Over-voltage and under-voltage protection circuit

Abstract

The utility model discloses an overvoltage and undervoltage protection circuit. The overvoltage and undervoltage protection circuit comprises a partial voltage detection module, an undervoltage protection control module and a switch module. The partial voltage detection module is electrically connected with the under-voltage protection control module and the switch module and is used for outputting a first detection voltage and a second detection voltage according to the input voltage; the under-voltage protection control module is electrically connected with the switch module and is used for outputting a first level voltage to the switch module when the first detection voltage is lower than a first set voltage and outputting a second level voltage to the switch module when the first detection voltage is higher than the first set voltage; switching off according to the second level voltage; and when the second detection voltage is higher than the second set voltage, the switch is switched on according to the second detection voltage. According to the technical scheme of the utility model, the overvoltage and undervoltage protection circuit can be suitable for application scenarios of wide-range input voltage, and the overvoltage and undervoltage protection circuit is simple in circuit, low in cost and suitable for mass production application.

Description

Technical Field

[0001] The utility model relates to the technical field of power protection, in particular to an overvoltage and undervoltage protection circuit. Background Art

[0002] In recent years, with the rapid development of the photovoltaic industry, the demand for power supplies has been increasing. The voltage of photovoltaic panels is affected by factors such as light / angle / cloud cover, and the input voltage of the photovoltaic fluctuates greatly. It is necessary to equip a perfect input voltage protection circuit on the power supply.

[0003] The existing overvoltage protection and undervoltage protection functions of power supply chips cannot be used in scenarios with a wide range of input voltages such as photovoltaic and high withstand voltage requirements. Therefore, there is an urgent need to design a protection circuit with a wide range of input voltages and high withstand voltage. Summary of the Utility Model

[0004] The utility model provides an overvoltage and undervoltage protection circuit to achieve overvoltage and undervoltage protection under a wide range of input voltages, with a simple circuit and low cost, and meeting the high withstand voltage requirements.

[0005] The utility model provides an overvoltage and undervoltage protection circuit, including: a voltage division detection module, an undervoltage protection control module, and a switch module;

[0006] The voltage division detection module is electrically connected to the undervoltage protection control module and the switch module respectively, and is used to output a first detection voltage to the undervoltage protection control module according to the input voltage, and is used to output a second detection voltage to the switch module according to the input voltage;

[0007] The undervoltage protection control module is electrically connected to the switch module, and is used to output a first level voltage to the switch module when the first detection voltage is lower than a first set voltage, and output a second level voltage to the switch module when the first detection voltage is higher than the first set voltage;

[0008] The switch module is used to conduct according to the first level voltage, and turn off according to the second level voltage; the switch module is also used to conduct according to the second detection voltage when the second detection voltage is higher than a second set voltage; the second set voltage is higher than the first set voltage.

[0009] Optionally, the undervoltage protection control module includes a first switch unit, a first end of the first switch unit is electrically connected to a power supply terminal, a second end of the first switch unit is electrically connected to a reference voltage terminal, and the reference voltage accessed by the reference voltage terminal is lower than the power supply voltage of the power supply terminal; the voltage division detection module includes a first voltage division output terminal, and the first voltage division output terminal is used to output the first detection voltage;

[0010] The control terminal of the first switching unit is electrically connected to the first voltage-dividing output terminal. The first switching unit is configured to turn off when the first detected voltage is lower than the first set voltage; and to turn on when the first detected voltage is higher than the first set voltage.

[0011] Optionally, the undervoltage protection control module further includes a protection resistor, which is connected in series between the power supply terminal and the first end of the first switching unit.

[0012] Optionally, the voltage-dividing detection module includes a voltage-dividing resistor connected in series between the first voltage-dividing output terminal and the reference voltage terminal; the overvoltage and undervoltage protection circuit further includes an undervoltage protection hysteresis module, which is electrically connected to the first end of the first switching unit and the first voltage-dividing output terminal respectively. The undervoltage protection hysteresis module is configured to, when the first switching unit is turned off, connect an additional voltage-dividing resistor in parallel between the first voltage-dividing output terminal and the reference voltage terminal.

[0013] Optionally, the undervoltage protection hysteresis module includes an additional voltage-dividing resistor and a second switching unit. The additional voltage-dividing resistor and the second switching unit are connected in series between the first voltage-dividing output terminal and the reference voltage terminal. The control terminal of the second switching unit is electrically connected to the first end of the first switching unit. The second switching unit is configured to turn on when the first switching unit is turned off.

[0014] Optionally, the undervoltage protection hysteresis module further includes a first voltage stabilization unit and a voltage-dividing unit. The voltage stabilization unit and the voltage-dividing unit are connected in series between the first end of the first switching unit and the reference voltage terminal in sequence. The output terminal of the voltage-dividing unit is electrically connected to the control terminal of the second switching unit.

[0015] Optionally, the switching module includes a third switching unit and a protection unit. The third switching unit is connected in series between the protection signal output terminal of the overvoltage and undervoltage protection circuit and the reference voltage terminal;

[0016] The protection unit is electrically connected to the voltage-dividing detection module, the undervoltage protection control module, and the control terminal of the third switching unit respectively. The protection unit is configured to stabilize and divide the second detected voltage and then output it to the control terminal of the third switching unit; and to stabilize and divide the first level voltage or the second level voltage and then output it to the control terminal of the third switching unit. The third switching unit is configured to turn on or off according to the voltage at its control terminal.

