Power supply circuit of display screen

Abstract

The utility model discloses a power supply circuit of a display screen. The circuit comprises a charge pump booster circuit, a charge pump negative voltage circuit and a turn-off booster circuit, the turn-off boost circuit comprises a turn-off circuit and a boost circuit; the first input end of the turn-off circuit is connected to the output end of the charge pump booster circuit; the second input end of the turn-off circuit is connected to the output end of the charge pump negative voltage circuit; the third input end of the turn-off circuit is powered by a first power supply; the output end of the turn-off circuit is connected with the input end of the booster circuit; the first output end of the booster circuit is connected to the input end of the charge pump booster circuit; the second output end of the booster circuit is connected to the input end of the charge pump negative voltage circuit; the third output end of the booster circuit outputs voltage. According to the power supply circuit of the display screen, the power supply circuit can be turned off when positive and negative bias voltages of the power supply circuit are overvoltage, and the safety of the display screen is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit, in particular to a power supply circuit of display screen. BACKGROUND

[0002] With the continuous development of liquid crystal display (LCD) technology, its power supply circuit is also constantly progressing to adapt to the needs of higher resolution, larger size and brighter display.

[0003] The traditional LCD display screen may affect the color and color gamut of the display screen under the condition of positive and negative bias overvoltage of the power supply circuit, thereby affecting the normal work of the entire LCD display screen or even causing serious damage to the LCD display screen.

[0004] Therefore, it is urgent to protect the power supply circuit of the display screen from overvoltage, thereby ensuring the normal work of the display screen. Invention content

[0005] Based on the above problems, the present application provides a power supply circuit of display screen, which aims to improve the safety of the display screen.

[0006] The present application discloses the following technical solutions:

[0007] The present application provides a power supply circuit of display screen, which includes a charge pump voltage boosting circuit, a charge pump negative voltage circuit and a turn-off voltage boosting circuit; the turn-off voltage boosting circuit includes a turn-off circuit and a voltage boosting circuit;

[0008] The first input end of the turn-off circuit is connected to the output end of the charge pump voltage boosting circuit; the second input end of the turn-off circuit is connected to the output end of the charge pump negative voltage circuit; the third input end of the turn-off circuit is powered by a first power supply; and the output end of the turn-off circuit is connected to the input end of the voltage boosting circuit;

[0009] The first output end of the voltage boosting circuit is connected to the input end of the charge pump voltage boosting circuit; the second output end of the voltage boosting circuit is connected to the input end of the charge pump negative voltage circuit; and the third output end of the voltage boosting circuit outputs a voltage.

[0010] Optionally, the circuit as described above, the turn-off circuit includes an AND gate IC chip, a first transistor, a first triode, a first resistor, a first capacitor and a second capacitor;

[0011] The A port of the AND gate IC chip is the second input end of the turn-off circuit; the B port of the AND gate IC chip is the first input end of the turn-off circuit; the Y port of the AND gate IC chip is connected to the base of the first triode; the power supply port of the AND gate IC chip is powered by the first power supply and connected to the first capacitor and then grounded;

[0012] The emitter of the first triode is connected to the ground; the collector of the first triode is connected to the gate of the first transistor; the collector of the first triode is connected to the source of the first transistor through the first resistor and connected to the drain of the first transistor through the second capacitor; the source of the first transistor is the third input terminal of the turn-off circuit; and the drain of the first transistor is the output terminal of the turn-off circuit.

[0013] Optionally, in the circuit, the first transistor is a PMOS transistor.

[0014] Optionally, in the circuit, the charge pump voltage boosting circuit comprises a charge voltage boosting circuit and a first overvoltage detection circuit.

[0015] The first input terminal of the charge voltage boosting circuit is the input terminal of the charge pump voltage boosting circuit; the output terminal of the first overvoltage detection circuit is the output terminal of the charge pump voltage boosting circuit; and the output terminal of the charge voltage boosting circuit is connected to the input terminal of the first overvoltage detection circuit.

[0016] Optionally, in the circuit, the first overvoltage detection circuit comprises a first voltage comparison IC chip, a second triode, second to seventh resistors and a third capacitor.

