A pixel driving circuit with adjustable current ratio and its control method

Abstract

The present invention discloses a pixel driving circuit with adjustable current ratio and its control method. The driving circuit includes: a pulse width modulation (PWM) circuit module, a pulse amplitude modulation (PAM) circuit module, and a current mirror circuit module; the PWM circuit module includes: a first transistor, a second transistor, a third transistor, and a first capacitor; the PAM circuit module includes: a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, a ninth transistor, a tenth transistor, and a third capacitor; the current mirror circuit module includes: an eleventh transistor, a twelfth transistor, and a thirteenth transistor; the present invention reduces the occupied area of the pixel driving circuit, increases the transmittance of the transparent display screen, and improves the resolution.

Description

Technical Field

[0001] The present invention relates to the technical field of displays, and particularly to a pixel driving circuit with adjustable current ratio and its control method. Background Art

[0002] With the development of display technology, according to different display devices, it can be divided into the following three display technologies, each of which has its own advantages and disadvantages. OLED (Organic Light-Emitting Diode) display technology: A self-luminous display technology, each pixel of which is made of organic materials, and no backlight is required to achieve self-luminescence. It has characteristics such as fast response time and wide viewing angle, and can be used in fields such as smartphone displays and tablet computers. Mini-LED display technology: As an improved LED backlight technology, it can achieve local dimming and has a long lifespan, etc., and can be used in the field of high-end TVs. Micro-LED display technology, each pixel emits light independently, with characteristics such as high brightness and high efficiency, and can be used in ultra-large-size displays and virtual reality head-mounted displays. Micro-LED is also regarded as the next-generation display technology.

[0003] However, the Micro-LED pixel driving circuit faces many challenges in practical applications. Most of the current Micro-LED display pixel driving circuits on the market generally follow the driving methods of OLED and Mini-LED pixel driving circuits, that is, Pulse Amplitude Modulation (PAM). Its working principle is as follows: By changing the magnitude of the data voltage to change the output current of the driving transistor, so that the diode emits light of different brightnesses. However, due to the low and unstable luminous efficiency of the Micro-LED chip under low-current driving, color deviation problems occur in the display of the display screen under low-current and low-gray-scale conditions. In addition, a pixel driving unit requires three sub-pixel driving circuits to drive micro-light-emitting diodes of three colors, namely R, G, and B, respectively, to achieve the display of different color pictures. This means that the display screen requires a large number of sub-pixel driving circuits, which makes a pixel unit occupy a large area, resulting in the inability to achieve a high resolution under the premise of a certain display screen size and reducing the display effect. Summary of the Invention

[0004] Object of the Invention: The object of the present invention is to provide a pixel driving circuit with adjustable current ratio and its control method, to achieve the effect of sharing one pixel driving circuit for three sub-pixels (R, G, B), and the three driving currents can achieve a certain proportional relationship, so as to solve the problems existing in the background art.

[0005] Technical Solution: A pixel driving circuit with adjustable current ratio according to the present invention includes: a Pulse Width Modulation (PWM) circuit module, a Pulse Amplitude Modulation (PAM) circuit module, and a current mirror circuit module; wherein,

[0006] The PWM circuit module includes: a first transistor, a second transistor, a third transistor, and a first capacitor;

[0007] Among them, the gate of the first transistor is connected to the source of the third transistor, the source is connected to the PWM_VDD voltage, and the drain is connected to the source of the second transistor;

[0008] The gate of the second transistor is connected to the first light-emitting signal PWM_EM, and the drain is connected to the PAM circuit module through a second capacitor;

[0009] The drain of the third transistor is connected to the gate of the first transistor through node A, the gate is connected to the first scan signal PWM_SCAN1, and the source is connected to the first reference voltage Vref1;

[0010] The PAM circuit module includes: a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, a ninth transistor, a tenth transistor, and a third capacitor;

[0011] Among them, the gate of the fourth transistor is connected to the drain of the sixth transistor, the third capacitor, and the second capacitor through node B, the source is connected to the drains of the eighth transistor and the ninth transistor through node C, and the drain is connected to the source of the fifth transistor;