[0017] Optionally, the voltage-dividing detection module includes a second voltage-dividing output terminal, which is configured to output a second detected voltage;

[0018] The protection unit includes a second voltage stabilizing unit, a third voltage stabilizing unit, a first resistor, a second resistor, and a third resistor;

[0019] The second voltage stabilizing unit and the first resistor are connected in series between the output end of the under-voltage protection control module and the control end of the third switching unit in sequence;

[0020] The third voltage stabilizing unit and the second resistor are connected in series between the second voltage division output end and the control end of the third switching unit in sequence;

[0021] The first end of the third resistor is electrically connected to the control end of the third switching unit, and the second end of the third resistor is electrically connected to the reference voltage terminal.

[0022] Optionally, the over-voltage and under-voltage protection circuit further includes an anti-reverse diode;

[0023] The positive electrode of the anti-reverse diode is electrically connected to the second resistor, and the negative electrode of the anti-reverse diode is electrically connected to the control end of the third switching unit;

[0024] Or, the positive electrode of the anti-reverse diode is electrically connected to the first resistor, and the negative electrode of the anti-reverse diode is electrically connected to the control end of the third switching unit.

[0025] Optionally, the voltage division detection module includes a detection input terminal and a reference voltage terminal, and a fourth resistor, a fifth resistor, and a sixth resistor connected in series between the detection input terminal and the reference voltage terminal; the detection input terminal is used to access the input voltage, and the reference voltage terminal is used to access the reference voltage;

[0026] The voltage division detection module further includes a first voltage division output end and a second voltage division output end; the common terminal of the fourth resistor and the fifth resistor serves as the second voltage division output end, and the second voltage division output end is used to output the second detection voltage; the common terminal of the fifth resistor and the sixth resistor serves as the first voltage division output end, and the first voltage division output end is used to output the first detection voltage.

[0027] In the technical solution of the embodiment of the present utility model, by providing a voltage-dividing detection module, an undervoltage protection control module, and a switching module, the voltage-dividing detection module can step down the input high voltage, output a first detection voltage to the undervoltage protection control module, and output a second detection voltage to the switching module. When the first detection voltage is lower than the first set voltage, the undervoltage protection control module outputs a first-level voltage to the switching module, and the switching module conducts, enabling the overvoltage and undervoltage protection circuit to implement the undervoltage protection function, and the power supply stops outputting. Or, when the first detection voltage is higher than the first set voltage, the undervoltage protection control module outputs a second-level voltage to the switching module, and the switching module cuts off, and the power supply outputs normally. Or, when the second detection voltage is higher than the second set voltage, the switching module conducts, enabling the overvoltage and undervoltage protection circuit to implement the overvoltage protection function, and the power supply stops outputting. Through this setting, the power supply can achieve overvoltage and undervoltage protection under high voltage and wide-range input voltages, especially suitable for application scenarios with photovoltaic input. At the same time, the circuit of the overvoltage and undervoltage protection circuit is simple, the cost is low, and it is suitable for mass production applications.

[0028] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present utility model, nor is it used to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. Brief Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of an overvoltage and undervoltage protection circuit provided by an embodiment of the present utility model;

[0031] Figure 2 It is a schematic structural diagram of another overvoltage and undervoltage protection circuit provided by an embodiment of the present utility model;

[0032] Figure 3 It is a schematic structural diagram of another overvoltage and undervoltage protection circuit provided by an embodiment of the present utility model;

[0033] Figure 4 It is a schematic structural diagram of another overvoltage and undervoltage protection circuit provided by an embodiment of the present utility model. Detailed Description of the Embodiments

[0034] To enable those skilled in the art to better understand the solution of the present utility model, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0035] It should be noted that the terms "first", "second", etc. in the description and claims of the present utility model and the above-mentioned accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present utility model described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0036] Figure 1 FIG. is a schematic structural diagram of an overvoltage and undervoltage protection circuit provided by an embodiment of the present utility model. Refer to Figure 1 , the overvoltage and undervoltage protection circuit includes a voltage division detection module 10, an undervoltage protection control module 20, and a switch module 30; the voltage division detection module 10 is electrically connected to the undervoltage protection control module 20 and the switch module 30 respectively, and is used to output a first detection voltage to the undervoltage protection control module 20 according to the input voltage, and is used to output a second detection voltage to the switch module 30 according to the input voltage; the undervoltage protection control module 20 is electrically connected to the switch module 30, and is used to output a first level voltage to the switch module 30 when the first detection voltage is lower than the first set voltage, and output a second level voltage to the switch module 30 when the first detection voltage is higher than the first set voltage; the switch module 30 is used to conduct according to the first level voltage and turn off according to the second level voltage; the switch module 30 is further used to conduct according to the second detection voltage when the second detection voltage is higher than the second set voltage; the second set voltage is higher than the first set voltage.

