Overvoltage and undervoltage detection circuit and protection circuit

Abstract

The invention relates to the technical field of power electronics, and discloses an overvoltage and undervoltage detection circuit and a protection circuit, the input end of an overvoltage detection unit and the input end of an undervoltage detection unit input the output voltage of a device to be protected, and the output end of the overvoltage detection unit is connected with the output end of the undervoltage detection unit. The power supply end of the overvoltage detection unit and the power supply end of the undervoltage detection unit input power supply voltage. When the overvoltage detection unit judges that the output voltage is greater than the first threshold voltage, the overvoltage detection unit outputs an overvoltage signal; when the overvoltage detection unit judges that the output voltage is smaller than the second threshold voltage, the undervoltage detection unit outputs an undervoltage signal; the first threshold voltage is greater than the second threshold voltage; the overvoltage detection unit and the undervoltage detection unit are both of hardware structures. The circuit is of a hardware structure, the structure is simple, the element cost is low, and the occupied space is small.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to an over-voltage and under-voltage detection circuit and a protection circuit. Background Art

[0002] With the development of science and technology, the application scenarios and computing processes of edge computing are becoming more and more complex and diverse. When edge servers are used in industrial sites, automated control, and intelligent driving, there will inevitably be various interferences such as surges, noise, and electromagnetics. Edge servers are used to move computing, storage, and network resources to edge locations close to users, and need to provide users with lower latency, higher bandwidth, and better experience, which places higher requirements on the stability of the power supply inside the server.

[0003] During the operation of the edge server, when the power supply voltage is higher than the rated voltage or lower than the rated voltage, it will cause harm to the edge server, causing a sudden power outage on the edge server that is difficult to maintain; or in the edge scenario, high-frequency pulses, surges and other interferences may damage the subsequent circuits, affecting the normal operation of the edge server or even damaging the edge server.

[0004] Existing overvoltage detection circuits usually include IC devices and require integrated detection software to perform overvoltage and undervoltage judgments, resulting in a complex overvoltage detection circuit structure and high cost. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to solve the problem of complex structure and high cost of over- and under-voltage protection circuits in the prior art, thereby providing an over- and under-voltage detection circuit and a protection circuit.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] In the first aspect, the present invention provides an over-voltage and under-voltage detection circuit, comprising: an overvoltage detection unit and an undervoltage detection unit, wherein the input end of the overvoltage detection unit and the input end of the undervoltage detection unit are both input with the output voltage of the device to be protected, the output end of the overvoltage detection unit is connected to the output end of the undervoltage detection unit, and the power supply end of the overvoltage detection unit and the power supply end of the undervoltage detection unit are both input with the power supply voltage; when the overvoltage detection unit determines that the output voltage is greater than a first threshold voltage, the overvoltage detection unit outputs an overvoltage signal; when the undervoltage detection unit determines that the output voltage is less than a second threshold voltage, the undervoltage detection unit outputs an undervoltage signal; the first threshold voltage is greater than the second threshold voltage; the overvoltage detection unit and the undervoltage detection unit are both hardware structures.

[0008] The over-voltage and under-voltage detection circuit provided by the present invention can simultaneously perform over-voltage detection and under-voltage detection on the output voltage of the protected device, and both the over-voltage detection unit and the under-voltage detection unit are simple hardware structures with low production cost and high integration. The entire detection process does not involve complex software control, thereby improving detection efficiency and accuracy.

[0009] In an optional embodiment, the overvoltage detection unit includes: a first comparison circuit and a first switching circuit, wherein the power supply end and the reverse input end of the first comparison circuit are both input with external voltage, the positive input end of the first comparison circuit is input with the output voltage of the device to be protected, and the output end of the first comparison circuit is connected to the control end of the first switching circuit; the first end of the first switching circuit is connected to the output end of the undervoltage detection unit, and the second end of the first switching circuit is grounded; when the first comparison circuit determines that the output voltage is greater than the first threshold voltage, the first comparison circuit controls the first switching circuit to be cut off, and the first end of the first switching circuit outputs an overvoltage signal; when the first comparison circuit determines that the output voltage is less than or equal to the first threshold voltage, the first comparison circuit controls the first switching circuit to be turned on, and the first end of the first switching circuit stops outputting the overvoltage signal; the magnitude of the first threshold voltage is adjusted by adjusting the resistance value of the resistor in the first comparison circuit.

[0010] In an optional embodiment, the first comparison circuit includes: a first threshold adjustment circuit and a first comparator, wherein the first end of the first threshold adjustment circuit inputs an external voltage, the second end of the first threshold adjustment circuit is connected to the reverse input end of the first comparator, the third end of the first threshold adjustment circuit is grounded, and the first threshold voltage is adjusted by adjusting the resistance value of the resistor in the first threshold adjustment circuit; the output voltage of the device to be protected is input to the positive input end of the first comparator, the external voltage is input to the power supply end of the first comparator, and the output end of the first comparator is connected to the control end of the first switch circuit; when the first comparator determines that the output voltage is greater than the first threshold voltage, the first comparator controls the first switch circuit to be cut off; when the first comparator determines that the output voltage is less than or equal to the first threshold voltage, the first comparator controls the first switch circuit to be turned on.