[0012] The gate of the fifth transistor is connected to the third scan signal PAM_SCAN2, and the drain is connected to node B;

[0013] The gate of the sixth transistor is connected to the second scan signal PAM_SCAN1, and the source is connected to the first reference voltage Vref1;

[0014] The gate of the seventh transistor is connected to the second light-emitting signal PAM_EM, the source is connected to the source of the fifth transistor, and the drain is respectively connected to the anodes of the red, green, and blue micro light-emitting diodes;

[0015] The gate of the eighth transistor is connected to the third scan signal PAM_SCAN2, the source is connected to the data voltage PAM_DATA, and the drain is connected to the drain of the ninth transistor through node C;

[0016] The gate of the ninth transistor is connected to the second light-emitting signal PAM_EM, and the source is connected to the PAM_VDD voltage;

[0017] The current mirror circuit module includes: an eleventh transistor, a twelfth transistor, and a thirteenth transistor;

[0018] The sources of the eleventh, twelfth, and thirteenth transistors are respectively connected to the cathodes of the red, green, and blue micro light-emitting diodes, the drains are commonly connected to the Vss voltage, and the gates are interconnected;

[0019] The gate of the eleventh transistor is connected to the source, and the gate of the twelfth transistor is connected to the source.

[0020] Further, in the current mirror circuit, the width-to-length ratios (W / L) of the eleventh transistor, the twelfth transistor, and the thirteenth transistor are different, such that the currents flowing through the three micro light-emitting diodes satisfy the following proportional relationship:

[0021] ;

[0022] ;

[0023] Wherein, , , are the width-to-length ratios of the eleventh transistor, the twelfth transistor, and the thirteenth transistor respectively; , , represent the light-emitting currents of the three colors of red, green, and blue respectively.

[0024] Further, the PWM circuit module is connected to node B of the PAM circuit module through a second capacitor, and is used to control the conduction time of the light-emitting path through the voltage scan signal SWEEP.

[0025] Further, one end of the third capacitor of the PAM circuit module is connected to node B, and the other end is connected to the PAM_VDD voltage, and is used to store the difference between the data voltage PAM_DATA and the threshold voltage V TH .

[0026] Further, one end of the first capacitor is connected to node A, and the other end is connected to the voltage scan signal SWEEP, and is used to store the voltage difference in the initialization stage.

[0027] Further, the ninth transistor is turned on in the light-emitting stage (b) to transfer the PAM_VDD voltage to node C to maintain the stability of the light-emitting path.

[0028] A pixel driving circuit control method with adjustable current ratio according to the present invention includes a PWM initialization stage, a PAM initialization stage, and a light-emitting stage, and includes the following steps:

[0029] PWM initialization stage: The first scan signal PWM_SCAN1 is at a low potential, and the other signals are at a high potential; the third transistor is turned on, the voltage of node A is initialized to the first reference voltage Vref1, and the voltage across the first capacitor is SWEEP-Vref1;

[0030] PAM initialization stage: The second scan signal PAM_SCAN1 is at a low potential, and the other signals are at a high potential; the sixth transistor and the tenth transistor are turned on, the voltage of node B is initialized to the first reference voltage Vref1, and the voltage of node D is initialized to the second reference voltage Vref2;

[0031] PAM data writing stage: The third scan signal PAM_SCAN2 is at a low potential, and the rest of the signals are at high potentials; the fifth and eighth transistors are turned on, and the voltage of node B is , and the voltage of node C is ; where is the data voltage of the PAM circuit, is the threshold voltage of the fourth transistor;

[0032] Emission stage:

[0033] (a) The first emission signal PWM_EM is at a low potential, the voltage scan signal SWEEP linearly decreases, and the voltage of node A is ; where Vref1 is the first reference voltage, is the change amount of the voltage scan signal SWEEP;

[0034] (b) Both the first emission signal PWM_EM and the second emission signal PAM_EM are at low potentials, the PAM circuit forms an emission path, and the red, green, and blue micro-LEDs emit light according to the current ratio;

[0035] (c) When the voltage of node A is lower than the threshold voltage of the first transistor, the emission path is turned off.

