Power supply circuit, display panel and display device

Abstract

This invention proposes a power supply circuit, a display panel, and a display device. The power supply circuit is connected to a secondary common voltage line. The power supply circuit includes a power-down detection module and a voltage output module. The detection terminal of the power-down detection module is connected to the power supply terminal of the panel, and the output terminal of the power-down detection module is connected to the control terminal of the voltage output module. The input terminals of the voltage output module are connected to both the primary common voltage terminal and the secondary common voltage terminal, and the output terminal of the voltage output module is connected to the secondary common voltage line. By outputting the secondary common voltage to the secondary common voltage line through the voltage output module when the panel is detected to be powered on, a secondary common voltage can be provided to the secondary pixels. When the panel is detected to be powered off, the primary common voltage is output to the secondary common voltage line through the voltage output module. This ensures that after the data line is short-circuited with the primary common voltage line, the voltages at both ends of the secondary pixels are the same, thereby avoiding the flickering problem.

Description

Technical Field

[0001] This utility model relates to the field of display, and in particular to a power supply circuit, a display panel, and a display device. Background Technology

[0002] Because LCD screens use a light transmission mechanism, and light passes through the liquid crystal at a near-vertical angle and shines forward, the best visual effect is achieved only when the LCD is directly in front of it. When viewing the LCD from an angle away from directly in front, distortion and dimming will occur. To improve this, most large-screen models now use an 8-domain subpixel architecture and use two different common voltages, namely CFCOM and SVCOM, which provide common voltages for the main domain and subdomain, respectively. When the screen is turned off, the data line is shorted to the common voltage line, making the voltage at both ends of the liquid crystal the same, thus turning the screen black. However, due to the setting of two common voltages, the voltage at both ends of the subdomain is different when shorted, causing the flickering white problem when the screen is turned off. Utility Model Content

[0003] The main purpose of this utility model is to propose a power supply circuit, a display panel, and a display device, which aims to solve the problem of screen flickering white when the power is off in the prior art.

[0004] To achieve the above objectives, this utility model provides a power supply circuit connected to a secondary common voltage line. The power supply circuit includes a power-down detection module and a voltage output module. The detection terminal of the power-down detection module is connected to the panel power supply terminal, the output terminal of the power-down detection module is connected to the control terminal of the voltage output module, the input terminals of the voltage output module are connected to both the primary common voltage terminal and the secondary common voltage terminal, and the output terminal of the voltage output module is connected to the secondary common voltage line. Wherein:

[0005] The power-down detection module is used to detect the power supply status of the panel power supply terminal and send a control signal to the voltage output module based on the detection result.

[0006] The voltage output module is used to output a main common voltage or a secondary common voltage to the secondary common voltage line according to the control signal. Specifically, when the panel power supply terminal is powered on, the secondary common voltage is output to the secondary common voltage line, and when the panel power supply terminal is powered off, the main common voltage is output to the secondary common voltage line.

[0007] Optionally, the power-down detection module includes a reference voltage unit, a voltage comparison unit, and a signal output unit; the reference voltage unit is connected to the reference voltage terminal of the voltage comparison unit, the input terminal of the voltage comparison unit is connected to the panel power supply terminal, the output terminal of the voltage comparison unit is connected to the input terminal of the signal output unit, and the output terminal of the signal output unit serves as the output terminal of the power-down detection module and is connected to the control terminal of the voltage output module; wherein:

[0008] The reference voltage unit is used to provide a reference voltage;

[0009] The voltage comparison unit is used to compare the reference voltage and the power supply voltage of the panel power supply terminal, and send the control signal corresponding to the comparison result to the voltage output module.

[0010] Optionally, the voltage comparison unit includes a first switching transistor, a second switching transistor, and an inverting subunit; wherein:

[0011] The control terminal of the first switching transistor is connected to the panel power supply terminal, the input terminal of the first switching transistor is connected to the reference voltage unit, and the output terminal of the first switching transistor is connected to the first input terminal of the signal output unit as the output terminal of the voltage comparison unit. The input terminal of the inverting subunit is connected to the panel power supply terminal, the output terminal of the inverting subunit is connected to the control terminal of the second switching transistor, the input terminal of the second switching transistor is connected to the reference voltage unit, and the output terminal of the second switching transistor is connected to the second input terminal of the signal output unit as the output terminal of the voltage comparison unit. The first switching transistor and the second switching transistor output different signals to the signal output unit when the panel power supply terminal is powered on or off.