[0011] In an optional embodiment, the first switching circuit includes: a first resistor, a second resistor, a first capacitor and a first controllable switch, wherein the first end of the first resistor is connected to the output end of the first comparison circuit, and the second end of the first resistor is connected to the first end of the second resistor, the first end of the first capacitor and the control end of the first controllable switch; the second end of the second resistor is connected to the second end of the first capacitor and the first end of the first controllable switch and then grounded; the second end of the first controllable switch is connected to the output end of the undervoltage detection unit; when the first comparison circuit determines that the output voltage is greater than the first threshold voltage, the first comparison circuit controls the first controllable switch to be turned off; when the first comparison circuit determines that the output voltage is less than or equal to the first threshold voltage, the first comparison circuit controls the first controllable switch to be turned on.

[0012] The over-voltage and under-voltage detection circuit provided by the present invention is composed of only resistors, capacitors and switch tubes, with low electrical component cost and simple circuit structure. The first controllable switch has good temperature stability, strong radiation resistance and low loss, and is more suitable for complex environmental conditions, thereby improving the scope of application of the over-voltage and under-voltage detection circuit.

[0013] In an optional embodiment, the undervoltage detection unit includes: a second comparison circuit and a second switch circuit, wherein the first end of the second switch circuit is connected to the output end of the overvoltage detection unit, the second end of the second switch circuit is grounded, and the control end of the second switch circuit is connected to the output end of the second comparison circuit; the power supply end and the positive input end of the second comparison circuit are both input with external voltage, and the reverse input end of the second comparison circuit is input with the output voltage of the device to be protected; when the second comparison circuit determines that the output voltage is less than the second threshold voltage, the second comparison circuit controls the second switch circuit to be cut off, and the first end of the second switch circuit outputs an undervoltage signal; when the second comparison circuit determines that the output voltage is greater than or equal to the second threshold voltage, the second comparison circuit controls the second switch circuit to be turned on, and the first end of the second switch circuit stops outputting the undervoltage signal; the magnitude of the second threshold voltage is adjusted by adjusting the resistance value of the resistor in the second comparison circuit.

[0014] In an optional embodiment, the second comparison circuit includes: a second threshold adjustment circuit and a second comparator, wherein the first end of the second threshold adjustment circuit inputs an external voltage, the second end of the second threshold adjustment circuit is connected to the positive input end of the second comparator, the third end of the second threshold adjustment circuit is grounded, and the second threshold voltage is adjusted by adjusting the resistance value of the resistor in the second threshold adjustment circuit; the output voltage of the device to be protected is input to the reverse input end of the second comparator, the external voltage is input to the power supply end of the second comparator, and the output end of the second comparator is connected to the control end of the second switch circuit; when the second comparator determines that the output voltage is less than the second threshold voltage, the second comparator controls the second switch circuit to be cut off; when the second comparator determines that the output voltage is greater than or equal to the second threshold voltage, the second comparator controls the second switch circuit to be turned on.

[0015] In an optional embodiment, the second switching circuit includes: a third resistor, a fourth resistor, a second capacitor and a second controllable switch, wherein the first end of the third resistor is connected to the output end of the second comparison circuit, and the second end of the third resistor is connected to the first end of the fourth resistor, the first end of the second capacitor and the control end of the second controllable switch; the second end of the fourth resistor is connected to the second end of the second capacitor and the first end of the second controllable switch and then grounded; the second end of the second controllable switch is connected to the output end of the overvoltage detection unit; when the second comparison circuit determines that the output voltage is less than the second threshold voltage, the second comparison circuit controls the second controllable switch to be turned off; when the second comparison circuit determines that the output voltage is greater than or equal to the second threshold voltage, the second comparison circuit controls the second controllable switch to be turned on.

[0016] The over-voltage and under-voltage detection circuit provided by the present invention is composed of only resistors, capacitors and switch tubes, with low electrical component cost and simple circuit structure. The second controllable switch has good temperature stability, strong radiation resistance and low loss, and is more suitable for complex environmental conditions, thereby improving the scope of application of the over-voltage and under-voltage detection circuit.

[0017] In a second aspect, the present invention provides a protection circuit, comprising: a switch unit and the over-voltage and under-voltage detection circuit of the first aspect, wherein the control end of the switch unit is connected to the output end of the overvoltage detection unit, the first end of the switch unit is connected to the input end of the overvoltage detection unit, and the second end of the switch unit is connected to the power supply end of the load; when there is no overvoltage signal or undervoltage signal, the switch unit is turned on, and the device to be protected charges the switch unit and supplies power to the load; when the switch unit is disconnected based on the overvoltage signal or undervoltage signal, the device to be protected stops supplying power to the load, and the switch unit releases all of its remaining power to the load to power the load.

[0018] The protection circuit provided by the present invention can timely cut off the output of the device to be protected when the output voltage of the device to be protected is overvoltage or undervoltage, so as to avoid high voltage damaging the load or low voltage affecting the normal operation of the load. The switch unit also has energy storage and discharge functions. When the output of the device to be protected is normal, the switch unit is charged. When the output voltage of the device to be protected is abnormal, the switch unit turns off the output of the device to be protected and uses the internally stored electric energy to provide short-term power supply for the load that cannot be suddenly powered off, thereby ensuring the normal operation of the load in a short time and providing operators with time to respond to failures.

