Over-voltage and under-voltage protection circuit, voltage control device and electronic equipment

Abstract

The utility model provides an overvoltage and undervoltage protection circuit, a voltage control device and electronic equipment. The overvoltage and undervoltage protection circuit comprises a voltage division unit, a comparison unit, a first switch unit and a second switch unit. Wherein the voltage dividing unit is used for dividing power supply voltage; the comparison unit is used for outputting a first level signal to the first switch unit when the power supply voltage is greater than or equal to the overvoltage protection voltage or the power supply voltage is less than or equal to the undervoltage protection voltage, and outputting a second level signal to the first switch unit when the power supply voltage is less than the overvoltage protection voltage and greater than the undervoltage protection voltage; the first switch unit is used for being switched off when receiving a first level signal and being switched on when receiving a second level signal; the second switch unit is used for being turned off when the first switch unit is turned off and being turned on when the first switch unit is turned on. The overvoltage and undervoltage protection circuit is relatively simple in circuit design and relatively low in circuit cost.

Description

Technical Field

[0001] The present application relates to the field of electronic circuits, and in particular to an overvoltage and undervoltage protection circuit, a voltage control device, and an electronic device. Background Art

[0002] At present, all circuits have a voltage operating range. Once the voltage operating range is exceeded, overvoltage or undervoltage will occur. Overvoltage and undervoltage will cause the circuit to be abnormal or malfunction. Therefore, it is necessary to set an overvoltage protection unit and an undervoltage protection unit in the circuit.

[0003] However, the circuit designs of current overvoltage protection units and undervoltage protection units are complex and costly. Utility Model Content

[0004] The main purpose of the present application is to provide an overvoltage and undervoltage protection circuit, a voltage control device and an electronic device, aiming to solve the problem that the circuit design of the current overvoltage protection unit and undervoltage protection unit is complex and the cost is high.

[0005] In a first aspect, the present application provides an overvoltage and undervoltage protection circuit, comprising a voltage dividing unit, a comparison unit, a first switch unit, and a second switch unit;

[0006] The input end of the voltage dividing unit is used to receive the supply voltage, and the voltage dividing unit is used to divide the supply voltage;

[0007] The input end of the comparison unit is connected to the first voltage dividing end of the voltage dividing unit, and the output end of the comparison unit is connected to the first end of the first switch unit; the comparison unit is used to output a first level signal to the first switch unit when the power supply voltage is greater than or equal to the overvoltage protection voltage, or when the power supply voltage is less than or equal to the undervoltage protection voltage; the comparison unit is also used to output a second level signal to the first switch unit when the power supply voltage is less than the overvoltage protection voltage and greater than the undervoltage protection voltage;

[0008] The second end of the first switch unit is connected to the first end of the second switch unit, and the third end of the first switch unit is used for grounding; the first switch unit is used for turning off when receiving a first level signal, and turning on when receiving a second level signal;

[0009] The second end of the second switch unit is used to connect to the load, and the third end of the second switch unit is connected to the input end of the voltage divider unit; the second switch unit is used to be turned off when the first switch unit is turned off, and turned on when the first switch unit is turned on.

[0010] In a second aspect, an embodiment of the present application further provides a voltage control device, including:

[0011] A voltage conversion circuit, used for receiving a supply voltage and performing voltage conversion on the supply voltage;

[0012] A control circuit, connected to the voltage conversion unit, and used to control the voltage conversion unit;

[0013] The overvoltage and undervoltage protection circuit as described in any one of the embodiments of the present application is connected to the power supply end of the control circuit to supply power to the control circuit.

[0014] In a third aspect, an embodiment of the present application further provides an electronic device, including:

[0015] Power interface;

[0016] The overvoltage and undervoltage protection circuit as described in any one of the embodiments of the present application is connected to the power interface.

