CN217824236U - Sensor power supply protection circuit - Google Patents
Sensor power supply protection circuit Download PDFInfo
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- CN217824236U CN217824236U CN202221278144.XU CN202221278144U CN217824236U CN 217824236 U CN217824236 U CN 217824236U CN 202221278144 U CN202221278144 U CN 202221278144U CN 217824236 U CN217824236 U CN 217824236U
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Abstract
The utility model discloses a sensor power supply protection circuit. The circuit includes: the voltage threshold setting circuit is used for setting an overvoltage threshold and an undervoltage threshold of the power supply voltage; the overvoltage protection circuit is connected with the voltage threshold setting circuit and used for cutting off the power supply loop when the power supply voltage is higher than the overvoltage threshold; the undervoltage protection circuit is respectively connected with the voltage threshold setting circuit and the overvoltage protection circuit and is used for cutting off the power supply loop when the power supply voltage is lower than the undervoltage threshold; the current limiting circuit is respectively connected with the overvoltage protection circuit and the undervoltage protection circuit and used for setting a current limiting threshold so as to limit the maximum current consumption of the rear circuit of the sensor through the current limiting threshold. The utility model discloses in, this sensor power supply protection circuit initiatively cuts off power supply loop under circuit excessive pressure, under-voltage state, and has the current limit function, can protect sensor rear end circuit comprehensively effectively.
Description
Technical Field
The utility model relates to a power supply protection technical field especially relates to a sensor power supply protection circuit.
Background
Along with the vigorous development of smart power grids, smart transportation, smart factories and new energy automobiles, the demand of sensors for state monitoring is also remarkably increased.
The increasing sophistication and sophistication of intelligent systems and components often interfere with the power supply circuitry that provides the source of power. Meanwhile, certain influence and even unrecoverable damage can be caused to the working state of the sensor, and further more serious accidents are caused.
The existing sensor has no protection capability against the interference of a power supply loop.
SUMMERY OF THE UTILITY MODEL
The utility model provides a sensor power supply protection circuit to solve the problem that current sensor does not possess power supply protective capability.
According to the utility model discloses an aspect provides a sensor power supply protection circuit, include:
the voltage threshold setting circuit is used for setting an overvoltage threshold and an undervoltage threshold of the power supply voltage;
the overvoltage protection circuit is connected with the voltage threshold setting circuit and used for cutting off a power supply loop when the power supply voltage is higher than the overvoltage threshold;
the under-voltage protection circuit is respectively connected with the voltage threshold setting circuit and the over-voltage protection circuit and is used for cutting off the power supply loop when the power supply voltage is lower than the under-voltage threshold;
the current limiting circuit is respectively connected with the overvoltage protection circuit and the undervoltage protection circuit and used for setting a current limiting threshold value so as to limit the maximum current consumption of the sensor rear-end circuit through the current limiting threshold value.
The utility model provides a sensor power supply protection circuit is applied to the sensor for the sensor possesses the power supply protective capacities. The sensor power supply protection circuit can actively cut off the power supply loop under the overvoltage state of the circuit and can also actively cut off the power supply loop under the undervoltage state of the circuit, has a current limiting function, and can comprehensively and effectively protect the sensor back-end circuit. The sensor power supply protection circuit has the advantages of comprehensive functions, simple structure and low cost, is suitable for mass production, and can be applied to various circuit structures.
It should be understood that the statements in this section are not intended to identify key or critical features of the embodiments of the present invention, nor are they intended to limit the scope of the invention. Other features of the present invention will become apparent from the following description.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic diagram of a sensor power supply protection circuit according to an embodiment of the present invention;
fig. 2 is a schematic diagram of another sensor power supply protection circuit provided by the embodiment of the present invention;
fig. 3 is a schematic diagram of another sensor power protection circuit provided by an embodiment of the present invention;
fig. 4 is a schematic diagram of another sensor power supply protection circuit provided in the embodiment of the present invention.
