Power management system and display device

Abstract

The application discloses a power management system and a display device. The power management system is used for providing voltage to a display panel, and comprises a voltage reduction circuit, a conversion circuit and a voltage increase circuit. The conversion circuit comprises a first conversion module, and the first conversion module is electrically connected with a voltage source. A first switch module comprises a first end and a second end, and the first end is electrically connected with the first conversion module. A second switch module comprises a third end and a fourth end, and the third end is electrically connected with the voltage source. A second conversion module is electrically connected with the second end and the fourth end respectively, and the second conversion module is electrically connected with a gate drive circuit. When the temperature of a thin film transistor is lower than a preset temperature, the first end and the second end are turned on, and the third end and the fourth end are turned off. When the temperature of the thin film transistor is greater than or equal to the preset temperature, the first end and the second end are turned off, and the third end and the fourth end are turned on, thereby guaranteeing the high voltage demand of the thin film transistor in a low-temperature environment and reducing the voltage conversion times.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display driving, in particular to a power management system and a display device. BACKGROUND

[0002] With the popularity of LCD (Liquid Crystal Display) and the increasingly prominent resource problem, the requirement for low power consumption of LCD is also higher and higher, so it is necessary to continuously develop low power consumption technology that is more energy-saving and power-saving.

[0003] In the related art, power supply of LCD usually applies various chips, and the required power supply voltages of various chips are also different, so a voltage conversion chip is needed to convert the input voltage into various voltages. Among them, the gate-on voltage VGH of the thin film transistor TFT (Thin Film Transistor) usually needs to be converted twice to be applicable to a low-temperature environment. However, each conversion is accompanied by a loss of power consumption, which in turn leads to an increase in power consumption of the LCD. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a power management system and a display device, aiming to solve the technical problem of high power consumption of LCD in the prior art.

[0005] To solve the above problems, in a first aspect, the present application provides a power management system for providing voltage to a display panel, the power management system comprising a step-down circuit, a conversion circuit and a step-up circuit, wherein the conversion circuit comprises:

[0006] a first conversion module, an input end of the first conversion module being electrically connected with a voltage source;

[0007] a first switch module comprising a first end and a second end, the first end being electrically connected with an output end of the first conversion module;

[0008] a second switch module comprising a third end and a fourth end, the third end being electrically connected with the voltage source;

[0009] a second conversion module, input ends of the second conversion module being respectively electrically connected with the second end and the fourth end, and an output end of the second conversion module being electrically connected with an input end of a gate drive module of the display panel;

[0010] When the temperature of a thin film transistor in the display panel is lower than a preset temperature, the first end and the second end are turned on, and the third end and the fourth end are turned off; when the temperature of the thin film transistor is greater than or equal to the preset temperature, the first end and the second end are turned off, and the third end and the fourth end are turned on.

[0011] Further, in the power management system, when the temperature of the thin film transistor is lower than a preset temperature, the temperature compensation voltage of the power management system is greater than or equal to a preset voltage; when the temperature of the thin film transistor is greater than or equal to the preset temperature, the temperature compensation voltage of the power management system is less than the preset voltage; the temperature compensation voltage is used to control the first switch module and the second switch module to be turned on or turned off.

[0012] Further, in the power management system, the power management system comprises a temperature compensation module, the first switch module further comprises a fifth terminal, and the second switch module further comprises a sixth terminal.

[0013] The one end of the temperature compensation module is electrically connected to the fifth terminal and the sixth terminal respectively, and is electrically connected to a constant current voltage source; the other end of the temperature compensation module is grounded.

[0014] Further, in the power management system, the temperature compensation module comprises a first resistor, a second resistor and a thermistor.

[0015] The first resistor and the thermistor are connected in parallel to form a first connection point and a second connection point; the first connection point is electrically connected to the fifth terminal and the sixth terminal respectively, and is electrically connected to the constant current voltage source; the second connection point is electrically connected to one end of the second resistor, and the other end of the second resistor is grounded.