[0036] Further, in the emission stage (b), the driving current of the red micro-LED is:

[0037] ;

[0038] where is the driving current of the red LED, is the carrier mobility, is the gate oxide capacitance, W and L are the width and length of the fourth transistor respectively, is the data voltage of the PAM circuit, is the power supply voltage of the PAM circuit, is the threshold voltage of the fourth transistor; is the gate-source voltage difference of the fourth transistor T4.

[0039] Further, in the emission stage (c), the voltage of node B rises from to, the fourth transistor gradually turns off, and the emission path terminates.

[0040] Further, the anodes of the red, green, and blue micro-LEDs are connected to the PAM circuit module through the seventh transistor, and the cathodes are connected to the Vss voltage through the current mirror circuit module.

[0041] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: The present invention uses the voltage of the PWM module circuit to control the on and off time of the light-emitting path of the PAM module, realizes voltage-controlled PWM dimming, can improve the light-emitting efficiency of micro light-emitting diodes, and reduce the power consumption of the display screen; and realizes the effect that three sub-pixels (R, G, B) share one pixel driving circuit, and the three driving currents can achieve a certain proportional relationship, reducing the occupied area of the pixel driving circuit, increasing the transmittance of the transparent display screen, and improving the resolution. Description of the Drawings

[0042] Figure 1 It is a schematic diagram of the circuit module of the present invention;

[0043] Figure 2 It is a schematic diagram of the circuit of the present invention;

[0044] Figure 3 It is a circuit timing diagram of the present invention;

[0045] Figure 4 It is a schematic diagram of the circuit in the PAM initialization stage in the method of the present invention;

[0046] Figure 5 It is a schematic diagram of the circuit in the PWM initialization stage in the method of the present invention;

[0047] Figure 6 It is a schematic diagram of the circuit in the PAM data writing stage in the method of the present invention;

[0048] Figure 7 It is a schematic diagram of the circuit in the light-emitting stage (a) in the method of the present invention;

[0049] Figure 8 It is a schematic diagram of the circuit in the light-emitting stage (b) in the method of the present invention;

[0050] Figure 9 It is a schematic diagram of the circuit in the light-emitting stage (c) in the method of the present invention. Detailed Embodiments

[0051] The technical solution of the present invention will be further described below with reference to the drawings.

[0052] As Figure 1 shown, an embodiment of the present invention provides a pixel driving circuit with adjustable Micro-LED current ratio, which includes three circuit modules, including: a PWM circuit module, a PAM circuit module, and a current mirror circuit module.

[0053] The specific circuit structure is as Figure 2As shown, it includes: the first transistor T1, the second transistor T2, the third transistor T3, the fourth transistor T4, the fifth transistor T5, the sixth transistor T6, the seventh transistor T7, the eighth transistor T8, the ninth transistor T9, the tenth transistor T10, the eleventh transistor T11, the twelfth transistor T12, the thirteenth transistor T13, the first capacitor C1, the second capacitor C2, and the third capacitor C3.

[0054] The specific connection method is as follows. The connection method of the PWM circuit includes: the gate of the first transistor T1 is connected to the source of the third transistor T3, the source of the first transistor T1 is connected to the PWM_VDD voltage, and the drain of the first transistor T1 is connected to the source of the second transistor T2. The gate of the second transistor T2 is connected to the first light-emitting signal PWM_EM, and the drain of the second transistor T2 is connected to one end of the second capacitor C2. The drain of the third transistor T3 is connected to the gate of the first transistor T1 through node A, the gate of the third transistor T3 is connected to the first scan signal PWM_SCAN1, and the source of the third transistor T3 is connected to the first reference voltage Vref1. The PWM module is connected to the PAM module through the second capacitor C2.

