, the second initialization stage t2, the threshold compensation stage t3, the third initialization stage t4, and the light-emitting stage t5 (only a portion of the light-emitting stage t5 is shown). A detailed timing diagram can be found as follows: Figure 9 As shown.

[0203] In some embodiments of this application, during the threshold compensation stage t3, the rising edge of the drive pulse in control signal S5n can precede the rising edge of the second drive pulse in control signal S4n. The falling edge of the drive pulse in control signal S5n can follow the falling edge of the second drive pulse in control signal S4n. That is, after transistor T7 is turned on, transistor T8 can be turned on a second time. And after transistor T8 is turned off a second time, transistor T7 can be turned off.

[0204] It should be noted that, Figure 9 The timing sequence of each of the following control signals: EM, S1n, S2n, S3n, and S4n Figure 5 The timing sequence of the light emission control signal EM, control signal S1n, control signal S2n, control signal S3n, and control signal S4n is the same, and will not be repeated in the embodiments of this application.

[0205] In the above embodiment, there are 2 driving pulses in the control signal S1n and 1 driving pulse in the control signal S2n. That is, the number of driving pulses in the control signal S1n can be greater than the number of driving pulses in the control signal S2n.

[0206] In one possible implementation, the number of drive pulses in the control signal S1n can also be equal to the number of drive pulses in the control signal S2n.

[0207] For example, such as Figure 10 As shown, there is one drive pulse in the control signal S2n, and there can also be one drive pulse in the control signal S1n. Therefore, during the entire driving process of the LED, transistor T3 can be turned on once, which can quickly complete the compensation of the threshold voltage of transistor T1.

[0208] It should be noted that, Figures 8 to 10 In the driving circuit corresponding to the timing diagram shown, transistors T7 and T8 are oxide thin-film transistors, which can therefore be used in static display devices with low image refresh rates, such as watches and e-book readers.

[0209] In the several embodiments provided in this application, it should be understood that the disclosed systems and devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0210] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0211] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0212] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0213] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A driving circuit, characterized in that, It includes a first transistor, a second transistor, a third transistor, a fourth transistor, an eighth transistor, and a storage capacitor; The first transistor is electrically connected to the first power supply, the second power supply, the first node, and the third node. The second terminal of the first transistor is electrically connected to the third node. The second transistor is electrically connected to the third node, the light-emitting control circuit, and the light-emitting diode. The third transistor is electrically connected to the first node, the first control circuit, and the second node. The fourth transistor is electrically connected to the second node, the second control circuit, and the third power supply. The storage capacitor is electrically connected to the second power supply and the first node. The second node is also electrically connected to the third node. The light-emitting process of the LED, in chronological order, includes: a first initialization stage, a second initialization stage, a threshold compensation stage, a third initialization stage, and a light-emitting stage. The first terminal of the eighth transistor is electrically connected to the third node, and the second terminal of the eighth transistor is electrically connected to the sixth power supply; the control terminal of the eighth transistor is electrically connected to the fourth control circuit. The storage capacitor is used to: store the first voltage provided by the first power supply through the first transistor; The first transistor is used to: control the voltage of the third node based on the first voltage stored in the storage capacitor and the second voltage provided by the second power supply; The second transistor is used to: control the driving current of the light-emitting diode according to the light-emitting control signal provided by the light-emitting control circuit and the voltage of the third node during the light-emitting phase; The third transistor is used to: control the control electrode voltage of the first transistor according to the first control signal provided by the first control circuit and the voltage of the second node during the second initialization phase, and to compensate the threshold voltage of the first transistor according to the first control signal and the first voltage provided by the first power supply during the threshold compensation phase. The fourth transistor is used to: control the voltage of the second node according to the second control signal provided by the second control circuit and the third voltage provided by the third power supply during the second initialization phase; The eighth transistor is used to: control the voltage of the third node according to the fourth control signal provided by the fourth control circuit and the sixth voltage provided by the sixth power supply during the first initialization phase and the third initialization phase; the voltage of the second node is equal to the voltage of the third node.

2. The driving circuit according to claim 1, characterized in that, Within one image refresh cycle, the number of drive pulses in the first control signal is greater than or equal to the number of drive pulses in the second control signal.

3. The driving circuit according to claim 1 or 2, characterized in that, Within one image refresh cycle, the number of driving pulses in the light emission control signal is greater than or equal to 2.

4. The driving circuit according to claim 1, characterized in that, The driving circuit also includes a fifth transistor and a sixth transistor; The first electrode of the fifth transistor is used to be electrically connected to the second power supply, the control electrode of the fifth transistor is used to be electrically connected to the light-emitting control circuit, and the second electrode of the fifth transistor is used to be electrically connected to the fourth node. The first terminal of the sixth transistor is used to be electrically connected to the first power supply, the control terminal of the sixth transistor is used to be electrically connected to the third control circuit, the second terminal of the sixth transistor is used to be electrically connected to the fourth node, and the fourth node is also used to be electrically connected to the first transistor. The fifth transistor is used to: control the voltage of the fourth node according to the light emission control signal and the second voltage; The sixth transistor is used to control the voltage of the fourth node according to the third control signal provided by the third control circuit and the first voltage.