[0017] The embodiment of the present application provides an overvoltage and undervoltage protection circuit, comprising a voltage dividing unit, a comparison unit, a first switch unit and a second switch unit. The voltage dividing unit is used to divide the supply voltage. The comparison unit is used to output a first level signal to the first switch unit when the supply voltage is greater than or equal to the overvoltage protection voltage, or when the supply voltage is less than or equal to the undervoltage protection voltage. The comparison unit is also used to output a second level signal to the first switch unit when the supply voltage is less than the overvoltage protection voltage and greater than the undervoltage protection voltage. The first switch unit is used to turn off when receiving the first level signal and turn on when receiving the second level signal. The first end of the second switch unit is connected to the first switch unit, the second end of the second switch unit is used to connect the load, and the third end of the second switch unit is used to connect the supply voltage. The second switch unit is used to turn off when the first switch unit is turned off, and turn on when the first switch unit is turned on. The first switch unit of the present application is turned off when receiving the first level signal, and the second switch unit is turned off with the turning off of the first switch unit, thereby turning off the path for the supply voltage to flow to the load, so as to provide overvoltage protection or undervoltage protection. The circuit design of the overvoltage and undervoltage protection circuit provided in the embodiment of the present application is relatively simple and does not require a high circuit cost, thus being able to solve the problem of high cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1A circuit diagram of an implementation of an overvoltage and undervoltage protection circuit provided in an embodiment of the present application;

[0020] Figure 2 A circuit diagram of an implementation of a voltage divider unit provided in an embodiment of the present application;

[0021] Figure 3 A circuit diagram of another implementation of a voltage divider unit provided in an embodiment of the present application;

[0022] Figure 4 A circuit diagram of an implementation of a comparison unit provided in an embodiment of the present application;

[0023] Figure 5 A circuit diagram of an implementation of a voltage divider unit and a comparison unit provided in an embodiment of the present application;

[0024] Figure 6 A circuit diagram of an implementation of a first switch unit provided in an embodiment of the present application;

[0025] Figure 7 A circuit diagram of an implementation of a voltage dividing unit, a comparison unit, and a first switch unit provided in an embodiment of the present application;

[0026] Figure 8 A circuit diagram of an implementation of a second switch unit provided in an embodiment of the present application;

[0027] Fig. 9 A circuit diagram of another implementation of the overvoltage and undervoltage protection circuit provided in an embodiment of the present application;

[0028] Fig.10 A schematic block diagram of a voltage control device provided in an embodiment of the present application;

[0029] Fig.11 A circuit diagram of an implementation of a voltage control device provided in an embodiment of the present application;

[0030] Fig.12 A schematic block diagram of an electronic device provided in an embodiment of the present application.

[0031] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0032] It should be noted that the terms "first" and "second" in the specification, claims and drawings of the present application are used to distinguish similar objects rather than to describe a specific order or sequence.

[0033] It should also be noted that the method disclosed in the embodiments of the present application or the method shown in the flowchart includes one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchangeable with each other, and some of the steps can also be deleted.

[0034] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0035] See also Figure 1 , Figure 1 A circuit diagram of an implementation of an overvoltage and undervoltage protection circuit provided in an embodiment of the present application.

[0036] like Figure 1 As shown, the overvoltage and undervoltage protection circuit 100 includes a voltage dividing unit 110 , a comparison unit 120 , a first switch unit 130 and a second switch unit 140 .

[0037] The input end of the voltage divider unit 110 is used to receive the power supply voltage Vg, and the voltage divider unit 110 is used to divide the power supply voltage Vg. The input end of the comparison unit 120 is connected to the first voltage divider end of the voltage divider unit 110, and the output end of the comparison unit 120 is connected to the first end of the first switch unit 130. The comparison unit 120 is used to output a first level signal to the first switch unit 130 when the power supply voltage Vg is greater than or equal to the overvoltage protection voltage, or when the power supply voltage Vg is less than or equal to the undervoltage protection voltage. The comparison unit 120 is also used to output a second level signal to the first switch unit 130 when the power supply voltage Vg is less than the overvoltage protection voltage and greater than the undervoltage protection voltage.