[0037] Among them, the overvoltage and undervoltage protection circuit can be integrated into the power supply. The power supply can also include a power control chip and a voltage conversion unit (e.g., DC-DC, Direct Current to Direct Current). The power control chip is used to control the output of the power supply, and the voltage conversion unit is used to convert the input voltage into a voltage matching the load electrical system. The overvoltage and undervoltage protection circuit can be connected to the power control chip, and the power control chip can be connected to the voltage conversion unit. The overvoltage and undervoltage protection circuit is used to implement the undervoltage protection function and the overvoltage protection function according to the input voltage, so that the power control chip outputs a control signal to control whether the voltage conversion unit normally converts, and further controls whether the power supply normally outputs. Exemplarily, when the input voltage is overvoltage or undervoltage, the overvoltage and undervoltage protection circuit can send a protection action signal to the power control chip, and the power control chip controls the voltage conversion unit to stop working according to the protection action signal, and the power supply stops outputting; when the overvoltage and undervoltage protection circuit is in a normal working state, the overvoltage and undervoltage protection circuit does not send a protection action signal to the power control chip, and the power control chip controls the voltage conversion unit to normally perform voltage conversion, and the power supply normally outputs.

[0038] The voltage division detection module 10 is used to divide the input voltage, and reduce the input high voltage to a low voltage. Specifically, the voltage division detection module 10 can respectively output a first detection voltage to the undervoltage protection control module 20 and a second detection voltage to the switch module 30 according to the input voltage. The first detection voltage and the second detection voltage are output from different output terminals of the voltage division detection module 10. The first detection voltage and the second detection voltage are not equal, and the magnitudes of the first detection voltage and the second detection voltage are both positively correlated with the magnitude of the input voltage. Exemplarily, the input high voltage can be 150V to 1500V. After passing through the voltage division detection module 10, the range of the first detection voltage can be 2.5V to 5V, and the range of the second detection voltage can be 5V to 10V. The setting of the voltage division detection module enables the overvoltage and undervoltage protection circuit to meet the high withstand voltage requirement, so that the overvoltage protection circuit can be applied to the application scenario with high voltage input.

[0039] The undervoltage protection control module 20 is used to output a first level voltage or a second level voltage according to the magnitude of the first detection voltage. Among them, since the magnitude of the first detection voltage is positively correlated with the magnitude of the input voltage, the magnitude of the first detection voltage can be used as a judgment basis for whether the input voltage is undervoltage. The undervoltage protection control module 20 can output different levels according to the magnitude relationship between the first detection voltage and the first set voltage. Among them, the first set voltage corresponds to the first protection voltage threshold for entering undervoltage protection. When the input voltage is equal to the first protection voltage threshold, the first detection voltage is equal to the first set voltage, and the magnitude of the first set voltage can be set according to the actual requirements of undervoltage protection.

[0040] The switch module 30 is used to conduct or cut off according to the first-level voltage and the second-level voltage output by the under-voltage protection control module 20, and is also used to conduct or cut off according to the magnitude relationship between the second detection voltage output by the voltage division detection module 10 and the second set voltage. Among them, since the magnitude of the second detection voltage is positively correlated with the magnitude of the input voltage, the magnitude of the second detection voltage can be used as a basis for judging whether the input voltage is overvoltage. Among them, the second set voltage corresponds to the second protection voltage threshold for entering overvoltage protection. When the input voltage is equal to the second protection voltage threshold, the second detection voltage is equal to the second set voltage, and the magnitude of the second set voltage can be set according to the actual requirements of overvoltage protection.

[0041] Specifically, when the voltage division detection module 10 outputs a first detection voltage according to the input voltage and the first detection voltage is higher than the first set voltage, at this time, the under-voltage protection control module 20 is turned on in response to the first detection voltage signal. Then, the under-voltage protection control module 20 outputs a second-level voltage to the switch module 30, and the switch module 30 is turned off in response to the second-level voltage, so that the power control chip can normally provide a driving signal and the power supply outputs normally. When the voltage division detection module 10 outputs a first detection voltage according to the input voltage and the first detection voltage is lower than the first set voltage, at this time, the under-voltage protection control module 20 is turned off in response to the first detection voltage signal. Then, the under-voltage protection control module 20 outputs a first-level voltage to the switch module 30, and the switch module 30 is turned on in response to the first-level voltage, so that the power control chip stops providing driving and the power supply stops outputting, thereby enabling the overvoltage and under-voltage protection circuit to achieve the under-voltage protection function. The voltage division detection module 10 can also output a second detection voltage according to the input voltage. When the second detection voltage is higher than the second set voltage, at this time, the switch module 30 is turned on in response to the second detection voltage, so that the power control chip stops providing driving and the power supply stops outputting, thereby enabling the overvoltage and under-voltage protection circuit to achieve the overvoltage protection function.

[0042] The technical solution of the embodiment of the present utility model, by providing a voltage-dividing detection module, an undervoltage protection control module and a switching module, the voltage-dividing detection module can step down the input high voltage, and output a first detection voltage to the undervoltage protection control module, and output a second detection voltage to the switching module. When the first detection voltage is lower than the first set voltage, the undervoltage protection control module outputs a first-level voltage to the switching module, and the switching module conducts, so that the overvoltage undervoltage protection circuit realizes the undervoltage protection function, and the power supply is in a stopped output state. Or, when the first detection voltage is higher than the first set voltage, the undervoltage protection control module outputs a second-level voltage to the switching module, and the switching module cuts off, and the power supply is in a normal output state. Or, when the second detection voltage is higher than the second set voltage, the switching module conducts, so that the overvoltage undervoltage protection circuit realizes the overvoltage protection function, and the power supply is in a stopped output state. Through this setting, the power supply can realize overvoltage and undervoltage protection under high voltage and wide-range input voltages, especially suitable for application scenarios with photovoltaic input. At the same time, the circuit of the overvoltage undervoltage protection circuit is simple and the cost is low, which is suitable for mass production applications.