[0017] The input terminal of the first overvoltage detection circuit is connected to the second resistor, and then connected to the third resistor and the fourth resistor respectively; the third resistor is connected to the ground; the fourth resistor is connected to the IN+ terminal of the first voltage comparison IC chip; the power supply terminal of the first voltage comparison IC chip is supplied with a second power supply; the second power supply is connected to the output terminal of the first voltage comparison IC chip and the base of a second triode after being connected to a fifth resistor; the second power supply is connected to the IN- terminal of the first voltage comparison IC chip after being connected to a sixth resistor; the emitter of the second triode is connected to the ground; the collector of the second triode is the output terminal of the first overvoltage detection circuit, and the collector of the second triode is connected to a third power supply after being connected to a seventh resistor.

[0018] Optionally, in the circuit, the fourth resistor is a current-limiting resistor.

[0019] Optionally, in the circuit, the charge pump voltage boosting circuit comprises a charge voltage boosting circuit and a first overvoltage detection circuit.

[0020] The first input terminal of the charge voltage boosting circuit is the input terminal of the charge pump voltage boosting circuit; the output terminal of the first overvoltage detection circuit is the output terminal of the charge pump voltage boosting circuit; and the output terminal of the charge voltage boosting circuit is connected to the input terminal of the first overvoltage detection circuit.

[0021] Optionally, in the circuit, the second overvoltage detection circuit comprises a second voltage comparison IC chip, eighth to thirteenth resistors and a fourth capacitor.

[0022] The input end of the second overvoltage detection circuit is connected to the eighth resistor, and then connected to the ninth resistor and the tenth resistor; the ninth resistor is connected to the fifth power supply; the tenth resistor is connected to the IN+ end of the second voltage comparison IC chip; the power supply end of the second voltage comparison IC chip is powered by the fourth power supply; the fourth power supply is connected to the output end of the second voltage comparison IC chip after being connected to the eleventh resistor; the fourth power supply is connected to the IN- end of the second voltage comparison IC chip after being connected to the twelfth resistor, and is grounded after being connected to the thirteenth resistor; and the output end of the second voltage comparison IC chip is the output end of the second overvoltage detection circuit.

[0023] Optionally, in the circuit, the tenth resistor is a current limiting resistor.

[0024] Optionally, in the circuit, the first power supply, the second power supply, the third power supply, the fourth power supply and the fifth power supply are VCC_3V3 power supplies.

[0025] When the voltage of the power supply circuit of the display screen is too high, low levels exist in the control signals output by the output end of the charge pump voltage boosting circuit and the output end of the charge pump negative voltage circuit, so that the low level control signals exist in the first input end of the turn-off circuit and the second input end of the turn-off circuit; when the voltage of the power supply circuit of the display screen is normal, high levels exist in the control signals output by the output end of the charge pump voltage boosting circuit and the output end of the charge pump negative voltage circuit, so that high level control signals exist in the first input end of the turn-off circuit and the second input end of the turn-off circuit. The turn-off circuit judges according to the control signals input by the first input end and the second input end, and is turned off when the voltage of the power supply circuit is too high, so that the first power supply cannot continue to supply power to the voltage boosting circuit, and the voltage boosting circuit is cut off, so that the charge pump voltage boosting circuit and the charge pump negative voltage circuit return to normal voltage, thereby avoiding that the display screen cannot work normally due to overvoltage of the positive and negative bias voltages of the power supply circuit, and improving the safety of the display screen. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative labor.

[0027] Figure 1 A structural schematic diagram of one embodiment of the power supply circuit of the display screen provided by the present application;

[0028] Figure 2The utility model provides a kind of circuit diagram of power supply circuit of display screen in which boost circuit can be turned off.

[0029] Figure 3 The utility model provides a kind of circuit diagram of charge pump boost circuit in the power supply circuit of display screen.

[0030] Figure 4 The utility model provides a kind of circuit diagram of charge pump negative voltage circuit in the power supply circuit of display screen. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the utility model.

[0032] It should be noted that all directionality indications (such as up, down, left, right, front, back, etc.) in the embodiments of the utility model are only used to explain the relative positional relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings). If the specific posture changes, the directionality indications also change accordingly.