[0038] The second end of the first switch unit 130 is connected to the first end of the second switch unit 140, and the third end of the first switch unit 130 is grounded. The first switch unit 130 is used to turn off when receiving a first level signal, and turn on when receiving a second level signal. The second end of the second switch unit 140 is used to connect the load 10, and the third end of the second switch unit 140 is connected to the input end of the voltage dividing unit 110. The second switch unit 140 is used to turn off when the first switch unit 130 is turned off, and turn on when the first switch unit 130 is turned on.

[0039] It should be noted that the supply voltage Vg can be input from an external power supply or an internal power supply in the same device. The load 10 can be an external power-consuming device or other loads in the same device. The overvoltage protection voltage and the undervoltage protection voltage can be pre-set, and the overvoltage protection voltage is greater than the undervoltage protection voltage.

[0040] It should be noted that, after dividing the power supply voltage Vg, the voltage dividing unit 110 outputs the divided power supply voltage Vg to the comparison unit 120. The comparison unit 120 outputs a first level signal when the power supply voltage Vg is greater than or equal to the overvoltage protection voltage, and the first level signal is, for example, a low level signal. When the power supply voltage Vg is less than or equal to the undervoltage protection voltage, the first level signal output by the comparison unit 120 may also be a low level signal because the power supply voltage Vg is a small signal voltage. On the contrary, when the power supply voltage Vg is less than the overvoltage protection voltage and greater than the undervoltage protection voltage, the power supply voltage Vg can be confirmed as a normal working voltage, so the second level signal output by the comparison unit 120 to the first switch unit 130 is, for example, a high level signal.

[0041] It should be noted that the first switch unit 130 is turned off when receiving the first level signal, and the second switch unit 140 is turned off when the first switch unit 130 is turned off, thereby cutting off the path for the power supply voltage Vg to flow to the load 10, so as to provide overvoltage protection or undervoltage protection. The first switch unit 130 is turned on when receiving the second level signal, and the second switch unit 140 is turned on when the first switch unit 130 is turned on, thereby turning on the path for the power supply voltage Vg to flow to the load 10, so that the load 10 can work normally. It can be seen from this that the circuit design of the overvoltage and undervoltage protection circuit 100 provided in the embodiment of the present application is relatively simple, and does not require a high circuit cost, so it can solve the problem of high cost.

[0042] In one embodiment, please refer to Figure 2 , Figure 2 This is a circuit diagram of an implementation of a voltage divider unit provided in an embodiment of the present application. Figure 2 As shown, the voltage divider unit 110 includes a resistor Ra and a resistor Rb. The first end of the resistor Ra serves as an input end of the voltage divider unit 110, and is used to receive a supply voltage Vg. The second end of the resistor Ra and the first end of the resistor Rb are connected, and the second end of the resistor Ra can serve as a first voltage divider end Ve1 of the voltage divider unit 110, and the second end of the resistor Rb is grounded.

[0043] In one embodiment, please refer to Figure 3 , Figure 3 This is a circuit diagram of another implementation of the voltage divider unit provided in the embodiment of the present application. Figure 3As shown, the voltage dividing unit 110 includes a second resistor R1, a third resistor R2 and a fourth resistor R3. The first end of the second resistor R1 is used to receive the supply voltage Vg, the second end of the second resistor R1 is connected to the first end of the third resistor R2, the second end of the third resistor R2 is connected to the first end of the fourth resistor R3, and both ends of the fourth resistor R3 are grounded. The second end of the second resistor R1 serves as the second voltage dividing end Ve2 of the voltage dividing unit 110, and the second end of the third resistor R2 serves as the first voltage dividing end Ve1 of the voltage dividing unit 110.

[0044] It should be noted that the resistance values ​​of the second resistor R1, the third resistor R2 and the fourth resistor R3 can be adjusted according to actual conditions. For example, the resistance values ​​of the second resistor R1, the third resistor R2 and the fourth resistor R3 can be determined according to the reference voltage of the first voltage divider terminal Ve1.

