TWI742967B - Pixel driving circuit - Google Patents

Abstract

A pixel driving circuit includes a light emitting unit, thirteen switches and two capacitors. A driving circuit of the light emitting unit passes only one of the switches to reduce power consumption. In addition, threshold voltages and operation voltages are compensated in the pixel driving circuit so that the light emitting unit can provide consistent brightness.

Description

Pixel drive circuit

This disclosure relates to a pixel driving circuit for light-emitting diodes.

At present, light-emitting diodes have been widely used in various types of displays. The brightness of the light-emitting diode when it emits light is related to the size of its driving current, and the size of its driving current is controlled by the driving transistor. However, because of the variation of the manufacturing process, the threshold voltage (Vth) of the driving transistor of each pixel in the display will be different, which will cause the light-emitting diodes in different pixels to have different values. The driving current makes the brightness of each light-emitting diode different, which in turn causes the problem of uneven brightness when the display displays a picture. In addition, the driving current is provided by the operating voltage, and the operating voltage is prone to a voltage drop due to the line resistance in the transmission path, which makes the operating voltage of each pixel different, which causes errors in the drive current.

Therefore, how to compensate for the threshold voltage of the driving transistor of the display pixel and also compensate for the operating voltage is the goal of the research by those skilled in the art.

The embodiment of the disclosure provides a pixel driving circuit, which includes the following components. The light emitting unit has a first end and a second end, and the first end of the light emitting unit is connected to the first operating voltage. The first switch has a control terminal, a first terminal and a second terminal. The first terminal of the first switch is connected to the second terminal of the light-emitting unit, and the second terminal of the first switch is connected to the second operating voltage. The second switch has a control terminal, a first terminal and a second terminal. The first terminal of the second switch is connected to the second operating voltage, the second terminal of the second switch is connected to the control terminal of the first switch, and the control of the second switch is The terminal is connected to the first control signal. The third switch has a control terminal, a first terminal and a second terminal. The first terminal of the third switch is connected to the second operating voltage, and the control terminal of the third switch is connected to the first control signal. The fourth switch has a control terminal, a first terminal, and a second terminal. The first terminal of the fourth switch is connected to the control terminal of the first switch and the second terminal of the second switch, and the control terminal of the fourth switch is connected to the third switch The second end. The fifth switch has a control terminal, a first terminal and a second terminal. The first terminal of the fifth switch is connected to the first voltage, and the second terminal of the fifth switch is connected to the second terminal of the third switch and the control of the fourth switch end. The sixth switch has a control terminal, a first terminal, and a second terminal. The first terminal of the sixth switch is connected to the control terminal of the fifth switch, and the second terminal of the sixth switch is connected to the second control signal. The control of the sixth switch The terminal is connected to the third control signal. The seventh switch has a control terminal, a first terminal, and a second terminal. The second terminal of the seventh switch is connected to the control terminal of the fifth switch and the first terminal of the sixth switch. The control terminal of the seventh switch is connected to the fourth control. Signal. The eighth switch has a control terminal, a first terminal, and a second terminal. The first terminal of the eighth switch is connected to a data voltage, and the second terminal of the eighth switch is connected to the control terminal of the eighth switch and the first terminal of the seventh switch. end. The first capacitor has a first terminal and a second terminal. The first terminal of the first capacitor is connected to the control terminal of the fifth switch, the first terminal of the sixth switch, and the second terminal of the seventh switch. The second terminal of the first capacitor The terminal is connected to the third control signal. The ninth switch has a control terminal, a first terminal, and a second terminal. The first terminal of the ninth switch is connected to the second terminal of the first switch and the second operating voltage, and the control terminal of the ninth switch is connected to the first control signal. The tenth switch has a control terminal, a first terminal, and a second terminal. The first terminal of the tenth switch is connected to the second terminal of the ninth switch, and the second terminal of the tenth switch is connected to a diode voltage. The control terminal of is connected to the first control signal. The second capacitor has a first terminal and a second terminal. The first terminal of the second capacitor is connected to the second terminal of the fourth switch, and the second terminal of the second capacitor is connected to the second terminal of the ninth switch and the second terminal of the tenth switch. The first end. The eleventh switch has a control terminal, a first terminal and a second terminal. The first terminal of the eleventh switch is connected to the second terminal of the fourth switch and the first terminal of the second capacitor. The second terminal of the eleventh switch Connected to the first operating voltage, the control terminal of the eleventh switch is connected to the third control signal. The twelfth switch has a control end, a first end, and a second end. The first end of the twelfth switch is connected to the second end of the fourth switch, the first end of the second capacitor, and the first end of the eleventh switch. The control terminal of the twelfth switch is connected to the fourth control signal. The thirteenth switch has a control end, a first end and a second end. The first end of the thirteenth switch is connected to the second end of the twelfth switch and the control end of the thirteenth switch. The second end of the thirteenth switch is The terminal is connected to a reference voltage.

