Micro LED driving circuit, driving system, display panel and pixel driving method
Patent Information
- Application Number
- CN202380067489.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-28
- Publication Date
- 2025-04-18
Smart Images
Figure CN119856212A_ABST
Abstract
Description
A Micro LED driving circuit, driving system, display panel and pixel driving method Technical Field
[0001] The present invention relates to the field of Micro LED display driving technology, and further to a Micro LED driving circuit, a driving system, a display panel, and a pixel driving method. Background Art
[0002] Micro LED display refers to a display technology that utilizes micron-sized LED pixel units and assembles them onto a driver panel to form a high-density LED display array. Due to the small size, high integration, and self-luminescence of Micro LED chips, they offer significant advantages over LCD and OLED in terms of brightness, resolution, contrast, energy consumption, lifespan, response speed, and thermal stability. Early LED display pixels were composed of LEDs in the three primary colors of red, green, and blue (R / G / B).
[0003] Referring to Figure 1, a schematic diagram of a conventional Micro LED display driver circuit is shown. The conventional Micro LED display driver circuit includes a first MOS transistor M1, a second MOS transistor M2, a current mirror, and a light-emitting unit (LED). The current mirror includes a symmetrically arranged third MOS transistor M3 and a fourth MOS transistor M4. The S poles of the first MOS transistor M1 and the second MOS transistor M2 are connected to the chip operating voltage VDD. The G pole of the first MOS transistor M1 is electrically connected to the enable signal EN, and the G pole of the second MOS transistor M2 is electrically connected to the display control signal SF. The D pole of the first MOS transistor M1 is electrically connected to the S pole of the third MOS transistor M3, and the D pole of the second MOS transistor M2 is electrically connected to the S pole of the fourth MOS transistor M4. The G pole of the third MOS transistor M3 is electrically connected to the G pole of the fourth MOS transistor M4, and the G pole of the third MOS transistor M3 is electrically connected to the D pole of the third MOS transistor M3. The D pole of the third MOS transistor M3 is electrically connected to the external external current Lin. The D pole of the fourth MOS transistor M4 is electrically connected to the anode of the LED, and the cathode of the LED is grounded.
[0004] In existing Micro LED display driver circuits, due to the current mismatch error in the current mirror (the third MOS transistor M3 and the fourth MOS transistor M4), the lighting brightness of each pixel in the Micro LED display panel varies, which can easily cause the uniformity of the displayed image to deteriorate and affect the display effect.
[0005] Summary of the Invention
[0006] In response to the technical problems raised in the background technology, the purpose of the present invention is to provide a Micro LED driving circuit, driving system, display panel and pixel driving method, which can overcome the problems of the prior art. By electrically connecting the substrate of the MOS tube of the current mirror to the gate of the MOS tube for receiving the driving signal, the turn-on voltage of the current mirror changes synchronously with the substrate voltage, thereby helping to reduce the problem of current mirror mismatch.
[0007] To achieve the above objectives, the present invention discloses a Micro LED driving circuit, which is characterized by comprising:
[0008] a first MOS transistor, wherein a first gate of the first MOS transistor is used to receive an enable signal;
[0009] a second MOS transistor, wherein a second gate of the second MOS transistor is used to receive a control signal, and a first source of the first MOS transistor and a second source of the second MOS transistor are electrically connected to the same voltage source;
[0010] A current mirror, comprising a third MOS transistor and a fourth MOS transistor, wherein a third source of the third MOS transistor is electrically connected to a first drain of the first MOS transistor, a third drain of the third MOS transistor serves as an input interface, and the third drain of the third MOS transistor is electrically connected to a third gate of the third MOS transistor; a fourth source of the fourth MOS transistor is electrically connected to a second drain of the second MOS transistor, a fourth drain of the fourth MOS transistor serves as an output interface, and the third gate of the third MOS transistor is electrically connected to a fourth gate of the fourth MOS transistor;
[0011] The first gate of the first MOS transistor is electrically connected to a third substrate of the third MOS transistor, and the second gate of the second MOS transistor is electrically connected to a fourth substrate of the fourth MOS transistor.