[0045] It is understandable that the second resistor R1, the third resistor R2, and the fourth resistor R3 may be composed of one or more resistors, respectively. The voltage dividing unit 110 may also include other resistors or other devices, which are not specifically limited in the embodiment of the present application.

[0046] In one embodiment, please refer to Figure 4 , Figure 4 This is a circuit diagram of an implementation of a comparison unit provided in an embodiment of the present application. Figure 4 As shown, the comparison unit 120 includes a controllable precision voltage-stabilizing source D1. The reference electrode of the controllable precision voltage-stabilizing source D1 is connected to the first voltage-dividing terminal Ve1 of the voltage-dividing unit 110 as the input terminal of the comparison unit 120. The cathode of the controllable precision voltage-stabilizing source D1 is grounded. The anode of the controllable precision voltage-stabilizing source D1 is connected to the first terminal Vr of the first switch unit 130 as the output terminal of the comparison unit 120. The anode of the controllable precision voltage-stabilizing source D1 is also connected to the second voltage-dividing terminal Ve2 of the voltage-dividing unit 110.

[0047] It should be noted that the first voltage dividing terminal Ve1 of the voltage dividing unit 110 is used to output a reference voltage to the reference pole of the controllable precision voltage regulator D1, and the reference voltage can be determined according to the overvoltage protection voltage. The controllable precision voltage regulator D1 can be turned on when the supply voltage Vg is greater than or equal to the overvoltage protection voltage, thereby outputting a first level signal to the first switch unit 130. The controllable precision voltage regulator D1 can also be turned off when the supply voltage Vg is less than or equal to the undervoltage protection voltage, thereby outputting a first level signal to the first switch unit 130. The controllable precision voltage regulator D1 can also output a second level signal to the first switch unit 130 when the supply voltage Vg is less than the overvoltage protection voltage and greater than the undervoltage protection voltage.

[0048] It should be noted that the use of controllable precision voltage regulator D1 as the comparison unit 120 does not require an additional reference source, the circuit is simple and has fewer components, and does not require a high circuit cost. At the same time, it can avoid the problem of no actual reference level before power-on for overvoltage and undervoltage protection.

[0049] Exemplarily, the controllable precision voltage regulator D1 is TL431, and TL431 is used as a comparator. The internal reference level of TL431 is 2.5V, that is, the reference voltage of the reference electrode is 2.5V. When the divided supply voltage Vg is less than 2.5V, D1 is turned off, and the first level signal is output to the second switch unit 140 through the anode of the controllable precision voltage regulator D1. When the divided supply voltage Vg is greater than or equal to 2.5V, D1 is turned on, and the first level signal is output to the first switch unit 130 through the anode of the controllable precision voltage regulator D1. In addition, when the supply voltage Vg is less than or equal to the undervoltage protection voltage, D1 is turned off, but because the voltage value of the supply voltage Vg at this time is small, the first level signal is also output to the second switch unit 140 through the anode of the controllable precision voltage regulator D1.

[0050] In one embodiment, the comparison unit 120 may also include other comparators, such as a differential comparator, an operational amplifier comparator, etc. Exemplarily, the comparison unit 120 may include a reference terminal, which is used to input a reference voltage, so that the corresponding first level signal or second level signal can be output under different comparison results between the supply voltage Vg and the overvoltage protection voltage and the undervoltage protection voltage, which is not specifically limited in the embodiment of the present application.

[0051] In one embodiment, if Figure 4 As shown, the comparison unit 120 further includes a first resistor R5, a first end of the first resistor R5 is connected to the second voltage dividing end Ve2 of the voltage dividing unit 110, and a second end of the first resistor R5 is connected to the anode of the controllable precision voltage stabilizing source D1. The supply voltage Vg can be divided by the first resistor R5, thereby providing protection for the controllable precision voltage stabilizing source D1.

[0052] In one embodiment, if Figure 5 As shown, the overvoltage and undervoltage protection circuit 100 further includes a power-on delay unit, which includes a first capacitor C2. The first end of the first capacitor C2 is connected to the second voltage dividing end Ve2 of the voltage dividing unit 110, and the second end of the first capacitor C2 is grounded.

