A detection protection circuit for a DC measurement amplifier with electromagnetic interference resistance

Abstract

The present invention discloses an anti-electromagnetic interference DC measurement amplifier detection protection circuit, which relates to the technical field of DC measurement amplifiers, and includes an amplifier power interface module, which is used to connect with the anti-electromagnetic interference DC measurement amplifier, a positive voltage source, a negative voltage source and a ground terminal, and control the transmission state of electric energy; a first sampling module, which is used for voltage sampling; a second sampling module, which is used for absolute value processing and voltage sampling; a connection state detection module, which is used to detect the connection state between the amplifier power interface module and the negative voltage source or the ground terminal; a signal transmission module, which is used to control the transmission path of the signal; a difference detection module, which is used to perform difference calculation on the input signal; a voltage anomaly judgment module, which is used to set a first voltage threshold and a second voltage threshold and perform voltage anomaly judgment; a protection control module, which is used for signal self-locking. The anti-electromagnetic interference DC measurement amplifier detection protection circuit of the present invention can perform power supply state detection on different power supply states, thereby improving work safety.

Description

Technical Field

[0001] The invention relates to the technical field of direct current measuring amplifiers, in particular to an electromagnetic interference resistant direct current measuring amplifier detection protection circuit. Background Art

[0002] An electromagnetic interference resistant DC measuring amplifier is a device designed to improve the electromagnetic compatibility of power electronic equipment, especially to ensure accurate measurement, amplification and transmission of DC signals when facing electromagnetic interference. The electromagnetic interference resistant DC measuring amplifier in the prior art generally has two power supply modes according to the selection and working mode of the amplifier, namely, positive voltage source power supply or positive and negative voltage source power supply. The absolute value of the negative voltage provided by the negative voltage source is equal to the positive voltage provided by the positive voltage source. In order to ensure the normal operation of the electromagnetic interference resistant DC measuring amplifier, a comparison device and a set voltage threshold range are generally used for voltage stabilization detection. However, due to the existence of two power supply modes, the number of detection thresholds and comparison devices required for the electromagnetic interference resistant DC measuring amplifier detection is large, which increases the complexity and cost of the detection circuit, and the detection means of the electromagnetic interference resistant DC measuring amplifier cannot be automatically changed according to the power supply mode. Therefore, it needs to be improved. Summary of the invention

[0003] The embodiment of the present invention provides an electromagnetic interference resistant direct current measurement amplifier detection protection circuit to solve the problems raised in the above background technology.

[0004] According to an embodiment of the present invention, an electromagnetic interference resistant DC measurement amplifier detection protection circuit is provided, comprising: an amplifier power interface module, a first sampling module, a second sampling module, a connection status detection module, a signal transmission module, a difference detection module, a voltage anomaly judgment module and a protection control module;

[0005] An amplifier power interface module is connected to the protection control module, and is used to be connected to an anti-electromagnetic interference DC measurement amplifier, to a positive voltage source, and to a negative voltage source or a ground terminal, and transmits a positive voltage provided by the positive voltage source to the connected anti-electromagnetic interference DC measurement amplifier, and transmits a negative voltage provided by the negative voltage source to the connected anti-electromagnetic interference DC measurement amplifier, and stops transmitting positive and negative voltages when receiving a protection signal output by the protection control module;

[0006] A first sampling module, connected to the amplifier power interface module, for sampling the positive voltage and outputting a first sampling signal;

[0007] A second sampling module, connected to the amplifier power interface module, for performing absolute value processing and voltage sampling on the negative voltage and outputting a second sampling signal;

[0008] A connection status detection module, connected to the amplifier power interface module, used to detect the connection status between the amplifier power interface module and the negative voltage source or the ground terminal, and output a first control signal when detecting that the amplifier power interface module is connected to the ground terminal;

[0009] A signal transmission module, connected to the first sampling module and the second sampling module, used to compare the voltages of the first sampling signal and the second sampling signal, and when the voltage of the first sampling signal is greater than the voltage of the second sampling signal, transmit the first sampling signal and the second sampling signal to the difference detection module, and when the voltage of the second sampling signal is greater than the voltage of the first sampling signal, switch the signal transmission path;

[0010] A difference detection module, connected to the signal transmission module, configured to perform a difference calculation on the first sampling signal and the second sampling signal and output the first difference signal, and perform a difference calculation on the second sampling signal and the first sampling signal and output the second difference signal;

[0011] a voltage anomaly judgment module, connected to the difference detection module and the connection state detection module, for setting a first voltage threshold when the first control signal is not received, and outputting a second control signal when the first difference signal or the second difference signal is greater than the first voltage threshold, and setting a second voltage threshold when the first control signal is received, and outputting a third control signal when the first difference signal is greater than the second voltage threshold;

[0012] The protection control module is connected to the voltage anomaly judgment module and is used to perform signal self-locking processing on the second control signal or the third control signal and output a protection signal.