[0012] Optionally, the signal output unit includes a third switch and a fourth switch; wherein:

[0013] The control terminal of the third switch is connected to the output terminal of the second switch as the second input terminal of the signal output unit. The input terminal of the third switch is connected to the output terminal of the first switch, and the output terminal of the third switch is connected to the main common voltage terminal. The control terminal of the fourth switch is connected to the output terminal of the first switch as the first input terminal of the signal output unit. The input terminal of the fourth switch is connected to the output terminal of the second switch, and the output terminal of the fourth switch is connected to the main common voltage terminal. The input terminal of the fourth switch is connected to the voltage output module as the first output terminal of the signal output unit, and the input terminal of the third switch is connected to the voltage output module as the second output terminal of the signal output unit.

[0014] Optionally, the voltage output module includes a main voltage output unit and a secondary voltage output unit; the control terminal of the main voltage output unit serves as the control terminal of the voltage output module and is connected to the output terminal of the power-down detection module; the input terminal of the main voltage output unit is connected to the main common voltage terminal; and the output terminal of the main voltage output unit is connected to the secondary common voltage line. The output terminal of the main voltage output unit is also connected to the control terminal of the secondary voltage output unit; the input terminal of the secondary voltage output unit is connected to the secondary common voltage terminal; and the output terminal of the secondary voltage output unit is connected to the secondary common voltage line.

[0015] Optionally, the main voltage output unit includes a fifth switching transistor and a sixth switching transistor; wherein:

[0016] The control terminal of the fifth switch is connected to the first output terminal of the power-down detection module, the output terminal of the fifth switch is connected to the main common voltage terminal, and the input terminal of the fifth switch is connected to the first control terminal of the auxiliary voltage output unit; the control terminal of the sixth switch is connected to the second output terminal of the power-down detection module, the output terminal of the sixth switch is connected to the main common voltage terminal, the input terminal of the sixth switch is connected to the second control terminal of the auxiliary voltage output unit, and the input terminal of the sixth switch is also connected to the auxiliary common voltage line.

[0017] Optionally, the secondary voltage output unit includes a seventh switch and an eighth switch; wherein:

[0018] The control terminal of the seventh switch is connected to the input terminal of the sixth switch as the second control terminal of the secondary voltage output unit. The input terminal of the seventh switch is connected to the secondary common voltage terminal, and the output terminal of the seventh switch is connected to the input terminal of the fifth switch. The control terminal of the eighth switch is connected to the input terminal of the seventh switch as the first control terminal of the secondary voltage output unit. The input terminal of the eighth switch is connected to the secondary common voltage terminal, and the output terminal of the eighth switch is connected to the secondary common voltage line.

[0019] Optionally, the first, second, seventh, and eighth switching transistors are PMOS transistors, and the third, fourth, fifth, and sixth switching transistors are NMOS transistors.

[0020] In addition, to achieve the above objectives, this utility model also provides a display panel, which includes a secondary common voltage line, a panel power supply terminal, a main common voltage terminal, a secondary common voltage terminal, and a power supply circuit as described above.

[0021] In addition, to achieve the above objectives, this utility model also provides a display device, which includes the display panel described above.

[0022] This utility model proposes a power supply circuit, a display panel, and a display device. The power supply circuit is connected to a secondary common voltage line. The power supply circuit includes a power-down detection module and a voltage output module. The detection terminal of the power-down detection module is connected to the panel power supply terminal, and the output terminal of the power-down detection module is connected to the control terminal of the voltage output module. The input terminals of the voltage output module are respectively connected to the main common voltage terminal and the secondary common voltage terminal, and the output terminal of the voltage output module is connected to the secondary common voltage line. The power-down detection module is used to detect the power supply status of the panel power supply terminal and send a control signal to the voltage output module based on the detection result. The voltage output module is used to output the main common voltage or the secondary common voltage to the secondary common voltage line according to the control signal. Specifically, when the panel power supply terminal is powered on, the secondary common voltage is output to the secondary common voltage line; when the panel power supply terminal is powered off, the main common voltage is output to the secondary common voltage line. The power supply status of the panel is detected by setting a power-off detection module. When the panel is detected to be powered on, the secondary common voltage is output to the secondary common voltage line through the voltage output module, so that the secondary common voltage can be provided to the secondary pixels. When the panel is detected to be powered off, the primary common voltage is output to the secondary common voltage line through the voltage output module. This ensures that the voltage at both ends of the secondary pixels is the same after the data line is shorted to the primary common voltage line, thereby avoiding the occurrence of the white flickering problem. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a functional block diagram of an embodiment of the power supply circuit of this utility model;

[0025] Figure 2 The circuit diagram shows the power supply circuit of this utility model.