[0012] The first gate of the first MOS transistor is electrically connected to a first substrate of the first MOS transistor, and the second gate of the second MOS transistor is electrically connected to a second substrate of the second MOS transistor.
[0013] The first MOS transistor, the second MOS transistor, the third MOS transistor and the fourth MOS transistor are PMOS transistors respectively.
[0014] A Micro LED driving system is also disclosed, which is characterized by comprising:
[0015] a Micro LED driving circuit, comprising the aforementioned Micro LED driving circuit; and
[0016] A light-emitting unit is electrically connected to an output interface of the Micro LED driving circuit.
[0017] Wherein, the light emitting unit is an LED, the output interface is electrically connected to an anode of the LED, and a cathode of the LED is grounded.
[0018] Also disclosed is a Micro LED display panel, characterized in that it includes an array consisting of two of the above-mentioned Micro LED driving systems and a driving backplane, the Micro LED driving circuit of the Micro LED driving system is integrated into the driving backplane, and the Micro LED driving system includes an LED located on one side of the driving backplane.
[0019] A Micro LED pixel driving method is also disclosed, which is characterized by comprising the following steps:
[0020] Inputting an enable signal to a first gate of a first MOS transistor of a driving circuit;
[0021] Inputting a control signal to a second gate of a second MOS transistor of the driving circuit;
[0022] Inputting a first driving signal having the same phase as that of a third substrate of a third MOS transistor of the driving circuit based on the enable signal; and
[0023] Inputting a second driving signal having the same phase as that of a fourth substrate of a fourth MOS transistor of the driving circuit based on the control signal;
[0024] The third MOS transistor and the fourth MOS transistor form a current mirror.
[0025] The method further comprises the following steps:
[0026] Inputting a third driving signal having the same phase as that of the first substrate of the first MOS transistor based on the enable signal; and
[0027] A fourth driving signal having the same phase as that of the control signal is input to a second substrate of the second MOS transistor.
[0028] The step of inputting the first driving signal having the same phase as that of the third substrate of the third MOS transistor of the driving circuit based on the enable signal further includes the following sub-steps:
[0029] electrically connecting the first gate of the first MOS transistor to the third substrate of the third MOS transistor; and
[0030] inputting the first driving signal having the same phase as that of the first substrate of the third MOS transistor of the driving circuit based on the enable signal; and
[0031] The step of inputting the second driving signal having the same phase as the fourth substrate of the fourth MOS transistor of the driving circuit based on the control signal further includes the following sub-steps:
[0032] electrically connecting the second gate of the second MOS transistor to the fourth substrate of the fourth MOS transistor; and
[0033] The second driving signal having the same phase as that of the fourth substrate of the fourth MOS transistor of the driving circuit is input based on the control signal.
[0034] The step of inputting the third driving signal having the same phase as that of the first substrate of the first MOS transistor based on the enable signal further includes the following sub-steps:
[0035] electrically connecting the first gate of the first MOS transistor to the first substrate of the first MOS transistor; and
[0036] inputting the third driving signal having the same phase as that of the first substrate of the first MOS transistor based on the enable signal; and
[0037] The step of inputting the fourth driving signal having the same phase as that of the second substrate of the second MOS transistor based on the control signal further includes the following sub-steps:
[0038] electrically connecting the second gate of the second MOS transistor to the second substrate of the second MOS transistor; and
[0039] The fourth driving signal having the same phase as that of the second MOS transistor is inputted to the second substrate based on the control signal.
[0040] Therefore, the Micro LED driving circuit, driving system, display panel, and pixel driving method provided by the present invention have at least one of the following beneficial effects:
[0041] 1. By electrically connecting the substrates (third substrate and fourth substrate) of the MOS transistors (third MOS transistor and fourth MOS transistor) of the current mirror to the gates (first gate and second gate) of the MOS transistors (first MOS transistor and first MOS transistor) for receiving the drive signal, the turn-on voltage of the current mirror changes synchronously with the substrate voltage, thereby helping to reduce the current mirror mismatch problem;
[0042] 2. By electrically connecting the first gate of the first MOS tube to the first substrate of the first MOS tube and the second gate of the second MOS tube to the second substrate of the second MOS tube, it is helpful to reduce the on-resistance R ON , increase the cut-off resistance R OFF . BRIEF DESCRIPTION OF THE DRAWINGS
[0043] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings, wherein like reference numerals generally represent like components in the exemplary embodiments of the present disclosure.
