Driving circuit and display panel

Abstract

The driving circuit and display panel provided in the embodiment of the present application include a first transistor, a light-emitting device, a low capacitor, a pulse width modulation module and a first detection control module. Specifically, a second transistor is provided in the pulse width modulation module. The pulse width modulation module can adjust the pulse width of the driving current flowing through the light-emitting device. Among them, the first detection control module can detect the threshold voltage of the second transistor and compensate the threshold voltage of the second transistor by external compensation, thereby improving the overall stability of the driving circuit, thereby ensuring the uniform brightness of the light-emitting device and improving the display effect of the Micro-LED display device.

Description

Technical Field

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

[0002] At present, Micro-LED (Micro Light Emitting Diode) display devices have good application prospects in display panels due to their advantages such as fast response, wide color gamut, high resolution, low energy consumption, high resolution, and high efficiency. Micro-LED display devices have become a hotspot for major panel manufacturers.

[0003] Among them, the driving methods of Micro-LED display devices are mainly divided into pulse amplitude modulation (PAM) driving and pulse width modulation (PWM) driving. At present, based on the advantages of each of them in driving, a driving method combining PWM driving and PAM driving has been developed. PWM driving is used to improve color point drift at low grayscale, and PAM driving is used to ensure high brightness at high grayscale.

[0004] Among them, in the existing driving circuit, the PWM module includes a driving transistor. As the use time of the display panel increases, the thin film transistor is prone to threshold voltage drift, so it is necessary to compensate the threshold voltage of the driving transistor of the PWM module to avoid the negative impact of the threshold voltage drift of the driving transistor of the PWM module on the driving circuit, so that the light-emitting device can remain stable. However, the existing driving circuit generally has no compensation or uses internal compensation to compensate the threshold voltage of the driving transistor. Among them, no compensation will cause the light of the light-emitting device to be unstable due to the threshold voltage drift of the driving transistor, and the internal compensation requires a large number of thin film transistors. As the resolution of the display panel increases, the pixel size gradually decreases, and the internal compensation method is no longer suitable for small-sized pixels.

[0005] Therefore, how to propose another method of driving circuit compensation to compensate the threshold voltage of the driving transistor of the PWM module is a difficult problem that existing panel manufacturers need to work hard to overcome. Summary of the invention

[0006] The purpose of the embodiments of the present application is to solve the technical problem of how to provide another method of driving circuit compensation to compensate the threshold voltage of the driving transistor of the PWM module.

[0007] The embodiment of the present application provides a driving circuit, including:

[0008] a first transistor, wherein a gate of the first transistor is electrically connected to a first node, one of a source and a drain of the first transistor is electrically connected to a first power supply terminal, and the other of the source and the drain of the first transistor is electrically connected to a second node;

[0009] a light emitting device, one end of which is electrically connected to the second node, and the other end of which is electrically connected to the second power supply terminal;

[0010] a first capacitor, wherein a first end of the first capacitor is electrically connected to the first node, and a second end of the first capacitor is electrically connected to the second node;

[0011] a pulse width modulation module, the pulse width modulation module receiving a pulse width modulation signal, a frequency sweep signal and a data signal, and being electrically connected to the first node and the first detection end, the pulse width modulation module comprising a second transistor, and the pulse width modulation module being used to adjust the pulse width of the driving current flowing through the light emitting device under the control of the pulse width modulation signal; and

[0012] A first detection control module, the first detection control module is connected to the pulse width modulation signal and is electrically connected to the first node and the first power supply terminal, and the first detection control module is used to control the first power supply terminal to be electrically connected to the first node under the control of the pulse width modulation signal when detecting the threshold voltage of the second transistor.

[0013] In the driving circuit described in the present application, the pulse width modulation module further includes a third transistor, a second capacitor and a third capacitor;

[0014] The gate of the third transistor is connected to the pulse width modulation signal, one of the source and the drain of the third transistor is connected to the data signal, and the other of the source and the drain of the third transistor is electrically connected to the third node;

[0015] The first end of the second capacitor is connected to the frequency sweep signal, and the second end of the second capacitor is electrically connected to the third node, so that the frequency sweep signal adjusts the potential of the third node through the second capacitor;

[0016] The first end of the third capacitor is electrically connected to the third node, and the second end of the third capacitor is electrically connected to the fourth node;

[0017] The gate of the second transistor is electrically connected to the third node, one of the source and the drain of the second transistor is electrically connected to the first node, the other of the source and the drain of the second transistor is electrically connected to the fourth node, and the fourth node is electrically connected to the first detection end.