[0016] Further, in the power management system, the first switch module comprises a first MOS tube.

[0017] The source of the first MOS tube is electrically connected to the output of the first conversion module, the drain of the first MOS tube is electrically connected to the input of the second conversion module, and the temperature compensation voltage is used to drive the gate of the first MOS tube to be turned on or turned off.

[0018] Further, in the power management system, the first switch module further comprises a first triode.

[0019] The collector of the first triode is electrically connected to the gate of the first MOS tube, the emitter of the first triode is grounded, and the base of the first triode is connected to the temperature compensation voltage.

[0020] Further, in the power management system, the second switch module comprises a second MOS tube.

[0021] The source of the second MOS is electrically connected with a voltage source, the drain of the second MOS is electrically connected with the input of the second conversion module, and the temperature compensation voltage is used to drive the gate of the second MOS to open or close.

[0022] Further, the second switch module further comprises a second transistor and a third transistor.

[0023] The collector of the second transistor is connected with a second voltage, the emitter of the second transistor is electrically connected with the base of the third transistor and grounded, the base of the second transistor is connected with the temperature compensation voltage, the base of the third transistor is connected with a third voltage, the collector of the third transistor is electrically connected with the gate of the second MOS, and the emitter of the third transistor is grounded.

[0024] Further, the first conversion module and the second conversion module comprise one or more of a Boost circuit and a Buck circuit.

[0025] In a second aspect, the application further provides a display device comprising a display panel, a driving system, and the power management system.

[0026] The power management system comprises a first conversion module, a first switch module, a second switch module and a second conversion module. The input of the first conversion module is electrically connected with a voltage source. The first end of the first switch module is electrically connected with the output of the first conversion module. The third end of the second switch module is electrically connected with the voltage source. The second end of the first switch module and the fourth end of the second switch module are both electrically connected with the input of the second conversion module. When the temperature of the thin film transistor is lower than a preset temperature, the first end and the second end of the first switch module are conducted, and the third end and the fourth end of the second switch module are disconnected, so that the thin film transistor is converted twice to be turned on in a low temperature environment. When the temperature of the thin film transistor is greater than or equal to the preset temperature, the first end and the second end of the first switch module are disconnected, and the third end and the fourth end of the second switch module are conducted, so that the voltage source is converted by the second conversion module to obtain a voltage capable of driving the thin film transistor to be turned on. Thus, the twice conversion in a non-low temperature environment is avoided, and the power consumption and cost of the liquid crystal display product are effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0028] Figure 1 Power supply architecture diagram of the display panel before improvement;

[0029] Figure 2 Structure schematic block diagram of the display device provided by the embodiments of the present application;

[0030] Figure 3 For Figure 2 Power supply architecture diagram of the power management system of the display device shown in the figure;

[0031] Figure 4 For Figure 2 Schematic block diagram of the conversion circuit of the power management system of the display device shown in the figure;

[0032] Figure 5 Circuit diagram of the temperature compensation module provided by the embodiments of the present application;

[0033] Figure 6 Circuit diagram of the first switch module provided by the embodiments of the present application;

[0034] Figure 7 Circuit diagram of the second switch module provided by the embodiments of the present application. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the scope of protection of the present application.

[0036] It should be understood that when used in the specification and the appended claims, the terms "comprise" and "include" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0037] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in this specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise.

[0038] It is further to be understood that the term "and / or" as used herein refers to a combination of one or more of the associated listed items, as well as all possible combinations of the associated listed items.

[0039] Currently, the applicant adopts the power supply architecture as shown in Figure 1 when designing the power supply architecture of the LCD. The power supply architecture includes a power management system, the power management system includes a 1.8V buck module and a power management module, the power management module can be a PMIC (Power Management IC), the PMIC can include a 1.2V buck module, a 3.3V buck module, a first conversion module, a second conversion module and a buck-boost module.