[0033] In addition, the description of "first", "second" and the like in the utility model is only for the purpose of description, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled in the art. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the utility model.

[0034] In the embodiments of the utility model, the first power supply~fifth power supply all adopt VCC_3V3 power supply.

[0035] The utility model provides a kind of display screen's power supply circuit. Referring to Figure 1 , it is a kind of structure schematic diagram of one embodiment of the power supply circuit of display screen provided by the utility model. As Figure 1As shown in the first embodiment of the utility model, the utility model technical scheme forms a display screen power supply circuit through the charge pump voltage boosting circuit 100, the charge pump negative voltage circuit 200 and the turn-off voltage boosting circuit 300;Among them, the turn-off voltage boosting circuit 300 includes the turn-off circuit 301 and the voltage boosting circuit 302.

[0036] The first input end 1 of the turn-off circuit 301 is connected to the output end 1 of the charge pump voltage boosting circuit 100;The second input end 2 of the turn-off circuit 301 is connected to the output end 1 of the charge pump negative voltage circuit 200;The third input end 3 of the turn-off circuit 301 is powered by the VCC_3V3 power supply;The output end 4 of the turn-off circuit 301 is connected to the input end 1 of the voltage boosting circuit 302.

[0037] The first output end 2 of the voltage boosting circuit 302 is connected to the input end 2 of the charge pump voltage boosting circuit 100;The second output end 3 of the voltage boosting circuit 302 is connected to the input end 2 of the charge pump negative voltage circuit 200;The third output end 4 of the voltage boosting circuit 302 outputs a voltage.

[0038] Referring to Figure 2 The figure is the circuit diagram of the turn-off voltage boosting circuit in the overvoltage protection circuit provided by the utility model. Among them, the turn-off circuit 301 includes the AND gate IC chip U2, the first triode Q1, the first transistor Q2, the first resistor R1, the first capacitor C1 and the second capacitor C2. Among them, the first transistor Q2 is a PMOS tube.

[0039] The A port of the AND gate IC chip U2 is the second input end 2 of the turn-off circuit 301, which is used for receiving the control signal BOOST1_EN2 output by the output end 1 of the charge pump negative voltage circuit 200;The B port of the AND gate IC chip U2 is the first input end 1 of the turn-off circuit 301, which is used for receiving the control signal BOOST1_EN2 output by the output end 1 of the charge pump voltage boosting circuit 100;The Y port of the AND gate IC chip U2 is connected to the base 1 of the first triode Q2;The power supply port VCC of the AND gate IC chip U2 is powered by the 3.3V power supply, and is connected to the ground after the first capacitor C6;The emitter 2 of the first triode Q2 is connected to the ground;The collector 3 of the first triode Q2 is connected to the gate 1 of the PMOS tube Q1;The collector 3 of the first triode Q2 is connected to the source 2 of the PMOS tube Q1 through the first resistor R1, and is connected to the drain 3 of the PMOS tube Q1 through the second capacitor C3;The source 2 of the PMOS tube Q1 is the third input end 3 of the turn-off circuit 301, which is powered by the VCC_3V3 power supply, and the capacitors C1 and C2 are used for circuit protection;The drain 3 of the PMOS tube Q1 is the output end 4 of the turn-off circuit.

[0040] When the power supply circuit of the display screen is working normally, the control signal BOOST1_EN1 input to the first input end 1 of the enableable-off circuit 301 and the control signal BOOST1_EN2 input to the second input end 2 are both high level, the first triode Q2 is turned on, and the first resistor R1 is pulled to the ground. At this time, the voltage VGS of the gate-source of the PMOS Q1 is less than the threshold voltage VGS(th) of the PMOS Q1, the PMOS Q1 is turned on, and the VCC_3V3 power supply input to the third input end 3 of the enableable-off circuit 301 supplies power to the boost circuit 302.

