Micro LED driving circuit, driving system, display panel and pixel driving method

Abstract

A Micro LED driving circuit, a driving system, a display panel and a pixel driving method, the Micro LED driving circuit comprising: a first MOS transistor (10), the gate of the first MOS transistor (10) being used for accessing an enable signal (EN); one end of the first phase inverter (40) is electrically connected to the grid electrode of the first MOS tube (10), and the other end of the first phase inverter (40) is electrically connected to the substrate of the first MOS tube (10); the source electrode of the first MOS tube (10) and the source electrode of the second MOS tube (20) are electrically connected to the same voltage source (VDD), and the grid electrode of the second MOS tube (20) is used for accessing a control signal (SF); the drain electrode of the first MOS transistor (10) and the drain electrode of the second MOS transistor (20) are both electrically connected to the current mirror (30), and the current mirror (30) is provided with an input interface (Lin) used for accessing external current and an output interface used for being electrically connected to an external light-emitting unit (50).

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 more specifically, 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-luminous nature 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] Refer to Figure 1, which shows a schematic diagram of the principle of an existing Micro LED display driver circuit. The existing Micro LED driver circuit includes a PMOS transistor M1, a PMOS transistor M2, a current mirror, and an LED. The current mirror includes two PMOS transistors M3 and M4 arranged in mirror symmetry. The source electrodes (also called the S electrode) of the PMOS transistors M1 and M2 are connected to the chip operating voltage VDD, the gate electrode (also called the G electrode) of the PMOS transistor M1 is electrically connected to the enable signal EN, the G electrode of the PMOS transistor M1 is electrically connected to the display control signal SF, the drain electrode (also called the D electrode) of the PMOS transistor M1 is electrically connected to the S electrode of the PMOS transistor M3, and the D electrode of the PMOS transistor M2 is electrically connected to the S electrode of the PMOS transistor M4. The G electrode of the PMOS tube M3 is electrically connected to the G electrode of the PMOS tube M4. The G electrode of the PMOS tube M3 is electrically connected to the D electrode of the PMOS tube M3. The D electrode of the PMOS tube M3 is electrically connected to the external current Lin. The D electrode of the PMOS tube M4 is electrically connected to the anode of the LED. The cathode of the display pixel LED is grounded.

[0004] According to the principle of the existing Micro LED display driving circuit, firstly, when the PMOS tube M1 and PMOS tube M2 in Figure 1 are turned on, there will be an on-resistance R ON , on-resistance R ON The larger the on-resistance, the higher the loss. Therefore, in order to reduce the loss, it is hoped that the on-resistance R ON Secondly, when the PMOS tube M1 and PMOS tube M2 in Figure 1 are in the cut-off state, under ideal conditions, the cut-off resistance R OFFThe current tends to infinity, and the cut-off current is zero. However, due to the non-ideal characteristics of the device, even when the first MOS tube M1 and the second MOS tube M2 are both in the cut-off state, there will still be a small leakage current. Since Micro LEDs are sensitive to current, a small current will also cause weak luminescence, affecting the working performance of Micro LEDs.

[0005] Summary of the Invention

[0006] In response to the technical problems existing in the current Micro LED driving circuits mentioned 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 shortcomings of the existing technology and use an inverter to electrically connect the gate and substrate of the MOS tube so that the gate and substrate of the MOS tube have opposite potentials, thereby reducing the on-resistance of the driving circuit and increasing the off-resistance.

[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 gate of the first MOS transistor is used to receive an enable signal;

[0009] a first inverter, one end of the first inverter being electrically connected to the gate of the first MOS transistor, and the other end of the first inverter being electrically connected to the substrate of the first MOS transistor;

[0010] a second MOS transistor, wherein the source of the first MOS transistor and the source of the second MOS transistor are electrically connected to the same voltage source, and the gate of the second MOS transistor is used to receive a control signal; and

[0011] A current mirror, to which the drain of the first MOS transistor and the drain of the second MOS transistor are electrically connected, and the current mirror has an input interface for accessing an external current and an output interface for electrically connecting to an external light-emitting unit.