[0040] Specifically, the 1.8V buck module is used to convert the voltage source Vin to obtain the required 1.8V voltage of the timing control module, the 1.2V buck module is used to convert the voltage source Vin to obtain the required 1.2V voltage of the timing control module, and the 3.3V buck module is used to convert the voltage source Vin to obtain the required 3.3V voltage of the timing control module. The 1.8V voltage and the 3.3V voltage can also be connected to the source chip. The 1.8V buck module, the 1.2V buck module and the 3.3V buck module are all composed of Buck (buck) circuits.

[0041] The buck-boost module is composed of a Buck (buck) circuit and a Boost (boost) circuit, and the buck-boost module can perform boost conversion alone or buck conversion alone. The buck-boost module is used to convert the voltage source Vin into the voltage VGL required by the gate drive circuit, which is -8V~10V.

[0042] The first conversion module is used to perform one-stage conversion on the voltage source Vin, and the one-stage converted voltage VAA can be connected to the source chip and the gamma chip while being used to perform two-stage conversion on the second conversion module. The first conversion module and the second conversion module are both composed of Boost (boost) circuits, and the second conversion module can perform boost conversion again on the one-stage converted voltage VAA to obtain the voltage VGH required by the thin film transistor gate to be opened, which is between 20V and 33V.

[0043] The reason why two conversion modules are used to boost the voltage source Vin in the power supply architecture of the LCD is that the input voltage source Vin is only 12V. If only one boost module is used for boost conversion, the 12V voltage can only be boosted to 28V, and the thin film transistor needs 33V VGH voltage to be turned on in a low temperature environment. Obviously, the 28V VGH voltage cannot adapt to the VGH voltage of the thin film transistor in a low temperature environment.

[0044] However, the thin film transistor does not need VGH voltage in a non-low temperature environment. When the thin film transistor is in a non-low temperature environment, if the voltage source Vin is converted twice, the power consumption loss will inevitably increase. For example, if the conversion efficiency of each conversion is 75%, the conversion efficiency after two conversions is 75% x 75% = 56%, and the thin film transistor in a non-low temperature environment will inevitably have a power consumption loss of 44%. Since the conversion efficiency of the IC monomer is limited by the process level of the semiconductor, how to further improve the efficiency of the entire system needs to focus on how to reduce the application scenario of the secondary conversion.

[0045] To solve the technical problem of large power consumption loss in the power supply architecture of the LCD, the application provides a power management system 100 and a display device 10.

[0046] Please refer to Figure 2 , Figure 2 is a structural schematic block diagram of the display device provided by the application.

[0047] The display device 10 of the application includes a display panel 300, a driving system 200 and a power management system 100. One end of the driving system 200 is electrically connected to the display panel 300, and the other end of the driving system 200 is electrically connected to the power management system 100. The display panel 300 includes a plurality of gate lines and a plurality of data lines, the plurality of gate lines and the plurality of data lines are cross-insulated arranged and form a plurality of sub-pixels in an array arrangement, two adjacent gate lines and two adjacent data lines cross them to define a sub-pixel, and each sub-pixel is provided with a thin film transistor to drive the sub-pixel to display. Taking a thin film transistor (TFT) liquid crystal display device as an example, each pixel unit includes at least one TFT.

[0048] Meanwhile, the display panel 300 can be a liquid crystal display panel. It should be noted that the type of the display panel 300 is not limited in the present application. The liquid crystal display panel mentioned in the present application can be a horizontal electric field type liquid crystal display panel, such as a Fringe Field Switching (FFS) type liquid crystal display panel or an In-Plane Switching (IPS) type liquid crystal display panel, or a vertical electric field type liquid crystal display panel, such as a Twisted Nematic (TN) type liquid crystal display panel or a Multi-domain Vertical Alignment (MVA) type liquid crystal display panel.