[0055] The connection method of the PAM circuit includes: the gate of the fourth transistor T4 is connected to the drain of the sixth transistor T6, the third capacitor C3, and one end of the second capacitor C2 through node B, the source of the fourth transistor T4 is connected to the drains of the eighth transistor T8 and the ninth transistor T9 through node C, and the drain of the fourth transistor T4 is connected to the source of the fifth transistor T5. The gate of the fifth transistor T5 is connected to the third scan signal PAM_SCAN2, and the drain of the fifth transistor T5 is connected to node B. The gate of the sixth transistor T6 is connected to the second scan signal PAM_SCAN1, and the source of the sixth transistor T6 is connected to the first reference voltage Vref1. The gate of the seventh transistor T7 is connected to the second light-emitting signal PAM_EM, the source of the seventh transistor T7 is connected to the source of the fifth transistor T5, and the drain of the seventh transistor T7 is respectively connected to three light-emitting units RLED, GLED, and BLED. The gate of the eighth transistor T8 is connected to the third scan signal PAM_SCAN2, the source of the eighth transistor T8 is connected to the data voltage PAM_DATA, and the drain of the eighth transistor T8 is connected to the drain of the ninth transistor T9 through node C. The gate of the ninth transistor T9 is connected to the second light-emitting signal PAM_EM, and the source of the ninth transistor T9 is connected to the PAM_VDD voltage. The PAM module is connected to the current mirror circuit module through three light-emitting units.

[0056] The connection mode of the current mirror circuit includes: the sources of the eleventh transistor T11, the twelfth transistor T12, and the thirteenth transistor T13 are respectively connected to the cathodes of RLED, GLED, and BLED, the drains of the eleventh transistor T11, the twelfth transistor T12, and the thirteenth transistor T13 are commonly connected to the Vss voltage, the gates of the eleventh transistor T11, the twelfth transistor T12, and the thirteenth transistor T13 are connected together, the gate and the source of the eleventh transistor T11 are connected, and the gate and the source of the twelfth transistor T12 are connected.

[0057] As Figure 3 shown, the first scan signal PWM_SCAN1, the second scan signal PAM_SCAN1, the third scan signal PAM_SCAN2, the first light-emitting signal PWM_EM, the second light-emitting signal PAM_EM, and the voltage scan signal SWEEP respectively provide high and low potentials. The working stage of the pixel driving circuit with adjustable Micro-LED current ratio is divided into four stages, including in sequence: the PWM initialization stage, the PAM initialization stage, the PAM data writing stage, and the light-emitting stage, where the light-emitting stage includes three stages (a), (b), and (c).

[0058] The embodiment of the present invention further provides a driving method for a Micro-LED pixel driving circuit, including the following steps:

[0059] As Figure 3 and Figure 4 shown, in the PWM initialization stage: the first scan signal PWM_SCAN1 provides a low potential, and the second scan signal PAM_SCAN1, the third scan signal PAM_SCAN2, the first light-emitting signal PWM_EM, the second light-emitting signal PAM_EM, and the voltage scan signal SWEEP provide high potentials. The third transistor T3 is turned on, and the first transistor T1, the second transistor T2, the fourth transistor T4, the fifth transistor T5, the sixth transistor T6, the seventh transistor T7, the eighth transistor T8, the ninth transistor T9, and the tenth transistor T10 are all turned off. At this time, the gate voltage value of the PWM module driving transistor T1 at node A is initialized to the reference voltage, and at this time, the voltage difference across the first capacitor C1 is;

[0060] Combined with Figure 3 and Figure 5As shown, in the PAM initialization stage: the second scan signal PAM_SCAN1 provides a low potential, and the first scan signal PWM_SCAN1, the third scan signal PAM_SCAN2, the first emission signal PWM_EM, the second emission signal PAM_EM, and the voltage scan signal SWEEP provide high potentials. The sixth transistor T6 and the tenth transistor T10 are turned on, and the first transistor T1, the second transistor T2, the third transistor T3, the fourth transistor T4, the fifth transistor T5, the seventh transistor T7, the eighth transistor T8, and the ninth transistor T9 are all turned off. At this time, the gate voltage value of the PAM module driving transistor T4 at node B is initialized to the first reference voltage ; the anode voltage value of the micro-LED at node D is initialized to the second reference voltage At this time, the voltage difference across the first capacitor C3 is ; at this time, the voltage differences across the three micro-LEDs are the turn-on voltages and they do not emit light.