Detailed Description
In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in other sequences than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Fig. 1 is a schematic diagram of a sensor power supply protection circuit according to an embodiment of the present invention. As shown in fig. 1, the sensor power supply protection circuit includes: a voltage threshold setting circuit 10 for setting an overvoltage threshold and an undervoltage threshold of the power supply voltage; the overvoltage protection circuit 20 is connected with the voltage threshold setting circuit 10 and is used for cutting off the power supply loop when the power supply voltage is higher than the overvoltage threshold; the undervoltage protection circuit 30 is respectively connected with the voltage threshold setting circuit 10 and the overvoltage protection circuit 20, and is used for cutting off a power supply loop when the power supply voltage is lower than the undervoltage threshold; the current limiting circuit 40 is respectively connected to the over-voltage protection circuit 20 and the under-voltage protection circuit 30, and is used for setting a current limiting threshold value so as to limit the maximum current consumption of the sensor back-end circuit through the current limiting threshold value.
In this embodiment, the sensor power supply protection circuit is used to protect a sensor circuit powered by positive and negative dual power supplies.
The voltage threshold setting circuit 10 is connected to the power supply loop and is used for setting an over-voltage threshold and an under-voltage threshold of the power supply voltage. The supply voltage is a voltage signal provided by the supply loop.
The overvoltage protection circuit 20 is connected to the power supply loop and connected to the voltage threshold setting circuit 10, and the overvoltage threshold can be obtained from the voltage threshold setting circuit 10. The overvoltage protection circuit 20 cuts off the power supply loop to protect the sensor back-end circuit by changing the operating state of the power supply loop when detecting that the power supply voltage is greater than the overvoltage threshold. Conversely, when the overvoltage protection circuit 20 detects that the supply voltage is less than or equal to the overvoltage threshold, the operating state of the power supply circuit is not switched, and the supply voltage is sequentially transmitted to the next circuit. The overvoltage protection of the power supply loop is realized.
The undervoltage protection circuit 30 is connected to the power supply loop and is respectively connected to the voltage threshold setting circuit 10 and the overvoltage protection circuit 20, and may obtain an undervoltage threshold from the voltage threshold setting circuit 10 and obtain a power supply voltage less than or equal to the overvoltage threshold from the overvoltage protection circuit 20. When detecting that the power supply voltage is smaller than the undervoltage threshold, the undervoltage protection circuit 30 switches off the power supply loop to protect the sensor back-end circuit by changing the operating state of the power supply loop. Conversely, when the undervoltage protection circuit 30 detects that the power supply voltage is greater than or equal to the undervoltage threshold, the operating state of the power supply loop is not switched, and the power supply voltage is sequentially transmitted to the next circuit. And the undervoltage protection of the power supply loop is realized.
The current limiting circuit 40 is respectively connected to the over-voltage protection circuit 20 and the under-voltage protection circuit 30, and is used for setting a current limiting threshold value so as to limit the maximum current consumption of the sensor back-end circuit through the current limiting threshold value. The current limiting circuit 40 may limit the maximum current consumption of the sensor back-end circuit, and prevent the circuit or device from being burned due to the power consumption increase caused by the abnormal state of the sensor back-end circuit. The current-limiting protection of the power supply loop is realized.
The utility model provides a sensor power supply protection circuit is applied to the sensor for the sensor possesses the power supply protective capacities. The sensor power supply protection circuit can actively cut off a power supply loop under the circuit overvoltage state and also can actively cut off the power supply loop under the circuit undervoltage state, has a current limiting function, and can comprehensively and effectively protect a sensor rear end circuit. The power supply protection circuit of the sensor has comprehensive functions, simple structure and low cost, is suitable for mass production, and can be applied to various circuit structures.