[0019] In an optional embodiment, the switch unit includes: a third switch circuit and an energy storage circuit, wherein the first end of the third switch circuit inputs the output voltage of the device to be protected, the second end of the third switch circuit is connected to the first end of the energy storage circuit and the power supply end of the load, and the control end of the third switch circuit is connected to the output end of the overvoltage detection unit; the second end of the energy storage circuit is grounded; when the third switch circuit is disconnected based on an overvoltage signal or an undervoltage signal, the device to be protected stops supplying power to the load, and the energy storage circuit releases all of its remaining power to the load to power the load; when there is no overvoltage signal or undervoltage signal, the third switch circuit is turned on, and the device to be protected charges the energy storage circuit and supplies power to the load.

[0020] In an optional embodiment, the protection circuit also includes: a controller, wherein the input end of the controller is connected to the first end of the switch unit, the output end of the controller is connected to the terminal, and the controller is used to send a fault alarm signal to the terminal based on the overvoltage signal and the undervoltage signal.

[0021] The protection circuit provided by the present invention can promptly notify the user through the terminal that the protected equipment has a fault, and remind the user to promptly handle and troubleshoot the fault, so as to avoid the load power outage lasting too long and affecting normal production work. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 is a composition diagram of an over-voltage and under-voltage detection circuit according to an embodiment of the present invention;

[0024] Figure 2 is a specific circuit structure diagram of an overvoltage detection unit according to an embodiment of the present invention;

[0025] Figure 3 is a specific circuit structure diagram of an undervoltage detection unit according to an embodiment of the present invention;

[0026] Figure 4 is a composition diagram of a protection circuit according to an embodiment of the present invention;

[0027] Figure 5 is a specific circuit structure diagram of a protection circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, 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 a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] The edge server has power supplies with multiple voltage levels. When the power supply voltage fluctuates, the precision components connected to the power supply output end are easily damaged by the impact voltage or cannot work normally under low voltage conditions. Therefore, for power supplies with multiple voltage levels, it is necessary to set up detection circuits that can determine whether the output voltage is overvoltage or undervoltage. However, due to the high cost of the edge server itself and the complex internal circuit composition, there is an urgent need for a low-cost, simple-structured over-voltage and under-voltage detection circuit that can adapt to multiple voltage levels.

[0033] In order to solve the above problems, this embodiment provides an over-voltage and under-voltage detection circuit 1, such as Figure 1As shown, it includes: an overvoltage detection unit 11 and an undervoltage detection unit 12; the input end of the overvoltage detection unit 11 and the input end of the undervoltage detection unit 12 are both input with the output voltage of the device to be protected, the output end of the overvoltage detection unit 11 is connected to the output end of the undervoltage detection unit 12, and the power supply end of the overvoltage detection unit 11 and the power supply end of the undervoltage detection unit 12 are both input with the supply voltage; the overvoltage detection unit 11 and the undervoltage detection unit 12 are both hardware structures.

[0034] Specifically, Figure 1 In the process, the technicians preset the first threshold voltage and the second threshold voltage in the overvoltage detection unit 11 and the undervoltage detection unit 12 respectively according to the normal output voltage range of the device to be protected, and the first threshold voltage is greater than the second threshold voltage. When the device to be protected has an output voltage, the overvoltage detection unit 11 compares the output voltage with the internal first threshold voltage, and the undervoltage detection unit 12 compares the output voltage with the internal second threshold voltage. When the overvoltage detection unit 11 determines that the output voltage is greater than the first threshold voltage, it outputs an overvoltage signal; when the undervoltage detection unit 12 determines that the output voltage is less than the second threshold voltage, it outputs an undervoltage signal.

[0035] Optionally, Figure 1 In the embodiment, the overvoltage detection unit 11 and the undervoltage detection unit 12 do not include software circuits, protection chips and other structures, and are only composed of basic electrical components such as voltage comparators, MOS tubes, resistors and capacitors, so that the overvoltage and undervoltage detection circuits are low in cost. Compared with software detection, the hardware has a stable working state and fast response speed, which can improve the detection efficiency and the accuracy of the detection results.

[0036] Exemplarily, the overvoltage detection unit includes: a voltage comparator, a resistor-capacitor filter unit and a MOS switch tube. The voltage comparator is used to compare the internal first threshold voltage with the output voltage of the device to be protected: when it is determined that the output voltage exceeds the first threshold voltage, the MOS switch switches the switch state to output an overvoltage signal; if it is determined that the output voltage is less than or equal to the first threshold voltage, the MOS switch switches the switch state to stop outputting the overvoltage signal; the resistor-capacitor filter unit is used to filter out interference signals in the circuit to improve the accuracy of the detection result.

[0037] Exemplarily, the undervoltage detection unit includes: a voltage comparator, a resistor-capacitor filter unit and a MOS switch tube. The voltage comparator is used to compare the internal second threshold voltage with the output voltage of the device to be protected: when it is determined that the output voltage exceeds the second threshold voltage, the MOS switch switches the switch state to output an undervoltage signal; if it is determined that the output voltage is less than or equal to the second threshold voltage, the MOS switch switches the switch state to stop outputting the undervoltage signal; the resistor-capacitor filter unit is used to filter out interference signals in the circuit to improve the accuracy of the detection result.

[0038] Optionally, the magnitudes of the first threshold voltage and the second threshold voltage may be adjusted by adjusting the magnitude of the supply voltage, or adjusting the voltage division inside the resistance adjustment unit of the resistors in the overvoltage detection unit and the undervoltage detection unit.