[0061] Combined with Figure 3 and Figure 6 As shown, in the PAM data writing stage: the third scan signal PAM_SCAN2 provides a low potential, and the first scan signal PWM_SCAN1, the second scan signal PAM_SCAN1, the first emission signal PWM_EM, the second emission signal PAM_EM, and the voltage scan signal SWEEP provide high potentials. The fifth transistor T5 and the eighth transistor T8 are turned on, and the first transistor T1, the second transistor T2, the third transistor T3, the fourth transistor T4, the sixth transistor T6, the seventh transistor T7, the ninth transistor T9, and the tenth transistor T10 are all turned off. At this time, the gate voltage value of the PAM module driving transistor T4 at node B is , the voltage value at node C is , the voltage difference across the first capacitor C3 is , the micro-LED maintains the previous state and does not emit light; is the power supply voltage of the PAM circuit; the threshold voltage of the fourth transistor T4, is the power supply voltage of the PAM circuit.

[0062] Combined with Figures 7 - 9 As shown, in the light emission stage: the light emission stage is divided into three stages, which are specifically as follows:

[0063] As Figure 7As shown, (a) stage: The first light-emitting signal PWM_EM provides a low potential, the first scan signal PWM_SCAN1, the second scan signal PAM_SCAN1, the third scan signal PAM_SCAN2, and the second light-emitting signal PAM_EM provide a high potential, and the voltage scan signal SWEEP linearly decreases starting from a high potential. The second transistor T2 is turned on, and the first transistor T1, the third transistor T3, the fourth transistor T4, the fifth transistor T5, the sixth transistor T6, the seventh transistor T7, the eighth transistor T8, the ninth transistor T9, and the tenth transistor T10 are all turned off. At this time, the voltage value at node A is , and the potentials at nodes B, C, and D maintain the previous state, and the micro light-emitting diode does not emit light. Among them, is the change amount of the voltage scan signal SWEEP.

[0064] As Figure 8 shown, (b) stage: The first light-emitting signal PWM_EM and the second light-emitting signal PAM_EM provide a low potential, the first scan signal PWM_SCAN1, the second scan signal PAM_SCAN1, and the third scan signal PAM_SCAN2 provide a high potential, and the voltage scan signal SWEEP maintains the previous state. The second transistor T2, the fourth transistor T4, the seventh transistor T7, and the ninth transistor T9 are all turned on, and the first transistor T1, the transistor T3, the fifth transistor T5, the sixth transistor T6, the eighth transistor T8, and the tenth transistor T10 are all turned off. At this time, the light-emitting path of the PAM circuit part is formed, and there is a driving current passing through the micro light-emitting diode RLED. At this time, the driving current formula is:

[0065] ;

[0066] Among them, is the driving current of the red light diode, is the carrier mobility, is the gate oxide capacitance, W and L are the width and length of the fourth transistor T4 respectively, is the data voltage of the PAM circuit, is the power supply voltage of the PAM circuit, is the threshold voltage of the fourth transistor T4; is the gate-source voltage difference of the fourth transistor T4.

[0067] Due to the existence of the current mirror circuit, according to the different width-to-length ratios of the eleventh transistor T11, the twelfth transistor T12, and the thirteenth transistor T13, the currents flowing through the three micro light-emitting diodes can show a proportional relationship, specifically as follows:

[0068] ;

[0069] ;

[0070] Among them, , , are the aspect ratios of the eleventh transistor, the twelfth transistor, and the thirteenth transistor, respectively; , respectively represent the emission currents of red, green, and blue colors; , , respectively represent the emission currents of red, green, and blue colors.