Fig. 2 is a schematic diagram of another sensor power supply protection circuit provided in the embodiment of the present invention. As shown in fig. 2, in the sensor power supply protection circuit, an optional voltage threshold setting circuit 10 includes a first threshold setting unit 11 and a second threshold setting unit 12; the first threshold setting unit 11 is configured to set a first over-voltage threshold and a first under-voltage threshold of the forward power supply voltage; the second threshold setting unit 12 is configured to set a second overvoltage threshold and a second undervoltage threshold of the negative supply voltage; the overvoltage protection circuit 20 includes a first overvoltage protection unit 21 and a second overvoltage protection unit 22; the first overvoltage protection unit 21 is used for overvoltage protection of the forward supply voltage; the second overvoltage protection unit 22 is used for overvoltage protection of the negative supply voltage; the undervoltage protection circuit 30 includes a first undervoltage protection unit 31 and a second undervoltage protection unit 32; the first undervoltage protection unit 31 is used for undervoltage protection of the forward supply voltage; the second undervoltage protection unit 32 is used for undervoltage protection of the negative supply voltage; the current limiting circuit 40 includes a first current limiting unit 41 and a second current limiting unit 42; the first current limiting unit 41 is used for setting a first current limiting threshold value and limiting the maximum current value of the forward power supply voltage; the second current limiting unit 42 is configured to set a second current limiting threshold and limit a maximum current value of the negative supply voltage.
In this embodiment, the first threshold setting unit 11, the first overvoltage protection unit 21, the first undervoltage protection unit 31, and the first current limiting unit 41 are connected to form a protection circuit for a forward power supply voltage, so as to implement an overvoltage protection function, an undervoltage protection function, and a current limiting function for the forward power supply voltage. The second threshold setting unit 12, the second overvoltage protection unit 22, the second undervoltage protection unit 32, and the second current limiting unit 42 are connected to form a protection circuit for negative supply voltage, so as to implement an overvoltage protection function, an undervoltage protection function, and a current limiting function for negative supply voltage. The sensor power supply protection circuit may be provided with only a protection circuit for a positive power supply voltage, may be provided with only a protection circuit for a negative power supply voltage, or may be provided with both as shown in fig. 2.
The first threshold setting unit 11 is connected to a supply loop of a forward supply voltage; the first overvoltage protection unit 21 is connected to a power supply loop of the forward supply voltage and is connected to the first threshold setting unit 11; the first undervoltage protection unit 31 is connected to a supply loop of the forward supply voltage, and is respectively connected to the first threshold setting unit 11 and the first overvoltage protection unit 21; the first current limiting unit 41 is connected to the first overvoltage protection unit 21 and the first undervoltage protection unit 31, respectively.
The second threshold setting unit 12 is connected to a power supply loop of a negative power supply voltage; the second overvoltage protection unit 22 is connected to a power supply loop of the negative power supply voltage, and is connected to the second threshold setting unit 12; the second undervoltage protection unit 32 is connected to a power supply loop of a negative power supply voltage, and is respectively connected to the second threshold setting unit 12 and the second overvoltage protection unit 22; the second current limiting unit 42 is connected to the second overvoltage protection unit 22 and the second undervoltage protection unit 32, respectively.
Fig. 3 is a schematic diagram of another sensor power supply protection circuit provided by an embodiment of the present invention. As shown in fig. 3, in the sensor power supply protection circuit, an optional first threshold setting unit 11 is composed of a first voltage regulator VZ1 and a second voltage regulator VZ 2; the cathode of the first voltage-regulator tube VZ1 is connected to the forward power supply loop, the anode of the first voltage-regulator tube VZ1 is connected with the first overvoltage protection unit 21, and the first voltage-regulator tube VZ1 sets a first overvoltage threshold value; the cathode of the second voltage-regulator tube VZ2 is connected with the first under-voltage protection unit 31, the anode is grounded GND, and the second voltage-regulator tube VZ2 sets a first under-voltage threshold value; the second threshold setting unit 12 is composed of a third regulator VZ3 and a fourth regulator VZ 4; the anode of the third voltage-regulator tube VZ3 is connected to a negative power supply loop, the cathode of the third voltage-regulator tube VZ3 is connected to the second overvoltage protection unit 22, and the third voltage-regulator tube VZ3 sets a second overvoltage threshold; the cathode of the fourth regulator VZ4 is grounded GND, the anode of the fourth regulator VZ4 is connected to the second under-voltage protection unit 32, and the fourth regulator VZ4 sets a second under-voltage threshold.