[0053] It should be noted that when the supply voltage Vg is connected to the overvoltage and undervoltage protection circuit 100, the first capacitor C2 needs to be charged first, so as to provide a power-on delay function. By setting a power-on delay unit, the circuit components can be well protected and transient faults are not likely to occur.

[0054] For example, Figure 5 As shown, when the power supply voltage Vg is just connected, the voltage of the second voltage divider terminal Ve2 is 0, and the voltage of C1 is also 0. Vg charges the capacitor C1 through the resistor R1, thereby providing a power-on delay function. It should be noted that the power-on delay time can be changed by changing the resistance values ​​of the resistors R1, R5, etc. and the size of the capacitor C1.

[0055] In one embodiment, please refer to Figure 6 , Figure 6 This is a circuit diagram of an implementation of the first switch unit provided in an embodiment of the present application. Figure 6 As shown, the first switch unit 130 includes an NMOS transistor Q1 and a fifth resistor R7. The gate of the NMOS transistor Q1 serves as the first terminal Vr of the first switch unit 130, and is connected to the output terminal of the comparison unit 120. The drain of the NMOS transistor Q1 serves as the second terminal Va of the first switch unit 130, and is connected to the first terminal of the second switch unit 140. The source of the NMOS transistor Q1 serves as the third terminal of the first switch unit 130, and is used for grounding. The fifth resistor R7 is connected between the gate and the drain of the NMOS transistor Q1.

[0056] It should be noted that the fifth resistor R7 is a voltage-stabilizing resistor. The NMOS tube Q1 can be turned off when receiving a first level signal, and turned on when receiving a second level signal. For example, the NMOS tube Q1 is turned off when receiving a low level signal, and turned on when receiving a high level signal. It is understandable that the first switch unit 130 may also include other components such as resistors, and the first switch unit 130 may also include switching devices such as triodes and PMOS tubes, and the embodiments of the present application do not specifically limit this.

[0057] In one embodiment, if Figure 7 As shown, the overvoltage and undervoltage protection circuit 100 also includes a power-on delay unit, which includes a second capacitor C2, and the second capacitor C2 is connected in parallel with the fifth resistor R7. It should be noted that when the supply voltage Vg is connected to the overvoltage and undervoltage protection circuit 100, the second capacitor needs to be charged first, so as to provide a power-on delay function. By setting the power-on delay unit, the circuit components can be well protected from transient faults.

[0058] For example, Figure 7 As shown in the figure, when the supply voltage Vg is just connected, the voltage at the Vr terminal is 0, Q1 is turned off, and Vg charges the capacitor C2 through the resistors R1 and R5. When the voltage at the Vr terminal reaches the conduction level of Q1, Q1 is turned on. By changing the resistance values ​​of resistors such as R1 and R5 and the size of capacitor C2, the time for point B to reach the conduction level of Q2 can be adjusted, thereby changing the power-on delay time.

[0059] In one embodiment, if Figure 8As shown, the second switch unit 140 includes a PMOS tube Q2, a sixth resistor R6 and a seventh resistor R4. The first end of the sixth resistor R6 is connected to the second end Va of the first switch unit 130 as the first end of the second switch unit 140. The second end of the sixth resistor R6 is connected to the gate of the PMOS tube Q2. The drain of the PMOS tube Q2 is used as the second end Vb of the second switch unit 140 for connecting the load 10. The source of the PMOS tube Q2 is connected to the input end of the voltage divider unit 110 as the third end of the second switch unit 140, so that the power supply voltage Vg can be connected. The seventh resistor R4 is connected between the gate and the drain of the PMOS tube Q2.