[0049] In addition, the display panel 300 mentioned in the present application can be used in a mobile phone, a tablet computer, a desktop computer, a laptop computer, an electronic reader, a handheld computer, an electronic display screen, a notebook computer, an Ultra-mobile Personal Computer (UMPC), a netbook, a cellular phone, a Personal Digital Assistant (PDA), an Augmented Reality (AR) \ Virtual Reality (VR) device, a media player, a wearable device, a digital camera, a car navigation device, etc.

[0050] Further, as shown in Figure 3 , the driving system 200 includes a timing control module, a source driving module and a gate driving module, wherein the timing control module can be a Timer Control Register (TCON), the source driving module can be a source driver IC, and the gate driving module can be a gate driver IC. Meanwhile, the driving system can also include a Gamma IC.

[0051] Please refer to Figure 3 and Figure 4 , Figure 3 , the power supply architecture diagram of the power management system of the display device shown in Figure 2 , and the schematic block diagram of the conversion circuit of the power management system of the display device shown in Figure 4 , and the schematic block diagram of the conversion circuit of the power management system of the display device shown in Figure 2 .

[0052] The power supply architecture of the power management system 100 includes a step-down circuit, a conversion circuit 111 and a step-up circuit, which can process the input first voltage to achieve the corresponding voltage provided to the display panel. The conversion circuit 111 includes a first conversion module, a first switch module, a second switch module and a second conversion module. The input end of the first conversion module is electrically connected with the voltage source. The first switch module includes a first end and a second end. The first end is electrically connected with the output end of the first conversion module. The second end is electrically connected with the input end of the second conversion module. The second switch module includes a third end and a fourth end. The third end is electrically connected with the voltage source. The fourth end is electrically connected with the input end of the second conversion module. The output end of the second conversion module is electrically connected with the input end of the gate drive module.

[0053] Specifically, in the process of using the above-mentioned power management system 100 to supply power to the display panel, when the temperature of the thin film transistor in the display panel is lower than the preset temperature, the first end and the second end of the first switch module are turned on, and the third end and the fourth end of the second switch module are turned off, thereby achieving twice conversion of the thin film transistor in the display panel to meet the opening of the thin film transistor in a low temperature environment. When the temperature of the thin film transistor in the display panel is greater than or equal to the preset temperature, the first end and the second end of the first switch module are turned off, and the third end and the fourth end of the second switch module are turned on. At this time, the voltage source is directly converted by the second conversion module to obtain a voltage capable of driving the thin film transistor to open, thereby avoiding twice conversion in a non-low temperature environment, thereby effectively reducing the power consumption and cost of the liquid crystal display product.

[0054] In the present embodiment, the first conversion module and the second conversion module are both step-up modules, which can be composed of Boost (step-up) circuits. The preset temperature is the critical temperature at which the first switch module and the second switch module are turned off or turned on, which is mainly determined by the amplitude at which the first conversion module and the second conversion module can step up the voltage. For example, the first conversion module can step up the 12V voltage to 16.8V voltage, and the second conversion module can step up the 12V voltage to 28V voltage. Meanwhile, the second conversion module can also step up the 16.8V voltage to 20V-33V voltage. At this time, the preset temperature can be set according to the 28V voltage.

[0055] That is, when the VHG voltage required by the temperature environment of the thin film transistor is higher than 28V, then at this time the first conversion module and the second conversion module need to be used for twice step-up conversion. When the VHG voltage required by the temperature environment of the thin film transistor is less than or equal to 28V, then at this time only the second conversion module is needed for once step-up conversion to reduce the power loss caused by multiple conversions.

[0056] In addition, the gate driving module can be a GOA (Gate Driven on Array) circuit or a gate chip, which can be selected according to actual requirements, and the application does not make specific limitations. Meanwhile, the conversion circuit 111 mentioned in the application can be directly integrated into a power management chip 110 (PMIC, Power Management IC) in priority, but is not limited thereto, and can be selected according to actual application, and the application does not make specific limitations.