The selectable first overvoltage protection unit 21 is composed of a first triode VT1, a first resistor R1 and a second resistor R2, wherein the first end of the second resistor R2 is connected with the cathode of a first voltage-regulator tube VZ1, the second end of the second resistor R2 is connected with the collector of the first triode VT1 and is connected into the first undervoltage protection unit 31, the first end of the first resistor R1 is connected with the anode of the first voltage-regulator tube VZ1 and is connected into the base of the first triode VT1, and the second end of the first resistor R1 and the emitter of the first triode VT1 are grounded GND together; the first overvoltage protection unit 21 is configured to output a low potential at a collector of the first transistor VT1 to cut off the forward power supply loop when the forward power supply voltage is higher than a first overvoltage threshold; the second overvoltage protection unit 22 is composed of a third triode VT3, a fifth resistor R5 and a sixth resistor R6, a first end of the sixth resistor R6 is connected with an anode of a third voltage regulator VZ3, a second end of the sixth resistor R6 is connected with a collector of the third triode VT3 and is connected to the second undervoltage protection unit 32, a first end of the fifth resistor R5 is connected with a cathode of the third voltage regulator VZ3 and is connected to a base of the third triode VT3, and a second end of the fifth resistor R5 and an emitter of the third triode VT3 are grounded GND; the second overvoltage protection unit 22 is configured to, when the negative power supply voltage is higher than the second overvoltage threshold, output a low potential from a collector of the third transistor VT3 to cut off the negative power supply loop.
The optional first undervoltage protection unit 31 is composed of a third resistor R3 and a second triode VT2, a first end of the third resistor R3 is connected with a cathode of the second voltage regulator VZ2 and is connected to a base of the second triode VT2, a second end of the third resistor R3 is respectively connected to the first overvoltage protection unit 21 and the first current limiting unit 41, and an emitter of the second triode VT2 is connected to the first current limiting unit 41; the first undervoltage protection unit 31 is configured to cut off the forward power supply loop when the forward power supply voltage is lower than a first undervoltage threshold; the second undervoltage protection unit 32 is composed of a seventh resistor and a R7 fourth triode VT4, a first end of the seventh resistor R7 is connected with an anode of the fourth voltage-regulator tube VZ4 and is connected to a base of the fourth triode VT4, a second end of the seventh resistor R7 is respectively connected with the second overvoltage protection unit 22 and the second current-limiting unit 42, and an emitter of the fourth triode VT4 is connected to the second current-limiting unit 42; the second under-voltage protection unit 32 is configured to cut off the negative supply loop when the negative supply voltage is lower than the second under-voltage threshold.
The optional first current limiting unit 41 is composed of a fourth resistor R4, the fourth resistor R4 is connected between the third resistor R3 and the emitter of the second triode VT2, and the first current limiting unit 41 limits the forward supply current to be not more than the first current limiting threshold by adjusting the voltage drop across the fourth resistor R4; the second current limiting unit 42 is formed by an eighth resistor R8, the eighth resistor R8 is connected between the seventh resistor R7 and the emitter of the fourth transistor VT4, and the second current limiting unit 42 limits the negative supply current to not exceed the second current limiting threshold by adjusting a voltage drop across the eighth resistor R8.
As described above, the first threshold setting unit 11, the first overvoltage protection unit 21, the first undervoltage protection unit 31, and the first current limiting unit 41 are connected to form a protection circuit for the forward supply voltage, so as to implement an overvoltage protection function, an undervoltage protection function, and a current limiting function for the forward supply voltage. The second threshold setting unit 12, the second overvoltage protection unit 22, the second undervoltage protection unit 32, and the second current limiting unit 42 are connected to form a protection circuit for negative supply voltage, so as to implement an overvoltage protection function, an undervoltage protection function, and a current limiting function for negative supply voltage.
The anode of a first voltage regulator VZ1 in the first threshold setting unit 11 is connected to the first end of a first resistor R1 in the first overvoltage protection unit 21; the cathode of the second regulator VZ2 in the first threshold setting unit 11 is connected to the first end of the third resistor R3 in the first undervoltage protection unit 31.