[0018] In the driving circuit described in the present application, the first detection control module includes a fourth transistor, the gate of the fourth transistor is connected to the pulse width modulation signal, one of the source and the drain of the fourth transistor is electrically connected to the first power supply terminal, and the other of the source and the drain of the fourth transistor is electrically connected to the first node.

[0019] In the driving circuit described in the present application, the driving circuit further includes a second detection control module;

[0020] The second detection control module receives a pulse amplitude modulation signal and is electrically connected to the second detection terminal and the second node. The second detection control module is used to control the second detection terminal to be electrically connected to the second node under the control of the pulse amplitude modulation signal when detecting the threshold voltage of the first transistor.

[0021] In the driving circuit described in the present application, the second detection control module includes a fifth transistor;

[0022] The gate of the fifth transistor is connected to the pulse amplitude modulation signal, one of the source and the drain of the fifth transistor is electrically connected to the second detection end, and the other of the source and the drain of the fifth transistor is electrically connected to the second node.

[0023] In the driving circuit described in the present application, when the threshold voltage of the first transistor is detected, the second power supply terminal is in a floating state.

[0024] In the driving circuit described in the present application, the driving circuit further includes a pulse amplitude modulation module;

[0025] The pulse amplitude modulation module receives the pulse amplitude modulation signal and the data signal and is electrically connected to the first node. The pulse amplitude modulation module is used to adjust the pulse amplitude of the driving current under the control of the pulse amplitude modulation signal.

[0026] In the driving circuit described in the present application, the pulse amplitude modulation module includes a sixth transistor;

[0027] The gate of the sixth transistor is connected to the pulse amplitude modulation signal, one of the source and the drain of the sixth transistor is connected to the data signal, and the other of the source and the drain of the sixth transistor is electrically connected to the first node.

[0028] In the driving circuit described in the present application, the potential of the first power supply terminal is higher than the potential of the data signal.

[0029] An embodiment of the present application further provides a display panel, which includes the driving circuit described above.

[0030] In the driving circuit group and the display panel provided in the embodiment of the present application, a first transistor, a light-emitting device, a low capacitor, a pulse width modulation module and a first detection control module are included. Specifically, a second transistor is provided in the pulse width modulation module. The pulse width modulation module can adjust the pulse width of the driving current flowing through the light-emitting device. Among them, the first detection control module can detect the threshold voltage of the second transistor and compensate the threshold voltage of the second transistor by external compensation, thereby improving the overall stability of the driving circuit, thereby ensuring the uniform brightness of the light-emitting device and improving the display effect of the Micro-LED display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a first structural schematic diagram of a driving circuit provided in an embodiment of the present application.

[0033] Figure 2 A second structural schematic diagram of the driving circuit provided in an embodiment of the present application.

[0034] Figure 3 A third structural schematic diagram of the driving circuit provided in an embodiment of the present application.

[0035] Figure 4 A fourth structural diagram of a driving circuit provided in an embodiment of the present application

[0036] Figure 5 This is a first circuit schematic diagram of a driving circuit provided in an embodiment of the present application.

[0037] Figure 6 A second circuit schematic diagram of the driving circuit provided in an embodiment of the present application.

[0038] Figure 7 A third circuit schematic diagram of the driving circuit provided in an embodiment of the present application.

[0039] Figure 8 A fourth circuit diagram of the driving circuit provided in an embodiment of the present application.

[0040] Fig. 9 This is a first timing diagram of the driving circuit provided in an embodiment of the present application.

[0041] Fig.10 This is a first circuit simulation diagram of the driving circuit provided in an embodiment of the present application.

[0042] Fig.11 This is a second timing diagram of the driving circuit provided in an embodiment of the present application.

[0043] Fig.12 A second circuit simulation diagram of the driving circuit provided in the embodiment of the present application

[0044] Fig.13 This is the third timing diagram of the driving circuit provided in an embodiment of the present application.