[0012] The current mirror comprises:

[0013] a third MOS transistor, wherein the source of the third MOS transistor is electrically connected to the drain of the first MOS transistor, the drain of the third MOS transistor serves as the input interface, and the drain of the third MOS transistor is electrically connected to the gate of the third MOS transistor; and

[0014] a fourth MOS transistor, wherein the source of the fourth MOS transistor is electrically connected to the drain of the second MOS transistor, the drain of the fourth MOS transistor serves as the output interface, and the gate of the third MOS transistor is electrically connected to the gate of the fourth MOS transistor.

[0015] The gate of the first MOS transistor is electrically connected to the substrate of the third MOS transistor, and the gate of the second MOS transistor is electrically connected to the substrate of the fourth MOS transistor.

[0016] The first MOS transistor, the second MOS transistor, the third MOS transistor and the fourth MOS transistor are PMOS transistors.

[0017] Wherein, it further includes a second inverter, one end of the second inverter is electrically connected to the gate of the second MOS tube, and the other end is electrically connected to the substrate of the second MOS tube.

[0018] The first inverter is used to reverse the phase of the signal at the gate of the first MOS transistor by 180°, and the second inverter is used to reverse the phase of the signal at the gate of the second MOS transistor by 180°.

[0019] A Micro LED driving system is also disclosed, which is characterized by comprising:

[0020] The aforementioned Micro LED driving circuit; and

[0021] A light-emitting unit is electrically connected to an output interface of the Micro LED driving circuit.

[0022] Wherein, the light emitting unit is an LED, the output interface is electrically connected to the anode of the LED, and the cathode of the LED is grounded.

[0023] A Micro LED display panel is also disclosed, characterized in that it includes an array consisting of two of the above-mentioned Micro LED driving systems.

[0024] A Micro LED pixel driving method is also disclosed, which is characterized by comprising the following steps:

[0025] Inputting a driving signal to a gate of a MOS transistor of a driving circuit; and

[0026] Based on the driving signal, an anti-phase driving signal having a phase difference of 180° with the driving signal is inputted into the substrate of the MOS transistor.

[0027] Wherein, in the step of inputting the driving signal to the gate of the MOS transistor of the driving circuit, the method further comprises:

[0028] Inputting a first driving signal to the gate of a first MOS transistor of the driving circuit, and inputting a second driving signal to the gate of a second MOS transistor of the driving circuit;

[0029] Furthermore, in the step of inputting an anti-phase driving signal having a phase difference of 180° with the driving signal to the substrate of the MOS transistor based on the driving signal, the method further includes the following steps:

[0030] Based on the first driving signal, inputting a first inverse driving signal having a phase difference of 180° with the first driving signal into the substrate of the first MOS transistor; and

[0031] Based on the second driving signal, a second inverse driving signal having a phase difference of 180° with the second driving signal is inputted into the substrate of the second MOS transistor.

[0032] The following steps are further included:

[0033] An inverter is provided between the gate and substrate of the MOS transistor to change the signal phase of the gate of the MOS transistor so that the substrate of the MOS transistor has an opposite phase.

[0034] The following steps are further included:

[0035] Changing the signal phase of the gate of the first MOS transistor by a first inverter disposed between the gate and the substrate of the first MOS transistor; and

[0036] A second inverter is provided between the gate of the second MOS transistor and the substrate to change the signal phase of the gate of the second MOS transistor.

[0037] Therefore, the present invention can achieve the following beneficial effects: 1. The gate and substrate of the MOS tube are electrically connected using an inverter so that the gate and substrate of the MOS tube have opposite potentials, thereby reducing the on-resistance of the drive circuit and increasing the off-resistance; 2. The gate of the first MOS tube is electrically connected to the substrate of the third MOS tube of the current mirror, and the gate of the second MOS tube is electrically connected to the substrate of the fourth MOS tube of the current mirror, which can reduce the magnitude of the turn-on voltage, thereby facilitating reduction of the mismatch of the current mirror. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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.

[0039] FIG1 is a Micro LED driving circuit in the prior art.

[0040] FIG2 is a schematic diagram of the circuit principle of the Micro LED driving system of the present invention.

[0041] FIG. 3 is a schematic diagram showing a circuit principle of a modified embodiment of the Micro LED driving system of the present invention.

[0042] FIG4 is a flow chart of a Micro LED driving method according to the present invention. DETAILED DESCRIPTION

[0043] 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.