In some embodiments, the pixel driving circuit sequentially operates in the first period, the second period, the third period, and the fourth period. During the first period, the first switch, the fourth switch, the fifth switch, the seventh switch, the ninth switch, and the twelfth switch are in the off state, and the second switch, the third switch, the sixth switch, the tenth switch, and the The eleventh switch is in the on state. In the second period, the first switch, the fourth switch, the fifth switch, the sixth switch, the ninth switch, and the eleventh switch are in the off state, and the second switch, the third switch, the seventh switch, the eighth switch, The tenth switch, the twelfth switch and the thirteenth switch are in a conducting state. In the first sub-period of the third period, the first switch to the seventh switch, the tenth switch, the eleventh switch, and the twelfth switch are in the off state, and the ninth switch is in the on state. In the second sub-period of the third period, the second switch, the third switch, the sixth switch, the seventh switch, and the tenth to twelfth switches are in the off state, and the first switch, the fourth switch, and the fifth switch And the ninth switch is in the conducting state. In the fourth period, the first switch, the fourth switch to the seventh switch, the ninth switch, the eleventh switch and the twelfth switch are in the off state, and the second switch, the third switch and the tenth switch are in the on state.

In some embodiments, the first to fourth switches, the sixth switch, the seventh switch, the tenth switch, the eleventh switch, the twelfth switch, and the thirteenth switch are N-type transistors, and the fifth switch, The eighth switch and the ninth switch are P-type transistors.

In some embodiments, the threshold voltage of the first switch matches the threshold voltage of the thirteenth switch, and the threshold voltage of the fifth switch matches the threshold voltage of the eighth switch.

In some embodiments, during the first period, the first control signal and the third control signal are at the first high level, the second control signal is at the second high level, and the fourth control signal is at the first low level. In the second period, the first control signal and the fourth control signal are at the first high level, the second control signal is at the second high level, and the third control signal is at the first low level. During the third period, the first control signal, the third control signal, and the fourth control signal are at the first low level, and the second control signal is gradually reduced from the second high level to the second low level. In the fourth period, the first control signal is the first high level, the second control signal is the second high level, and the third control signal and the fourth control signal are the first low level.

In some embodiments, the first operating voltage is greater than the second operating voltage, and the first operating voltage is greater than or equal to the first voltage.

In some embodiments, the above-mentioned light-emitting unit is a light-emitting diode.

In some embodiments, the size of the above-mentioned light-emitting diode is sub-millimeter.

In some embodiments, the above-mentioned pixel driving circuit is disposed in the display panel.

In some embodiments, the above-mentioned pixel driving circuit is disposed in the backlight module.

In the above-mentioned pixel driving circuit, the threshold voltage and the operating voltage can be compensated, and it has the effect of saving power consumption.

Regarding the “first”, “second”, etc. used in this text, it does not particularly mean the order or sequence, but only to distinguish elements or operations described in the same technical terms.