[0026] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0027] Explanation of icon numbers:

[0028] label name label name 100 Power-down detection module VIN Power supply voltage 200 Voltage output module CFCOM Main common voltage Q1~Q8 First to eighth switching transistors SCOM Secondary common voltage LS Secondary common voltage line VDD Reference voltage Detailed Implementation

[0029] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0032] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0033] This utility model provides a power supply circuit for use in a display panel. Please refer to [link / reference]. Figure 1 , Figure 1 This is a functional block diagram of an embodiment of the power supply circuit of this utility model. In this embodiment, the power supply circuit is connected to the secondary common voltage line Ls; the power supply circuit includes a power-down detection module 100 and a voltage output module 200. The detection terminal of the power-down detection module 100 is connected to the panel power supply terminal, the output terminal of the power-down detection module 100 is connected to the control terminal of the voltage output module 200, the input terminals of the voltage output module 200 are respectively connected to the main common voltage terminal and the secondary common voltage terminal, and the output terminal of the voltage output module 200 is connected to the secondary common voltage line Ls; wherein:

[0034] The power-down detection module 100 is used to detect the power supply status of the panel power supply terminal and send a control signal to the voltage output module 200 based on the detection result.

[0035] The voltage output module 200 is used to output the main common voltage CFCOM or the secondary common voltage SCOM to the secondary common voltage line Ls according to the control signal. Specifically, when the panel power supply terminal is powered on, the secondary common voltage SCOM is output to the secondary common voltage line Ls, and when the panel power supply terminal is powered off, the main common voltage CFCOM is output to the secondary common voltage line Ls.

[0036] The secondary common voltage line Ls is a signal line that provides a common voltage to the sub-pixels within the plane. Correspondingly, a primary common voltage line is also provided within the plane, which provides a common voltage to the primary pixels within the plane. It can be understood that in an 8-domain or other multi-domain sub-pixel structure, a pixel is set as a combination of multiple sub-pixels, and the light emission directions of different sub-pixels are different. Generally, sub-pixels are divided into primary pixels and secondary pixels. The primary pixels are provided with a common voltage by the primary common voltage line, and the secondary pixels are provided with a common voltage by the secondary common voltage line Ls. The values ​​of the common voltages provided by the primary and secondary common voltage lines Ls are different. Because the common voltages of the primary and secondary pixels are different, therefore... Under the same data signal, the voltages at the ends of the main pixel and the sub-pixel are different, corresponding to different flip angles of the liquid crystal, thus meeting the viewing needs of different viewing angles. When the power is off, the data line is shorted to the main common voltage line to restore the liquid crystal to a non-flip state, achieving a black screen. After shorting, the voltages at both ends of the main pixel are the same as the voltage of the main common voltage line, that is, the voltages at both ends are the same, the voltage difference is 0, and the liquid crystal can restore the non-flip state. However, the voltages at both ends of the sub-pixel are different, one end is the voltage of the main common voltage line, and the other end is the voltage of the sub-common voltage line Ls. Therefore, the liquid crystal will flip based on the actual voltage difference, thus causing the corresponding pixel to display, i.e., the problem of white flickering when the power is off.

[0037] The power-off detection module 100 is used to detect the power-on and power-off states of the display panel. It is understood that for sub-pixels, their common voltage requirements differ depending on whether the display panel is powered on or off. Specifically, when the display panel is powered on, to achieve a wide viewing angle, the common voltage of the sub-pixels needs to be set differently from that of the main pixels; that is, the sub-common voltage line Ls needs to provide a different magnitude of common voltage than the main common voltage line. When the display panel is powered off, to avoid the problem of white flickering during power-off, the common voltage of the sub-pixels needs to be set the same as that of the main pixels, so that when the pixel line is shorted to the main common voltage line, the voltage at both ends of the sub-pixel remains consistent; that is, the sub-common voltage line Ls needs to provide the same magnitude of common voltage as the main common voltage line. Therefore, in this embodiment, the power-off detection module 100 is set to detect the power-on and power-off states of the display panel, thereby determining what kind of common voltage the sub-common voltage line Ls needs to output, and then controlling the voltage output module 200 so that the voltage output module 200 outputs a common voltage that meets the requirements of the current power-on and power-off states to the sub-common voltage line Ls.