The cathode of the third regulator VZ3 in the second threshold setting unit 12 is connected to the first end of the fifth resistor R5 in the second overvoltage protection unit 22; the anode of the fourth regulator VZ4 in the second threshold setting unit 12 is connected to the first end of the seventh resistor R7 in the second under-voltage protection unit 32.
The second end of the second resistor R2 in the first overvoltage protection unit 21 is connected to the second end of the third resistor R3 in the first undervoltage protection unit 31.
The second end of the sixth resistor R6 in the second overvoltage protection unit 22 is connected to the second end of the seventh resistor R7 in the second undervoltage protection unit 32.
The second end of the third resistor R3 in the first under-voltage protection unit 31 is further connected to the first end of the fourth resistor R4 in the first current limiting unit 41; the emitter of the second transistor VT2 in the first undervoltage protection unit 31 is connected to the second end of the fourth resistor R4 in the first current limiting unit 41.
The second end of the seventh resistor R7 in the second under-voltage protection unit 32 is further connected to the first end of the eighth resistor R8 in the second current limiting unit 42; an emitter of the fourth transistor VT4 in the second undervoltage protection unit 32 is connected to a second end of the eighth resistor R8 in the second current limiting unit 42.
For the forward supply voltage V1, the following is described:
when the forward power supply voltage is higher than the first overvoltage threshold, the collector of the first triode VT1 outputs a low potential, namely a V3 low potential, so that the second triode VT2 is cut off, and the forward power supply loop is cut off. Specifically, when the cathode voltage V1 of the first voltage regulator VZ1 is higher than a first overvoltage threshold, the first voltage regulator VZ1 is turned on, and the anode voltage V2 of the first voltage regulator VZ1 is raised, so that the first triode VT1 is turned on. At this time, the collector output voltage V3 of the first transistor VT1 approaches the ground potential, causing the second transistor VT2 to turn off, cutting off the electrical connection of the output Vout + to the forward power supply loop.
When the forward supply voltage is lower than the first overvoltage threshold, the collector of the first transistor VT1 outputs a high potential, and the forward supply voltage flows through the first overvoltage protection unit 21 into the first undervoltage protection unit 31. Specifically, when the cathode voltage V1 of the first voltage regulator VZ1 is lower than the first overvoltage threshold, the first voltage regulator VZ1 is turned off, and meanwhile, the anode voltage V2 of the first voltage regulator VZ1 is grounded through the first resistor R1, so that the first triode VT1 is turned off.
When the forward supply voltage is lower than the first overvoltage threshold and higher than the first undervoltage threshold, the V4 outputs a high potential to turn on the second transistor VT2, and the forward supply voltage passes through the fourth resistor R4 and then is output through Vout +. Specifically, when V1 is lower than the first overvoltage threshold and higher than the first undervoltage threshold, the second regulator VZ2 is turned on, the high potential of V4 turns on the second transistor VT2, and at this time, the output Vout + is connected to the forward power supply loop.
When the forward power supply voltage is lower than the first undervoltage threshold value, the second voltage-regulator tube VZ2 is not conducted, so that the second triode VT2 is cut off, and the forward power supply loop is cut off. Specifically, when V1 is lower than the first undervoltage threshold, V4 has a low potential, and the second regulator VZ2 is not turned on, so that the second triode VT2 is turned off, and the electrical connection between the output Vout + and the forward power supply loop is cut off.
When the output Vout + is connected into a forward power supply loop, the forward power supply current can be limited not to exceed a first current limiting threshold value by adjusting the voltage drop at the two ends of the fourth resistor R4, and the forward power supply current limiting function is realized. The positive supply voltage V1 is output through Vout + after overvoltage, undervoltage and current limiting.
For a negative supply voltage V6, as follows:
when the negative power supply voltage is higher than the second overvoltage threshold, the collector of the third triode VT3 outputs a low potential, i.e., a V8 low potential, so that the fourth triode VT4 is turned off, thereby cutting off the negative power supply loop. Specifically, when the anode voltage V6 of the third regulator VZ3 is higher than the second overvoltage threshold, the third regulator VZ3 is turned on, and simultaneously, the cathode voltage V7 of the third regulator VZ3 is pulled low, so that the third transistor VT3 is turned on. At this point, the collector output voltage V8 of the third transistor VT3 approaches ground potential, causing the fourth transistor VT4 to turn off, disconnecting the output Vout — from the negative supply loop.