[0045] Fig.14 A third circuit simulation diagram of the driving circuit provided in the embodiment of the present application

[0046] Fig.15 A schematic diagram of the structure of a display panel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0048] The transistors used in all embodiments of the present application can be thin film transistors or field effect transistors or other devices with the same characteristics. Since the source and drain of the transistors used here are symmetrical, their source and drain are interchangeable. In the embodiment of the present application, in order to distinguish the two poles of the transistor other than the gate, one of the poles is called the source and the other is called the drain. According to the form in the accompanying drawings, the middle end of the switching transistor is specified as the gate, the signal input end is the source, and the output end is the drain. In addition, the transistors used in the embodiments of the present application may include P-type transistors and / or N-type transistors, wherein the P-type transistor is turned on when the gate is low and turned off when the gate is high, and the N-type transistor is turned on when the gate is high and turned off when the gate is low.

[0049] See also Figure 1 , Figure 1 This is a first structural diagram of a driving circuit provided in an embodiment of the present application. Figure 1 As shown, the driving circuit 10 provided in the embodiment of the present application includes a light emitting device D, a first transistor T1, a first capacitor C1, a pulse width modulation module 101 and a first detection control module 102. It should be noted that the light emitting device D can be a mini light emitting diode, a micro light emitting diode or an organic light emitting diode.

[0050] The gate of the first transistor T1 is electrically connected to the first node Q, one of the source and the drain of the first transistor T1 is electrically connected to the first power supply terminal VDD, and the other of the source and the drain of the first transistor T1 is electrically connected to the second node S. One end of the light emitting device D is electrically connected to the second node S, and the other end of the light emitting device D is electrically connected to the second power supply terminal VSS. The first end of the first capacitor C1 is electrically connected to the first node Q, and the second end of the first capacitor C1 is electrically connected to the second node S. The pulse width modulation module 101 is connected to the pulse width modulation signal SPWM(n), the sweep signal sweep and the data signal Data, and is electrically connected to the first node Q and the first detection terminal Vref1. The pulse width modulation module 101 includes a second transistor T2. The first detection control module 102 is connected to the pulse width modulation signal SPWM(n), and is electrically connected to the first node Q and the first power supply terminal VDD.

[0051] It should be noted that, in the embodiment of the present application, it is only necessary to ensure that the light emitting device D is connected in series to the light emitting circuit formed by the first power supply terminal VDD and the second power supply terminal VSS. Figure 1 The driving circuit 10 shown only illustrates a specific position of the light emitting device D. That is, the light emitting device D can be connected in series at any position on the light emitting circuit.

[0052] Specifically, the first transistor T1 is used to control the driving current flowing through the light emitting device D. The pulse width modulation module 101 is used to adjust the pulse width of the driving current flowing through the light emitting device D under the control of the pulse width modulation signal SPWM(n). The first detection control module 102 is used to control the first power supply terminal VDD to be electrically connected to the first node Q under the control of the pulse width modulation signal SPWM(n) when detecting the threshold voltage of the second transistor T2.

[0053] The driving circuit 10 provided in the embodiment of the present application detects the threshold voltage of the second transistor T2 through the first detection control module 102, and compensates the threshold voltage of the second transistor T2 by means of external compensation, thereby improving the overall stability of the driving circuit 10, thereby ensuring the uniform brightness of the light-emitting device D and improving the display effect of the Micro-LED display device.

[0054] It should be noted that the first power supply terminal VDD and the second power supply terminal VSS are both used to output a preset voltage value. In addition, in the embodiment of the present application, the potential output by the first power supply terminal VDD is greater than the potential of the second power supply terminal VSSS. Specifically, the potential of the second power supply terminal VSS can be the potential of the ground terminal. Of course, it can be understood that the potential of the second power supply terminal VSS can also be other.

[0055] See also Figure 2 , Figure 2This is a second structural diagram of the driving circuit provided in the embodiment of the present application. Figure 2 As shown, the driving circuit 10 provided in the embodiment of the present application further includes a second detection control module 104. The second detection control module 104 is connected to the pulse amplitude modulation signal SPAM(n) and is electrically connected to the second detection terminal Vref2 and the second node S. The second detection control module 104 is used to control the second detection terminal Vref2 to be electrically connected to the second node S under the control of the pulse amplitude modulation signal SPAM(n) when detecting the threshold voltage of the first transistor T1.