[0041] When the voltage of the power supply circuit of the display screen is too high, there is a low level in the control signal BOOST1_EN1 input to the first input end 1 of the enableable-off circuit 301 and the control signal BOOST1_EN2 input to the second input end 2, the first triode Q2 cannot be turned on, and the first resistor R1 does not have a voltage drop. At this time, the voltage VGS of the gate-source of the PMOS Q1 is 0V, which is greater than the threshold voltage VGS(th) of the PMOS Q1, the PMOS Q1 is turned off, the third input end 3 of the enableable-off circuit 301 is disconnected with the boost circuit 302, and the input VCC_3V3 power supply cannot supply power to the boost circuit 302.

[0042] Further, the boost circuit 302 includes a boost IC chip U1, an inductor L1, a diode D1, a capacitor C4, a capacitor C5, and resistors R2-R4. Among them, the capacitor C4 and the capacitor C5 are used for circuit protection; the resistor R2 is used for current limiting; the boost IC chip U1 includes a VIN port, an EN port, a SW port, a GND port, and an FB port.

[0043] When the power supply circuit of the display screen is working normally, the VCC_3V3 power supply inputted from the third input end 3 of the turn-off circuit 301 supplies power to the boost circuit 302 through the input end 1 of the boost circuit 302. In the boost circuit 302, the VCC_3V3 power supply is connected to one end of the inductor L1, the VIN port of the boost IC chip U1 and one end of the resistor R2 respectively. The other end of the inductor L1 is connected to the SW port of the boost IC chip U1 and the anode of the diode D1 after outputting the output voltage VCC_BOOST; wherein the output voltage VCC_BOOST is inputted to the charge pump boost circuit 100 and the charge pump boost circuit 200 as the input voltage through the first output end 2 and the second output end 3 of the boost circuit 302 respectively. The other end of the resistor R2 is connected to the EN port of the boost IC chip U1; the GND port of the boost IC chip U1 is grounded; the FB port of the boost IC chip U1 is connected to one end of the resistor R3 and one end of the resistor R4 respectively, the other end of the resistor R4 is connected to the ground, and the other end of the resistor R3 is connected to the cathode of the diode D1, so that the FB port of the boost IC chip U1 feeds back and adjusts the resistor R3 and the resistor R4 and then outputs the voltage VCC_AVDD through the third output end 4 of the boost circuit 302.

[0044] Referring to Figure 3 The figure is a circuit diagram of a charge pump boost circuit in an overvoltage protection circuit provided by the utility model. The charge pump boost circuit 100 comprises a charge boost circuit 101 and a first overvoltage detection circuit 102.

[0045] Among them, the first input end 1 of the charge boost circuit 101 is the input end 2 of the charge pump boost circuit 100; the output end 1 of the first overvoltage detection circuit 102 is the output end 1 of the charge pump boost circuit 100; the output end 2 of the charge boost circuit 101 is connected to the input end 2 of the first overvoltage detection circuit 102.

[0046] Specifically, the charge boost circuit 101 comprises a resistor R5, capacitors C7-C9 and a diode D2. One end of the capacitor C7 is connected to the first output end 2 of the boost circuit 302 to output the voltage VCC_BOOST, the other end is connected to the diode D2, the anode of the diode D2 is inputted with a positive voltage of 12V to output the voltage VCC_VGH from the cathode of the diode D2 through the charge pump principle. At the same time, the cathode of the diode D2 is connected to the ground after connecting the resistor R5, the capacitor C8 and the capacitor C9 respectively.

[0047] Specifically, the first overvoltage detection circuit 102 includes a first voltage comparison IC chip U3, a second transistor Q3, a second resistor R6 to a seventh resistor R11, and a third capacitor C10. The first voltage comparison IC chip U3 is of the model NCV2202SN2T1G, and includes an IN+ port, an IN- port, a VEE port, a VCC port, and an OUT port.