[0038] This embodiment uses a power-off detection module 100 to detect the power supply status of the panel. When the panel is detected to be powered on, the voltage output module 200 outputs the secondary common voltage SCOM to the secondary common voltage line Ls, so that the secondary common voltage SCOM can be provided to the sub-pixels. When the panel is detected to be powered off, the voltage output module 200 outputs the primary common voltage CFCOM to the secondary common voltage line Ls, so that after the data line is shorted to the primary common voltage line, the voltages at both ends of the sub-pixels are the same, thereby avoiding the occurrence of the white flickering problem.

[0039] Further, the power-down detection module 100 includes a reference voltage unit, a voltage comparison unit, and a signal output unit; the reference voltage unit is connected to the reference voltage VDD terminal of the voltage comparison unit, the input terminal of the voltage comparison unit is connected to the panel power supply terminal, the output terminal of the voltage comparison unit is connected to the input terminal of the signal output unit, and the output terminal of the signal output unit serves as the output terminal of the power-down detection module 100 and is connected to the control terminal of the voltage output module 200; wherein:

[0040] The reference voltage unit is used to provide a reference voltage VDD;

[0041] The voltage comparison unit is used to compare the reference voltage VDD and the power supply voltage VIN of the panel power supply terminal, and send the control signal corresponding to the comparison result to the voltage output module 200.

[0042] The reference voltage VDD is used to provide a benchmark for judging the magnitude of the voltage at the power supply terminal of the panel.

[0043] When the panel is powered on, the supply voltage VIN at the panel power supply terminal is relatively high, such as the rated voltage; when the panel is powered off, the supply voltage VIN at the panel power supply terminal is relatively low, such as 0. It should be noted that since the reference voltage unit is also located inside the display panel, if the reference voltage unit also directly uses the power supply terminal of the panel, the reference voltage unit will also lose its power source when the panel is powered off. Therefore, in order to ensure that the reference voltage unit can still provide the reference voltage VDD when the panel is powered off, the power supply of the reference voltage unit can be set independently, and the power supply of the reference voltage unit is not affected by the panel power supply terminal.

[0044] In order to determine the power-on / off state of the panel by comparing the reference voltage VDD with the supply voltage VIN, the specific value of the reference voltage VDD is set to be greater than the supply voltage VIN when the panel is powered off, and less than the supply voltage VIN when the panel is powered on. This allows the comparison between the reference voltage VDD and the supply voltage VIN to produce different results when the panel is powered on or off, thereby indicating the power-on / off state.

[0045] The voltage comparison unit is used to compare the reference voltage VDD with the supply voltage VIN, and outputs the corresponding control signal according to the comparison result. It can be understood that when the comparison result indicates that the supply voltage VIN is greater than the reference voltage VDD, the output control signal indicates that the secondary common voltage SCOM is output to the secondary common voltage line Ls. When the comparison result indicates that the supply voltage VIN is less than the reference voltage VDD, the output control signal indicates that the primary common voltage CFCOM is output to the secondary common voltage line Ls.

[0046] In this embodiment, by setting a reference voltage unit and a voltage comparison unit, the power-on and power-off states of the panel can be accurately detected, and then a control signal that meets the power-on and power-off requirements can be output to the voltage output module 200.

[0047] Furthermore, the voltage comparison unit includes a first switch Q1, a second switch Q2, and an inverting subunit; wherein:

[0048] The control terminal of the first switch Q1 is connected to the panel power supply terminal, the input terminal of the first switch Q1 is connected to the reference voltage unit, and the output terminal of the first switch Q1 is connected to the first input terminal of the signal output unit as the output terminal of the voltage comparison unit. The input terminal of the inverting subunit is connected to the panel power supply terminal, the output terminal of the inverting subunit is connected to the control terminal of the second switch Q2, the input terminal of the second switch Q2 is connected to the reference voltage unit, and the output terminal of the second switch Q2 is connected to the second input terminal of the signal output unit as the output terminal of the voltage comparison unit. When the first switch Q1 and the second switch Q2 are powered on or off at the panel power supply terminal, they output different signals to the signal output unit.

[0049] The inverting sub-unit is used to invert the input signal before outputting it. Specifically, when the panel is powered on, the power supply voltage VIN at the panel power supply terminal is high, and after passing through the inverting sub-unit, it becomes low. Conversely, when the panel is powered off, the power supply voltage VIN at the panel power supply terminal is low, and after passing through the inverting sub-unit, it becomes high.