[0057] The conversion circuit 111 provided in the application includes a first conversion module, a first switch module, a second switch module and a second conversion module. The input end of the first conversion module is connected to a voltage source Vin. The first end of the first switch module is electrically connected to the output end of the first conversion module. The third end of the second switch module is connected to the voltage source Vin. The second end of the first switch module and the fourth end of the second switch module are both electrically connected to the input end of the second conversion module. When the temperature of the thin film transistor is lower than a preset temperature, the first end and the second end of the first switch module are turned on, and the third end and the fourth end of the second switch module are turned off, so as to realize twice conversion of the thin film transistor to meet the opening of the thin film transistor in a low-temperature environment. When the temperature of the thin film transistor is greater than or equal to the preset temperature, the first end and the second end of the first switch module are turned off, and the third end and the fourth end of the second switch module are turned on, so as to realize direct conversion of the voltage source Vin by the second conversion module to obtain a voltage capable of driving the thin film transistor to open. Thus, twice conversion in a non-low-temperature environment is avoided, and the power consumption of the LCD is reduced.

[0058] In some embodiments, when the temperature of the thin film transistor in the display panel is lower than a preset temperature, the temperature compensation voltage VT of the power management system 100 is greater than or equal to a preset voltage. When the temperature of the thin film transistor in the display panel is greater than or equal to the preset temperature, the temperature compensation voltage VT of the power management system 100 is less than the preset voltage. The temperature compensation voltage VT is used to control the first switch module and the second switch module to be turned on or turned off.

[0059] In the embodiment, the turning on and turning off of the first end and the second end of the first switch module and the third end and the fourth end of the second switch module are determined by the relationship between the temperature compensation voltage VT and the preset voltage of the power management system 100, and the relationship between the temperature compensation voltage VT and the preset voltage corresponds to the relationship between the temperature of the thin film transistor and the preset temperature.

[0060] In other words, when the temperature of the thin film transistor in the display panel is lower than the preset temperature, the temperature compensation voltage VT of the power management system 100 is greater than or equal to the preset voltage, the temperature compensation voltage VT controls the first switch module to be conductive between the first end and the second end, and controls the second switch module to be disconnected between the third end and the fourth end, at this time, the VGH voltage required by the thin film transistor is obtained by the first conversion module and the second conversion module in turn for voltage conversion; when the temperature of the thin film transistor in the display panel is greater than or equal to the preset temperature, the temperature compensation voltage VT of the power management system 100 is less than the preset voltage, the temperature compensation voltage VT controls the first switch module to be disconnected between the first end and the second end, and controls the second switch module to be conductive between the third end and the fourth end, at this time, the VGH voltage required by the thin film transistor can be directly obtained by the second conversion module for voltage conversion. The preset voltage can be 1.7V.

[0061] In some embodiments, the power management system 100 includes a temperature compensation module, the first switch module further includes a fifth end, and the second switch module further includes a sixth end; wherein one end of the temperature compensation module is electrically connected to the fifth end of the first switch module and the sixth end of the second switch module respectively, and is electrically connected to a constant current voltage source; the other end of the temperature compensation module is grounded.

[0062] Specifically, the temperature compensation module is self-contained in the power management system 100, thereby avoiding the need for additional control modules. One end of the temperature compensation module is connected to a constant current voltage source (such as 20uA) inside the power management system 100, and is electrically connected to the fifth end of the first switch module and the sixth end of the second switch module to achieve the temperature compensation voltage VT. The fifth end is a control end for driving the first switch module to be conductive or disconnected between the first end and the second end, and the sixth end is a control end for driving the second switch module to be conductive or disconnected between the third end and the fourth end.

[0063] Further, in some embodiments, as shown in Figure 5 The temperature compensation module includes a first resistor, a second resistor and a thermistor; wherein the first resistor and the thermistor are connected in parallel to form a first connection point and a second connection point; the first connection point is electrically connected to the fifth end of the first switch module and the sixth end of the second switch module respectively, and is electrically connected to a constant current voltage source; the second connection point is electrically connected to one end of the second resistor, and the other end of the second resistor is grounded.