[0013] As a further solution of the present invention: the amplifier power interface module includes a power interface, a first thyristor, a second thyristor, a first constant voltage source, a first resistor, a first triode and an electromagnetic interference resistant DC measurement amplifier interface;

[0014] Preferably, the first end of the power interface is connected to the anode of the first thyristor, the second end of the power interface is connected to the cathode of the second thyristor, the cathode of the first transistor is connected to the first power terminal of the anti-electromagnetic interference DC measuring amplifier, the anode of the second thyristor is connected to the second power terminal of the anti-electromagnetic interference DC measuring amplifier, the control end of the first thyristor and the control end of the second thyristor are both connected to the collector of the first transistor and connected to the first power supply through the first resistor, the emitter of the first transistor is grounded, and the base of the first transistor is connected to the protection control module.

[0015] As a further solution of the present invention: the first sampling module includes a ninth resistor and a tenth resistor;

[0016] Preferably, the first end of the ninth resistor is connected to the first power supply end of the anti-electromagnetic interference DC measurement amplifier, and the second end of the ninth resistor is connected to the signal transmission module and grounded through the tenth resistor.

[0017] As a further solution of the present invention: the second sampling module includes a second resistor, a third resistor, a fourth resistor, a first operational amplifier, a first crystal diode, a second crystal diode, a fifth resistor, a sixth resistor, a second operational amplifier, a seventh resistor and an eighth resistor;

[0018] Preferably, the inverting end of the first operational amplifier is connected to one end of the third resistor and one end of the fourth resistor and is connected to the second power supply end of the anti-electromagnetic interference DC measuring amplifier through the second resistor, the other end of the third resistor is connected to the anode of the first crystal diode and is connected to one end of the sixth resistor and the inverting end of the second operational amplifier through the fifth resistor, the other end of the fourth resistor is connected to the cathode of the second crystal diode and the in-phase end of the second operational amplifier, the output end of the first operational amplifier is connected to the cathode of the first crystal diode and the anode of the second crystal diode, the in-phase end of the first operational amplifier is grounded, the output end of the second operational amplifier is connected to the other end of the sixth resistor and is connected to the signal transmission module and the first end of the eighth resistor through the seventh resistor, and the second end of the eighth resistor is grounded.

[0019] As a further solution of the present invention: the signal transmission module includes a first comparison device, a first inverter and a first switch;

[0020] Preferably, the inverting end of the first comparison device, the third end and the first end of the first switching switch are all connected to the second end of the ninth resistor, the inverting end of the first comparison device, the eighth end and the tenth end of the first switching switch are all connected to the first end of the eighth resistor, the output end of the first comparison device is connected to the input end of the first inverter, the fifth end and the sixth end of the first switching switch, and the output end of the first inverter is connected to the twelfth end and the thirteenth end of the first switching switch.

[0021] As a further solution of the present invention: the difference detection module includes an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor and a third operational amplifier;

[0022] Preferably, the in-phase terminal of the third operational amplifier is connected to one end of the eleventh resistor and is grounded through the twelfth resistor, the other end of the eleventh resistor is connected to the fourth end and the eleventh end of the first switching switch, the inverting terminal of the third operational amplifier is connected to the first end of the fourteenth resistor and is connected to the second end and the ninth end of the first switching switch through the thirteenth resistor, and the output end of the third operational amplifier is connected to the second end of the fourteenth resistor and the voltage abnormality judgment module.

[0023] As a further solution of the present invention: the connection status detection module includes a second comparison device and a third inverter;

[0024] Preferably, the inverting end of the second comparison device is connected to the second power supply end of the anti-electromagnetic interference DC measurement amplifier, the non-inverting end of the second comparison device is grounded, the output end of the second comparison device is connected to the input end of the third inverter, and the output end of the third inverter is connected to the voltage anomaly judgment module.