[0039] The over-voltage and under-voltage detection circuit provided in this embodiment can simultaneously perform over-voltage detection and under-voltage detection on the output voltage of the protected device, and the over-voltage detection unit and the under-voltage detection unit are both simple hardware structures with low production cost and high integration. The entire detection process does not involve complex software control, thereby improving detection efficiency and accuracy.

[0040] In some optional embodiments, such as Figure 2 As shown, the overvoltage detection unit 11 includes: a first comparison circuit 111 and a first switch circuit 112, wherein the power supply end and the reverse input end of the first comparison circuit 111 are both input with the external voltage P5V, the positive input end of the first comparison circuit 111 is input with the output voltage P3V3_IN of the device to be protected, and the output end of the first comparison circuit 111 is connected to the control end of the first switch circuit 112; the first end of the first switch circuit 112 (i.e., an end for outputting an overvoltage signal) is connected to the output end of the undervoltage detection unit 12, and the second end of the first switch circuit 112 is grounded.

[0041] Specifically, Figure 2 When the first comparison circuit 111 determines that the output voltage P3V3_IN is greater than the first threshold voltage, the first comparison circuit 111 controls the first switch circuit 112 to be turned off, and the first end of the first switch circuit 112 outputs an overvoltage signal; when the first comparison circuit 111 determines that the output voltage P3V3_IN is less than or equal to the first threshold voltage, the first comparison circuit 111 controls the first switch circuit 112 to be turned on, and the first end of the first switch circuit 112 stops outputting the overvoltage signal; the first threshold voltage is adjusted by adjusting the resistance value of the resistor in the first comparison circuit 111.

[0042] Optionally, the first threshold voltage in the first comparison circuit 111 can be determined by the voltage at the intersection of resistors connected in series, in parallel, or in series and parallel. When the resistance value of some of the resistors is changed, the voltage at the intersection changes after voltage division, thereby achieving an adjustable first threshold voltage. Figure 2 In the figure, the first comparison circuit 111 includes: a first threshold adjustment circuit 1111 and a first comparator U1, wherein the first end of the first threshold adjustment circuit 1111 is input with an external voltage P5V, the second end of the first threshold adjustment circuit 1111 is connected to the reverse input end of the first comparator U1, and the third end of the first threshold adjustment circuit 1111 is grounded.

[0043] Optionally, the first threshold adjustment circuit 1111 may be composed of a plurality of resistors connected in series, in parallel, or in series and in parallel. For example, Figure 2 As shown, the first threshold adjustment circuit 1111 includes a resistor R1 and a resistor R2. The operator can achieve different degrees of voltage division of the external voltage P5V by changing the resistance values ​​of the resistors R1 and R2, so that the voltage input to the reverse input terminal of the first comparator U1, that is, the first threshold voltage, can be flexibly adjusted.

[0044] Specifically, Figure 2 In the embodiment, the output voltage P3V3_IN of the device to be protected is input to the positive input terminal of the first comparator U1, the external voltage P5V is input to the power supply terminal of the first comparator U1, and the output terminal of the first comparator U1 is connected to the control terminal of the first switch circuit 112; when the first comparator U1 determines that the output voltage P3V3_IN is greater than the first threshold voltage, the first comparator U1 controls the first switch circuit 112 to be turned off; when the first comparator U1 determines that the output voltage P3V3_IN is less than or equal to the first threshold voltage, the first comparator U1 controls the first switch circuit 112 to be turned on.

[0045] For example, Figure 2 In the embodiment, when the voltage of the positive input terminal +IN of the first comparator U1 is greater than the voltage of the reverse input terminal -IN, the output terminal OUT of the first comparator U1 outputs a low level; when the voltage of the positive input terminal +IN of the first comparator U1 is less than the voltage of the reverse input terminal -IN, the output terminal OUT of the first comparator U1 outputs a high level. The comparison logic of the first comparator U1 can be set according to the specific circuit structure, and is again not limited.

[0046] Optionally, a filter capacitor may be provided at the port of the first comparator U1 connected to the power supply or the port connected to the ground, so as to reduce high-frequency noise and ripples in the signal and improve the stability of the signal.

[0047] Specifically, Figure 2 In the embodiment, the first switch circuit 112 includes: a first resistor R3, a second resistor R4, a first capacitor C2 and a first controllable switch Q1, wherein a first end of the first resistor R3 is connected to the output end of the first comparison circuit 111, and a second end of the first resistor R3 is connected to a first end of the second resistor R4, a first end of the first capacitor C2 and a control end of the first controllable switch Q1; a second end of the second resistor R4 is connected to a second end of the first capacitor C2 and a first end of the first controllable switch Q1 and then grounded; and a second end of the first controllable switch Q1 (i.e., an end outputting an overvoltage signal) is connected to the output end of the undervoltage detection unit 12.

[0048] Specifically, Figure 2In order to improve the stability of the overvoltage detection circuit, the first controllable switch Q1 uses a MOS tube with good temperature stability, strong radiation resistance and low loss. When the first comparison circuit 111 determines that the output voltage P3V3_IN is greater than the first threshold voltage, that is, the voltage at the positive input terminal of the first comparator U1 is greater than the voltage at the reverse input terminal, the output terminal of the first comparator U1 is low level, and the gate of the first controllable switch Q1 is also low level; because the source of the first controllable switch Q1 is grounded, and the voltage difference between the gate and the source is the conduction voltage drop of the first controllable switch Q1, the first controllable switch Q1 is turned off, and the drain is connected to P3V3_IN to output a high level signal.