[0043] Figure 2 FIG. is a schematic structural diagram of another overvoltage undervoltage protection circuit provided by the embodiment of the present utility model. Refer to Figure 2 , on the basis of the above embodiment, the undervoltage protection control module 20 includes a first switch unit 21. The first end A2 of the first switch unit 21 is electrically connected to the power supply terminal L1, and the second end B2 of the first switch unit 21 is electrically connected to the reference voltage terminal L2. The reference voltage VREF applied to the reference voltage terminal L2 is lower than the power supply voltage VCC of the power supply terminal L1; the voltage-dividing detection module 10 includes a first voltage-dividing output terminal O1, and the first voltage-dividing output terminal O1 is used for outputting a first detection voltage; the control terminal K2 of the first switch unit 21 is electrically connected to the first voltage-dividing output terminal O1, and the first switch unit 21 is used for turning off when the first detection voltage is lower than the first set voltage; and for turning on when the first detection voltage is higher than the first set voltage.

[0044] Among them, the reference voltage terminal L2 can be grounded, that is, the reference voltage VREF is the ground voltage (0V).

[0045] Optionally, the control terminal K3 of the switching module 30 is connected to the power supply terminal L1.

[0046] Among them, the switching module 30 can conduct when the control terminal K3 is at a high level and cut off when the control terminal K3 is at a low level; or can cut off when the control terminal K3 is at a high level and conduct when the control terminal K3 is at a low level.

[0047] Optionally, the first switching unit 21 may include a precision voltage reference device, such as an AS431 or TL431 device. In the following embodiments, the first switching unit 21 is taken as an AS431 for illustration.

[0048] Specifically, when the first voltage dividing output terminal O1 of the voltage dividing detection module 10 outputs a first detection voltage and the first detection voltage is higher than the first set voltage, at this time, after the control terminal K2 of the undervoltage protection control module 20 receives the first detection voltage, the first terminal A2 and the second terminal B2 of the first switching unit 21 are turned on, so that the input of the control terminal K3 of the switching module 30 is at a low level, and the switching module 30 is turned off. Furthermore, the power control chip can normally provide a driving signal and the power supply outputs normally. When the first voltage dividing output terminal O1 of the voltage dividing detection module 10 outputs a first detection voltage and the first detection voltage is lower than the first set voltage, at this time, after the control terminal K2 of the undervoltage protection control module 20 receives the first detection voltage, the first terminal A2 and the second terminal B2 of the first switching unit 21 are disconnected, so that the power supply voltage VCC provides a high level for the control terminal K3 of the switching module 30, and the switching module 30 is in a conducting state, so that the power control chip stops providing driving and the power supply stops outputting, and thus the overvoltage and undervoltage protection circuit realizes the undervoltage protection function. Exemplarily, since the trigger signal of the AS431 is 2.5V, the first set voltage may be 2.5V. When the first voltage dividing output terminal O1 of the voltage dividing detection module 10 outputs a first detection voltage higher than 2.5V, the first terminal A2 and the second terminal B2 of the undervoltage protection control module 20 are turned on, and the input signal of the control terminal K3 of the switching module 30 is at a low level (0V), and the switching module 30 is turned off. Furthermore, the power control chip can normally provide a driving signal and the power supply outputs normally. When the first voltage dividing output terminal O1 of the voltage dividing detection module 10 outputs a first detection voltage lower than 2.5V, the first terminal A2 and the second terminal B2 of the undervoltage protection control module 20 are turned off, and the input signal of the control terminal K3 of the switching module 30 is at a high level (VCC), and the switching module 30 is turned on. Furthermore, the power control chip stops providing a driving signal and the power supply stops outputting.

[0049] The technical solution provided by the embodiment of the present utility model, by connecting the control terminal of the first switching unit to the first voltage dividing output terminal of the voltage dividing detection module, enables the first switching unit to be turned on or off according to the voltage of the first voltage dividing output terminal, thereby realizing the undervoltage protection function or enabling the power control chip to normally provide driving, and can ensure the stability of the circuit. At the same time, by realizing the undervoltage protection and normal driving functions, the reliability of the entire system can be improved, the service life of the device can be extended, and the risk of damage can be reduced.

[0050] Optionally, continue to refer to Figure 2, the undervoltage protection control module further includes a protection resistor R7, and the protection resistor R7 is connected in series between the power supply terminal L1 and the first end A2 of the first switch unit 21.

[0051] Among them, the protection resistor R7 is used for current limiting.

[0052] Specifically, when the first end A2 and the second end B2 of the first switch unit 21 are disconnected, the power supply voltage VCC provides a high level to the control end K3 of the switch module 30. Since it passes through the protection resistor R7, the current input to the switch module 30 will not be too large. It can avoid damage to the switch module caused by excessive current and improve the stability and reliability of the system.