[0044] Referring to FIG2 , the present invention discloses a Micro LED driving system, comprising a first MOS transistor 10, a second MOS transistor 20, a current mirror 30, a first inverter 40, and a light-emitting unit 50. The gate of the first MOS transistor 10 is used to receive an enable signal EN. One end of the first inverter 40 is electrically connected to the gate of the first MOS transistor 10, and the other end is electrically connected to the substrate of the first MOS transistor 10. The first inverter 40 is used to invert the phase of the signal at the gate of the first MOS transistor 10 by 180 degrees. The source of the first MOS transistor 10 and the source of the second MOS transistor 20 are electrically connected to the same voltage source VDD, and the gate of the second MOS transistor 20 is used to receive a control signal SF. The drain of the first MOS transistor 10 and the drain of the second MOS transistor 20 are both electrically connected to the current mirror 30. The current mirror 30 has an input interface for receiving an external current Lin and an output interface for electrically connecting to an external light-emitting unit 50. The light-emitting unit 50 is electrically connected to the output interface of the current mirror 30. In some embodiments, the first MOS transistor 10 and the second MOS transistor 20 are both SOI devices (Silicon-On-Insulator).

[0045] The first MOS transistor 10 acts as the master control switch. When the first MOS transistor 10 is turned off, the light-emitting unit 50 cannot be illuminated regardless of the switch state of the second MOS transistor 20. The second MOS transistor 20 acts as a direct control switch for the light-emitting unit 50. When the first MOS transistor 10 is in the on state, the switch state of the second MOS transistor 20 controls whether the light-emitting unit 50 is illuminated. The current mirror 30 provides constant current protection for the input current of the light-emitting unit 50.

[0046] When the first MOS tube 10 and the second MOS tube 20 are both in the on state, there will be an on-resistance equivalent resistance R in the circuit. ON , and its calculation formula is:

[0047] 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, WRepresents the width of the MOS tube.

[0048] In the technical solution provided by the present invention, the gate and substrate (also called B pole) of the first MOS transistor 10 are electrically connected using a first inverter 40, so that the signal phase difference between the gate and substrate of the first MOS transistor 10 is 180 degrees.

[0049] When the driving circuit is in the on state, when the enable signal EN is at a low level, the first MOS transistor 10 is turned on. Due to the inverting effect of the first inverter 40, the substrate of the first MOS transistor 10 is at a high level. The voltage V between the source and substrate of the first MOS transistor 10 is SB Decrease, according to the turn-on voltage V TH (Can also be expressed as V T ) can be used to determine V TH With V SB V TH The calculation formula is as follows:

[0050] In V TH In the calculation formula, V TH0 Represents the initial voltage, V SB Represents the voltage between the source and the substrate, and the rest are MOS tube constants.

[0051] According to R ON The calculation formula is: when the turn-on voltage V TH (V T ) decreases, the on-resistance R ON It is reduced, which helps to reduce the loss when the circuit is in the on state.

[0052] When the driving circuit is in the cut-off state, when the enable signal is high, the first MOS transistor 10 is cut off. Due to the action of the first inverter 40, the substrate of the first MOS transistor 10 is low, and the voltage V between the source and the substrate is SB Increase, according to the turn-on voltage V TH (Can also be expressed as V T ) can be used to determine V TH With V SB According to the cut-off equivalent resistance R OFF The calculation formula can determine R OFF With the turn-on voltage V TH The equivalent resistance R OFF The calculation formula is as follows:

[0053] When the driving circuit is in the cut-off state, the equivalent resistance R OFFIncreasing it can reduce the leakage current, reduce the black level when the light emitting unit 50 is in the off state, and improve the display performance.

[0054] 2 , further, the current mirror 30 includes a third MOS transistor 31 and a fourth MOS transistor 32. The source of the third MOS transistor 31 is electrically connected to the drain of the first MOS transistor 10, the drain of the third MOS transistor 31 serves as an input interface, and the drain of the third MOS transistor 31 is electrically connected to the gate of the third MOS transistor 31. The source of the fourth MOS transistor 32 is electrically connected to the drain of the second MOS transistor 20, the drain of the fourth MOS transistor 32 serves as an output interface, and the gate of the third MOS transistor 31 is electrically connected to the gate of the fourth MOS transistor 32.

[0055] 3 , in some embodiments, the gate of the first MOS transistor 10 is electrically connected to the substrate of the third MOS transistor 31 , and the gate of the second MOS transistor 20 is electrically connected to the substrate of the fourth MOS transistor 32 .