[0025] As a further solution of the present invention: the voltage abnormality judgment module includes a second triode, a third triode, a fifteenth resistor, a sixteenth resistor, a second inverter and a fourth crystal diode;

[0026] Preferably, the collector of the second transistor is connected to the collector of the third transistor, the emitter of the second transistor is connected to one end of the sixteenth resistor and the cathode of the fourth crystal diode through the fifteenth resistor, the other end of the sixteenth resistor is connected to the emitter of the third transistor, the base of the second transistor is connected to the output end of the second inverter, the input end of the second inverter is connected to the base of the third transistor and the output end of the third inverter, and the anode of the fourth crystal diode is connected to the protection control module.

[0027] As a further solution of the present invention: the protection control module includes a fifth crystal diode, a sixth crystal diode, a seventeenth resistor, a second constant voltage source and a first logic device;

[0028] Preferably, the anode of the fifth crystal diode is connected to the anode of the fourth crystal diode, the cathode of the fifth crystal diode is connected to the A end of the first logic device and the cathode of the sixth crystal diode, the anode of the sixth crystal diode is connected to the F end of the first logic device and the base of the first transistor, and the B end of the first logic device is connected to the second constant voltage source through the seventeenth resistor.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: the detection and protection circuit of the anti-electromagnetic interference DC measurement amplifier of the present invention performs voltage sampling on the positive voltage source connected to the amplifier power interface module by the first sampling module, detects the connection status of the amplifier power interface module with the negative voltage source and the ground terminal by the connection status detection module, and performs absolute value and voltage sampling processing by the second sampling module. When the amplifier power interface module is connected to the negative voltage source, the difference detection module cooperates with the signal transmission module to perform subtraction calculation on the signals output by the first sampling module and the second sampling module, and when the signal obtained after the subtraction is greater than the first voltage threshold set by the voltage anomaly judgment module, the protection control module controls the amplifier power interface module to perform power-off protection. When the amplifier power interface module is connected to the ground terminal, the second voltage threshold set by the voltage anomaly judgment module is used to judge whether a power anomaly occurs, and when an anomaly occurs, power-off protection is performed. Different power supply states can be detected, thereby improving the working safety of the anti-electromagnetic interference DC measurement amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0031] Figure 1 A schematic block diagram of a principle of an electromagnetic interference resistant DC measurement amplifier detection protection circuit provided by an embodiment of the present invention.

[0032] Figure 2 A circuit diagram of an electromagnetic interference resistant DC measurement amplifier detection protection circuit provided by an embodiment of the present invention.

[0033] Figure 3 A circuit diagram of a voltage anomaly judgment module provided in an embodiment of the present invention.

[0034] Figure 4 A circuit diagram of a protection control module provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] In one embodiment, see Figure 1 , an anti-electromagnetic interference DC measurement amplifier detection protection circuit, comprising: an amplifier power interface module 1, a first sampling module 2, a second sampling module 3, a connection state detection module 4, a signal transmission module 5, a difference detection module 6, a voltage anomaly judgment module 7 and a protection control module 8;

[0037] Specifically, the amplifier power interface module 1 is connected to the protection control module 8, and is used to be connected to the anti-electromagnetic interference DC measurement amplifier, to the positive voltage source, to the negative voltage source or the ground terminal, to transmit the positive voltage provided by the positive voltage source to the connected anti-electromagnetic interference DC measurement amplifier, and to transmit the negative voltage provided by the negative voltage source to the connected anti-electromagnetic interference DC measurement amplifier, and to stop transmitting the positive voltage and the negative voltage when receiving the protection signal output by the protection control module 8;

[0038] A first sampling module 2, connected to the amplifier power interface module 1, for sampling the positive voltage and outputting a first sampling signal;

[0039] A second sampling module 3, connected to the amplifier power interface module 1, for performing absolute value processing and voltage sampling on the negative voltage and outputting a second sampling signal;

[0040] A connection status detection module 4 is connected to the amplifier power interface module 1 and is used to detect the connection status between the amplifier power interface module 1 and the negative voltage source or the ground terminal, and output a first control signal when the amplifier power interface module 1 is detected to be connected to the ground terminal;

[0041] A signal transmission module 5, connected to the first sampling module 2 and the second sampling module 3, for comparing the voltages of the first sampling signal and the second sampling signal, and transmitting the first sampling signal and the second sampling signal to the difference detection module 6 when the voltage of the first sampling signal is greater than the voltage of the second sampling signal, and switching the signal transmission path when the voltage of the second sampling signal is greater than the first sampling signal;