FIG. 1 is a circuit structure diagram of a pixel driving circuit according to an embodiment. The pixel driving circuit 100 can be arranged on a backlight module of a display device to provide a backlight, or arranged as a pixel in a display panel, and the present disclosure is not limited thereto. The pixel driving circuit 100 includes a light emitting unit 110, switches T1 to T13, a first capacitor C1 and a second capacitor C2. The light-emitting unit 110 is, for example, a light-emitting diode, and the size of the light-emitting diode may be sub-millimeter level or other suitable sizes, and the present disclosure is not limited thereto.

The light-emitting unit 110 has a first terminal 110-1 and a second terminal 110-2, and the first terminal 110-1 of the light-emitting unit 110 is connected to the operating voltage VDD. The switch T1 has a control terminal T1-3, a first terminal T1-1, and a second terminal T1-2. The first terminal T1-1 of the switch T1 is connected to the second terminal 110-2 of the light-emitting unit 110, and the second terminal 110-2 of the switch T1 The terminal T1-2 is connected to the operating voltage VSS. In this embodiment, the operating voltage VSS is lower than the operating voltage VDD. The switch T2 has a control terminal T2-3, a first terminal T2-1, and a second terminal T2-2. The first terminal T2-1 of the switch T2 is connected to the operating voltage VSS, and the second terminal T2-2 of the switch T2 is connected to the switch The control terminal T1-3 of T1 and the control terminal T2-3 of the switch T2 are connected to the control signal EM. The switch T3 has a control terminal T3-3, a first terminal T3-1, and a second terminal T3-2. The first terminal T3-1 of the switch T3 is connected to the operating voltage VSS, and the control terminal T3-3 of the switch T3 is connected to the control signal EM. The switch T4 has a control terminal T4-3, a first terminal T4-1, and a second terminal T4-2. The first terminal T4-1 of the switch T4 is connected to the control terminal T1-3 of the switch T1 and the second terminal T2 of the switch T2. -2, the control terminal T4-3 of the switch T4 is connected to the second terminal T3-2 of the switch T3. The switch T5 has a control terminal T5-3, a first terminal T5-1 and a second terminal T5-2. The first terminal T5-1 of the switch T5 is connected to the voltage VH, and the second terminal T5-2 of the switch T5 is connected to the switch T3 The second terminal T3-2 of the switch T4 and the control terminal T4-3 of the switch T4. The switch T6 has a control terminal T6-3, a first terminal T6-1, and a second terminal T6-2. The first terminal T6-1 of the switch T6 is connected to the control terminal T5-3 of the switch T5, and the second terminal T6 of the switch T6 -2 is connected to the control signal V _sweep , and the control terminal T6-3 of the switch T6 is connected to the control signal S1. The switch T7 has a control terminal T7-3, a first terminal T7-1 and a second terminal T7-2. The second terminal T7-2 of the switch T7 is connected to the control terminal T5-3 of the switch T5 and the first terminal T6 of the switch T6. -1, the control terminal T7-3 of the switch T7 is connected to the control signal S2. The switch T8 has a control terminal T8-3, a first terminal T8-1, and a second terminal T8-2. The first terminal T8-1 of the switch T8 is connected to the data voltage V _DATA , and the second terminal T8-2 of the switch T8 is connected to The control terminal T8-3 of the switch T8 and the first terminal T7-1 of the switch T7. The first capacitor C1 has a first terminal C1-1 and a second terminal C1-2. The first terminal C1-1 of the first capacitor C1 is connected to the control terminal T5-3 of the switch T5 and the first terminal T6-1 of the switch T6. The second terminal T7-2 of the switch T7 and the second terminal C1-2 of the first capacitor C1 are connected to the control signal V _sweep .