[0056] When the enable signal or the control signal is at a low level, according to the MOS conduction characteristics, the first MOS transistor 10 and the second MOS transistor 20 are turned on, and the current mirror 30 composed of the third MOS transistor 31 and the fourth MOS transistor 32 also starts to work. Since the gate of the first MOS transistor 10 is electrically connected to the substrate of the third MOS transistor 31, and the gate of the second MOS transistor 20 is electrically connected to the substrate of the fourth MOS transistor 32, the substrates of the third MOS transistor 31 and the fourth MOS transistor 32 are at a low level, and the turn-on voltage of the third MOS transistor 31 and the fourth MOS transistor 32 is reduced. According to the mismatch calculation formula of the current mirror 30, it can be determined that the turn-on voltage V TH When it is reduced, it is beneficial to reduce the mismatch of the current mirror. The mismatch calculation formula of the current mirror 30 is as follows:

[0057] When the enable signal or control signal is at a high level, according to the conduction characteristics of the MOS, 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 gate of the first MOS transistor 10 is electrically connected to the substrate of the third MOS transistor 31, and the gate of the second MOS transistor 20 is electrically connected to the 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, thereby reducing leakage.

[0058] In some embodiments, the first MOS transistor 10, the second MOS transistor 20, the third MOS transistor 31, and the fourth MOS transistor 32 are all PMOS transistors. In some embodiments, the first MOS transistor 10, the second MOS transistor 20, the third MOS transistor 31, and the fourth MOS transistor 32 are all NMOS transistors.

[0059] Referring to Figure 2 , the Micro LED driving system further includes a second inverter 60 , one end of which is electrically connected to the gate of the second MOS transistor 20 , and the other end of which is electrically connected to the substrate of the second MOS transistor 20 . The second inverter 60 is capable of inverting the phase of the signal at the gate of the second MOS transistor 20 by 180 degrees. Its operating principle in the driving system is similar to that of the first inverter 40 and is not further described here.

[0060] In some embodiments, the light emitting unit 50 is an LED, the output interface of the current mirror 30 is connected to the anode of the LED, and the cathode of the LED is grounded.

[0061] In some embodiments, a Micro LED display panel is further provided, including a driving panel and a Micro LED array. The Micro LED array is arranged on the driving panel, and the driving panel includes a Micro LED driving system array corresponding to the Micro LEDs.

[0062] Referring to FIG. 4 , in some embodiments, a pixel driving method of a Micro LED is further provided, including:

[0063] S100: Inputting a driving signal to the gate of the MOS transistor of the driving circuit;

[0064] S200: Based on the driving signal, inputting an anti-phase driving signal having a phase difference of 180° with the driving signal into the substrate of the MOS transistor.

[0065] In some embodiments, in the above step S100, inputting a driving signal to the gate of the MOS transistor of the driving circuit further includes:

[0066] S101: Input a first driving signal to the gate of a first MOS transistor of a driving circuit, and input a second driving signal to the gate of a second MOS transistor of the driving circuit.

[0067] In some embodiments, the first driving signal is an enable signal, and the second driving signal is a control signal.

[0068] In some embodiments, in the above step S200, based on the driving signal, inputting an anti-phase driving signal having a phase difference of 180° with the driving signal to the substrate of the MOS transistor further includes:

[0069] S201: Based on the first driving signal, input a first inverse driving signal having a phase difference of 180° with the first driving signal to the substrate of the first MOS transistor;

[0070] S202: Based on the second driving signal, input a second inverse driving signal having a phase difference of 180° with the second driving signal to the substrate of the second MOS transistor.

[0071] In some embodiments, an inverter disposed between the gate and substrate of the MOS transistor changes the signal phase of the gate so that the substrate has an opposite phase. Specifically, a first inverter 40 disposed between the substrate and gate of the first MOS transistor creates a 180° phase difference between the substrate and gate of the first MOS transistor; and a second inverter 60 disposed between the substrate and gate of the second MOS transistor creates a 180° phase difference between the substrate and gate of the second MOS transistor.

[0072] In some implementations, a circuit can be provided to input a voltage opposite to the gate to the substrate of the first MOS transistor and to input a voltage opposite to the gate to the substrate of the second MOS transistor.