[0056] It should be noted that not only the threshold voltage of the second transistor T2 will affect the overall stability of the driving circuit 10, but also the threshold voltage of the first transistor T1 will affect the stability of the driving circuit 10. Therefore, it is necessary to set up a second detection control module 104 for detecting the threshold voltage of the first transistor T1, and to compensate the threshold voltage of the first transistor T1 by means of external compensation, so as to improve the overall stability of the driving circuit 10, thereby ensuring the uniformity of the light emitting brightness of the light emitting device D and improving the display effect of the Micro-LED display device.

[0057] When detecting the threshold voltage of the first transistor T1, the second power supply terminal VSS needs to be in a floating state. The floating state means that the input pin of the logic device is not connected to any level. Due to the internal structure of the logic device, when its input pin is suspended, it is equivalent to the pin being connected to a high level.

[0058] It should be noted that when the threshold voltage of the first transistor T1 is detected, the first transistor T1 is in the on state, and will charge the second node S, and the potential of the second node S will rise accordingly. Since the potential of the second power supply terminal VSS is generally 0V, a voltage difference will be formed between the potential of the second node S and the potential of the second power supply terminal VSS, thereby causing the light-emitting device D to emit light. The light-emitting device D will affect the potential of the second node S, and since the threshold voltage of the first transistor T1 is obtained by detecting the potential of the second node S and calculating, the light-emitting device D will affect the accuracy of the threshold voltage of the first transistor T1 obtained.

[0059] Therefore, in the embodiment of the present application, when detecting the threshold voltage of the first transistor T1, the second power supply terminal VSS is placed in a floating state, so that the light-emitting device D will not emit light, and will not affect the potential of the second node S. This will improve the accuracy of the threshold voltage of the first transistor T1 obtained, thereby ensuring that the light-emitting brightness of the light-emitting device D is uniform, and improving the display effect of the Micro-LED display device.

[0060] It should be noted that the first detection end Vref1 and the second detection end Vref2 can be the same detection end.

[0061] It should be noted that when the first detection terminal Vref1 and the second detection terminal Vref2 can be the same detection terminal, a switch needs to be set to connect the detection terminal to different nodes in different detection stages, thereby improving the accuracy of the detection result. In addition, after the detection compensation is completed, when the driving circuit 10 provided in the embodiment of the present application is used to drive the light-emitting device D to emit light, a switch needs to be used to disconnect the connection between the detection terminal and the second node S and the fourth node m, so that the second node S and the fourth node m are connected to the reference low-level signal, so that the light-emitting device D emits light.

[0062] See also Figure 3 , Figure 3 This is a third structural diagram of the driving circuit provided in the embodiment of the present application. Figure 3 As shown, the driving circuit 10 provided in the embodiment of the present application further includes a pulse amplitude modulation module 103, which is connected to the pulse amplitude modulation signal SPAM(n) and the data signal Data, and is electrically connected to the first node Q. The pulse amplitude modulation module 103 is used to adjust the pulse amplitude of the driving current flowing through the light-emitting device D under the control of the pulse amplitude modulation signal SPAM(n).

[0063] See also Figure 4 , Figure 4 This is a fourth structural diagram of a driving circuit provided in an embodiment of the present application. Figure 4 As shown, the driving circuit 10 provided in the embodiment of the present application further includes a switch module 105. The switch module 105 is electrically connected to the second power supply terminal VSS and the light emitting device D.

[0064] The switch module 105 is used to make the second power supply terminal VSS in a floating state when detecting the threshold voltage of the first transistor T1 .

[0065] It should be noted that when the threshold voltage of the first transistor T1 is detected, the first transistor T1 is in the on state, and will charge the second node S, and the potential of the second node S will rise accordingly. Since the potential of the second power supply terminal VSS is generally 0V, a voltage difference will be formed between the potential of the second node S and the potential of the second power supply terminal VSS, thereby causing the light-emitting device D to emit light. The light-emitting device D will affect the potential of the second node S, and since the threshold voltage of the first transistor T1 is obtained by detecting the potential of the second node S and calculating, the light-emitting device D will affect the accuracy of the threshold voltage of the first transistor T1 obtained.

[0066] In the embodiment of the present application, by setting up a switch module 105, when detecting the threshold voltage of the first transistor T1, the end of the light-emitting device D connected to the second power supply terminal VSS can be disconnected, so that the light-emitting device D is in a floating state, so that the light-emitting device D will not emit light, and will not affect the potential of the second node S, which will improve the accuracy of the threshold voltage of the first transistor T1 obtained, thereby ensuring the uniformity of the light-emitting brightness of the light-emitting device D and improving the display effect of the Micro-LED display device.