5. The driving circuit according to claim 4, characterized in that, The first transistor is specifically used for: The voltage of the third node is controlled based on the voltage of the fourth node and the control electrode voltage of the first transistor.

6. The driving circuit according to claim 4 or 5, characterized in that, Within one image refresh cycle, the frequency of the drive pulse in the third control signal is equal to the image refresh frequency.

7. The driving circuit according to claim 4, characterized in that, The driving circuit also includes a seventh transistor; The first terminal of the seventh transistor is electrically connected to the anode of the light-emitting diode, and the second terminal of the seventh transistor is electrically connected to the fifth power supply. The control electrode of the seventh transistor is used to be electrically connected to the fourth control circuit, or the control electrode of the seventh transistor is used to be electrically connected to the fifth control circuit. The seventh transistor is used to: control the anode voltage of the light-emitting diode according to the fourth control signal and the fifth voltage provided by the fifth power supply; or, control the anode voltage of the light-emitting diode according to the fifth control signal provided by the fifth control circuit and the fifth voltage.

8. The driving circuit according to claim 7, characterized in that, Within one image refresh cycle, the number of driving pulses in the fourth control signal is greater than or equal to the number of driving pulses in the light emission control signal.

9. The driving circuit according to claim 8, characterized in that, Within one image refresh cycle, the frequency of the drive pulse in the fifth control signal is equal to the image refresh frequency.

10. The driving circuit according to any one of claims 7 to 9, characterized in that, The frequency of the driving pulse in the fourth control signal is N / 2 times the frequency of the driving pulse in the third control signal; where N≥2 and N is an integer.

11. The driving circuit according to any one of claims 7 to 9, characterized in that, The first transistor, the second transistor, the fifth transistor, and the sixth transistor are all low-temperature polycrystalline silicon thin-film transistors; The third transistor and the fourth transistor are both oxide thin-film transistors.

12. The driving circuit according to claim 11, characterized in that, The seventh transistor and the eighth transistor are both low-temperature polycrystalline silicon thin-film transistors.

13. The driving circuit according to claim 12, characterized in that, The falling edge of the first drive pulse in the fourth control signal follows the rising edge of the first drive pulse in the light emission control signal.

14. The driving circuit according to claim 12 or 13, characterized in that, The falling edge of the last drive pulse in the fourth control signal follows the falling edge of the last drive pulse in the first control signal. The rising edge of the last drive pulse in the fourth control signal precedes the falling edge of the first drive pulse in the light emission control signal.

15. The driving circuit according to claim 12 or 13, characterized in that, The falling edge of the drive pulse in the fifth control signal precedes the falling edge of the last drive pulse in the fourth control signal. The rising edge of the drive pulse in the fifth control signal follows the rising edge of the last drive pulse in the fourth control signal.

16. The driving circuit according to claim 11, characterized in that, The seventh transistor and the eighth transistor are both oxide thin-film transistors.

17. The driving circuit according to claim 16, characterized in that, The rising edge of the first driving pulse in the fourth control signal follows the rising edge of the first driving pulse in the light emission control signal.

18. The driving circuit according to claim 16 or 17, characterized in that, The rising edge of the last drive pulse in the fourth control signal follows the falling edge of the last drive pulse in the first control signal. The falling edge of the last drive pulse in the fourth control signal precedes the falling edge of the first drive pulse in the light emission control signal.

19. The driving circuit according to claim 16 or 17, characterized in that, The rising edge of the drive pulse in the fifth control signal precedes the rising edge of the last drive pulse in the fourth control signal. The falling edge of the drive pulse in the fifth control signal follows the falling edge of the last drive pulse in the fourth control signal.

20. The driving circuit according to any one of claims 12, 13, 16, and 17, characterized in that, The rising edge of the drive pulse in the third control signal precedes the falling edge of the last drive pulse in the first control signal.

21. The driving circuit according to any one of claims 12, 13, 16, and 17, characterized in that, The number of driving pulses for the first control signal, the second control signal, the third control signal, and the fifth control signal is respectively during the high-level period of the first driving pulse of the light emission control signal.

22. A display device, characterized in that, It includes a first power supply, a second power supply, a third power supply, a light-emitting control circuit, a first control circuit, a second control circuit, a plurality of light-emitting diodes, and a plurality of driving circuits as described in any one of claims 1 to 21; The first power supply, the second power supply, the third power supply, the light-emitting control circuit, the first control circuit, and the second control circuit are respectively used to be electrically connected to each of the plurality of driving circuits, and the plurality of light-emitting diodes are used to be electrically connected to the plurality of driving circuits one-to-one. Each driving circuit is used to control the driving current of the corresponding light-emitting diode.

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