[0073] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A Micro LED driving circuit, characterized in that include: a first MOS transistor, wherein a gate of the first MOS transistor is used to receive an enable signal; a first inverter, one end of the first inverter being electrically connected to the gate of the first MOS transistor, and the other end of the first inverter being electrically connected to the substrate of the first MOS transistor; a second MOS transistor, wherein the source of the first MOS transistor and the source of the second MOS transistor are electrically connected to the same voltage source, and the gate of the second MOS transistor is used to access a control signal; as well as A current mirror, the drain of the first MOS tube and the drain of the second MOS tube are electrically connected to the current mirror, and the current mirror has an input interface for accessing an external current and an output interface for electrically connecting to an external light-emitting unit.

2. The Micro LED driving circuit according to claim 1, characterized in that: The current mirror comprises: a third MOS tube, wherein the source of the third MOS tube is electrically connected to the drain of the first MOS tube, the drain of the third MOS tube serves as the input interface, and the drain of the third MOS tube is electrically connected to the gate of the third MOS tube; and a fourth MOS tube, wherein the source of the fourth MOS tube is electrically connected to the drain of the second MOS tube, the drain of the fourth MOS tube serves as the output interface, and the gate of the third MOS tube is electrically connected to the gate of the fourth MOS tube.

3. The Micro LED driving circuit according to claim 2, characterized in that: The gate of the first MOS tube is electrically connected to the substrate of the third MOS tube, and the gate of the second MOS tube is electrically connected to the substrate of the fourth MOS tube.

4. The Micro LED driving circuit according to claim 2, characterized in that: The first MOS tube, the second MOS tube, the third MOS tube and the fourth MOS tube are PMOS tubes.

5. The Micro LED driving circuit according to any one of claims 1 to 4, characterized in that: It further includes a second inverter, one end of the second inverter is electrically connected to the gate of the second MOS tube, and the other end of the second inverter is electrically connected to the substrate of the second MOS tube.

6. The Micro LED driving circuit according to claim 5, characterized in that: The first inverter is used to invert the phase of the signal at the gate of the first MOS transistor by 180°, and the second inverter is used to invert the phase of the signal at the gate of the second MOS transistor by 180°.

7. A Micro LED driving system, characterized in that: include: The Micro LED driving circuit according to any one of claims 1 to 6; as well as A light-emitting unit is electrically connected to an output interface of the Micro LED driving circuit.

8. The Micro LED driving system according to claim 7, characterized in that: The light emitting unit is an LED, the output interface is electrically connected to the anode of the LED, and the cathode of the LED is grounded.

9. A Micro LED display panel, characterized in that: An array comprising two or more Micro LED driving systems as described in claim 7.

10. A Micro LED pixel driving method, characterized in that: The following steps are involved: Inputting a driving signal to a gate of a MOS tube of a driving circuit; as well as Based on the driving signal, an anti-phase driving signal having a phase difference of 180° with the driving signal is input to the substrate of the MOS tube.

11. The Micro LED pixel driving method according to claim 10, characterized in that: The step of inputting the driving signal to the gate of the MOS tube of the driving circuit further includes: Inputting a first driving signal to the gate of a first MOS transistor of the driving circuit, and inputting a second driving signal to the gate of a second MOS transistor of the driving circuit; Furthermore, in the step of inputting an anti-phase driving signal having a phase difference of 180° with the driving signal to the substrate of the MOS tube based on the driving signal, the following steps are further included: Based on the first driving signal, inputting a first anti-phase driving signal having a phase difference of 180° with the first driving signal to the substrate of the first MOS transistor; and Based on the second driving signal, a second inverse driving signal having a phase difference of 180° with the second driving signal is input to the substrate of the second MOS transistor.

12. The Micro LED pixel driving method according to claim 10, characterized in that: Further comprising the steps of: By means of an inverter arranged between the gate and substrate of the MOS tube, the signal phase of the gate of the MOS tube is changed so that the substrate of the MOS tube has an opposite phase.

13. The Micro LED pixel driving method according to claim 11, characterized in that: Further comprising the steps of: By means of a first inverter disposed between the gate of the first MOS tube and the substrate, a signal phase of the gate of the first MOS tube is changed; as well as The signal phase of the gate of the second MOS tube is changed by a second inverter arranged between the gate of the second MOS tube and the substrate.

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