[0067] It should be noted that other methods may also be used to make the second power supply terminal VSS in a floating state when detecting the threshold voltage of the first transistor T1, which is not specifically limited here.

[0068] Please visit Figure 5 , Figure 5 The first circuit diagram of the driving circuit provided in the embodiment of the present application is shown in FIG. Figure 1 , Figure 5 As shown, the pulse width modulation module 101 includes a second transistor T2, a third transistor T3, a second capacitor C2 and a third capacitor C3. The first detection control module 102 includes a fourth transistor T4.

[0069] The gate of the second transistor T2 is electrically connected to the third node P, one of the source and the drain of the second transistor T2 is electrically connected to the first node Q, the other of the source and the drain of the second transistor T2 is electrically connected to the fourth node m, and the fourth node m is electrically connected to the first detection terminal Vref1. The gate of the third transistor T3 is connected to the pulse width modulation signal SPWM(n), one of the source and the drain of the third transistor T3 is connected to the data signal Data, and the other of the source and the drain of the third transistor T3 is electrically connected to the third node S. The first end of the second capacitor C2 is connected to the sweep signal sweep, and the second end of the second capacitor C2 is electrically connected to the third node P. The sweep signal sweep adjusts the potential of the third node P through the second capacitor C2.

[0070] The gate of the fourth transistor T4 is connected to the pulse width modulation signal SPWM(n), one of the source and the drain of the fourth transistor T4 is electrically connected to the first power supply terminal VDD, and the other of the source and the drain of the fourth transistor T4 is electrically connected to the first node Q.

[0071] It should be noted that the first transistor T1, the second transistor T2, the third transistor T3 and the fourth transistor T4 may be one or more of a low-temperature polysilicon thin film transistor, an oxide semiconductor thin film transistor or an amorphous silicon thin film transistor. Further, the transistors in the driving circuit 10 provided in the embodiment of the present application may be set to be transistors of the same type, thereby avoiding the influence of the differences between different types of transistors on the driving circuit 10.

[0072] See also Figure 6 , Figure 6 A second circuit diagram of a driving circuit provided in an embodiment of the present application. Figure 2 , Figure 6 As shown, Figure 6 The driving circuit 10 shown is Figure 5 The difference between the driving circuit 10 shown is that the driving circuit 10 further includes a second detection control module 104 , and the second detection control module 104 includes a fifth transistor T5 .

[0073] The gate of the fifth transistor T5 is connected to the pulse amplitude modulation signal SPAM(n), one of the source and the drain of the fifth transistor T5 is electrically connected to the second detection end Vref2, and the other of the source and the drain of the fifth transistor T5 is electrically connected to the second node S.

[0074] See also Figure 7 , Figure 7 The third circuit diagram of the driving circuit provided in the embodiment of the present application is shown in FIG. Figure 3 , Figure 7 As shown, Figure 7 The driving circuit 10 shown is Figure 6 The difference between the driving circuit 10 shown is that the driving circuit 10 further includes a pulse amplitude modulation module 103, and the pulse amplitude modulation module 103 includes a sixth transistor T6.

[0075] The gate of the sixth transistor T6 is connected to the pulse amplitude modulation signal SPAM(n), one of the source and the drain of the sixth transistor T6 is connected to the data signal Data, and the other of the source and the drain of the sixth transistor T6 is electrically connected to the first node Q.

[0076] See also Figure 4 , Figure 8 This is a fourth circuit diagram of a driving circuit provided in an embodiment of the present application. Figure 4 , Figure 8 As shown, Figure 8 The driving circuit 10 shown is Figure 7The difference of the driving circuit 10 shown is that the driving circuit 10 further includes a switch N. A first end of the switch N is electrically connected to the light emitting device D, and a second end of the switch N is electrically connected to the second power supply terminal VSS.

[0077] When the driving circuit 10 is in the state of detecting the threshold voltage of the first transistor T1, the switch N is in the disconnected state, and the light emitting device D is not connected to the second power supply terminal VSS. When the driving circuit 10 is in other states, the switch N is in the connected state, and the light emitting device D is connected to the second power supply terminal VSS.