The switch T9 has a control terminal T9-3, a first terminal T9-1, and a second terminal T9-2. The first terminal T9-1 of the switch T9 is connected to the second terminal T1-2 of the switch T1 and the operating voltage VSS. The switch T9 The control terminal T9-3 is connected to the control signal EM. The switch T10 has a control terminal T10-3, a first terminal T10-1, and a second terminal T10-2. The first terminal T10-1 of the switch T10 is connected to the second terminal T9-2 of the switch T9, and the second terminal of the switch T10 T10-2 is connected to the diode voltage V _LED , and the control terminal T10-3 of the switch T10 is connected to the control signal EM. The second capacitor C2 has a first terminal C2-1 and a second terminal C2-2. The first terminal C2-1 of the second capacitor C2 is connected to the second terminal T4-2 of the switch T4, and the second terminal of the second capacitor C2 C2-2 is connected to the second terminal T9-2 of the switch T9 and the first terminal T10-1 of the switch T10. The switch T11 has a control terminal T11-3, a first terminal T11-1, and a second terminal T11-2. The first terminal T11-1 of the switch T11 is connected to the second terminal T4-2 of the switch T4 and the second terminal T4-2 of the second capacitor C2. One terminal C2-1, the second terminal T11-2 of the switch T11 is connected to the operating voltage VDD, and the control terminal T11-3 of the switch T11 is connected to the control signal S1. The switch T12 has a control terminal T12-3, a first terminal T12-1, and a second terminal T12-2. The first terminal T12-1 of the switch T12 is connected to the second terminal T4-2 of the switch T4 and the second terminal T4-2 of the second capacitor C2. One terminal C2-1 and the first terminal T11-1 of the switch T11, and the control terminal T12-3 of the switch T12 is connected to the control signal S2. The switch T13 has a control terminal T13-3, a first terminal T13-1, and a second terminal T13-2. The first terminal T13-1 of the switch T13 is connected to the second terminal T12-2 of the switch T12 and the control terminal T13 of the switch T13 -3, the second terminal T13-2 of the switch T13 is connected to the reference voltage Vref.

In this embodiment, the switches T1 to T13 are, for example, thin film transistors, where the switches T1 to T4, T6, T7, and T10 to T13 are N-type transistors, and the switches T5, T8, and T9 are P-type transistors. Crystal. In addition, the threshold voltage of the switch T1 is matched to the threshold voltage of the switch T13, and the threshold voltage of the switch T5 is matched to the threshold voltage of the switch T8. The effect of the threshold voltage matching will be described in detail below.

FIG. 2 is a timing diagram of various control signals in the pixel driving circuit according to an embodiment. Please refer to FIG. 2, the pixel driving circuit sequentially operates in the first period 210, the second period 220, the third period 230, and the fourth period 240, and after the fourth period 240 ends, it returns to the first period 210.

FIG. 3 is a schematic diagram showing the switching of the pixel driving circuit in the first period according to an embodiment. 2 and 3, the first period 210 is used to reset the pixel driving circuit 100. In the first period 210, the control signal S1 and the control signal EM are at the high level V _GH , the control signal S2 is at the low level V _GL , and the control signal V _sweep is at the high level V _{sweep_H} , where the high level V _GH can be the same Or different from the high level V _{sweep_H} , this disclosure is not limited to this. Therefore, in the first period 210, the switches T1, T4, T5, T7, T9, and T12 are in the off state. In addition, the switches T2, T3, T6, T10, and T11 are in an on state. During this period, the potentials of node A and node D are the same as the operating voltage VSS; the potential of node B is the same as the operating voltage VDD; the potential of node C is the same as the diode voltage V _LED ; and the potential of node E is the same as the control signal V _sweep .

FIG. 4 is a schematic diagram showing the switching of the pixel driving circuit in the second period according to an embodiment. 2 and 4, the second period 220 is used for voltage compensation. In the second period 220, the control signal S1 is at the low level V _GL , the control signal S2, the control signal EM is at the high level V _GH , and the control signal V _sweep is at the high level V _{sweep_H} . Therefore, the switches T1, T4, T5, T6, T9, and T11 are in the off state, and the switches T2, T3, T7, T8, T12, and T13 are in the on state. During this period, the potentials of the node A and the node D are the same as the operating voltage VSS. The potential of the node B is V _ref +V _{TH_T13} , where V _{TH_T13} is the threshold voltage of the switch T13. The potential of the node C is the same as the diode voltage V _LED . The potential of the node E is V _DATA -|V _{TH_T8} |, where V _{TH_T8} is the threshold voltage of the switch T8.