[0048] Specifically, the input voltage of the input end 2 of the first overvoltage detection circuit 102 is the voltage VCC_VGH, which is connected to the second resistor R6, and then connected to one end of the third resistor R7 and one end of the fourth resistor R8. The other end of the third resistor R7 is connected to the ground, and the other end of the fourth resistor R8 is connected to the IN+ end of the first voltage comparison IC chip U3. The second resistor R6 and the third resistor R7 are used for voltage division of VCC_VGH, and the fourth resistor R8 is used for current limiting. The power supply port (i.e., the VCC port) of the first voltage comparison IC chip U3 is powered by a VCC_3V3 power supply; at the same time, the VCC_3V3 power supply is connected to the output end (i.e., the OUT port) of the first voltage comparison IC chip U3 and the base end 1 of the second transistor Q3 after being connected to the fifth resistor R9; the VCC_3V3 power supply is connected to the IN- end of the first voltage comparison IC chip U3 after being connected to the sixth resistor R10, to serve as a reference voltage; the VCC_3V3 power supply is connected to the ground through the third capacitor C10 and the VEE end of the first voltage comparison IC chip U3, and the emitter end 2 of the second transistor Q3 is also connected to the ground; the collector end 3 of the second transistor Q3 is connected to the VCC_3V3 power supply after being connected to the seventh resistor R11, and the collector end 3 of the power supply second transistor Q3 is the output end 1 of the first overvoltage detection circuit 102, for outputting a control signal BOOST1_EN1.

[0049] When the voltage at the IN+ end of the first voltage comparison IC chip U3 is greater than the voltage at the IN- end, the voltage VCC_VGH is in an overvoltage state, the OUT end of the first voltage comparison IC chip U3 will output a high level, Q3 is turned on, and the control signal BOOST1_EN1 is pulled to the ground. At this time, the output control signal BOOST1_EN1 is low.

[0050] When the voltage at the IN+ end of the first voltage comparison IC chip U3 is less than the voltage at the IN- end, the VCC_VGH is in a normal state, the OUT end of the first voltage comparison IC chip U3 will output a low level, Q3 is turned off, and the control signal BOOST1_EN1 is pulled to VCC_3V3 through the seventh resistor R11. At this time, the output control signal BOOST1_EN1 is high.

[0051] Referring to Figure 4The figure is a circuit diagram of a charge pump negative voltage circuit in an overvoltage protection circuit provided by the utility model. The charge pump negative voltage circuit 200 comprises a charge negative voltage circuit 201 and a second overvoltage detection circuit 202.

[0052] The first input end 1 of the charge negative voltage circuit 201 is the input end 2 of the charge pump negative voltage circuit 200; the output end 1 of the second overvoltage detection circuit 202 is the output end 1 of the charge pump negative voltage circuit 200; and the output end 2 of the charge negative voltage circuit 201 is connected to the input end 2 of the second overvoltage detection circuit 202.

[0053] Specifically, the charge negative voltage circuit 201 comprises a resistor R12, capacitors C11-C13 and a diode D3. One end of the capacitor C11 is connected to the first output end 2 of the negative voltage circuit 302 to output a voltage VCC_BOOST, the other end is connected to the diode D3, the cathode of the diode D3 is grounded, so as to output a voltage VCC_VGL from the anode of the diode D3 through the charge pump principle. Meanwhile, the anode of the diode D3 is connected to the ground after being connected to the resistor R12, the capacitor C12 and the capacitor C13 respectively.

[0054] Specifically, the second overvoltage detection circuit 202 comprises a second voltage comparison IC chip U4, eighth to thirteenth resistors R13-R18 and a fourth capacitor C14. The second voltage comparison IC chip U4 comprises an IN+ port, an IN- port, a VEE port, a VCC port and an OUT port.

[0055] Specifically, the input voltage of the input end 2 of the second overvoltage detection circuit 202 is the voltage VCC_VGL, and after being connected to the eighth resistor R13, the eighth resistor R13 is connected to one end of the ninth resistor R14 and one end of the tenth resistor R15 respectively, the other end of the ninth resistor R14 is connected to a VCC_3V3 power supply, and the other end of the tenth resistor R15 is connected to the IN+ end of the second voltage comparison IC chip U4. The eighth resistor R13 and the ninth resistor R14 are used for voltage division of VCC_VGL, and the tenth resistor R15 is used for current limiting. The power supply port (i.e. the VCC port) of the second voltage comparison IC chip U4 is powered by the VCC_3V3 power supply; meanwhile, the VCC_3V3 power supply is connected to the ground through the fourth capacitor C14 and the VEE end of the second voltage comparison IC chip U4. The VCC_3V3 power supply is connected to the output end (i.e. the OUT port) of the second voltage comparison IC chip U4 after being connected to the eleventh resistor R16, and serves as the output end 1 of the second overvoltage detection circuit 202, and is used for outputting a control signal BOOST1_EN2. The VCC_3V3 power supply is also connected to the IN- end of the second voltage comparison IC chip U4 after being connected to the twelfth resistor R17, so as to serve as a reference voltage, and the IN- end of the second voltage comparison IC chip U4 is grounded after being connected to the thirteenth resistor R18.