[0050] In this embodiment, the first switch Q1 and the second switch Q2 are PMOS transistors, with the input terminal of the switch being the source and the output terminal being the drain.

[0051] The gate of the first switching transistor Q1 is connected to the power supply terminal of the panel, and the source is connected to the reference voltage unit. Since the first switching transistor Q1 is a PMOS transistor, when the gate voltage is greater than the source voltage, that is, when the supply voltage VIN is greater than the reference voltage VDD, the first switching transistor Q1 is turned off; and when the gate voltage is less than the source voltage, that is, when the supply voltage VIN is less than the reference voltage VDD, the first switching transistor Q1 is turned on.

[0052] The gate of the second switch Q2 is connected to the panel power supply terminal through the inverting sub-unit. Therefore, the gate level of the second switch Q2 is always opposite to that of the first switch Q1. Thus, when the supply voltage VIN is greater than the reference voltage VDD, the gate voltage of the second switch Q2 is less than the source voltage, and the second switch Q2 is turned on. When the supply voltage VIN is less than the reference voltage VDD, the gate voltage of the second switch Q2 is greater than the source voltage, and the second switch Q2 is turned off.

[0053] When the first switch Q1 is off and the second switch Q2 is on, the reference voltage VDD flows out through the output terminal of the second switch Q2; when the first switch Q1 is on and the second switch Q2 is off, the reference voltage VDD flows out through the output terminal of the first switch Q1. The output terminals of the first switch Q1 and the second switch Q2 are respectively connected to the input terminals of the signal output unit. Therefore, the signal output unit can determine the power-on / off state of the panel based on the different signals output by the first switch Q1 and the second switch Q2.

[0054] Furthermore, the signal output unit includes a third switch Q3 and a fourth switch Q4; wherein:

[0055] The control terminal of the third switch Q3 is connected to the output terminal of the second switch Q2 as the second input terminal of the signal output unit. The input terminal of the third switch Q3 is connected to the output terminal of the first switch Q1, and the output terminal of the third switch Q3 is connected to the main common voltage terminal. The control terminal of the fourth switch Q4 is connected to the output terminal of the first switch Q1 as the first input terminal of the signal output unit. The input terminal of the fourth switch Q4 is connected to the output terminal of the second switch Q2, and the output terminal of the fourth switch Q4 is connected to the main common voltage terminal. The input terminal of the fourth switch Q4 is connected to the voltage output module 200 as the first output terminal of the signal output unit, and the input terminal of the third switch Q3 is connected to the voltage output module 200 as the second output terminal of the signal output unit.

[0056] In this embodiment, the third switch Q3 and the fourth switch Q4 are NMOS transistors, with the input terminal of the switch being the drain and the output terminal being the source.

[0057] When the first switch Q1 is off and the second switch Q2 is on, the gate of the third switch Q3 is at the reference voltage VDD, and the source is at the main common voltage CFCOM. It should be noted that the reference voltage VDD is greater than the main common voltage CFCOM. At this time, the gate voltage of the third switch Q3 is greater than the source voltage, and the third switch Q3 is on. The gate of the fourth switch Q4 receives the main common voltage CFCOM through the third switch Q3. The gate voltage of the fourth switch Q4 is equal to the source voltage, and the fourth switch Q4 is off. At this time, the drain of the fourth switch Q4 outputs the reference voltage VDD to the voltage output module 200, and the drain of the third switch Q3 outputs the main common voltage CFCOM to the voltage output module 200.

[0058] When the first switch Q1 is turned on and the second switch Q2 is turned off, the gate of the fourth switch Q4 is at the reference voltage VDD, and the source is at the main common voltage CFCOM. At this time, the gate voltage of the fourth switch Q4 is greater than the source voltage, and the fourth switch Q4 is turned on. The gate of the third switch Q3 receives the main common voltage CFCOM through the fourth switch Q4. The gate voltage of the third switch Q3 is equal to the source voltage, and the third switch Q3 is turned off. At this time, the drain of the third switch Q3 outputs the reference voltage VDD value to the voltage output module 200, and the drain of the fourth switch Q4 outputs the main common voltage CFCOM to the voltage output module 200.

[0059] The third switch Q3 and the fourth switch Q4 output different signals to the voltage output module 200 under different power-on and power-off states. Therefore, the voltage output module 200 can determine the power-on and power-off state of the panel based on the signals output by the third switch Q3 and the fourth switch Q4, and then output the required voltage to the secondary common voltage line Ls.