[0049] Specifically, Figure 2 In the embodiment, when the first comparison circuit 111 determines that the output voltage P3V3_IN is less than the first threshold voltage, that is, the voltage at the positive input terminal of the first comparator U1 is less than the voltage at the reverse input terminal, the output terminal of the first comparator U1 is at a high level, the gate of the first controllable switch Q1 is also at a high level and is turned on and grounded, and the drain outputs a low level signal.

[0050] It should be noted that, in this embodiment, when the high level signal output by the drain of the first controllable switch is an overvoltage signal, the overvoltage signal may also be a pulse signal, an edge signal, etc., and its form is not limited here.

[0051] In some optional embodiments, such as Figure 3 As shown, the undervoltage detection unit includes: a second comparison circuit 121 and a second switch circuit 122, wherein the first end of the second switch circuit 122 (i.e., an end that outputs an undervoltage signal) is connected to the output end of the overvoltage detection unit 11, the second end of the second switch circuit 122 is grounded, and the control end of the second switch circuit 122 is connected to the output end of the second comparison circuit 121; the power supply end and the positive input end of the second comparison circuit 121 are both input with an external voltage P5V, and the reverse input end of the second comparison circuit 121 is input with the output voltage P3V3_IN of the device to be protected.

[0052] Specifically, Figure 3 When the second comparison circuit 121 determines that the output voltage P3V3_IN is less than the second threshold voltage, the second comparison circuit 121 controls the second switch circuit 122 to be turned off, and the first end of the second switch circuit 122 outputs an undervoltage signal; when the second comparison circuit 121 determines that the output voltage P3V3_IN is greater than or equal to the second threshold voltage, the second comparison circuit 121 controls the second switch circuit 122 to be turned on, and the first end of the second switch circuit 122 stops outputting the undervoltage signal; the second threshold voltage is adjusted by adjusting the resistance value of the resistor in the second comparison circuit 121.

[0053] Optionally, the second threshold voltage in the second comparison circuit 121 can be determined by the voltage at the intersection of resistors connected in series, in parallel, or in series and parallel. When the resistance value of some of the resistors is changed, the voltage at the intersection changes after voltage division, thereby achieving an adjustable second threshold voltage.

[0054] Specifically, Figure 3 In the figure, the second comparison circuit 121 includes: a second threshold adjustment circuit 1211 and a second comparator U2, wherein the first end of the second threshold adjustment circuit 1211 inputs the external voltage P5V, the second end of the second threshold adjustment circuit 1211 is connected to the positive input end of the second comparator U2, and the third end of the second threshold adjustment circuit 1211 is grounded.

[0055] Optionally, the second threshold adjustment circuit 1211 may be composed of a plurality of resistors connected in series, in parallel, or in series and in parallel. For example, Figure 3 As shown, the second threshold adjustment circuit 1211 includes a resistor R5 and a resistor R6. The operator can achieve different degrees of voltage division of the external voltage P5V by changing the resistance values ​​of the resistors R5 and R6, so that the voltage input to the positive input terminal of the second comparator U2, that is, the second threshold voltage, can be flexibly adjusted.

[0056] Specifically, Figure 3 In the embodiment, the output voltage P3V3_IN of the device to be protected is input to the reverse input terminal of the second comparator U2, the external voltage P5V is input to the power supply terminal of the second comparator U2, and the output terminal of the second comparator U2 is connected to the control terminal of the second switch circuit 122; when the second comparator U2 determines that the output voltage P3V3_IN is less than the second threshold voltage, the second comparator U2 controls the second switch circuit 122 to be turned off; when the second comparator U2 determines that the output voltage P3V3_IN is greater than or equal to the second threshold voltage, the second comparator U2 controls the second switch circuit 122 to be turned on.

[0057] For example, Figure 3 In the embodiment, when the voltage at the reverse input terminal -IN of the second comparator U2 is less than the voltage at the forward input terminal +IN, the output terminal OUT of the second comparator U2 outputs a low level; when the voltage at the reverse input terminal -IN of the second comparator U2 is greater than the voltage at the forward input terminal +IN, the output terminal OUT of the second comparator U2 outputs a high level. The comparison logic of the second comparator U2 can be set according to the specific circuit structure, and is again not limited.

[0058] Optionally, a filter capacitor may be provided at the port of the second comparator U2 connected to the power supply or the port connected to the ground, so as to reduce high-frequency noise and ripple in the signal and improve the stability of the signal.

[0059] Specifically, Figure 3In the embodiment, the second switch circuit 122 includes: a third resistor R7, a fourth resistor R8, a second capacitor C3 and a second controllable switch Q2, wherein a first end of the third resistor R7 is connected to the output end of the second comparison circuit 121, a second end of the third resistor R7 is connected to a first end of the fourth resistor R8, a first end of the second capacitor C3 and a control end of the second controllable switch Q2; a second end of the fourth resistor R8 is connected to a second end of the second capacitor C3 and a first end of the second controllable switch Q2 and then grounded; a second end of the second controllable switch Q2 (i.e., an end for outputting an undervoltage signal) is connected to the output end of the overvoltage detection unit 11.