[0044] FIG1 is a diagram of a Micro LED driving circuit in the prior art.
[0045] FIG2 is a schematic diagram of a Micro LED driving circuit provided by the present invention.
[0046] FIG3 is a schematic diagram of a first variant embodiment of the Micro LED driving circuit provided by the present invention.
[0047] FIG4 is a flow chart of the Micro LED pixel driving method provided by the present invention. DETAILED DESCRIPTION
[0048] The preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although preferred embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.
[0049] The present invention will be further described in detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.
[0050] Before describing the solution of the present invention, we first introduce several calculation formulas for relevant parameters of MOS tube operation:
[0051] Referring to Figure 2, a schematic diagram of the circuit structure of the Micro LED driving system provided by the present invention is shown. The Micro LED driving system includes a first MOS transistor 10, a second MOS transistor 20, a current mirror 30, and a light-emitting unit 40. The first source of the first MOS transistor 10 and the second source of the second MOS transistor 20 are electrically connected to the operating voltage VDD. The first gate of the first MOS transistor 10 is used to receive the enable signal EN, and the second gate of the second MOS transistor 20 is used to receive the control signal SF. The current mirror 30 includes a third MOS transistor 31 and a fourth MOS transistor 32. The third source of the third MOS transistor 31 is electrically connected to the first drain of the first MOS transistor 10, the fourth source of the fourth MOS transistor 32 is electrically connected to the second drain of the second MOS transistor 20, and the third gate of the third MOS transistor 31 is electrically connected to the fourth gate of the fourth MOS transistor 32. The first gate of the first MOS transistor 10 is electrically connected to the third substrate of the third MOS transistor 31, and the second gate of the second MOS transistor 20 is electrically connected to the fourth substrate of the fourth MOS transistor 32. The third drain of the third MOS transistor 31 is used to access the external current Lin. The fourth drain of the fourth MOS transistor is used to be electrically connected to the anode of the light emitting unit 40. The cathode of the light emitting unit 40 is grounded.
[0052] In the Micro LED drive system provided by the present invention, the first MOS transistor 10 serves as the master control switch. When the first MOS transistor 10 is turned off, the light-emitting unit 40 cannot be illuminated regardless of the switch state of the second MOS transistor 20. The second MOS transistor 20 serves as a direct control switch for the light-emitting unit 40. When the first MOS transistor 10 is operating in the on state, the switch state of the second MOS transistor 20 can control whether the light-emitting unit 40 is illuminated.
[0053] The current mirror 30 can play a role in constant current protection for the current input to the light-emitting unit 40. In the Micro LED driving system provided by the present invention, the third substrate of the third MOS transistor 31 is electrically connected to the first gate of the first MOS transistor 10, and the fourth substrate of the fourth MOS transistor 32 is electrically connected to the second gate of the second MOS transistor 20, so that the turn-on voltage V th As the substrate voltage V B increases with the increase of substrate voltage V B , thereby helping to reduce the mismatch problem of the current mirror 30.
[0054] For example, when the enable signal EN or the control signal SF is at a low level, according to the MOS conduction characteristics, the first MOS transistor 10 and the second MOS transistor are turned on 20, and the current mirror 30 composed of the third MOS transistor 31 and the fourth MOS transistor 32 also starts to work. Since the first gate of the first MOS transistor 10 is electrically connected to the third substrate of the third MOS transistor 31, and the second gate of the second MOS transistor 20 is electrically connected to the fourth substrate of the fourth MOS transistor 32, the third substrate of the third MOS transistor 31 and the fourth substrate of the fourth MOS transistor 32 are at a low level, and the turn-on voltage V th According to the current mirror mismatch calculation formula, it can be determined that the turn-on voltage V th When decreasing, Reduce, according to the current mirror mismatch calculation formula can be determined Reducing this helps reduce the mismatch of the current mirror 30, thereby improving the uniformity of the displayed image. The current mirror mismatch calculation formula is as follows:
[0055] In the above current mirror mismatch calculation formula, I D is the input current of the current mirror 30, ΔI D is the difference between the output current and the input current of the current mirror 30, V th is the turn-on voltage (also called threshold voltage), V GS is the voltage between the source and drain.