[0053] Figure 3 This is a schematic structural diagram of another overvoltage and undervoltage protection circuit provided by the embodiment of the present invention. Refer to Figure 3 , on the basis of the above embodiments, the voltage division detection module 10 includes a voltage division resistor R6 connected in series between the first voltage division output terminal O1 and the reference voltage terminal L2; the overvoltage and undervoltage protection circuit further includes an undervoltage protection hysteresis module 22, and the undervoltage protection hysteresis module 22 is respectively electrically connected to the first end A2 and the first voltage division output terminal O1 of the first switch unit 21. The undervoltage protection hysteresis module 22 is used to parallelly connect an additional voltage division resistor R8 between the first voltage division output terminal O1 and the reference voltage terminal L2 when the first switch unit 21 is turned off.

[0054] Among them, the undervoltage protection hysteresis module 22 is used to prevent the power supply from switching back and forth between the undervoltage protection state and the normal working state, and improve the circuit stability. The additional voltage division resistor R8 is used to be connected in parallel with the voltage division resistor R6 so that the resistance value becomes smaller, and further make the voltage value at which the power supply enters the undervoltage protection state different from the voltage value required for the power supply to recover from the undervoltage protection state to the normal working state.

[0055] Specifically, when the first end A2 and the second end B2 of the first switch unit 21 are disconnected, the power supply voltage VCC provides a high level for the control end K3 of the switch module 30. The switch module 30 is in the conducting state, causing the power supply control chip to stop providing drive and the power supply to stop outputting. Thus, the overvoltage and undervoltage protection circuit realizes the undervoltage protection function. Meanwhile, during the undervoltage protection process, since the first switch unit 21 is conducting, the additional voltage-dividing resistor R8 and the voltage-dividing resistor R6 are in parallel, and thus the resistance value decreases. When the output voltages of the voltage-dividing detection module 10 are the same, the voltage division of the voltage-dividing resistor R6 decreases at this time. If it is necessary to exit the undervoltage protection, the required input voltage will be greater than the input voltage when entering the undervoltage protection. Exemplarily, if the input voltage drops from the normal input range to the first protection voltage threshold (for example, 130V), the voltage at the first voltage-division output end O1 of the voltage-dividing detection module 10 is lower than the first set voltage, and the undervoltage protection is entered. If you want to return to the normal working state, since the resistance value decreases after the voltage-dividing resistor R6 is in parallel with the additional voltage-dividing resistor R8, therefore, the input resistance needs to be increased to the third protection voltage threshold (for example, 140V) at this time to ensure that the voltage at the first voltage-division output end O1 of the voltage-dividing detection module 10 is higher than the first set voltage, enabling the power supply to work normally. The first protection voltage threshold is less than the third protection voltage threshold. Optionally, both the first protection voltage threshold and the third protection voltage threshold are less than the minimum voltage value of the normal working range of the power supply.

[0056] The technical solution provided by the embodiment of the present utility model, by setting the undervoltage protection hysteresis module, makes the voltage value for the power supply to enter the undervoltage protection different from the voltage value for the power supply to return to the normal working state from the undervoltage protection state, which can avoid the power supply from switching back and forth between the undervoltage protection state and the normal working state and improve the circuit stability.

[0057] Optionally, continue to refer to Figure 3 , the undervoltage protection hysteresis module 22 includes an additional voltage-dividing resistor R8 and a second switch unit 221. The additional voltage-dividing resistor R8 and the second switch unit 221 are connected in series between the first voltage-division output end O1 and the reference voltage end L2. The control end of the second switch unit 221 is electrically connected to the first end A2 of the first switch unit 21, and the second switch unit 221 is used to conduct when the first switch unit 21 is turned off.

[0058] Among them, the second switch unit 221 may include a first switching transistor Q1. The control end of the first switching transistor Q1 is electrically connected to the first end A2 of the first switch unit 21. The first pole of the first switching transistor Q1 is connected to the additional voltage-dividing resistor R8, and the second pole of the first switching transistor Q1 is connected to the reference voltage end L2.

[0059] Specifically, when the first detection voltage output from the first voltage division output terminal O1 of the voltage division detection module 10 is too low, that is, the first detection voltage is lower than the first set voltage, the first end A2 and the second end B2 of the first switch unit 21 are disconnected, and the power supply voltage VCC provides a high level for the control terminal of the second switch unit 221, so that the second switch unit 221 is turned on, and then the additional voltage division resistor R8 and the voltage division resistor R6 are in a parallel state, realizing the under-voltage protection hysteresis function.

[0060] Optionally, continuing to refer to Figure 3 , the under-voltage protection hysteresis module 22 further includes a first voltage stabilization unit 222 and a voltage division unit 223. The voltage stabilization unit 222 and the voltage division unit 223 are connected in series between the first end A2 of the first switch unit 21 and the reference voltage terminal L2 in sequence, and the output terminal of the voltage division unit 223 is electrically connected to the control terminal of the second switch unit 221.