[0060] Specifically, Figure 3 In order to improve the stability of the overvoltage detection circuit, the second controllable switch Q2 uses a MOS tube with good temperature stability, strong radiation resistance and low loss. When the second comparison circuit 121 determines that the output voltage P3V3_IN is less than the second threshold voltage, that is, the voltage at the reverse input terminal of the second comparator U2 is less than the voltage at the forward input terminal, the output terminal of the second comparator U2 is low level, and the gate of the second controllable switch Q2 is also low level; because the source of the second controllable switch Q2 is grounded, and the voltage difference between the gate and the source is the conduction voltage drop of the second controllable switch Q2, the second controllable switch Q2 is turned off, and the drain is connected to P3V3_IN to output a high level signal.

[0061] Specifically, Figure 3 In the embodiment, when the second comparison circuit 121 determines that the output voltage P3V3_IN is greater than the second threshold voltage, that is, the voltage at the reverse input terminal of the second comparator U2 is greater than the voltage at the forward input terminal, the output terminal of the second comparator U2 is at a high level, and the gate of the second controllable switch Q2 is also at a high level and is turned on and grounded, and the drain outputs a low level signal.

[0062] It should be noted that, in this embodiment, when the high level signal output by the drain of the second controllable switch is an undervoltage signal, the undervoltage signal may also be a pulse signal, an edge signal, etc., and its form is not limited here. And when the overvoltage detection circuit determines that the output voltage is equal to the first threshold voltage, the overvoltage signal is not output, or when the undervoltage detection circuit determines that the output voltage is equal to the second threshold voltage, the undervoltage signal is not output.

[0063] This embodiment provides a protection circuit, such as Figure 4 As shown, it includes: a switch unit 2 and an over-voltage and under-voltage detection circuit 1 of the above embodiments and any optional implementation manner thereof, wherein the control end of the switch unit 2 is connected to the output end of the overvoltage detection unit 11, the first end of the switch unit 2 is connected to the input end of the overvoltage detection unit 11, and the second end of the switch unit 2 is connected to the power supply end of the load.

[0064] Specifically, Figure 4In the embodiment, when the output voltage P3V3_IN of the device to be protected is within the range of the first threshold voltage and the second threshold voltage, the overvoltage detection unit 11 and the undervoltage detection unit 12 do not output an overvoltage signal or an undervoltage signal to the control end of the switch unit 2, and the switch unit 2 maintains the on state, so that the device to be protected charges the switch unit 2 and supplies power to the load; when the output voltage P3V3_IN of the device to be protected is greater than the first threshold voltage or less than the second threshold voltage, the overvoltage detection unit 11 outputs an overvoltage signal or the undervoltage detection unit 12 outputs an undervoltage signal to the control end of the switch unit 2, and the switch unit 2 switches to the cut-off state, so that the device to be protected stops supplying power to the load, and at the same time, the switch unit 2 releases all of its remaining power to the load to supply power to the load.

[0065] Optionally, the switch unit includes an energy storage structure. When the device to be protected shuts down its output and the load is an edge server or other device that cannot be suddenly powered off, the switch unit can provide short-term power supply to the load to ensure normal operation of the load in a short period of time and reduce economic losses.

[0066] The protection circuit provided in this embodiment can cut off the output of the device to be protected in time when the output voltage of the device to be protected is overvoltage or undervoltage, so as to avoid high voltage damaging the load or low voltage affecting the normal operation of the load. The switch unit also has energy storage and discharge functions. When the output of the device to be protected is normal, the switch unit is charged. When the output voltage of the device to be protected is abnormal, the switch unit turns off the output of the device to be protected and uses the internally stored electric energy to provide short-term power supply to the load that cannot be suddenly powered off, so as to ensure the normal operation of the load in a short time and provide operators with time to respond to failures.

[0067] In some optional embodiments, such as Figure 5 As shown, the switch unit 2 includes: a third switch circuit 21 and an energy storage circuit 22, wherein the first end of the third switch circuit 21 inputs the output voltage P3V3_IN of the device to be protected, the second end of the third switch circuit 21 is connected to the first end of the energy storage circuit 22 and the power supply end of the load, and the control end of the third switch circuit 21 is connected to the output end of the overvoltage detection unit 11; the second end of the energy storage circuit 22 is grounded.

[0068] Specifically, Figure 5 In the embodiment, the third switch circuit 21 includes filter capacitors C5, C6 and C7, MOS tube Q3, discharge resistor R9 and current limiting resistor R10, R9 is used to quickly discharge the static electricity between the gate and source of MOS tube Q3. The energy storage circuit 22 includes an anti-reverse diode D1, a super capacitor C8, filter capacitors C9 and C10.

[0069] Optionally, the overvoltage signal and the undervoltage signal in this embodiment are both high-level signals. Figure 5In the embodiment, when the output voltage P3V3_IN of the device to be protected is within the range of the first threshold voltage and the second threshold voltage, the overvoltage detection unit 11 and the undervoltage detection unit 12 do not output an overvoltage signal or an undervoltage signal, and the gate of Q3 is at a low level. At this time, the voltage difference between the source and the gate of Q3 is greater than its conduction voltage drop, Q3 is turned on, and the device to be protected charges the supercapacitor C8 while supplying power to the load.