[0064] In this embodiment, the fifth end of the first switch module and the sixth end of the second switch module are both electrically connected to the first connection point to access the temperature compensation voltage VT. The resistance value of the thermistor changes with temperature, and the resistance value increases as the temperature decreases. Therefore, according to the formula U=I*R, when the temperature of the thin film transistor decreases, the temperature compensation voltage VT increases.

[0065] In some embodiments, as shown in Figure 6 The first switch module includes a first MOS tube Q1; wherein the source of the first MOS tube Q1 is electrically connected to the output of the first conversion module, the drain of the first MOS tube Q1 is electrically connected to the input of the second conversion module, and the temperature compensation voltage VT is used to drive the gate of the first MOS tube Q1 to open or close.

[0066] In the embodiment, a resistor R1 is arranged between the source and the gate of the first MOS tube Q1, the source of the first MOS tube Q1 corresponds to the first end of the first switch module, the drain of the first MOS tube Q1 corresponds to the second end of the first switch module, the gate of the first MOS tube Q1 corresponds to the fifth end of the first switch module, and the opening or closing of the gate of the first MOS tube Q1 is controlled by the temperature compensation voltage VT. When the temperature compensation voltage VT is greater than or equal to a preset voltage, the temperature compensation voltage VT is used to control the gate of the first MOS tube Q1 to be grounded, so as to realize the conduction of the first MOS tube Q1; when the temperature compensation voltage VT is less than the preset voltage, the temperature compensation voltage VT is used to control the gate of the first MOS tube Q1 not to be grounded, so as to realize the disconnection of the first MOS tube Q1. The first MOS tube Q1 can be a P-channel MOS tube.

[0067] Continuing to refer to Figure 6 The first switch module further includes a first triode Q2; wherein the collector of the first triode Q2 is electrically connected to the gate of the first MOS tube Q1, the emitter of the first triode Q2 is grounded, and the base of the first triode Q2 is connected to the temperature compensation voltage VT.

[0068] In the embodiment, the first switch module is composed of the first MOS tube Q1 and the first triode Q2, the base of the first triode Q2 is connected to the temperature compensation voltage VT through a resistor R2, and a resistor R3 is arranged between the base and the emitter of the first triode Q2. When the temperature compensation voltage VT is greater than or equal to a preset voltage, the first triode Q2 is turned on, at this time, the voltage at the gate of the first MOS tube Q1 is pulled down to the ground, the source and the drain of the first MOS tube Q1 are turned on, the voltage VAA converted by the first conversion module from the voltage source Vin is input to the second conversion module through the source and the drain of the first MOS tube Q1 in sequence and with the voltage VAA'; when the temperature compensation voltage VT is less than the preset voltage, the first triode Q2 is turned off, at this time, the voltage at the gate of the first MOS tube Q1 is not pulled down to the ground, and the first MOS tube Q1 is turned off.

[0069] In some embodiments, as shown in Figure 7As shown, the second switch module comprises a second MOS tube Q3; wherein the source of the second MOS tube Q3 is electrically connected with the voltage source Vin, the drain of the second MOS tube Q3 is electrically connected with the input end of the second conversion module, and the temperature compensation voltage VT is used to drive the gate of the second MOS tube Q3 to open or close.

[0070] In the embodiment, the source and the gate of the second MOS tube Q3 are provided with the resistor R9, the source of the second MOS tube Q3 is equivalent to the third end of the second switch module, the drain of the second MOS tube Q3 is equivalent to the fourth end of the second switch module, the gate of the second MOS tube Q3 is equivalent to the fifth end of the second switch module, and the opening or closing of the gate of the second MOS tube Q3 is also controlled by the temperature compensation voltage VT. When the temperature compensation voltage VT is less than the preset voltage, the temperature compensation voltage VT is used to control the gate of the second MOS tube Q3 to be grounded, so as to realize the conduction of the second MOS tube Q3; when the temperature compensation voltage VT is greater than or equal to the preset voltage, the temperature compensation voltage VT is used to control the gate of the second MOS tube Q3 not to be grounded, so as to realize the disconnection of the second MOS tube Q3. The second MOS tube Q3 can be a P-channel MOS tube.