[0060] It should be noted that the sixth resistor R6 is a voltage-dividing resistor, the seventh resistor R4 is a voltage-stabilizing resistor, and both the sixth resistor R6 and the seventh resistor R4 can provide protection. The PMOS tube Q2 is turned off when the first switch unit 130 is turned off, and is turned on when the first switch unit 130 is turned on. It is understandable that the second switch unit 140 can also be an NMOS tube, and the second switch unit 140 can also include other components such as resistors, and the second switch unit 140 can also include switching devices such as triodes, which are not specifically limited in the embodiments of the present application.

[0061] In the overvoltage and undervoltage protection circuit 100 described in the above embodiment, the first switch unit 130 is turned off when receiving the first level signal, and the second switch unit 140 is turned off when the first switch unit 130 is turned off, thereby cutting off the path for the power supply voltage Vg to flow to the load 10, thereby providing overvoltage protection or undervoltage protection. The first switch unit 130 is turned on when receiving the second level signal, and the second switch unit 140 is turned on when the first switch unit 130 is turned on, thereby turning on the path for the power supply voltage Vg to flow to the load 10, so that the load 10 can work normally. It can be seen from this that the circuit design of the overvoltage and undervoltage protection circuit 100 provided in the embodiment of the present application is relatively simple, and does not require a high circuit cost, so it can solve the problem of high cost.

[0062] The following Fig. 9 Taking the overvoltage and undervoltage protection circuit provided in the embodiment of the present application as an example, the overvoltage and undervoltage protection circuit is described.

[0063] like Fig. 9 As shown, the supply voltage Vg is, for example, the power supply voltage VCC, and the load is RL. D1 uses TL431 as a comparator, and the internal reference level of TL431 is 2.5V, that is, the reference voltage at point A is 2.5V. When <2.5V, D1 is turned off, and when greater than or equal to 2.5V, D1 is turned on.

[0064] Overvoltage: When VCC is overvoltage, after the voltage at point A is greater than 2.5V by resistors R1 and R2, D1 is turned on, point B is at a low level, Q1 is turned off, and point C is at a high level, causing Q2 to be turned off to achieve overvoltage protection function.

[0065] Undervoltage: When the VCC voltage is too low, the voltage at point A is less than 2.5V, D1 is high resistance, and after voltage division by resistors (R1, R2, R3, R5, R7), the voltage at point B cannot reach the on-voltage of Q1, so Q2 is always in the off state, and VCC cannot be loaded on the load RL.

[0066] Normal operation: When the voltage of A is less than 2.5V, D1 is turned off, and after voltage division by resistors (R1, R2, R3, R5, R7), the gate of Q2 is at a high level, Q1 is turned on, and the voltage at point C is at a low level after voltage division by R4 and R6, Q2 (P tube) is turned on, and VCC is loaded on the load RL.

[0067] It should be noted that the advantages of the overvoltage and undervoltage protection circuit provided in the embodiment of the present application are: low cost, simple circuit, few components, no need to add additional reference source, and at the same time having the advantage of power-on delay.

[0068] Please refer to Fig.10 , Fig.10 A schematic block diagram of a voltage control device provided in an embodiment of the present application.

[0069] like Fig.10 As shown, the voltage control device 200 includes:

[0070] The voltage conversion circuit 210 is used to receive a supply voltage and perform voltage conversion on the supply voltage;

[0071] A control circuit 220 connected to the voltage conversion unit 210 and configured to control the voltage conversion unit 210;

[0072] The overvoltage and undervoltage protection circuit 230 described in the above embodiment is connected to the power supply terminal of the control circuit 220 to supply power to the control circuit 220 .

[0073] The overvoltage and undervoltage protection circuit 230 may be the overvoltage and undervoltage protection circuit 100 described in the above embodiment. The control circuit 220 may include a control chip, and the voltage conversion circuit 210 may include a transformer, and of course may include other devices, which are not specifically limited in the present embodiment.