[0060] Furthermore, the voltage output module 200 includes a main voltage output unit and a secondary voltage output unit; the control terminal of the main voltage output unit serves as the control terminal of the voltage output module 200 and is connected to the output terminal of the power-down detection module 100; the input terminal of the main voltage output unit is connected to the main common voltage terminal; and the output terminal of the main voltage output unit is connected to the secondary common voltage line Ls. The output terminal of the main voltage output unit is also connected to the control terminal of the secondary voltage output unit; the input terminal of the secondary voltage output unit is connected to the secondary common voltage terminal; and the output terminal of the secondary voltage output unit is connected to the secondary common voltage line Ls.

[0061] The main voltage output unit is used to output the main common voltage CFCOM to the secondary common voltage line Ls; the secondary voltage output unit is used to output the secondary common voltage SCOM to the secondary common voltage line Ls.

[0062] The power-down detection module 100 outputs different control signals based on the different power-on and power-off states of the panel. In this embodiment, the main voltage output unit and the secondary voltage output unit switch the output voltage to the secondary common voltage line Ls based on the control signal. Specifically, when the control signal indicates that the secondary common voltage SCOM is output to the secondary common voltage line Ls, the main voltage output unit does not output voltage, while the secondary voltage output unit outputs the secondary common voltage SCOM provided by the secondary common voltage terminal to the secondary common voltage line Ls. When the control signal indicates that the main common voltage CFCOM is output to the secondary common voltage line Ls, the main voltage output unit outputs the main common voltage CFCOM provided by the main common voltage terminal to the secondary common voltage line Ls, while the secondary voltage output unit does not output voltage.

[0063] This embodiment enables the switching between the main common voltage CFCOM and the secondary common voltage SCOM outputs by setting a main voltage output unit and a secondary voltage output unit.

[0064] Furthermore, the main voltage output unit includes a fifth switch Q5 and a sixth switch Q6; wherein:

[0065] The control terminal of the fifth switch Q5 is connected to the first output terminal of the power-down detection module 100, the output terminal of the fifth switch Q5 is connected to the main common voltage terminal, and the input terminal of the fifth switch Q5 is connected to the first control terminal of the secondary voltage output unit. The control terminal of the sixth switch Q6 is connected to the second output terminal of the power-down detection module 100, the output terminal of the sixth switch Q6 is connected to the main common voltage terminal, the input terminal of the sixth switch Q6 is connected to the second control terminal of the secondary voltage output unit, and the input terminal of the sixth switch Q6 is also connected to the secondary common voltage line Ls.

[0066] In this embodiment, the fifth switch Q5 and the sixth switch Q6 are NMOS transistors, with the input terminal of the switch being the drain and the output terminal being the source.

[0067] When the first output terminal of the current detection module 100 outputs a high level, i.e., the reference voltage VDD, and the second output terminal outputs a low level, i.e., the main common voltage CFCOM, the gate of the fifth switch Q5 is the reference voltage VDD, and the source is the main common voltage CFCOM, so the fifth switch Q5 is turned on; the gate and source of the sixth switch Q6 are both the main common voltage CFCOM, so the sixth switch Q6 is turned off; at this time, the sixth switch Q6 does not output the main common voltage CFCOM.

[0068] When the first output terminal of the current detection module 100 outputs a low level and the second output terminal outputs a high level, the gate and source of the fifth switch Q5 are both at the main common voltage CFCOM, so the fifth switch Q5 is turned off. The gate of the sixth switch Q6 is at the reference voltage VDD, and the source is at the main common voltage CFCOM, so the sixth switch Q6 is turned on. At this time, the sixth switch Q6 outputs the main common voltage CFCOM to the secondary common voltage line Ls.

[0069] In this embodiment, the main common voltage CFCOM is output when the panel is powered off by setting the fifth switch Q5 and the sixth switch Q6.

[0070] Furthermore, the secondary voltage output unit includes a seventh switch Q7 and an eighth switch Q8; wherein:

[0071] The control terminal of the seventh switch Q7 serves as the second control terminal of the secondary voltage output unit and is connected to the input terminal of the sixth switch Q6. The input terminal of the seventh switch Q7 is connected to the secondary common voltage terminal, and the output terminal of the seventh switch Q7 is connected to the input terminal of the fifth switch Q5. The control terminal of the eighth switch Q8 serves as the first control terminal of the secondary voltage output unit and is connected to the input terminal of the seventh switch Q7. The input terminal of the eighth switch Q8 is connected to the secondary common voltage terminal, and the output terminal of the eighth switch Q8 is connected to the secondary common voltage line Ls.