[0071] Continuing to refer to Figure 7 , the second switch module further comprises a second transistor Q4 and a third transistor Q5; wherein the collector of the second transistor Q4 is connected to the second voltage; the emitter of the second transistor Q4 is electrically connected with the base of the third transistor Q5 and grounded; the base of the second transistor Q4 is connected to the temperature compensation voltage VT; the base of the third transistor Q5 is connected to the third voltage, the collector of the third transistor Q5 is electrically connected with the gate of the second MOS tube Q3, and the emitter of the third transistor Q5 is grounded.

[0072] In the embodiment, the second voltage and the third voltage can both be 3.3V voltage, which can be provided by the 3.3V voltage reduction module in the power management system 100. The collector of the second transistor Q4 is connected to the second voltage through the resistor R7, the resistor R6 is arranged between the base and the emitter of the second transistor Q4, the base of the second transistor Q4 is connected to the temperature compensation voltage VT through the resistor R5; the base of the third transistor Q5 is connected to the third voltage through the resistor R8 at the same time, and is also directly grounded, the base and the emitter of the third transistor Q5 are electrically connected through the resistor R10, the emitter of the third transistor Q5 is grounded, and the collector of the third transistor Q5 is electrically connected with the gate of the second MOS tube Q3.

[0073] Specifically, when the temperature compensation voltage VT is less than the preset voltage, the second transistor Q4 is turned off, and the third transistor Q5 is turned on. At this time, the gate of the second MOS Q3 is pulled down to the ground, the second MOS Q3 is turned on, and the voltage source Vin is sequentially input to the second conversion module through the source and drain of the second MOS Q3.

[0074] With reference to Figure 6 and Figure 7 , the specific principle of the first switch module and the second switch module being turned on and off is as follows:

[0075] When the temperature compensation voltage VT is less than 1.7V, the first switch module is turned off, and the second switch module is turned on. Specifically, the first transistor Q2 is an NPN transistor, the voltage Vbe between the base and the emitter of the first transistor Q2 is less than 0.7V, the first transistor Q2 is turned off, at this time, the voltage at the gate of the first MOS Q1 is not pulled down to the ground, and the first MOS Q1 is turned off; the second transistor Q4 and the third transistor Q5 are both NPN transistors, the voltage Vbe between the base and the emitter of the second transistor Q4 is less than 0.7V, the second transistor Q4 is turned off, and since the base of the third transistor Q5 is connected to a 3.3V voltage, the voltage Vbe between the base and the emitter of the third transistor Q5 is 1.65V, which is greater than 0.7V, at this time, the third transistor Q5 is turned on, the gate of the second MOS Q3 is pulled down to the ground, and the second MOS Q3 is turned on.

[0076] When the temperature compensation voltage VT is greater than or equal to 1.7V, the first switch module is turned on, and the second switch module is turned off. Specifically, the voltage Vbe between the base and the emitter of the first transistor Q2 is greater than 0.7V, the first transistor Q2 is turned on, at this time, the gate of the first MOS Q1 is pulled down to the ground, and the first MOS Q1 is turned on; the voltage Vbe between the base and the emitter of the second transistor Q4 is greater than 0.7V, the second transistor Q4 is turned on, the emitter of the second transistor Q4 and the base of the third transistor Q5 are simultaneously pulled down to the ground, at this time, the voltage Vbe between the base and the emitter of the third transistor Q5 is equal to 0, the third transistor Q5 is turned off, and the gate of the second MOS Q3 is not pulled down to the ground, and the second MOS Q3 is turned off.

[0077] Further, in some embodiments, the first conversion module and the second conversion module include one or more of a Boost circuit, a Buck circuit.