[0061] Among them, the first voltage stabilization unit 222 may include a first voltage stabilizing diode ZD1, and the voltage division unit 223 may include a first voltage division resistor R9 and a second voltage division resistor R10. The first pole of the first voltage stabilizing diode ZD1 is connected to the first end A2 of the first switch unit 21, the second pole of the first voltage stabilizing diode ZD1 is connected to the first end of the first voltage division resistor R9, the second end of the first voltage division resistor R9 is connected to the first end of the second voltage division resistor R10, and the second end of the second voltage division resistor R10 is connected to the reference voltage terminal L2. The first voltage stabilizing diode ZD1 is used to keep the voltage in the circuit at a stable level.

[0062] Specifically, when the first detection voltage output from the first voltage division output terminal O1 of the voltage division detection module 10 is too low, that is, the first detection voltage is lower than the first set voltage, the first end A2 and the second end B2 of the first switch unit 21 are disconnected, and the power supply voltage VCC provides a high level for the control electrode of the first switching transistor Q1. Due to the existence of the first voltage stabilizing diode ZD1, the first voltage division resistor R9 and the second voltage division resistor R10, the voltage input from the power supply voltage VCC to the control electrode of the first switching transistor Q1 will not be too high, which can avoid damage to the first switching transistor Q1 caused by excessive current.

[0063] Figure 4 This is a schematic structural diagram of another over-voltage and under-voltage protection circuit provided by an embodiment of the present invention. Refer to Figure 4, based on the above embodiments, the switch module 30 includes a third switch unit 31 and a protection unit 32. The third switch unit 31 is connected in series between the protection signal output terminal FAULT of the overvoltage and undervoltage protection circuit and the reference voltage terminal L2. The protection unit 32 is electrically connected to the voltage division detection module 10, the undervoltage protection control module 20, and the control terminal of the third switch unit 31 respectively. The protection unit 32 is configured to stabilize and divide the second detection voltage and then output it to the control terminal of the third switch unit 31; and to stabilize and divide the first level voltage or the second level voltage and then output it to the control terminal of the third switch unit 31. The third switch unit 31 is configured to conduct or cut off according to the voltage at its own control terminal.

[0064] Among them, the protection signal output terminal FAULT of the overvoltage and undervoltage protection circuit is connected to the power control chip.

[0065] Optionally, the overvoltage and undervoltage protection circuit includes an eleventh resistor R11. The third switch unit 31 may include a second switching transistor Q2. The control electrode of the second switching transistor Q2 is connected to the protection unit 32. The first pole of the second switching transistor Q2 is connected to the first end of the eleventh resistor R11. The second pole of the second switching transistor Q2 is connected to the reference voltage terminal L2. The second end of the eleventh resistor R11 is connected to the protection signal output terminal FAULT of the overvoltage and undervoltage protection circuit.

[0066] Specifically, when the first voltage division output terminal O1 of the voltage division detection module 10 outputs a first detection voltage and the first detection voltage is higher than the first set voltage, the first switch unit 21 conducts, the input of the control terminal of the second switching transistor Q2 is at a low level, and further the second switching transistor Q2 cuts off. The protection signal output terminal FAULT of the overvoltage and undervoltage protection circuit outputs a high level, and the power control chip can normally provide a driving signal, and the power supply outputs normally. When the first voltage division output terminal O1 of the voltage division detection module 10 outputs a second detection voltage and the first detection voltage is higher than the second set voltage, the input of the control terminal of the second switching transistor Q2 is at a high level, the second switching transistor Q2 conducts, the protection signal output terminal FAULT of the overvoltage and undervoltage protection circuit is pulled low and outputs a low level, and the power control chip stops providing a driving signal, and the power supply stops outputting.

[0067] Optionally, continue to refer to Figure 4, the voltage division detection module 10 includes a second voltage division output terminal O2, and the second voltage division output terminal O2 is used to output a second detection voltage; the protection unit 32 includes a second voltage stabilization unit 321, a third voltage stabilization unit 322, a first resistor R1, a second resistor R2, and a third resistor R3; the second voltage stabilization unit 321 and the first resistor R1 are sequentially connected in series between the output terminal of the undervoltage protection control module and the control terminal of the third switch unit 31; the third voltage stabilization unit 322 and the second resistor R2 are sequentially connected in series between the second voltage division output terminal O2 and the control terminal of the third switch unit 31; the first end of the third resistor R3 is electrically connected to the control terminal of the third switch unit 31, and the second end of the third resistor R3 is electrically connected to the reference voltage terminal L2.

[0068] Among them, the second voltage stabilization unit 321 may include a second voltage stabilizing diode ZD2, the third voltage stabilization unit 322 may include a third voltage stabilizing diode ZD3, the first pole of the second voltage stabilizing diode ZD2 is connected to the first end A2 of the first switch unit 21, the second pole of the second voltage stabilizing diode ZD2 is connected to the first resistor R1, the first pole of the third voltage stabilizing diode ZD3 is connected to the second voltage division output terminal O2 of the voltage division detection module 10, and the second pole of the third voltage stabilizing diode ZD3 is connected to the second resistor R2. The third resistor R3 is used for voltage division.

[0069] Specifically, when the first end A2 and the second end B2 of the first switch unit 21 are disconnected, the power supply voltage VCC provides a high level for the control pole of the second switching transistor Q2. Due to the existence of the second voltage stabilizing diode ZD2 and the first resistor R1, the voltage of the power supply voltage VCC input to the control pole of the second switching transistor Q2 will not be too high. When the second detection voltage output by the second voltage division output terminal O2 of the voltage division detection module 10 is higher than the second set voltage, the second detection voltage provides a high level for the control pole of the second switching transistor Q2. Due to the existence of the third voltage stabilizing diode ZD3 and the second resistor R2, the voltage of the power supply voltage VCC input to the control pole of the second switching transistor Q2 will not be too high.