[0074] For example, Fig.11As shown, the voltage control device 200 can be a flyback power supply, which includes a voltage conversion circuit 210, a control circuit 220 and an overvoltage and undervoltage protection circuit 230. Among them, the input end of the voltage conversion circuit 210 is used to connect the power supply voltage VBUS, and the voltage conversion circuit 210 includes a transformer T1. The input end of the overvoltage and undervoltage protection circuit 230 is also used to connect the power supply voltage VBUS, and the output end of the overvoltage and undervoltage protection circuit 230 is used to output the target voltage VCC. The control circuit 220 includes a control chip U1 and a third switch Q3. The output end of the overvoltage and undervoltage protection circuit 230 is connected to the power supply end of the control chip U1. When the power supply voltage VBUS is overvoltage or undervoltage, the overvoltage and undervoltage protection circuit 230 is in an off state, thereby shutting off the power supply to the control chip U1, and the third switch Q3 is disconnected, so that the voltage conversion circuit 210 does not work. When the power supply voltage VBUS is a normal operating voltage, the overvoltage and undervoltage protection circuit 230 provides the target voltage VCC to the control chip U1, and the control chip U1 outputs an enable signal such as a pwm signal to the third switch Q3, thereby controlling the conduction time of the third switch Q3, so that the voltage conversion circuit 210 can perform voltage conversion on the power supply voltage VBUS.

[0075] That is to say, Fig.11 As shown, when the VBUS voltage is normal, the voltage of C1 is divided to make Q1 conduct. The voltage of C1 is loaded on C2 as VCC, which is used to start U1. After U1 starts, transformer T1 works. The secondary coil of transformer T1 is connected to Q2 through diode D2, so the secondary of transformer T1 is continuously powered to ensure long-term operation of U1, forming a closed loop. When VBUS is overvoltage, D1 is turned on to pull the gate of Q1 down to a low level and Q1 is turned off, so that Q2 is turned off and VCC cannot be continuously powered, U1 stops working, and the transformer stops energy transmission. When the VBUS voltage is too low, Q1 cannot be turned on and U1 cannot start.

[0076] It can be understood that the beneficial effects that can be achieved by the electronic device provided in the embodiments of the present application can refer to the beneficial effects of the overvoltage and undervoltage protection circuits in the corresponding embodiments provided above, and will not be repeated here.

[0077] Please refer to Fig.12 , Fig.12 A schematic block diagram of an electronic device provided in an embodiment of the present application.

[0078] like Fig.12 As shown, the electronic device 300 includes:

[0079] The power interface 310 and the overvoltage and undervoltage protection circuit 320 described in the above embodiment, the overvoltage and undervoltage protection circuit 320 is connected to the power interface.

[0080] The power interface 310 may be a power input interface or a power output interface. When the power interface 310 is a power input interface, it may be used to connect an external power source, so that the power interface 310 may provide a power supply voltage to the overvoltage and undervoltage protection circuit 320. When the power interface 310 is a power output interface, it may be used to connect a load, so that the power interface 310 may provide power to the load. The overvoltage and undervoltage protection circuit 320 may be the overvoltage and undervoltage protection circuit 100 described in the above embodiment.

[0081] In one embodiment, the electronic device 300 further includes an internal power source, such as a battery module, which includes one or more energy storage units, such as one or more batteries. Multiple batteries can be connected in series or in parallel to form the battery module.

[0082] It can be understood that the beneficial effects that can be achieved by the electronic device provided in the embodiments of the present application can refer to the beneficial effects of the overvoltage and undervoltage protection circuits in the corresponding embodiments provided above, and will not be repeated here.

[0083] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0084] The disclosure above provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described above. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0085] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0086] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present application.

Claims

1. An overvoltage and undervoltage protection circuit, It is characterized in that It includes a voltage dividing unit, a comparison unit, a first switch unit and a second switch unit; The input end of the voltage dividing unit is used to receive the supply voltage, and the voltage dividing unit is used to divide the supply voltage; The input end of the comparison unit is connected to the first voltage dividing end of the voltage dividing unit, and the output end of the comparison unit is connected to the first end of the first switch unit; the comparison unit is used to output a first level signal to the first switch unit when the supply voltage is greater than or equal to the overvoltage protection voltage, or when the supply voltage is less than or equal to the undervoltage protection voltage; The comparison unit is further configured to output a second level signal to the first switch unit when the supply voltage is less than the overvoltage protection voltage and greater than the undervoltage protection voltage; The second end of the first switch unit is connected to the first end of the second switch unit, and the third end of the first switch unit is used for grounding; the first switch unit is used for turning off when receiving a first level signal, and turning on when receiving a second level signal; The second end of the second switch unit is used to connect to the load, and the third end of the second switch unit is connected to the input end of the voltage divider unit; the second switch unit is used to be turned off when the first switch unit is turned off, and turned on when the first switch unit is turned on.