[0056] In some embodiments, the on-resistance R can be increased by electrically connecting the third substrate of the third MOS transistor 31 to the first gate of the first MOS transistor 10 and the fourth substrate of the fourth MOS transistor 32 to the second gate of the second MOS transistor 20. OFF size, thus helping to reduce leakage current.
[0057] For example, when the enable signal EN or the control signal SF is at a high level, according to the MOS conduction characteristics, the first MOS transistor 10 and the second MOS transistor 20 are turned off, and the current mirror 30 composed of the third MOS transistor 31 and the fourth MOS transistor 32 also stops working. Since the first gate of the first MOS transistor 10 is electrically connected to the third substrate of the third MOS transistor 31, and the second gate of the second MOS transistor 20 is electrically connected to the fourth substrate of the fourth MOS transistor 32, the turn-on voltage V th is high level, that is, the turn-on voltage V th Increase.
[0058] According to the cut-off resistance R OFF The calculation formula can determine V th Increasing can help increase the cut-off resistance ROFF The size of the cut-off resistor R OFF The calculation formula is as follows:
[0059] In the above R OFF In the calculation formula, i D Indicates the current flowing to the MOS tube, λ indicates the MOS tube constant, μC ox Indicates the MOS tube constant, L indicates the length of the MOS tube, v GS is the voltage between the source and drain, v DS is the voltage between the gate and drain, V T represents the turn-on voltage (also expressed as V th ).
[0060] Referring to Figure 3, there is shown a schematic diagram of the circuit structure of a variant embodiment of the Micro LED driving system provided by the present invention. Referring to Figure 3, the first gate of the first MOS tube 10 is electrically connected to the first substrate of the first MOS tube 20, and the second gate of the second MOS tube 20 is electrically connected to the second substrate of the second MOS tube 20. In some embodiments, the first MOS tube and the second MOS are both configured as SOI devices. By electrically connecting the first gate of the first MOS tube 10 to the first substrate of the first MOS tube 20 and the second gate of the second MOS tube 20 to the second substrate of the second MOS tube 20, it can help to reduce the on-resistance R ON , increase the cut-off resistance R OFF .
[0061] For example, when the Micro LED driving system provided by the present invention is in the on state, when the control signal SF is at a low level, according to the MOS transistor conduction characteristics, the second MOS transistor 20 is turned on, and the second substrate of the second MOS transistor 20 is at a low level, then the turn-on voltage V TH Also decreases, and then according to R ON The calculation formula of R ON Reduced, thus helping to reduce the loss when the drive circuit is in the on state. ON The calculation formula is as follows:
[0062] In the above R ON In the calculation formula, v GS Represents the gate voltage, V T Represents the turn-on voltage, μC ox Represents the MOS tube constant, L represents the MOS tube length, and W represents the MOS tube width.
[0063] For example, when the Micro LED driving system provided by the present invention is in the off state, when the control signal SF is at a high level, according to the MOS tube cut-off characteristic, the second MOS tube 20 is cut off, the second substrate of the second MOS tube 20 is at a high level, and the turn-on voltage V T (V TH ) also increases, then Decrease, then Increase, that is, R OFF Increase, thus helping to reduce the leakage current when the drive circuit is in the off state. OFF The calculation formula is as follows:
[0064] In the above R OFF In the calculation formula, i D Indicates the current flowing to the MOS tube, λ indicates the MOS tube constant, μC ox Indicates the MOS tube constant, L indicates the length of the MOS tube, v GS is the voltage between the source and drain, v DS is the voltage between the gate and drain, V T represents the turn-on voltage (also expressed as V th ).
[0065] In some embodiments, the present invention further provides a Micro LED display panel, comprising an array consisting of two or more of the above-mentioned Micro LED driving systems and a driving backplane, wherein the Micro LED driving circuit of the Micro LED driving system is integrated into the driving backplane, and the LED of the Micro LED driving system is located on one side of the driving backplane.