FIG. 5 is a schematic diagram showing the switching of the pixel driving circuit in the first sub-period in the third period according to an embodiment. 2 and 5, the third period 230 is divided into a first sub-period 230-1 and a second sub-period 230-2. In the first sub-period 230-1, the light-emitting unit 110 is turned off, and in the second sub-period 230-1 During the period 230-2, the light-emitting unit 110 is turned on and emits light. The lengths of the first sub-period 230-1 and the second sub-period 230-2 are determined by the data voltage V _DATA . In other words, in this embodiment, the light-emitting unit 110 is driven in a pulse width modulation (PWM) manner, thereby determining the brightness of the pixel. Specifically, in the third period 230, the control signal S1, the control signal S2, and the control signal EM are at the low level V _GL , and the control signal V _sweep is gradually reduced from the high level V _{sweep_H} to the low level V _{sweep_L} , where The low level V _{sweep_L} can be the same or different from the low level V _GL , and the present disclosure is not limited thereto.

V _sweep，其中

V _sweep表示控制訊號V _sweep的變化量，由於控制訊號V _sweep的電位是逐漸降低，因此節點E的電位也會逐漸的降低，當以下數學式1成立時，開關T5會切換為導通狀態，接著會進入第二子期間230-2。 [數學式1]

>0 In the first sub-period 230-1, the switches T1 to T7, T10, T11, and T12 are in the off state, and the switch T9 is in the on state. At this time, the potentials of the node A, the node C, and the node D are the same as the operating voltage VSS. The potential of node C _{changes from V LED in the} second period 220 to VSS in the first sub-period 230-1, and the amount of change is VSS-V _LED , so the potential of node B _{changes from V ref} +V _{TH_T13} to V _ref +V _{TH_T13} +VSS-V _LED . Similarly, the potential of node E is V _DATA -|V _{TH_T8} |+

V _sweep , where

Change amount V _sweep a control signal V _sweep, since the control signal V _sweep potential is gradually reduced, the potential of the node E will gradually decrease, when the following Equation 1 is satisfied, the switch T5 is switched to a conducting state, and then Will enter the second sub-period 230-2. [Math 1]

>0

為開關T5的臨界電壓。值得注意的是，由於開關T5的臨界電壓匹配於開關T8的臨界電壓，因此在數學式1中兩個臨界電壓

、

相互抵消，也就是說刪除了開關T5的臨界電壓的影響。此外，當資料電壓V _DATA越大時，數學式1越早成立，也就越早進入第二子期間230-2。 Where V _E represents the potential of node E,

Is the critical voltage of switch T5. It is worth noting that, since the threshold voltage of switch T5 matches the threshold voltage of switch T8, the two threshold voltages in Equation 1

,

Cancel each other, that is to say, delete the influence of the critical voltage of switch T5. In addition, when the data voltage V _DATA is greater, the earlier mathematical formula 1 is established, and the earlier the second sub-period 230-2 is entered.

V _sweep。除此之外，由於開關T5為導通狀態，節點D的電位相同於電壓V _H。在此實施例中，操作電壓VDD大於等於電壓V _H，但電壓V _H大到足夠導通開關T4。電壓V _H會施加在開關T4的控制端T4-3上使得開關T4處於導通狀態，節點A與節點B的電位相同於V _ref+V _{TH_T13}+VSS-V _LED，藉此導通開關T1以產生電流I _LED，此電流I _LED流經發光單元110與開關T1。電流I _LED的大小如以下數學式2所示，其中K為常數，V _A為節點A的電位，臨界電壓

、

相互抵銷。 [數學式2]