When the negative supply voltage is lower than the second overvoltage threshold, the collector of the third transistor VT3 outputs a high potential, and the negative supply voltage flows through the second overvoltage protection unit 22 into the second undervoltage protection unit 32. Specifically, when the anode voltage V6 of the third regulator VZ3 is lower than the second overvoltage threshold, the third regulator VZ3 is turned off, and meanwhile, the cathode voltage V7 of the third regulator VZ3 is pulled high by the fifth resistor R5, so that the third triode VT3 is turned off.
When the negative power supply voltage is lower than the second overvoltage threshold and higher than the second undervoltage threshold, the V8 outputs a high potential to turn on the fourth transistor VT4, and the negative power supply voltage passes through the eighth resistor R8 and then is output through Vout-. Specifically, when V6 is lower than the second overvoltage threshold and higher than the second undervoltage threshold, the fourth voltage regulator VZ4 is turned on by the high voltage of V8, the fourth transistor VT4 is turned on by the high potential of V9, and at this time, vout — is output and connected to the negative power supply loop.
When the negative power supply voltage is lower than the second undervoltage threshold, the fourth voltage-regulator tube VZ4 is not conducted, so that the fourth triode VT4 is cut off, and the negative power supply loop is cut off. Specifically, when V6 is lower than the second undervoltage threshold, V8 has a low potential, and the fourth regulator VZ4 is not turned on, so that the fourth transistor VT4 is turned off, and the electrical connection between the output Vout and the negative power supply loop is cut off.
When the output Vout is connected to the negative power supply loop, the negative power supply current can be limited not to exceed the second current limiting threshold value by adjusting the voltage drop at the two ends of the eighth resistor R8, so that the negative power supply current limiting function is realized. The negative supply voltage V6 is output through Vout-after over-voltage, under-voltage and current-limited.
As shown in fig. 3, the optional sensor power protection circuit further includes: the reverse connection preventing unit 51, the common mode inhibiting unit 52 and the surge inhibiting unit 53 are connected in sequence; an anti-reverse connection unit 51 connected in series to the power supply circuit; a common mode rejection unit 52 connected in series to the power supply loop for rejecting an interference signal of the power supply voltage output from the reverse connection preventing unit 51; the surge suppression unit 53 is connected in parallel to the power supply circuit, and is configured to absorb an abnormal surge signal of the power supply voltage output from the common mode suppression unit 52.
The optional reverse connection prevention unit 51 comprises a first diode VD1 for reverse connection prevention of positive power supply and a second diode VD2 for reverse connection prevention of negative power supply; the common mode rejection unit 52 is a four-terminal or two-terminal choke device L; the surge suppression unit 53 includes a first suppression diode TVS1 for positive supply surge suppression and a second suppression diode TVS2 for negative supply surge suppression.
The reverse-connection preventing unit 51 can prevent damage caused by erroneous wiring of the sensor.
The common mode rejection unit 52 is located immediately after the reverse connection preventing unit 51 and is used for rejecting the common mode interference signal abnormally superposed on the power supply terminal.
The surge suppressing unit 53 is located immediately after the common mode suppressing unit 52, and is used for absorbing abnormal surge interference signals at the power supply end and preventing damage to the sensor back-end circuit.
The utility model provides a sensor power supply protection circuit, have prevent reverse connection, restrain common mode and surge interference's function, ensure that sensor power supply signal composition is clean; meanwhile, the power supply loop is actively cut off under the states of reverse connection, overvoltage and undervoltage of the circuit, and the current limiting function is realized, so that the sensor rear-end circuit can be comprehensively and effectively protected, the sensor does not work when the power supply is in overvoltage or undervoltage, the current is limited under the abnormal conditions that the sensor rear-end circuit is short-circuited or devices are invalid and the like, and the permanent damage and even fire caused by continuous work under the fault state are avoided. The utility model discloses the sensor power supply protection circuit function is comprehensive and the principle is simple, the facilitate promotion.