[0056] When the voltage at the IN+ terminal of the second voltage comparison IC chip U4 is greater than the voltage at the IN- terminal, the voltage VCC_VGL is in the normal state, and the OUT terminal of the second voltage comparison IC chip U4 outputs a high level, and BOOST1_EN2 is pulled to VCC_3V3 through the eleventh resistor R16. At this time, the output control signal BOOST1_EN2 is high.

[0057] When the voltage at the IN+ terminal of the second voltage comparison IC chip U4 is less than the voltage at the IN- terminal, the voltage VCC_VGL is in the overvoltage state, and the OUT terminal of the second voltage comparison IC chip U4 outputs a low level, and BOOST1_EN2 is pulled to ground. At this time, the output control signal BOOST1_EN2 is low.

[0058] For example, if VCC_VGL = -12V is set as the normal state, VCC_VGL = -12.5V is set as the overvoltage state, VCC_3V3 = 3.3V, R13 = 100kohm, R14 = 20kohm, R15 = 1kohm, R17 = 100kohm, and R18 = 27kohm. When VCC_VGL = -12V, in the normal state, through calculation, VIN+ = 750mV, VIN- = 701mV, at this time VIN+ > VIN-, the second voltage comparison IC chip U4 is in the overvoltage state, therefore, the OUT terminal of the second voltage comparison IC chip U4 outputs a high level, and the control signal BOOST1_EN2 is pulled to VCC_3V3 through the eleventh resistor R16, outputting a high level. When VCC_VGL = -12.5V, in the overvoltage state, through calculation, VIN+ = 667mV, VIN- = 701mV, at this time VIN+ < VIN-, the second voltage comparison IC chip U4 is in the normal state, therefore, the OUT terminal of the second voltage comparison IC chip U4 outputs a low level, and the control signal BOOST1_EN2 is pulled to GND, outputting a low level.

[0059] The charge pump voltage boosting circuit 100 and the charge pump voltage dropping circuit 200 output control signals BOOST1_EN1 and BOOST1_EN2 respectively. When the power supply circuit of the display screen is in a normal state, the output control signals BOOST1_EN1 and BOOST1_EN2 are both high level, the cut-off circuit is in a conduction state, and the VCC_3V3 power supply supplies power to the voltage boosting circuit 302. When the power supply circuit of the display screen is in an overvoltage state, the charge pump voltage boosting circuit 100 or the charge pump voltage dropping circuit 200 is overvoltage, the control signal BOOST1_EN1 or the control signal BOOST1_EN2 has a low level signal, the cut-off circuit is in an open circuit state, that is, the VCC_3V3 power supply is cut off to supply power to the voltage boosting circuit 302, thereby avoiding damage to the display screen caused by overvoltage, and improving the reliability and stability of the display screen.

[0060] According to the disclosure and teaching of the above description, those skilled in the art of the present application can also make appropriate changes and modifications to the above embodiments. Therefore, the present application is not limited to the specific embodiments disclosed and described above, and some modifications and changes of the present application should fall within the protection scope of the claims of the present application. In addition, although some specific terms are used in the specification, these terms are only for convenience of explanation and do not constitute any limitation on the present application.

Claims

1. A power supply circuit for a display screen, characterized by The application relates to a power supply circuit, which comprises a charge pump voltage boosting circuit, a charge pump voltage reducing circuit and a turn-off voltage boosting circuit; the turn-off voltage boosting circuit comprises a turn-off circuit and a voltage boosting circuit; a first input end of the turn-off circuit is connected to an output end of the charge pump voltage boosting circuit; a second input end of the turn-off circuit is connected to an output end of the charge pump voltage reducing circuit; a third input end of the turn-off circuit is powered by a first power supply; and an output end of the turn-off circuit is connected to an input end of the voltage boosting circuit; a first output end of the voltage boosting circuit is connected to an input end of the charge pump voltage boosting circuit; a second output end of the voltage boosting circuit is connected to an input end of the charge pump voltage reducing circuit; and a third output end of the voltage boosting circuit outputs a voltage.