[0072] In this embodiment, the seventh switch Q7 and the eighth switch Q8 are PMOS transistors, with the input terminal of the switch being the source and the output terminal being the drain.

[0073] When the first output terminal of the current detection module 100 outputs a high level and the second output terminal outputs a low level, the seventh switch Q7 is turned on and the eighth switch Q8 is turned off. The gate of the eighth switch Q8 is the main common voltage CFCOM, and the source is the secondary common voltage SCOM. The gate voltage of the eighth switch Q8 is less than the source voltage, so the eighth switch Q8 is turned on and outputs the secondary common voltage SCOM to the secondary common voltage line Ls. The gate and source of the seventh switch Q7 are both at the secondary common voltage SCOM, so the seventh switch Q7 is turned off.

[0074] When the first output terminal of the current detection module 100 outputs a low level and the second output terminal outputs a high level, the seventh switch Q7 is turned off and the eighth switch Q8 is turned on. The gate of the seventh switch Q7 is the main common voltage CFCOM, and the source is the secondary common voltage SCOM. The gate voltage of the seventh switch Q7 is less than the source voltage, so the seventh switch Q7 is turned on. The gate and source of the eighth switch Q8 are both the secondary common voltage SCOM, so the eighth switch Q8 is turned off and does not output the secondary common voltage SCOM.

[0075] This embodiment achieves the output of the secondary common voltage SCOM when the panel is powered on by setting the seventh switch Q7 and the eighth switch Q8.

[0076] The overall implementation principle of this application is explained below:

[0077] When the panel is powered on: the first switch Q1 is off, the second switch Q2 is on, the third switch Q3 is on, the fourth switch Q4 is off, the fifth switch Q5 is on, the sixth switch Q6 is off, the seventh switch Q7 is off, and the eighth switch Q8 is on. The secondary common voltage SCOM is output to the secondary common voltage line Ls through the eighth switch Q8 to achieve a wide viewing angle display.

[0078] When the panel is powered off: the first switch Q1 is turned on, the second switch Q2 is turned off, the third switch Q3 is turned off, the fourth switch Q4 is turned on, the fifth switch Q5 is turned off, the sixth switch Q6 is turned on, the seventh switch Q7 is turned on, and the eighth switch Q8 is turned off. The main common voltage CFCOM is output to the secondary common voltage line Ls through the sixth switch Q6 to avoid the white flashing when the power is off.

[0079] This utility model also protects a display panel, which includes a secondary common voltage line Ls, a panel power supply terminal, a main common voltage terminal, a secondary common voltage line Ls, and a power supply circuit. The structure of the power supply circuit can be referred to the above embodiment, and will not be repeated here. Therefore, since the display panel of this embodiment adopts the above-described power supply circuit technical solution, the display panel has all the beneficial effects of the above-described power supply circuit.

[0080] This utility model also protects a display device, which includes a display panel. The structure of the display panel can be referred to in the above embodiments, and will not be repeated here. Therefore, since the display device of this embodiment adopts the technical solution of the above-described display panel, the display device has all the beneficial effects of the above-described display panel.

[0081] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element. The sequence numbers of the above-described embodiments are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0082] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A power supply circuit, characterized in that, The power supply circuit is connected to the secondary common voltage line; the power supply circuit includes a power-down detection module and a voltage output module. The detection terminal of the power-down detection module is connected to the panel power supply terminal, the output terminal of the power-down detection module is connected to the control terminal of the voltage output module, the input terminals of the voltage output module are connected to the main common voltage terminal and the secondary common voltage terminal respectively, and the output terminal of the voltage output module is connected to the secondary common voltage line; wherein: The power-down detection module is used to detect the power supply status of the panel power supply terminal and send a control signal to the voltage output module based on the detection result. The voltage output module is used to output a main common voltage or a secondary common voltage to the secondary common voltage line according to the control signal. Specifically, when the panel power supply terminal is powered on, the secondary common voltage is output to the secondary common voltage line, and when the panel power supply terminal is powered off, the main common voltage is output to the secondary common voltage line.

2. The power supply circuit as described in claim 1, characterized in that, The power-down detection module includes a reference voltage unit, a voltage comparison unit, and a signal output unit. The reference voltage unit is connected to the reference voltage terminal of the voltage comparison unit, the input terminal of the voltage comparison unit is connected to the panel power supply terminal, the output terminal of the voltage comparison unit is connected to the input terminal of the signal output unit, and the output terminal of the signal output unit serves as the output terminal of the power-down detection module and is connected to the control terminal of the voltage output module. The reference voltage unit is used to provide a reference voltage; The voltage comparison unit is used to compare the reference voltage and the power supply voltage of the panel power supply terminal, and send the control signal corresponding to the comparison result to the voltage output module.