Fig. 4 is a schematic diagram of another sensor power supply protection circuit provided in the embodiment of the present invention. The sensor power supply protection circuit supplies power to the sensor with a single power supply.
When the sensor power supply protection circuit supplies power to the forward power supply, the working principle of the sensor power supply protection circuit is the same as that of the forward power supply loop in fig. 3.
When the sensor power supply protection circuit supplies power to the negative power supply, the working principle of the sensor power supply protection circuit is the same as that of the negative power supply loop in fig. 3.
It should be understood that various forms of the flows shown above may be used, with steps reordered, added, or deleted. For example, the steps described in the present invention may be executed in parallel, may be executed sequentially, or may be executed in different orders, as long as the desired result of the technical solution of the present invention can be achieved, and the present invention is not limited thereto.
The above detailed description does not limit the scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made in accordance with design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A sensor power supply protection circuit, comprising:
the voltage threshold setting circuit is used for setting an overvoltage threshold and an undervoltage threshold of the power supply voltage;
the overvoltage protection circuit is connected with the voltage threshold setting circuit and is used for cutting off a power supply loop when the power supply voltage is higher than the overvoltage threshold;
the under-voltage protection circuit is respectively connected with the voltage threshold setting circuit and the over-voltage protection circuit and is used for cutting off the power supply loop when the power supply voltage is lower than the under-voltage threshold;
the current limiting circuit is respectively connected with the overvoltage protection circuit and the undervoltage protection circuit and used for setting a current limiting threshold value so as to limit the maximum current consumption of the sensor rear-end circuit through the current limiting threshold value.
2. The sensor power supply protection circuit of claim 1, wherein the voltage threshold setting circuit comprises a first threshold setting unit and a second threshold setting unit; the first threshold setting unit is used for setting a first overvoltage threshold and a first undervoltage threshold of the forward power supply voltage; the second threshold setting unit is used for setting a second overvoltage threshold and a second undervoltage threshold of the negative power supply voltage;
the overvoltage protection circuit comprises a first overvoltage protection unit and a second overvoltage protection unit; the first overvoltage protection unit is used for overvoltage protection of the forward power supply voltage; the second overvoltage protection unit is used for overvoltage protection of the negative power supply voltage;
the undervoltage protection circuit comprises a first undervoltage protection unit and a second undervoltage protection unit; the first undervoltage protection unit is used for undervoltage protection of the forward power supply voltage; the second undervoltage protection unit is used for undervoltage protection of the negative power supply voltage;
the current limiting circuit comprises a first current limiting unit and a second current limiting unit; the first current limiting units are respectively used for setting a first current limiting threshold value and limiting the maximum current value of the forward power supply voltage; the second current limiting unit is used for setting a second current limiting threshold value and limiting the maximum current value of the negative power supply voltage.
3. The sensor power supply protection circuit according to claim 2, wherein the first threshold setting unit is composed of a first voltage regulator tube and a second voltage regulator tube; the cathode of the first voltage-regulator tube is connected with a forward power supply loop, the anode of the first voltage-regulator tube is connected with the first overvoltage protection unit, and the first voltage-regulator tube sets the first overvoltage threshold value; the cathode of the second voltage-stabilizing tube is connected with the first undervoltage protection unit, the anode of the second voltage-stabilizing tube is grounded, and the second voltage-stabilizing tube sets the first undervoltage threshold value;
the second threshold setting unit consists of a third voltage-regulator tube and a fourth voltage-regulator tube; the anode of the third voltage-regulator tube is connected with a negative power supply loop, the cathode of the third voltage-regulator tube is connected with the second overvoltage protection unit, and the third voltage-regulator tube sets the second overvoltage threshold; the cathode of the fourth voltage-regulator tube is grounded, the anode of the fourth voltage-regulator tube is connected with the second undervoltage protection unit, and the fourth voltage-regulator tube sets the second undervoltage threshold value.