FIG. 6 is a schematic diagram showing the switching of the pixel driving circuit in the second sub-period in the third period according to an embodiment. 2 and 6, in the second sub-period 230-2, the switches T2, T3, T6, T7, T10~T12 are in the off state, and the switches T1, T4, T5, and T9 are in the on state. The potential of node C is the same as the operating voltage VSS, and the potential of node E is the same as V _DATA -|V _{TH_T8} |+

V _sweep . In addition, since the switch T5 is turned on, the potential of the node D is the same as the voltage V _H. In this embodiment, the operating voltage VDD is greater than or equal to the voltage V _H , but the voltage V _{H is} large enough to turn on the switch T4. The voltage V _H will be applied to the control terminal T4-3 of the switch T4 to make the switch T4 in the on state, and the potentials of the node A and the node B are the same as V _ref +V _{TH_T13} +VSS-V _LED , thereby turning on the switch T1 to generate current I _LED , the current I _LED flows through the light-emitting unit 110 and the switch T1. The magnitude of the current I _LED is shown in the following mathematical formula 2, where K is a constant, V _A is the potential of node A, and the critical voltage

,

Offset each other. [Math 2]

Through the compensation of the operating voltage VSS and the threshold voltage, the current I _LED has nothing to do with the operating voltage VSS and the threshold voltage of any switch. In the conventional technology, the driving current has passed through more than two switches. When the current is large, a voltage drop may occur, which may cause the switch to enter the linear region. Increasing the cross voltage between the operating voltage VDD and VSS can solve this problem, but it increases Power consumption. In contrast, the current I _LED only flows through one switch T1, so it has the effect of reducing power consumption.

FIG. 7 is a schematic diagram showing the switching of the pixel driving circuit in the fourth period according to an embodiment. 2 and FIG. 7, the fourth period 240 is used to turn off the light-emitting unit 110. In the fourth period 240, the control signal S1 and the control signal S2 are at the low level V _GL , the control signal EM is at the high level V _GH , and the control signal V _sweep is at the high level V _{sweep_H} . During this period, the switches T1, T4 to T7, T9, T11, and T12 are in an off state, and the switches T2, T3, and T10 are in an on state. The potentials of the node A and the node D are the same as the operating voltage VSS. The potential of node B is V _ref +V _{TH_T13} . The potential of the node C is the same as the diode voltage V _LED . The potential of the node E is V _DATA -|V _{TH_T8} |.

In the above embodiment, "connection" may be a direct connection.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be subject to those defined by the attached patent application scope.

100: pixel drive circuit 110: light-emitting unit C1: first capacitor C2: second capacitor T1~T13: switch I _LED : current 110-1, C1-1, C2-1, T1-1, T2-1, T3 -1, T4-1, T5-1, T6-1, T7-1, T8-1, T9-1, T10-1, T11-1, T12-1, T13-1: First end 110-2, C1-2, C2-2, T1-2, T2-2, T3-2, T4-2, T5-2, T6-2, T7-2, T8-2, T9-2, T10-2, T11- 2, T12-2, T13-2: second end T1-3, T2-3, T3-3, T4-3, T5-3, T6-3, T7-3, T8-3, T9-3, T10 -3, T11-3, T12-3, T13-3: control terminals A, B, C, D, E: node VDD, VSS: operating voltage S1, S2, EM, V _sweep : control signal V _H : voltage V _DATA : data voltage V _LED : diode voltage V _ref : reference voltage 210: first period 220: second period 230: third period 230-1: first sub-period 230-2: second sub-period 240: first Four-period V _GH , V _{sweep_H} : high level V _GL , V _{sweep_L} : low level

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings. FIG. 1 is a circuit structure diagram of a pixel driving circuit according to an embodiment. FIG. 2 is a timing diagram of various control signals in the pixel driving circuit according to an embodiment. FIG. 3 is a schematic diagram showing the switching of the pixel driving circuit in the first period according to an embodiment. FIG. 4 is a schematic diagram showing the switching of the pixel driving circuit in the second period according to an embodiment. FIG. 5 is a schematic diagram showing the switching of the pixel driving circuit in the first sub-period in the third period according to an embodiment. FIG. 6 is a schematic diagram showing the switching of the pixel driving circuit in the second sub-period in the third period according to an embodiment. FIG. 7 is a schematic diagram showing the switching of the pixel driving circuit in the fourth period according to an embodiment.