[0078] It should be noted that a transistor may also be used as the switch N, so that the light emitting device D can be more conveniently controlled to be disconnected from the second power supply terminal VSS, which is more conducive to detecting the threshold voltage of the first transistor T1.

[0079] See also Fig. 9 as well as Fig.10 , Fig. 9 This is a first timing diagram of the driving circuit provided in an embodiment of the present application. Fig.10 This is a first circuit simulation diagram of the driving circuit provided in the embodiment of the present application. Specifically, Fig. 9 This is a timing diagram used by the driving circuit 10 provided in the embodiment of the present application to detect the threshold voltage of the second transistor T2. Fig.10 This is a diagram showing a voltage variation of the fourth node m when the driving circuit 10 provided in an embodiment of the present application detects the threshold voltage of the second transistor T2 .

[0080] Among them, initially, the pulse width modulation signal SPWM(n) is written to a high potential, the third transistor T3 and the fourth transistor T4 are turned on, the first node Q is electrically connected to the first power supply terminal VDD, the first node Q becomes a high potential, and provides a constant voltage high potential signal for the second transistor T2. Then, the data signal Data is written to a high potential, the potential of the data signal Data is written to the third node P, and the fourth transistor T4 is turned on. The first node Q starts to charge the fourth node m, and the potential of the fourth node m starts to rise until the difference between the potential of the third node P and the potential of the fourth node m is equal to the threshold voltage of the second transistor T2, and the fourth node m will stop charging.

[0081] It should be noted that, by subtracting the detected potential of the fourth node m from the potential of the third node P, the threshold voltage of the second transistor T2 can be obtained.

[0082] The potential of the first power supply terminal VDD is greater than the potential of the data signal Data.

[0083] It should be noted that when the potential of the first power supply terminal VDD is greater than the potential of the data signal Data, the second transistor T2 operates in a saturation region, so that a more accurate value can be obtained when detecting the threshold voltage of the second transistor T2.

[0084] The first detection terminal Vref1 and the second detection terminal Vref2 can be connected to the same detection signal Vref.

[0085] See also Fig.11 as well as Fig.12 , Fig.11 This is a second timing diagram of the driving circuit provided in an embodiment of the present application. Fig.12 This is a second circuit simulation diagram of the driving circuit provided in the embodiment of the present application. Specifically, Fig.11 This is a timing diagram used by the driving circuit 10 provided in the embodiment of the present application to detect the threshold voltage of the first transistor T1. Fig.12 This is a diagram showing a voltage variation of the second node m when the driving circuit 10 provided in an embodiment of the present application detects the threshold voltage of the first transistor T1 .

[0086] In which, initially, the pulse width modulation signal SPWM(n) is written to a high potential, the third transistor T3 and the fourth transistor T4 are turned on, the data signal Data is at a low potential, and the third node P is written to 0V, so that the second transistor T2 can be prevented from turning on due to the negative drift of the threshold voltage. At this time, the switch N is in an off state, so that the light-emitting device D is in a suspended state, and the light-emitting device D cannot emit light. Then, the pulse amplitude modulation signal SPAM(n) is written to a high potential, the pulse width modulation signal SPWM(n) is written to a low potential, the fifth transistor T5 and the sixth transistor T6 are turned on, and the third transistor T3 and the fourth transistor T4 are turned off. Then, the data signal Data is written to a high potential, the potential of the data signal Data is written to the first node Q, the first transistor T1 is turned on, the first power supply terminal VDD starts to charge the second node S, and the potential of the second node S starts to rise until the difference between the potential of the first node Q and the potential of the second node S is equal to the threshold voltage of the first transistor T1, and the second node S stops charging.

[0087] It should be noted that by subtracting the detected potential of the second node S from the potential of the first node Q, the threshold voltage of the first transistor T1 can be obtained.

[0088] The potential of the first power supply terminal VDD is greater than the potential of the data signal Data.

[0089] It should be noted that when the potential of the first power supply terminal VDD is greater than the potential of the data signal Data, the second transistor T2 operates in a saturation region, so that a more accurate value can be obtained when detecting the threshold voltage of the second transistor T2.

[0090] The first detection terminal Vref1 and the second detection terminal Vref2 can be connected to the same detection signal Vref.