[0066] Referring to FIG4 , the present invention further provides a Micro LED pixel driving method, comprising the following steps:
[0067] Step S1: inputting an enable signal to the first gate of the first MOS transistor 10 of the driving circuit;
[0068] Step S2: inputting a control signal to the second gate of the second MOS transistor 20 of the driving circuit;
[0069] Step S3: inputting a first driving signal having the same phase as that of the third substrate of the third MOS transistor 31 of the driving circuit based on the enable signal; and
[0070] Step S4: inputting a second driving signal having the same phase as that of the fourth substrate of the fourth MOS transistor 32 of the driving circuit based on the control signal;
[0071] The third MOS transistor 31 and the fourth MOS transistor 32 form a current mirror.
[0072] Furthermore, the pixel driving method of the Micro LED provided by the present invention further includes the following steps:
[0073] Step S5: inputting a third driving signal having the same phase as that of the first substrate of the first MOS transistor 10 based on the enable signal;
[0074] Step S6: inputting a fourth driving signal having the same phase as that of the second substrate of the second MOS transistor 20 based on the control signal.
[0075] Specifically, the above step S3 further includes the following sub-steps:
[0076] Sub-step S31: electrically connecting the first gate of the first MOS transistor 10 to the third substrate of the third MOS transistor 31; and
[0077] Sub-step S32: inputting a first driving signal having the same phase as that of the third substrate of the third MOS transistor 31 of the driving circuit based on the enable signal.
[0078] The above step S4 further includes the following sub-steps:
[0079] Sub-step S41: electrically connecting the second gate of the second MOS transistor 20 to the fourth substrate of the fourth MOS transistor 32; and
[0080] Sub-step S42: inputting a second driving signal having the same phase as that of the fourth substrate of the fourth MOS transistor 32 of the driving circuit based on the control signal.
[0081] In some embodiments, the third substrate of the third MOS transistor 31 is electrically connected to a driving backplane. When an enable signal is input to the first gate of the first MOS transistor 10 via the driving backplane, a first drive signal having the same phase as the enable signal is input to the third substrate of the third MOS transistor 31 via the driving backplane. Similarly, the fourth substrate of the fourth MOS transistor is electrically connected to the driving backplane. When a control signal is input to the second gate of the second MOS transistor 20 via the driving backplane, a second drive signal having the same phase as the control signal is input to the fourth substrate of the fourth MOS transistor 32 via the driving backplane.
[0082] Specifically, the above step S5 further includes the following sub-steps:
[0083] Sub-step S51: electrically connecting the first gate of the first MOS transistor 10 to the first substrate of the first MOS transistor 10; and
[0084] Sub-step S52 : inputting a third driving signal having the same phase as that of the first substrate of the first MOS transistor 10 based on the enable signal.
[0085] The above step S6 further includes the following sub-steps:
[0086] Sub-step S61: electrically connecting the second gate of the second MOS transistor 20 to the second substrate of the second MOS transistor 20; and
[0087] Sub-step S62: inputting a fourth driving signal having the same phase as that of the second substrate of the second MOS transistor 20 based on the control signal.
[0088] In some embodiments, the first substrate of the first MOS transistor 10 is electrically connected to a driving backplane. When an enable signal is input to the first gate of the first MOS transistor 10 via the driving backplane, a first drive signal having the same phase as the enable signal is input to the first substrate of the first MOS transistor 10 via the driving backplane. Similarly, the second substrate of the second MOS transistor 20 is electrically connected to the driving backplane. When a control signal is input to the second gate of the second MOS transistor 20 via the driving backplane, a second drive signal having the same phase as the control signal is input to the second substrate of the second MOS transistor 20 via the driving backplane.