4. The sensor power supply protection circuit according to claim 3, wherein the first overvoltage protection unit is composed of a first triode, a first resistor and a second resistor, a first end of the second resistor is connected with a cathode of the first voltage regulator tube, a second end of the second resistor is connected with a collector of the first triode and connected to the first undervoltage protection unit, a first end of the first resistor is connected with an anode of the first voltage regulator tube and connected to a base of the first triode, and a second end of the first resistor is commonly grounded with an emitter of the first triode; the first overvoltage protection unit is used for outputting a low potential to cut off a forward power supply loop by a collector of the first triode when the forward power supply voltage is higher than the first overvoltage threshold;
the second overvoltage protection unit is composed of a third triode, a fifth resistor and a sixth resistor, wherein the first end of the sixth resistor is connected with the anode of the third voltage regulator tube, the second end of the sixth resistor is connected with the collector electrode of the third triode and is connected with the second undervoltage protection unit, the first end of the fifth resistor is connected with the cathode of the third voltage regulator tube and is connected with the base electrode of the third triode, and the second end of the fifth resistor and the emitter electrode of the third triode are grounded together; and the second overvoltage protection unit is used for outputting a low potential to cut off a negative power supply loop by the collector of the third triode when the negative power supply voltage is higher than the second overvoltage threshold.
5. The sensor power supply protection circuit according to claim 3, wherein the first undervoltage protection unit is composed of a third resistor and a second triode, a first end of the third resistor is connected with a cathode of the second voltage regulator tube and is connected to a base of the second triode, a second end of the third resistor is respectively connected to the first overvoltage protection unit and the first current limiting unit, and an emitter of the second triode is connected to the first current limiting unit; the first undervoltage protection unit is used for cutting off a forward power supply loop when the forward power supply voltage is lower than the first undervoltage threshold value;
the second under-voltage protection unit is composed of a seventh resistor and a fourth triode, the first end of the seventh resistor is connected with the anode of the fourth voltage-regulator tube and is connected with the base of the fourth triode, the second end of the seventh resistor is respectively connected with the second over-voltage protection unit and the second current-limiting unit, and the emitter of the fourth triode is connected with the second current-limiting unit; the second undervoltage protection unit is configured to cut off a negative power supply loop when the negative power supply voltage is lower than the second undervoltage threshold.
6. The sensor power supply protection circuit of claim 5, wherein the first current limiting unit is composed of a fourth resistor, the fourth resistor is connected between the third resistor and the emitter of the second triode, and the first current limiting unit limits a forward supply current to not exceed the first current limiting threshold by adjusting a voltage drop across the fourth resistor;
the second current limiting unit is composed of an eighth resistor, the eighth resistor is connected between the seventh resistor and the emitter of the fourth triode, and the second current limiting unit limits that negative supply current does not exceed the second current limiting threshold value by adjusting voltage drop between two ends of the eighth resistor.
7. The sensor power supply protection circuit of claim 1, further comprising: the anti-reverse unit, the common mode suppression unit and the surge suppression unit are connected in sequence;
the reverse connection preventing unit is connected in series into the power supply loop;
the common mode rejection unit is connected in series to the power supply loop and used for rejecting interference signals of the power supply voltage output from the reverse connection prevention unit;
the surge suppression unit is connected in parallel to the power supply loop and used for absorbing abnormal surge signals of the power supply voltage output from the common mode suppression unit.
8. The sensor power supply protection circuit of claim 7, wherein the reverse connection prevention unit comprises a first diode for reverse connection prevention of a positive power supply and a second diode for reverse connection prevention of a negative power supply;
the common mode rejection unit is a four-end or double-end choke device;
the surge suppression unit comprises a first suppression diode used for positive power supply surge suppression and a second suppression diode used for negative power supply surge suppression.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221278144.XU CN217824236U (en) | 2022-05-25 | 2022-05-25 | Sensor power supply protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221278144.XU CN217824236U (en) | 2022-05-25 | 2022-05-25 | Sensor power supply protection circuit |
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| CN217824236U true CN217824236U (en) | 2022-11-15 |
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| CN202221278144.XU Active CN217824236U (en) | 2022-05-25 | 2022-05-25 | Sensor power supply protection circuit |
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| CN (1) | CN217824236U (en) |
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