100: Pixel drive circuit

110: light-emitting unit

C1: The first capacitor

C2: second capacitor

T1~T13: switch

110-1, C1-1, C2-1, T1-1, T2-1, T3-1, T4-1, T5-1, T6-1, T7-1, T8-1, T9-1, T10- 1, T11-1, T12-1, T13-1: first end

110-2, C1-2, C2-2, T1-2, T2-2, T3-2, T4-2, T5-2, T6-2, T7-2, T8-2, T9-2, T10- 2, T11-2, T12-2, T13-2: second end

T1-3, T2-3, T3-3, T4-3, T5-3, T6-3, T7-3, T8-3, T9-3, T10-3, T11-3, T12-3, T13- 3: Control terminal

A, B, C, D, E: node

VDD, VSS: operating voltage

S1, S2, EM, V _sweep : control signal

V _H : Voltage

V _DATA : data voltage

V _LED : Diode voltage

V _ref : reference voltage

Claims (9)

A pixel driving circuit includes: a light-emitting unit having a first end and a second end, the first end of the light-emitting unit is connected to a first operating voltage; a first switch having a control end, a A first terminal and a second terminal, the first terminal of the first switch is connected to the second terminal of the light-emitting unit, and the second terminal of the first switch is connected to a second operating voltage; a second switch , Having a control terminal, a first terminal and a second terminal, the first terminal of the second switch is connected to the second operating voltage, and the second terminal of the second switch is connected to the Control terminal, the control terminal of the second switch is connected to a first control signal; a third switch has a control terminal, a first terminal and a second terminal, the first terminal of the third switch is connected to For the second operating voltage, the control terminal of the third switch is connected to the first control signal; a fourth switch has a control terminal, a first terminal and a second terminal, and the first terminal of the fourth switch Terminal is connected to the control terminal of the first switch and the second terminal of the second switch, the control terminal of the fourth switch is connected to the second terminal of the third switch; a fifth switch has a control Terminal, a first terminal and a second terminal, the first terminal of the fifth switch is connected to a first voltage, the second terminal of the fifth switch is connected to the second terminal of the third switch and the The control end of the fourth switch; a sixth switch having a control end, a first end and a second end, the first end of the sixth switch is connected to the control end of the fifth switch, the first The second end of the six switch is connected to a second control signal, and the control end of the sixth switch is connected to a third control signal; a seventh switch has a control end, a first end and a second end, The second end of the seventh switch is connected to the control end of the fifth switch and the first end of the sixth switch, and the control end of the seventh switch is connected to a fourth control signal; an eighth switch , Having a control terminal, a first terminal and a second terminal, the first terminal of the eighth switch is connected to a data voltage, and the second terminal of the eighth switch is connected to the control terminal of the eighth switch And the first terminal of the seventh switch; a first capacitor having a first terminal and a second terminal, the first terminal of the first capacitor is connected to the control terminal of the fifth switch, the sixth switch The first terminal of the seventh switch and the second terminal of the seventh switch, the second terminal of the first capacitor is connected to the third control signal; a ninth switch has a control terminal, a first terminal and a first terminal Two terminals, the first terminal of the ninth switch is connected to the second terminal of the first switch and the second operating voltage, the control terminal of the ninth switch is connected to the first control signal; a tenth switch , Having a control terminal, a first terminal and a second terminal, the first terminal of the tenth switch is connected to the second terminal of the ninth switch, and the second terminal of the tenth switch is connected to a second terminal Polar body voltage, the control terminal of the tenth switch is connected to the first control signal; a second capacitor has a first terminal and a second terminal, and the first terminal of the second capacitor is connected to the fourth switch The second end of the second capacitor, the first Two ends are connected to the second end of the ninth switch and the first end of the tenth switch; an eleventh switch has a control end, a first end and a second end, the eleventh switch The first end of the eleventh switch is connected to the second end of the fourth switch