[0070] Specifically, Figure 5 In the embodiment, when the output voltage P3V3_IN of the device to be protected is greater than the first threshold voltage, the overvoltage detection unit 11 outputs an overvoltage signal, or when it is less than the second threshold voltage, the undervoltage detection unit 12 outputs an undervoltage signal, so that the gate of Q3 is at a high level. At this time, the voltage difference between the source and the gate of Q3 is less than its conduction voltage drop, Q3 is cut off, and the device to be protected is disconnected from the energy storage circuit 22 and the load, and stops supplying power to the load. At this time, the supercapacitor C8 starts to discharge and provides short-term power supply to the load. Avoid sudden power failure and damage to the load, causing economic losses.

[0071] Specifically, the protection circuit also includes: a controller 3, such as Figure 5 As shown, the input end of the controller 3 is connected to the first end of the switch unit 2, and the output end of the controller 3 is connected to the terminal. After the controller 3 collects the overvoltage signal or the undervoltage signal, it generates an alarm signal and sends it directly to the terminal to remind the user that an overvoltage or undervoltage situation has occurred and that timely troubleshooting is required.

[0072] Optionally, the first threshold adjustment circuit and the second threshold adjustment circuit may both include an adjustable resistor, such as a sliding rheostat, and the adjustment end of each adjustable resistor is respectively connected to an output end of the controller. The operator can input a resistance adjustment instruction to the controller according to the output voltage of different devices to be protected, so that the controller automatically adjusts the voltage division degree of the adjustable resistor according to the resistance adjustment instruction, thereby realizing flexible adjustment of the first threshold voltage and the second threshold voltage in the first threshold adjustment circuit and the second threshold adjustment circuit, improving the automation degree of the circuit, and expanding the application scope of the over-voltage and under-voltage detection circuit.

[0073] Optionally, the protection circuit can also be provided with a short-circuit protection unit that prevents the protected device from short-circuiting by monitoring the output current of the protected device, a surge protection unit that uses a transient voltage suppression diode to prevent the protected device from being struck by lightning and / or static electricity, etc. Technical personnel in this field can set the protection type as needed and reasonably adjust the output logic of the protected device according to the monitored object.

[0074] Optionally, the protection circuit can also be provided with multiple over-voltage and under-voltage detection circuits to monitor multiple levels of output voltage of the protected device at the same time. The output end of each over-voltage and under-voltage detection circuit is connected to the first end of the switch unit. When any level of voltage is outside the preset range, the switch unit is controlled to be disconnected, so that the output of the protected device is turned off.

[0075] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An over-voltage and under-voltage detection circuit, characterized in that: include: Overvoltage detection unit and undervoltage detection unit, wherein: The input end of the overvoltage detection unit and the input end of the undervoltage detection unit are both input with the output voltage of the device to be protected, the output end of the overvoltage detection unit is connected to the output end of the undervoltage detection unit, and the power supply end of the overvoltage detection unit and the power supply end of the undervoltage detection unit are both input with the supply voltage; When the overvoltage detection unit determines that the output voltage is greater than the first threshold voltage, the overvoltage detection unit outputs an overvoltage signal; when the undervoltage detection unit determines that the output voltage is less than the second threshold voltage, the undervoltage detection unit outputs an undervoltage signal; The first threshold voltage is greater than the second threshold voltage; The overvoltage detection unit and the undervoltage detection unit are both hardware structures.

2. The over-voltage and under-voltage detection circuit according to claim 1, characterized in that: The overvoltage detection unit includes: a first comparison circuit and a first switch circuit, wherein: The power supply terminal and the reverse input terminal of the first comparison circuit are both input with external voltage, the positive input terminal of the first comparison circuit is input with the output voltage of the device to be protected, and the output terminal of the first comparison circuit is connected to the control terminal of the first switch circuit; A first end of the first switch circuit is connected to the output end of the undervoltage detection unit, and a second end of the first switch circuit is grounded; When the first comparison circuit determines that the output voltage is greater than the first threshold voltage, the first comparison circuit controls the first switch circuit to be turned off, and the first end of the first switch circuit outputs an overvoltage signal; When the first comparison circuit determines that the output voltage is less than or equal to the first threshold voltage, the first comparison circuit controls the first switch circuit to be turned on, and the first end of the first switch circuit stops outputting the overvoltage signal; The magnitude of the first threshold voltage is adjusted by adjusting the resistance value of the resistor in the first comparison circuit.

3. The over-voltage and under-voltage detection circuit according to claim 2, characterized in that: The first comparison circuit includes: a first threshold adjustment circuit and a first comparator, wherein: The first terminal of the first threshold adjustment circuit inputs an external voltage, the second terminal of the first threshold adjustment circuit is connected to the inverting input terminal of the first comparator, the third terminal of the first threshold adjustment circuit is grounded, and the magnitude of the first threshold voltage is adjusted by adjusting the resistance value of the resistor in the first threshold adjustment circuit; The positive input terminal of the first comparator inputs the output voltage of the device to be protected, the power supply terminal of the first comparator inputs the external voltage, and the output terminal of the first comparator is connected to the control terminal of the first switch circuit; When the first comparator determines that the output voltage is greater than the first threshold voltage, the first comparator controls the first switch circuit to be turned off; When the first comparator determines that the output voltage is less than or equal to the first threshold voltage, the first comparator controls the first switch circuit to be turned on.