2. The overvoltage and undervoltage protection circuit according to claim 1, It is characterized in that The comparison unit includes a controllable precision voltage stabilization source; The reference electrode of the controllable precision voltage-stabilizing source serves as the input terminal of the comparison unit; the cathode of the controllable precision voltage-stabilizing source is grounded; The anode of the controllable precision voltage-stabilizing source serves as the output terminal of the comparison unit, and the anode of the controllable precision voltage-stabilizing source is also connected to the second voltage-dividing terminal of the voltage-dividing unit.

3. The overvoltage and undervoltage protection circuit according to claim 2, It is characterized in that The comparison unit further includes a first resistor, a first end of the first resistor is connected to the second voltage-dividing end of the voltage-dividing unit, and a second end of the first resistor is connected to the anode of the controllable precision voltage-stabilizing source.

4. The overvoltage and undervoltage protection circuit according to claim 2, It is characterized in that The voltage dividing unit includes a second resistor, a third resistor and a fourth resistor; The first end of the second resistor is used to receive the power supply voltage, the second end of the second resistor is connected to the first end of the third resistor, the second end of the third resistor is connected to the first end of the fourth resistor, and both ends of the fourth resistor are grounded; The second end of the second resistor serves as the second voltage dividing end of the voltage dividing unit, and the second end of the third resistor serves as the first voltage dividing end of the voltage dividing unit.

5. The overvoltage and undervoltage protection circuit according to claim 2, It is characterized in that The overvoltage and undervoltage protection circuit further includes a power-on delay unit, and the power-on delay unit includes a first capacitor; A first end of the first capacitor is connected to a second voltage-dividing end of the voltage-dividing unit, and a second end of the first capacitor is grounded.

6. The overvoltage and undervoltage protection circuit according to any one of claims 1 to 5, It is characterized in that The first switch unit includes an NMOS tube and a fifth resistor; the gate of the NMOS tube serves as the first end of the first switch unit, the drain of the NMOS tube serves as the second end of the first switch unit, and the source of the NMOS tube serves as the third end of the first switch unit; The fifth resistor is connected between the gate and the drain of the NMOS tube.

7. The overvoltage and undervoltage protection circuit according to claim 6, It is characterized in that The overvoltage and undervoltage protection circuit further includes a power-on delay unit, and the power-on delay unit includes a second capacitor, and the second capacitor is connected in parallel with the fifth resistor.

8. The overvoltage and undervoltage protection circuit according to any one of claims 1 to 5, It is characterized in that The second switch unit includes a PMOS tube, a sixth resistor and a seventh resistor; The first end of the sixth resistor serves as the first end of the second switch unit, and the second end of the sixth resistor is connected to the gate of the PMOS tube; The drain of the PMOS tube serves as the second end of the second switch unit, and the source of the PMOS tube serves as the third end of the second switch unit; The seventh resistor is connected between the gate and the drain of the PMOS tube.

9. A voltage control device, It is characterized in that include: A voltage conversion circuit, used for receiving a supply voltage and performing voltage conversion on the supply voltage; A control circuit, connected to the voltage conversion unit, and used to control the voltage conversion unit; The overvoltage and undervoltage protection circuit according to any one of claims 1 to 8 is connected to the power supply terminal of the control circuit to supply power to the control circuit.

10. An electronic device, It is characterized in that include: Power interface; The overvoltage and undervoltage protection circuit according to any one of claims 1 to 8, connected to the power interface.

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