[0091] See also Fig.13 as well as Fig.14 , Fig.13 This is the third timing diagram of the driving circuit provided in an embodiment of the present application. Fig.14 This is a third circuit simulation diagram of the driving circuit provided in the embodiment of the present application. Fig.13 As shown, the light-emitting device D of the driving circuit provided in the embodiment of the present application emits light in the stage t3.

[0092] In the first stage t1, the pulse width modulation signal SPWM(n) is written to a high potential, the third transistor T3 and the fourth transistor T4 are turned on, the data signal Data is at a low potential, and 0V is written to the third node P, thereby preventing the second transistor T2 from being turned on due to the negative drift of the threshold voltage.

[0093] In the second stage t2: the pulse amplitude modulation signal SPAM(n) is written to a high potential, the pulse width modulation signal SPWM(n) is written to a low potential, the fifth transistor T5 and the sixth transistor T6 are turned on, the third transistor T3 and the fourth transistor T4 are turned off, the data signal Data is written to a high potential, the potential of the data signal Data is written to the first node Q, the first transistor T1 is turned on, and the potential of the first power supply terminal VDD is at 0V, and the light-emitting device D does not emit light.

[0094] In the third stage t3: the first power supply terminal VDD changes from a low potential to a high potential. The light-emitting device D starts to emit light, and the sweep signal sweep raises the voltage value of the third node P through the second capacitor C2. The raising speed determines the light-emitting time of the light-emitting device D. When the voltage of the third node P is equal to the threshold voltage of the second transistor T2, the second transistor T2 is turned on, Vref1 is a low potential, and the potential is written to the first node Q. The first transistor T1 is turned off, and the light-emitting device D does not emit light. Specifically, in the third stage t3, different voltage values ​​are written to the third node P to adjust the light-emitting time of the light-emitting device D, that is, pulse width modulation.

[0095] It should be noted that the first detection terminal Vref1 and the second detection terminal Vref2 can be connected to the same detection signal Vref. When the driving circuit provided in the embodiment of the present application is used to make the light-emitting device D emit light normally, the first detection terminal Vref1 and the second detection terminal Vref2 are connected to a constant low-level potential. Specifically, the potential connected to the first detection terminal Vref1 and the second detection terminal Vref2 can be the potential of the ground terminal. Of course, it can be understood that the potential connected to the first detection terminal Vref1 and the second detection terminal Vref2 can also be other.

[0096] Among them, in the first stage t1, the potential of the first power supply terminal VDD is 0V. The potential of the data signal Data is between 0V and 10V. The sweep signal sweep is 10V. The potentials of the second power supply terminal VSS and the second detection terminal Vref2 are both 0V. In the second stage t2, the potential of the first power supply terminal VDD is 0V. The potential of the data signal Data is between 0V and 10V, but it is lower than that in the first stage t1. The sweep signal sweep is 0V. The potentials of the second power supply terminal VSS and the second detection terminal Vref2 are both 0V. In the third stage t3, the potential of the first power supply terminal VDD is 12V. The potential of the data signal Data is 0V. The sweep signal sweep gradually rises from 0V to 10V. The potentials of the second power supply terminal VSS and the second detection terminal Vref2 are both 0V.

[0097] In the driving circuit provided in the embodiment of the present application, a first transistor, a light-emitting device, a low capacitor, a pulse width modulation module and a first detection control module are included. Specifically, a second transistor is provided in the pulse width modulation module. The pulse width modulation module can adjust the pulse width of the driving current flowing through the light-emitting device. Among them, the first detection control module can detect the threshold voltage of the second transistor and compensate the threshold voltage of the second transistor by external compensation, thereby improving the overall stability of the driving circuit, thereby ensuring the uniform brightness of the light-emitting device and improving the display effect of the Micro-LED display device.

[0098] See also Fig.15 , Fig.15 The present invention also provides a display panel 200, including a plurality of pixel units 2000 arranged in an array, each pixel unit 2000 including the above-mentioned driving circuit 10, and the details can be referred to the above description of the driving circuit 10, which will not be described here.

[0099] In the display panel provided in the embodiment of the present application, a first transistor, a light-emitting device, a low capacitor, a pulse width modulation module and a first detection control module are included. Specifically, a second transistor is provided in the pulse width modulation module. The pulse width modulation module can adjust the pulse width of the driving current flowing through the light-emitting device. Among them, the first detection control module can detect the threshold voltage of the second transistor and compensate the threshold voltage of the second transistor by external compensation, thereby improving the overall stability of the driving circuit, thereby ensuring the uniform brightness of the light-emitting device and improving the display effect of the Micro-LED display device.