[0071] Through this circuit structure, the effect of sharing one pixel driving circuit by three sub-pixels (R, G, B) can be achieved, and a certain proportional relationship can be achieved among the three driving currents, reducing the area occupied by the pixel driving circuit, increasing the transmittance of the transparent display screen, and improving the resolution.

[0072] As Figure 9 shown, in stage (c): when the voltage of node A is lower than the threshold voltage of the first transistor, the first transistor T1 slowly turns on from off. At this time, the voltage passes through the conduction of the first transistor T1 and the second transistor T2 to one end of the second capacitor, causing the voltage value at node B to increase. The fourth transistor T4 slowly turns off from on, and the light-emitting path disappears, and the micro light-emitting diode stops emitting light. Through the above circuit structure, the time for turning on and off the light-emitting path of the PAM module is controlled by the voltage of the PWM module circuit, realizing voltage-controlled PWM dimming, which can improve the light-emitting efficiency of the micro light-emitting diode and reduce the power consumption of the display screen.

Claims

1. A pixel driving circuit with adjustable current ratio, characterized in that Including: Pulse Width Modulation (PWM) circuit module, Pulse Amplitude Modulation (PAM) circuit module, and current mirror circuit module; among them, the PWM circuit module includes: a first transistor (T1), a second transistor (T2), a third transistor (T3), and a first capacitor (C1); among them, the gate of the first transistor (T1) is connected to the source of the third transistor (T3), the source is connected to the PWM_VDD voltage, and the drain is connected to the source of the second transistor (T2); the gate of the second transistor (T2) is connected to the first light-emitting signal PWM_EM, and the drain is connected to the PAM circuit module through a second capacitor (C2); the drain of the third transistor (T3) is connected to the gate of the first transistor (T1) through node A, the gate is connected to the first scan signal PWM_SCAN1, and the source is connected to the first reference voltage (Vref1); the PAM circuit module includes: a fourth transistor (T4), a fifth transistor (T5), a sixth transistor (T6), a seventh transistor (T7), an eighth transistor (T8), a ninth transistor (T9), a tenth transistor (T10), and a third capacitor (C3); among them, the gate of the fourth transistor (T4) is connected to the drain of the sixth transistor (T6), the third capacitor (C3), and the second capacitor (C2) through node B, the source is connected to the drains of the eighth transistor (T8) and the ninth transistor (T9) through node C, and the drain is connected to the source of the fifth transistor (T5); the gate of the fifth transistor (T5) is connected to the third scan signal PAM_SCAN2, and the drain is connected to node B; the gate of the sixth transistor (T6) is connected to the second scan signal PAM_SCAN1, and the source is connected to the first reference voltage (Vref1); the gate of the seventh transistor (T7) is connected to the second light-emitting signal PAM_EM, the source is connected to the source of the fifth transistor (T5), and the drain is respectively connected to the anodes of red, green, and blue micro light-emitting diodes; the gate of the eighth transistor (T8) is connected to the third scan signal PAM_SCAN2, the source is connected to the data voltage PAM_DATA, and the drain is connected to the drain of the ninth transistor (T9) through node C; the gate of the ninth transistor (T9) is connected to the second light-emitting signal PAM_EM, and the source is connected to the PAM_VDD voltage; the current mirror circuit module includes: an eleventh transistor (T11), a twelfth transistor (T12), a thirteenth transistor (T13); the sources of the eleventh transistor (T11), the twelfth transistor (T12), and the thirteenth transistor (T13) are respectively connected to the cathodes of red, green, and blue micro light-emitting diodes, the drains are commonly connected to the Vss voltage, and the gates are interconnected; the gate of the eleventh transistor (T11) is connected to its source, and the gate of the twelfth transistor (T12) is connected to its source; the PWM circuit module is connected to node B of the PAM circuit module through the second capacitor (C2) and is used to control the conduction time of the light-emitting path through the voltage sweep signal (SWEEP).One end of the third capacitor (C3) of the PAM circuit module is connected to node B, and the other end is connected to the PAM_VDD voltage, which is used to store the difference between the data voltage PAM_DATA and the threshold voltage (V; TH ) 2. The pixel driving circuit with adjustable current ratio according to claim 1, wherein In the current mirror circuit: the width-to-length ratios of the eleventh transistor (T11), the twelfth transistor (T12), and the thirteenth transistor (T13) are different, such that the currents flowing through the three micro light-emitting diodes satisfy the following proportional relationship: ； ； Among them, , , are the width-to-length ratios of the eleventh transistor (T11), the twelfth transistor (T12), and the thirteenth transistor (T13), respectively; , , represent the light-emitting currents of red, green, and blue colors, respectively.