and the first end of the second capacitor, the second end of the eleventh switch is connected to the first operating voltage, the eleventh switch The control end of the twelfth switch is connected to the third control signal; a twelfth switch has a control end, a first end and a second end, and the first end of the twelfth switch is connected to the fourth switch The second terminal, the first terminal of the second capacitor, and the first terminal of the eleventh switch, the control terminal of the twelfth switch is connected to the fourth control signal; and a thirteenth switch, It has a control terminal, a first terminal and a second terminal. The first terminal of the thirteenth switch is connected to the second terminal of the twelfth switch and the control terminal of the thirteenth switch. The second end of the thirteen switch is connected to a reference voltage. The pixel driving circuit according to claim 1, wherein the pixel driving circuit sequentially operates in a first period, a second period, a third period, and a fourth period, wherein during the first period, The first switch, the fourth switch, the fifth switch, the seventh switch, the ninth switch, and the twelfth switch are in an off state, and the second switch, the third switch, the sixth switch, The tenth switch and the eleventh switch are in a conducting state, wherein during the second period, the first switch, the fourth switch, and the first switch The fifth switch, the sixth switch, the ninth switch, and the eleventh switch are in the cut-off state, the second switch, the third switch, the seventh switch, the eighth switch, the tenth switch, and the first switch The twelfth switch and the thirteenth switch are in the conducting state, wherein during a first sub-period of the third period, the first switch to the seventh switch, the tenth switch, the eleventh switch, and the The twelfth switch is in the off state, the ninth switch is in the on state, and in a second sub-period of the third period, the second switch, the third switch, the sixth switch, and the seventh switch The switch and the tenth switch to the twelfth switch are in the off state, the first switch, the fourth switch, the fifth switch, and the ninth switch are in the on state, wherein during the fourth period, the The first switch, the fourth switch to the seventh switch, the ninth switch, the eleventh switch, and the twelfth switch are in the off state, and the second switch, the third switch, and the tenth switch are in the cut-off state. In the on state, the threshold voltage of the first switch matches the threshold voltage of the thirteenth switch, and the threshold voltage of the fifth switch matches the threshold voltage of the eighth switch. The pixel drive circuit according to claim 2, wherein the first switch to the fourth switch, the sixth switch, the seventh switch, the tenth switch, the eleventh switch, the twelfth switch, and The thirteenth switch is an N-type transistor, and the fifth switch, the eighth switch, and the ninth switch are P-type transistors. The pixel driving circuit according to claim 3, wherein in the first period, the first control signal and the third control signal are at a first high level, and the second control signal is at a second high level The fourth control signal is a first low level, and during the second period, the first control signal and the fourth control signal are the first high level, and the second control signal is the first high level. Two high levels, the third control signal is the first low level, and during the third period, the first control signal, the third control signal, and the fourth control signal are the first low level , The second control signal is gradually reduced from the second high level to a second low level, wherein during the fourth period, the first control signal is the first high level, and the second control signal Is the second high level, and the third control signal and the fourth control signal are the first low level. The pixel driving circuit according to claim 4, wherein the first operating voltage is greater than the second operating voltage, and the first operating voltage is greater than or equal to the first voltage. The pixel driving circuit according to claim 1, wherein the light-emitting unit is a light-emitting diode. The pixel driving circuit according to claim 6, wherein the size of the light-emitting diode is sub-millimeter. The pixel driving circuit according to claim 1, wherein the pixel driving circuit is provided in a display panel. The pixel driving circuit according to claim 1, wherein the pixel driving circuit is arranged in a backlight module.

Images