4. The over-voltage and under-voltage detection circuit according to claim 2, characterized in that: The first switch circuit includes: a first resistor, a second resistor, a first capacitor and a first controllable switch, wherein: A first end of the first resistor is connected to an output end of the first comparison circuit, and a second end of the first resistor is connected to a first end of the second resistor, a first end of the first capacitor, and a control end of the first controllable switch; The second end of the second resistor is connected to the second end of the first capacitor and the first end of the first controllable switch and then grounded; The second end of the first controllable switch is connected to the output end of the undervoltage detection unit; When the first comparison circuit determines that the output voltage is greater than the first threshold voltage, the first comparison circuit controls the first controllable switch to be turned off; When the first comparison circuit determines that the output voltage is less than or equal to the first threshold voltage, the first comparison circuit controls the first controllable switch to be turned on.

5. The over-voltage and under-voltage detection circuit according to claim 1, characterized in that: The undervoltage detection unit includes: a second comparison circuit and a second switch circuit, wherein: A first end of the second switch circuit is connected to the output end of the overvoltage detection unit, a second end of the second switch circuit is grounded, and a control end of the second switch circuit is connected to the output end of the second comparison circuit; The power supply terminal and the positive input terminal of the second comparison circuit are both input with an external voltage, and the negative input terminal of the second comparison circuit is input with an output voltage of the device to be protected; When the second comparison circuit determines that the output voltage is less than the second threshold voltage, the second comparison circuit controls the second switch circuit to be turned off, and the first end of the second switch circuit outputs an undervoltage signal; When the second comparison circuit determines that the output voltage is greater than or equal to the second threshold voltage, the second comparison circuit controls the second switch circuit to be turned on, and the first end of the second switch circuit stops outputting the undervoltage signal; The magnitude of the second threshold voltage is adjusted by adjusting the resistance value of the resistor in the second comparison circuit.

6. The over-voltage and under-voltage detection circuit according to claim 5, characterized in that: The second comparison circuit includes: a second threshold adjustment circuit and a second comparator, wherein: The first end of the second threshold adjustment circuit inputs an external voltage, the second end of the second threshold adjustment circuit is connected to the positive input end of the second comparator, the third end of the second threshold adjustment circuit is grounded, and the magnitude of the second threshold voltage is adjusted by adjusting the resistance value of the resistor in the second threshold adjustment circuit; The output voltage of the device to be protected is input to the inverting input terminal of the second comparator, an external voltage is input to the power supply terminal of the second comparator, and the output terminal of the second comparator is connected to the control terminal of the second switch circuit; When the second comparator determines that the output voltage is less than the second threshold voltage, the second comparator controls the second switch circuit to be turned off; When the second comparator determines that the output voltage is greater than or equal to the second threshold voltage, the second comparator controls the second switch circuit to be turned on.

7. The over-voltage and under-voltage detection circuit according to claim 6, characterized in that: The second switch circuit includes: a third resistor, a fourth resistor, a second capacitor and a second controllable switch, wherein: The first end of the third resistor is connected to the output end of the second comparison circuit, and the second end of the third resistor is connected to the first end of the fourth resistor, the first end of the second capacitor and the control end of the second controllable switch; The second end of the fourth resistor is connected to the second end of the second capacitor and the first end of the second controllable switch and then grounded; The second end of the second controllable switch is connected to the output end of the overvoltage detection unit; When the second comparison circuit determines that the output voltage is less than the second threshold voltage, the second comparison circuit controls the second controllable switch to be turned off; When the second comparison circuit determines that the output voltage is greater than or equal to the second threshold voltage, the second comparison circuit controls the second controllable switch to be turned on.

8. A protection circuit, characterized in that: include: A switch unit and an over-voltage and under-voltage detection circuit according to any one of claims 1 to 7, wherein: The control end of the switch unit is connected to the output end of the overvoltage detection unit, the first end of the switch unit is connected to the input end of the overvoltage detection unit, and the second end of the switch unit is connected to the power supply end of the load; When there is no overvoltage signal or undervoltage signal, the switch unit is turned on, and the device to be protected charges the switch unit and supplies power to the load; When the switch unit is disconnected based on the overvoltage signal or the undervoltage signal, the device to be protected stops supplying power to the load, and the switch unit releases all of its remaining power to the load to supply power to the load.

9. The protection circuit according to claim 8, characterized in that: The switch unit includes: a third switch circuit and an energy storage circuit, wherein: The first end of the third switch circuit inputs the output voltage of the device to be protected, the second end of the third switch circuit is connected to the first end of the energy storage circuit and the power supply end of the load, and the control end of the third switch circuit is connected to the output end of the overvoltage detection unit; The second end of the energy storage circuit is grounded; When the third switch circuit is disconnected based on the overvoltage signal or the undervoltage signal, the device to be protected stops supplying power to the load, and the energy storage circuit releases all of its remaining power to the load to supply power to the load; When there is no overvoltage signal or undervoltage signal, the third switch circuit is turned on, and the device to be protected charges the energy storage circuit and supplies power to the load.

10. The protection circuit according to any one of claims 8 to 9, characterized in that: Also includes: controller, where The input end of the controller is connected to the first end of the switch unit, the output end of the controller is connected to the terminal, and the controller is used to send a fault alarm signal to the terminal based on the overvoltage signal and the undervoltage signal.

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