[0070] Optionally, continue to refer to Figure 4 , the overvoltage undervoltage protection circuit further includes an anti-reverse diode D1; the positive pole of the anti-reverse diode D1 is electrically connected to the second resistor R2, and the negative pole of the anti-reverse diode D1 is electrically connected to the control terminal of the third switch unit 31; alternatively, the positive pole of the anti-reverse diode D1 is electrically connected to the first resistor R1, and the negative pole of the anti-reverse diode D1 is electrically connected to the control terminal of the third switch unit 31.

[0071] Among them, the connection relationship of the anti-reverse diode D1 is related to the power supply VCC and the magnitude of the voltage output by the second voltage division output terminal O2 of the voltage division detection module 10. Exemplarily, when the power supply VCC is higher than the voltage output by the second voltage division output terminal O2 of the voltage division detection module 10, the positive electrode of the anti-reverse diode D1 is electrically connected to the second resistor R2, and the negative electrode of the anti-reverse diode D1 is electrically connected to the control terminal of the third switch unit 31. When the power supply VCC is lower than the voltage output by the second voltage division output terminal O2 of the voltage division detection module 10, the positive electrode of the anti-reverse diode D1 is electrically connected to the first resistor R1, and the negative electrode of the anti-reverse diode D1 is electrically connected to the control terminal of the third switch unit 31.

[0072] Optionally, continuing to refer to Figure 4 , the voltage division detection module 10 includes a detection input terminal L3 and a reference voltage terminal L2, and a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6 connected in series between the detection input terminal L3 and the reference voltage terminal L2; the detection input terminal L3 is used to connect the input voltage Vin, and the reference voltage terminal L2 is used to connect the reference voltage GND; the voltage division detection module 10 further includes a first voltage division output terminal O1 and a second voltage division output terminal O2; the common terminal of the fourth resistor R4 and the fifth resistor R5 serves as the second voltage division output terminal O2, and the second voltage division output terminal O2 is used to output a second detection voltage; the common terminal of the fifth resistor R5 and the sixth resistor R6 serves as the first voltage division output terminal O1, and the first voltage division output terminal O1 is used to output a first detection voltage.

[0073] Specifically, when the first voltage division output terminal O1 of the voltage division detection module 10 outputs a first detection voltage and the first detection voltage is higher than the first set voltage, at this time, after the control terminal K2 of the undervoltage protection control module 20 receives the first detection voltage, the first terminal A2 and the second terminal B2 of the first switch unit 21 are conducted, so that the control poles of the first switch tube Q1 and the second switch tube Q2 both input low levels. Further, both the first switch tube Q1 and the second switch tube Q2 are in the off state, and the power control chip can normally provide a driving signal, and the power supply outputs normally. When the first voltage division output terminal O1 of the voltage division detection module 10 outputs a first detection voltage and the first detection voltage is lower than the first set voltage, at this time, after the control terminal K2 of the undervoltage protection control module 20 receives the first detection voltage, further, the first terminal A2 and the second terminal B2 of the first switch unit 21 are disconnected, so that the power supply voltage VCC provides a high level for the control terminal K3 of the switch module 30. Further, the control poles of the first switch tube Q1 and the second switch tube Q2 both input high levels. Further, both the first switch tube Q1 and the second switch tube Q2 are in the on state. When the second switch tube Q2 is conducted, the protection signal output terminal FAULT of the overvoltage undervoltage protection circuit is pulled low and outputs a low level, and the power control chip can stop providing the driving signal, and the power supply stops outputting power supply, realizing the undervoltage protection function. At the same time, when the first switch tube Q1 is conducted, the additional voltage division resistor R8 and the voltage division resistor R6 are in a parallel state, realizing the undervoltage protection hysteresis function. When the second detection voltage output by the second voltage division output terminal O2 of the voltage division detection module 10 is higher than the second set voltage, the second detection voltage provides a high level for the control pole of the second switch tube Q2. Further, the second switch tube Q2 is conducted, and the protection signal output terminal FAULT of the overvoltage undervoltage protection circuit outputs a low level, and the power control chip can stop providing the driving signal, and the power supply stops outputting, realizing the overvoltage protection function.

[0074] It should be noted that in the above embodiments, both the first switch tube Q1 and the second switch tube Q2 can be field effect transistors. Among them, both the first switch tube Q1 and the second switch tube Q2 are described by taking N-type tubes as examples. In other embodiments, according to different circuit structures, both the first switch tube Q1 and the second switch tube Q2 can also be P-type tubes, or one is an N-type tube and the other is a P-type tube.