3. The power supply circuit as described in claim 2, characterized in that, The voltage comparison unit includes a first switching transistor, a second switching transistor, and an inverting subunit; wherein: The control terminal of the first switching transistor is connected to the panel power supply terminal, the input terminal of the first switching transistor is connected to the reference voltage unit, and the output terminal of the first switching transistor is connected to the first input terminal of the signal output unit as the output terminal of the voltage comparison unit. The input terminal of the inverting subunit is connected to the panel power supply terminal, the output terminal of the inverting subunit is connected to the control terminal of the second switching transistor, the input terminal of the second switching transistor is connected to the reference voltage unit, and the output terminal of the second switching transistor is connected to the second input terminal of the signal output unit as the output terminal of the voltage comparison unit. The first switching transistor and the second switching transistor output different signals to the signal output unit when the panel power supply terminal is powered on or off.

4. The power supply circuit as described in claim 3, characterized in that, The signal output unit includes a third switch and a fourth switch; wherein: The control terminal of the third switch is connected to the output terminal of the second switch as the second input terminal of the signal output unit. The input terminal of the third switch is connected to the output terminal of the first switch, and the output terminal of the third switch is connected to the main common voltage terminal. The control terminal of the fourth switch is connected to the output terminal of the first switch as the first input terminal of the signal output unit. The input terminal of the fourth switch is connected to the output terminal of the second switch, and the output terminal of the fourth switch is connected to the main common voltage terminal. The input terminal of the fourth switch is connected to the voltage output module as the first output terminal of the signal output unit, and the input terminal of the third switch is connected to the voltage output module as the second output terminal of the signal output unit.

5. The power supply circuit as described in claim 1, characterized in that, The voltage output module includes a main voltage output unit and a secondary voltage output unit. The control terminal of the main voltage output unit serves as the control terminal of the voltage output module and is connected to the output terminal of the power-down detection module. The input terminal of the main voltage output unit is connected to the main common voltage terminal, and the output terminal of the main voltage output unit is connected to the secondary common voltage line. The output terminal of the main voltage output unit is also connected to the control terminal of the secondary voltage output unit. The input terminal of the secondary voltage output unit is connected to the secondary common voltage terminal, and the output terminal of the secondary voltage output unit is connected to the secondary common voltage line.

6. The power supply circuit as described in claim 5, characterized in that, The main voltage output unit includes a fifth switching transistor and a sixth switching transistor; wherein: The control terminal of the fifth switch is connected to the first output terminal of the power-down detection module, the output terminal of the fifth switch is connected to the main common voltage terminal, and the input terminal of the fifth switch is connected to the first control terminal of the auxiliary voltage output unit; the control terminal of the sixth switch is connected to the second output terminal of the power-down detection module, the output terminal of the sixth switch is connected to the main common voltage terminal, the input terminal of the sixth switch is connected to the second control terminal of the auxiliary voltage output unit, and the input terminal of the sixth switch is also connected to the auxiliary common voltage line.

7. The power supply circuit as described in claim 6, characterized in that, The secondary voltage output unit includes a seventh switch and an eighth switch; wherein: The control terminal of the seventh switch is connected to the input terminal of the sixth switch as the second control terminal of the secondary voltage output unit. The input terminal of the seventh switch is connected to the secondary common voltage terminal, and the output terminal of the seventh switch is connected to the input terminal of the fifth switch. The control terminal of the eighth switch is connected to the input terminal of the seventh switch as the first control terminal of the secondary voltage output unit. The input terminal of the eighth switch is connected to the secondary common voltage terminal, and the output terminal of the eighth switch is connected to the secondary common voltage line.

8. The power supply circuit as described in any one of claims 2 to 7, characterized in that, The first, second, seventh, and eighth switching transistors are PMOS transistors, while the third, fourth, fifth, and sixth switching transistors are NMOS transistors.

9. A display panel, characterized in that, The display panel includes a secondary common voltage line, a panel power supply terminal, a main common voltage terminal, a secondary common voltage terminal, and a power supply circuit as described in any one of claims 1 to 8.

10. A display device, characterized in that, The display device includes the display panel as described in claim 9.

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