Claims
1. A Micro LED driving circuit, characterized in that: include: a first MOS transistor, wherein a first gate of the first MOS transistor is used to receive an enable signal; a second MOS transistor, a second gate of the second MOS transistor being used for receiving a control signal, a first source of the first MOS transistor and a second source of the second MOS transistor being electrically connected to the same voltage source; A current mirror, comprising a third MOS tube and a fourth MOS tube, wherein a third source of the third MOS tube is electrically connected to a first drain of the first MOS tube, a third drain of the third MOS tube serves as an input interface, and the third drain of the third MOS tube is electrically connected to a third gate of the third MOS tube; a fourth source of the fourth MOS tube is electrically connected to a second drain of the second MOS tube, a fourth drain of the fourth MOS tube serves as an output interface, and the third gate of the third MOS tube is electrically connected to a fourth gate of the fourth MOS tube; The first gate of the first MOS tube is electrically connected to a third substrate of the third MOS tube, and the second gate of the second MOS tube is electrically connected to a fourth substrate of the fourth MOS tube.
2. The Micro LED driving circuit according to claim 1, characterized in that: The first gate of the first MOS tube is electrically connected to a first substrate of the first MOS tube, and the second gate of the second MOS tube is electrically connected to a second substrate of the second MOS tube.
3. The Micro LED driving circuit according to claim 1, characterized in that: The first MOS tube, the second MOS tube, the third MOS tube and the fourth MOS tube are PMOS tubes respectively.
4. A Micro LED driving system, characterized in that: include: A Micro LED driving circuit, comprising the Micro LED driving circuit according to any one of claims 1 to 3; as well as A light-emitting unit is electrically connected to an output interface of the Micro LED driving circuit.
5. The Micro LED driving system according to claim 4, characterized in that: The light emitting unit is an LED, the output interface is electrically connected to an anode of the LED, and a cathode of the LED is grounded.
6. A Micro LED display panel, characterized in that: An array comprising two or more Micro LED driving systems according to claim 4 or 5 and a driving backplane, wherein a Micro LED driving circuit of the Micro LED driving system is integrated in the driving backplane, and an LED included in the Micro LED driving system is located on one side of the driving backplane.
7. A Micro LED pixel driving method, characterized in that: The following steps are involved: Inputting an enable signal to a first gate of a first MOS tube of a driving circuit; Inputting a control signal to a second gate of a second MOS tube of the driving circuit; Based on the enable signal, a third substrate of a third MOS tube of the driving circuit is input with a phase A first driving signal with the same phase; as well as Based on the control signal, a second driving signal having the same phase is inputted to a fourth substrate of a fourth MOS transistor of the driving circuit; The third MOS tube and the fourth MOS tube form a current mirror.
8. The Micro LED pixel driving method according to claim 7, characterized in that: Further comprising the steps of: Inputting a third driving signal having the same phase as that of the first MOS transistor to a first substrate based on the enable signal; and A fourth driving signal having the same phase as that of the second MOS transistor is inputted to a second substrate of the second MOS transistor based on the control signal.
9. The Micro LED pixel driving method according to claim 7, characterized in that: The step of inputting the first driving signal having the same phase as the third substrate of the third MOS transistor of the driving circuit based on the enable signal further includes the following sub-steps: electrically connecting the first gate of the first MOS transistor to the third substrate of the third MOS transistor; and Inputting the first driving signal having the same phase as the third substrate of the third MOS transistor of the driving circuit based on the enable signal; as well as The step of inputting the second driving signal having the same phase as the fourth substrate of the fourth MOS transistor of the driving circuit based on the control signal further includes the following sub-steps: electrically connecting the second gate of the second MOS tube to the fourth substrate of the fourth MOS tube; and The second driving signal having the same phase as that of the fourth substrate of the fourth MOS transistor of the driving circuit is input based on the control signal.
10. The Micro LED pixel driving method according to claim 8, characterized in that: The step of inputting the third driving signal having the same phase as that of the first substrate of the first MOS transistor based on the enable signal further includes the following sub-steps: electrically connecting the first gate of the first MOS transistor to the first substrate of the first MOS transistor; and Inputting the third driving signal having the same phase as that of the first substrate of the first MOS transistor based on the enable signal; as well as The step of inputting the fourth driving signal having the same phase as that of the second substrate of the second MOS transistor based on the control signal further includes the following sub-steps: electrically connecting the second gate of the second MOS tube to the second substrate of the second MOS tube; and The fourth driving signal having the same phase as that of the second MOS transistor is input to the second substrate based on the control signal.