3. The pixel driving circuit with adjustable current ratio according to claim 1, wherein One end of the first capacitor (C1) is connected to node A, and the other end is connected to the voltage scan signal SWEEP, for storing the voltage difference in the initialization stage.

4. The pixel driving circuit according to claim 1, wherein The ninth transistor (T9) conducts in the light-emitting stage (b), transferring the PAM_VDD voltage to node C to maintain the stability of the light-emitting path.

5. The pixel driving circuit with adjustable current ratio according to claim 1, wherein The anodes of the red, green, and blue micro light-emitting diodes are connected to the PAM circuit module through the seventh transistor (T7), and the cathodes are connected to the Vss voltage through the current mirror circuit module.

6. A method for controlling a pixel driving circuit with adjustable current ratio according to claim 1, characterized in that, Including a PWM initialization stage, a PAM initialization stage, and a light-emitting stage, including the following steps: PWM initialization stage: The first scan signal PWM_SCAN1 is at a low potential, and the other signals are at high potentials; the third transistor (T3) conducts, the voltage of node A is initialized to the first reference voltage Vref1, and the voltage across the first capacitor (C1) is SWEEP - Vref1. PAM initialization stage: The second scan signal PAM_SCAN1 is at a low potential, and the other signals are at high potentials; the sixth transistor (T6) and the tenth transistor (T10) conduct, the voltage of node B is initialized to the first reference voltage Vref1, and the voltage of node D is initialized to the second reference voltage Vref2. PAM data writing stage: The third scan signal PAM_SCAN2 is at a low potential, and the rest of the signals are at a high potential; The fifth transistor (T5) and the eighth transistor (T8) are turned on, and the voltage of node B is , and the voltage of node C is ; Among them, is the data voltage of the PAM circuit, the threshold voltage of the fourth transistor (T4); Light-emitting stage: (a) The first light-emitting signal PWM_EM is at a low potential, the voltage sweep signal SWEEP linearly decreases, and the voltage at node A is ; where Vref1 is the first reference voltage, is the change amount of the voltage sweep signal SWEEP; (b) The first light-emitting signal PWM_EM and the second light-emitting signal PAM_EM are both at low potentials, the PAM circuit forms a light-emitting path, and the red, green, and blue micro light-emitting diodes emit light according to the current ratio. (c) When the voltage of node A is lower than the threshold voltage of the first transistor (T1), the light-emitting path is turned off.

7. A method for controlling a pixel driving circuit with adjustable current ratio according to claim 5, characterized in that, In the light-emitting stage (b), the driving current of the red micro light-emitting diode is: ； Among them, is the drive current of the red light-emitting diode, is the carrier mobility, is the gate oxide capacitance, and W and L are the width and length of the fourth transistor (T4) respectively, is the data voltage of the PAM circuit, is the power supply voltage of the PAM circuit, is the threshold voltage of the fourth transistor (T4); is the gate-source voltage difference of the fourth transistor T4.

8. A method for controlling a pixel driving circuit with adjustable current ratio according to claim 5, characterized in that, In the light-emitting stage (c), the voltage of node B rises from... to..., the fourth transistor (T4) gradually turns off, and the light-emitting path terminates.

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