[0100] The above is a detailed introduction to a driving circuit and a display panel provided in an embodiment of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A driving circuit, characterized in that: include: a first transistor, wherein a gate of the first transistor is electrically connected to a first node, one of a source and a drain of the first transistor is electrically connected to a first power supply terminal, and the other of the source and the drain of the first transistor is electrically connected to a second node; a light emitting device, one end of which is electrically connected to the second node, and the other end of which is electrically connected to the second power supply terminal; a first capacitor, wherein a first end of the first capacitor is electrically connected to the first node, and a second end of the first capacitor is electrically connected to the second node; a pulse width modulation module, the pulse width modulation module is connected to a pulse width modulation signal, a frequency sweep signal and a data signal, and is electrically connected to the first node and the first detection end, the pulse width modulation module comprises a second transistor and a third transistor, the gate of the second transistor is electrically connected to the third node, one of the source and the drain of the second transistor is electrically connected to the first node, the other of the source and the drain of the second transistor is electrically connected to a fourth node, and the fourth node is electrically connected to the first detection end, the gate of the third transistor is connected to the pulse width modulation signal, one of the source and the drain of the third transistor is connected to the data signal, and the other of the source and the drain of the third transistor is electrically connected to the third node, and the pulse width modulation module is used to adjust the pulse width of the driving current flowing through the light-emitting device under the control of the pulse width modulation signal; as well as A first detection control module, the first detection control module is connected to the pulse width modulation signal and is electrically connected to the first node and the first power supply terminal, and the first detection control module is used to control the first power supply terminal to be electrically connected to the first node under the control of the pulse width modulation signal when detecting the threshold voltage of the second transistor.

2. The driving circuit according to claim 1, characterized in that: The pulse width modulation module also includes a second capacitor and a third capacitor; The first end of the second capacitor is connected to the frequency sweep signal, and the second end of the second capacitor is electrically connected to the third node, so that the frequency sweep signal adjusts the potential of the third node through the second capacitor; A first end of the third capacitor is electrically connected to the third node, and a second end of the third capacitor is electrically connected to a fourth node.

3. The driving circuit according to claim 1, characterized in that: The first detection control module includes a fourth transistor, a gate of the fourth transistor is connected to the pulse width modulation signal, one of the source and the drain of the fourth transistor is electrically connected to the first power supply terminal, and the other of the source and the drain of the fourth transistor is electrically connected to the first node.

4. The driving circuit according to claim 1, characterized in that: The driving circuit also includes a second detection control module; The second detection control module receives a pulse amplitude modulation signal and is electrically connected to the second detection terminal and the second node. The second detection control module is used to control the second detection terminal to be electrically connected to the second node under the control of the pulse amplitude modulation signal when detecting the threshold voltage of the first transistor.

5. The driving circuit according to claim 4, characterized in that: The second detection control module includes a fifth transistor; The gate of the fifth transistor is connected to the pulse amplitude modulation signal, one of the source and the drain of the fifth transistor is electrically connected to the second detection end, and the other of the source and the drain of the fifth transistor is electrically connected to the second node.

6. The driving circuit according to claim 4, characterized in that: When the threshold voltage of the first transistor is detected, the second power terminal is in a floating state.

7. The driving circuit according to claim 4, characterized in that: The driving circuit also includes a pulse amplitude modulation module; The pulse amplitude modulation module receives the pulse amplitude modulation signal and the data signal and is electrically connected to the first node. The pulse amplitude modulation module is used to adjust the pulse amplitude of the driving current under the control of the pulse amplitude modulation signal.

8. The driving circuit according to claim 7, characterized in that: The pulse amplitude modulation module includes a sixth transistor; The gate of the sixth transistor is connected to the pulse amplitude modulation signal, one of the source and the drain of the sixth transistor is connected to the data signal, and the other of the source and the drain of the sixth transistor is electrically connected to the first node.

9. The driving circuit according to claim 1, characterized in that: The potential of the first power supply terminal is higher than the potential of the data signal.

10. A display panel, characterized in that: The invention comprises a driving circuit as claimed in any one of claims 1 to 9.

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