[0075] It should be understood that the various forms of the flow shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0076] The above specific embodiments do not constitute a limitation to the protection scope of the present utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An overvoltage and undervoltage protection circuit, characterized in that, Including: A voltage division detection module, an undervoltage protection control module, and a switch module; The voltage division detection module is electrically connected to the undervoltage protection control module and the switch module respectively, and is used to output a first detection voltage to the undervoltage protection control module according to the input voltage, and is used to output a second detection voltage to the switch module according to the input voltage; The undervoltage protection control module is electrically connected to the switch module, and is used to output a first level voltage to the switch module when the first detection voltage is lower than a first set voltage, and to output a second level voltage to the switch module when the first detection voltage is higher than the first set voltage; The switch module is used to conduct according to the first level voltage and to turn off according to the second level voltage; The switch module is further used to conduct according to the second detection voltage when the second detection voltage is higher than a second set voltage; the second set voltage is higher than the first set voltage.

2. The overvoltage and undervoltage protection circuit according to claim 1, wherein The undervoltage protection control module includes a first switch unit. The first end of the first switch unit is electrically connected to the power supply terminal, and the second end of the first switch unit is electrically connected to the reference voltage terminal. The reference voltage accessed by the reference voltage terminal is lower than the power supply voltage of the power supply terminal; the voltage division detection module includes a first voltage division output terminal, and the first voltage division output terminal is used to output the first detection voltage; The control end of the first switch unit is electrically connected to the first voltage division output terminal. The first switch unit is used to turn off when the first detection voltage is lower than the first set voltage; and is used to conduct when the first detection voltage is higher than the first set voltage.

3. The overvoltage and undervoltage protection circuit according to claim 2, wherein The undervoltage protection control module further includes a protection resistor, and the protection resistor is connected in series between the power supply terminal and the first end of the first switch unit.

4. The overvoltage and undervoltage protection circuit according to claim 2, wherein The voltage division detection module includes voltage division resistors connected in series between the first voltage division output terminal and the reference voltage terminal; the overvoltage and undervoltage protection circuit further includes an undervoltage protection hysteresis module. The undervoltage protection hysteresis module is electrically connected to the first end of the first switch unit and the first voltage division output terminal respectively. The undervoltage protection hysteresis module is used to parallel an additional voltage division resistor between the first voltage division output terminal and the reference voltage terminal when the first switch unit is turned off.

5. The overvoltage and undervoltage protection circuit according to claim 4, characterized in that, The undervoltage protection hysteresis module includes an additional voltage division resistor and a second switch unit. The additional voltage division resistor and the second switch unit are connected in series between the first voltage division output terminal and the reference voltage terminal. The control end of the second switch unit is electrically connected to the first end of the first switch unit. The second switch unit is used to conduct when the first switch unit is turned off.

6. The overvoltage and undervoltage protection circuit according to claim 5, characterized in that, The undervoltage protection hysteresis module further includes a first voltage stabilizing unit and a voltage division unit. The voltage stabilizing unit and the voltage division unit are connected in series between the first end of the first switch unit and the reference voltage terminal in sequence. The output terminal of the voltage division unit is electrically connected to the control end of the second switch unit.

7. The overvoltage and undervoltage protection circuit according to claim 1, characterized in that, The switch module includes a third switch unit and a protection unit. The third switch unit is connected in series between the protection signal output terminal of the overvoltage and undervoltage protection circuit and the reference voltage terminal; The protection unit is electrically connected to the voltage division detection module, the undervoltage protection control module, and the control end of the third switching unit respectively. The protection unit is used to stabilize and divide the voltage of the second detection voltage and then output it to the control end of the third switching unit; and is used to stabilize and divide the voltage of the first level voltage or the second level voltage and then output it to the control end of the third switching unit; the third switching unit is used to conduct or cut off according to the voltage at its control end.

8. The overvoltage and undervoltage protection circuit according to claim 7, wherein, The voltage division detection module includes a second voltage division output end, and the second voltage division output end is used to output the second detection voltage; The protection unit includes a second voltage stabilization unit, a third voltage stabilization unit, a first resistor, a second resistor, and a third resistor; The second voltage stabilization unit and the first resistor are connected in series between the output end of the undervoltage protection control module and the control end of the third switching unit in sequence; The third voltage stabilization unit and the second resistor are connected in series between the second voltage division output end and the control end of the third switching unit in sequence; The first end of the third resistor is electrically connected to the control end of the third switching unit, and the second end of the third resistor is electrically connected to the reference voltage terminal.

9. The overvoltage and undervoltage protection circuit according to claim 8, characterized in that, An anti-reverse diode is further included; The positive electrode of the anti-reverse diode is electrically connected to the second resistor, and the negative electrode of the anti-reverse diode is electrically connected to the control end of the third switching unit; Alternatively, the positive electrode of the anti-reverse diode is electrically connected to the first resistor, and the negative electrode of the anti-reverse diode is electrically connected to the control end of the third switching unit.

10. The overvoltage and undervoltage protection circuit according to any one of claims 1-9, characterized in that, The voltage division detection module includes a detection input end and a reference voltage end, and a fourth resistor, a fifth resistor, and a sixth resistor connected in series between the detection input end and the reference voltage end; the detection input end is used to connect the input voltage, and the reference voltage end is used to connect the reference voltage; The voltage division detection module further includes a first voltage division output end and a second voltage division output end; the common end of the fourth resistor and the fifth resistor serves as the second voltage division output end, and the second voltage division output end is used to output the second detection voltage; the common end of the fifth resistor and the sixth resistor serves as the first voltage division output end, and the first voltage division output end is used to output the first detection voltage.

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