2. The circuit of claim 1, wherein, The turn-off circuit comprises an AND gate IC chip, a first transistor, a first triode, a first resistor, a first capacitor and a second capacitor; an A port of the AND gate IC chip is a second input end of the turn-off circuit; a B port of the AND gate IC chip is a first input end of the turn-off circuit; a Y port of the AND gate IC chip is connected to a base of the first triode; a power supply port of the AND gate IC chip is powered by the first power supply and is connected to the first capacitor and then grounded; an emitter of the first triode is connected to the ground; and a collector of the first triode is connected to a gate of the first transistor; the collector of the first triode is connected to a source of the first transistor through the first resistor and is connected to a drain of the first transistor through the second capacitor; the source of the first transistor is a third input end of the turn-off circuit; and the drain of the first transistor is an output end of the turn-off circuit.

3. The circuit of claim 2, wherein, The first transistor is a PMOS transistor.

4. The circuit of claim 1, wherein, The charge pump voltage boosting circuit comprises a charge voltage boosting circuit and a first overvoltage detection circuit; a first input end of the charge voltage boosting circuit is an input end of the charge pump voltage boosting circuit; an output end of the first overvoltage detection circuit is an output end of the charge pump voltage boosting circuit; and an output end of the charge voltage boosting circuit is connected to an input end of the first overvoltage detection circuit.

5. The circuit of claim 4, wherein, The first overvoltage detection circuit comprises a first voltage comparison IC chip, a second triode, a second resistor, a seventh resistor and a third capacitor; the input end of the first overvoltage detection circuit is connected to the second resistor, and then is connected to the third resistor and a fourth resistor respectively; the third resistor is connected to the ground; and the fourth resistor is connected to an IN+ end of the first voltage comparison IC chip; a power supply port of the first voltage comparison IC chip is powered by a second power supply; the second power supply is connected to an output end of the first voltage comparison IC chip and a base of the second triode after being connected to a fifth resistor; the second power supply is connected to an IN- end of the first voltage comparison IC chip after being connected to a sixth resistor; an emitter of the second triode is connected to the ground; a collector of the second triode is an output end of the first overvoltage detection circuit, and the collector of the second triode is connected to a third power supply after being connected to a seventh resistor.

6. The circuit of claim 5, wherein, The fourth resistor is a current-limiting resistor.

7. The circuit of claim 1, wherein, The charge pump negative voltage circuit comprises a charge negative voltage circuit and a second overvoltage detection circuit. The first input end of the charge negative voltage circuit is the input end of the charge pump negative voltage circuit; the output end of the second overvoltage detection circuit is the output end of the charge pump negative voltage circuit; and the output end of the charge negative voltage circuit is connected to the input end of the second overvoltage detection circuit.

8. The circuit of claim 7, wherein, The second overvoltage detection circuit comprises a second voltage comparison IC chip, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor and a fourth capacitor. The input end of the second overvoltage detection circuit is connected to the eighth resistor, and then connected to the ninth resistor and the tenth resistor; the ninth resistor is connected to a fifth power supply; the tenth resistor is connected to the IN+ end of the second voltage comparison IC chip; the power supply port of the second voltage comparison IC chip is powered by a fourth power supply; the fourth power supply is connected to the output end of the second voltage comparison IC chip after being connected to the eleventh resistor; the fourth power supply is connected to the IN- end of the second voltage comparison IC chip after being connected to the twelfth resistor, and is grounded after being connected to the thirteenth resistor; and the output end of the second voltage comparison IC chip is the output end of the second overvoltage detection circuit.

9. The circuit of claim 8, wherein, The tenth resistor is a current-limiting resistor.

10. The circuit of any one of claims 1-9, wherein, The power supplies of the circuit are all VCC_3V3 power supplies.

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