[0078] Specifically, the first conversion module and the second conversion module mentioned in the present application preferentially select a Boost circuit, but they can also be composed of a Boost circuit and a Buck circuit, which can be designed according to actual application, and the present application does not make specific limitations here.

[0079] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0080] The above is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A power management system for supplying voltage to a display panel, characterized in that, The power management system comprises a step-down circuit, a conversion circuit and a step-up circuit, wherein the conversion circuit comprises: a first conversion module, an input end of the first conversion module being electrically connected with a voltage source; a first switch module, comprising a first end and a second end, the first end being electrically connected with an output end of the first conversion module; a second switch module, comprising a third end and a fourth end, the third end being electrically connected with the voltage source; a second conversion module, input ends of the second conversion module being electrically connected with the second end and the fourth end respectively, an output end of the second conversion module being electrically connected with an input end of a gate drive module of the display panel; when a temperature of a thin film transistor in the display panel is lower than a preset temperature, the first end and the second end are turned on, and the third end and the fourth end are turned off; when the temperature of the thin film transistor is greater than or equal to the preset temperature, the first end and the second end are turned off, and the third end and the fourth end are turned on.

2. The power management system of claim 1, wherein, when the temperature of the thin film transistor is lower than the preset temperature, a temperature compensation voltage of the power management system is greater than or equal to a preset voltage; when the temperature of the thin film transistor is greater than or equal to the preset temperature, the temperature compensation voltage of the power management system is less than the preset voltage; the temperature compensation voltage is used for controlling the first switch module and the second switch module to be turned on or turned off.

3. The power management system of claim 2, wherein, The power management system further comprises a temperature compensation module, the first switch module further comprises a fifth end, and the second switch module further comprises a sixth end; wherein one end of the temperature compensation module is electrically connected with the fifth end and the sixth end respectively, and is electrically connected with a constant current voltage source; the other end of the temperature compensation module is grounded.

4. The power management system of claim 3, wherein, The temperature compensation module comprises a first resistor, a second resistor and a thermistor; wherein the first resistor and the thermistor are connected in parallel to form a first connection point and a second connection point; the first connection point is electrically connected with the fifth end and the sixth end respectively, and is electrically connected with the constant current voltage source; the second connection point is electrically connected with one end of the second resistor, and the other end of the second resistor is grounded.

5. The power management system of claim 2, wherein, The first switch module comprises a first MOS tube; wherein a source of the first MOS tube is electrically connected with an output end of the first conversion module, a drain of the first MOS tube is electrically connected with an input end of the second conversion module, and the temperature compensation voltage is used for driving a gate of the first MOS tube to be turned on or turned off.

6. The power management system of claim 5, wherein, The first switch module further comprises a first triode; wherein a collector of the first triode is electrically connected with the gate of the first MOS tube, an emitter of the first triode is grounded, and a base of the first triode is connected with the temperature compensation voltage.

7. The power management system of claim 2, wherein, The second switch module comprises a second MOS tube; wherein a source of the second MOS tube is electrically connected with the voltage source, a drain of the second MOS tube is electrically connected with an input end of the second conversion module, and the temperature compensation voltage is used for driving a gate of the second MOS tube to be turned on or turned off.

8. The power management system of claim 7, wherein, The second switch module further comprises a second triode and a third triode; The collector of the second triode is connected to a second voltage; the emitter of the second triode is electrically connected to the base of the third triode and grounded; the base of the second triode is connected to the temperature compensation voltage; the base of the third triode is connected to a third voltage, the collector of the third triode is electrically connected to the gate of the second MOS tube, and the emitter of the third triode is grounded.

9. The power management system of claim 1, wherein, The first conversion module and the second conversion module comprise one or more of a Boost circuit and a Buck circuit.

10. A display device, characterized by comprising: The display device comprises a display panel, a driving system, and a power management system as claimed in any one of claims 1-9.

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