[0042] A difference detection module 6, connected to the signal transmission module 5, for performing a difference calculation on the first sampling signal and the second sampling signal and outputting a first difference signal, and performing a difference calculation on the second sampling signal and the first sampling signal and outputting a second difference signal;

[0043] A voltage anomaly judgment module 7 is connected to the difference detection module 6 and the connection state detection module 4, and is used to set a first voltage threshold when the first control signal is not received, and output a second control signal when the first difference signal or the second difference signal is greater than the first voltage threshold, and to set a second voltage threshold when the first control signal is received, and output a third control signal when the first difference signal is greater than the second voltage threshold;

[0044] The protection control module 8 is connected to the voltage anomaly judgment module 7 and is used to perform signal self-locking processing on the second control signal or the third control signal and output a protection signal.

[0045] In a specific embodiment, the amplifier power interface module 1 may adopt an amplifier power interface circuit composed of a power interface, an anti-electromagnetic interference DC measurement amplifier interface, a thyristor, a triode, etc., which may be connected to a positive voltage source, a negative voltage source or a ground terminal, so as to power the connected anti-electromagnetic interference DC measurement amplifier; the first sampling module 2 may adopt a first sampling circuit composed of a resistor to perform voltage sampling; the second sampling module 3 may adopt a second sampling circuit composed of a resistor, an operational amplifier and a crystal diode, which may perform absolute value processing on the negative voltage, and then perform voltage division processing on the processed signal; the connection status detection module 4 may adopt a connection status detection circuit composed of a comparison device and an inverter, which may detect the connection status of the anti-electromagnetic interference DC measurement amplifier interface with the negative voltage source and the ground terminal; the signal transmission module 5 may adopt a signal transmission circuit composed of a comparison device, an inverter and a switching switch, etc., which may detect the first sampling The voltage size of the output signal of the sampling module 2 and the second sampling module 3 is measured, and the signals output by the first sampling module 2 and the second sampling module 3 are transmitted to the difference detection module 6; the above-mentioned difference detection module 6 can adopt a difference detection circuit composed of a resistor and an operational amplifier, and can perform subtraction processing on the input signal, and then judge the degree of voltage change; the above-mentioned voltage abnormality judgment module 7 can adopt a difference detection circuit composed of a triode, a resistor, a crystal diode, etc., and can set a first voltage threshold and a second voltage threshold. The first voltage threshold is the voltage threshold set when the anti-electromagnetic interference DC measurement amplifier interface is connected to the negative voltage source, and the second voltage threshold is the voltage threshold set when the anti-electromagnetic interference DC measurement amplifier interface is connected to the ground terminal, and voltage abnormality judgment is performed; the above-mentioned protection control module 8 can adopt a protection control circuit composed of a logic device, a resistor, a crystal diode, etc., and perform self-locking processing on the input high-level state signal.

[0046] In another embodiment, see Figure 1 , Figure 2 , Figure 3 and Figure 4 , the amplifier power interface module 1 includes a power interface, a first thyristor S1, a second thyristor S2, a first constant voltage source VCC2, a first resistor R1, a first transistor V1 and an anti-electromagnetic interference DC measurement amplifier interface;

[0047] Specifically, the first end of the power interface is connected to the anode of the first thyristor S1, the second end of the power interface is connected to the cathode of the second thyristor S2, the cathode of the first transistor is connected to the first power end of the anti-electromagnetic interference DC measurement amplifier, the anode of the second thyristor S2 is connected to the second power end of the anti-electromagnetic interference DC measurement amplifier, the control end of the first thyristor S1 and the control end of the second thyristor S2 are both connected to the collector of the first transistor V1 and connected to the first power supply through the first resistor R1, the emitter of the first transistor V1 is grounded, and the base of the first transistor V1 is connected to the protection control module 8.

[0048] In a specific embodiment, the first thyristor S1 and the second thyristor S2 can both be unidirectional thyristors; the first transistor V1 can be an NPN transistor; the first end of the power interface is connected to a positive voltage source, and the second end of the power interface is connected to a negative voltage source or a ground terminal, so as to provide a positive voltage for the first end of the anti-electromagnetic interference DC measurement amplifier interface and provide a negative voltage or zero potential for the second end of the anti-electromagnetic interference DC measurement amplifier interface.

[0049] Further, the first sampling module 2 includes a ninth resistor R9 and a tenth resistor R10;

[0050] Specifically, a first end of the ninth resistor R9 is connected to a first power supply end of the anti-electromagnetic interference DC measurement amplifier, and a second end of the ninth resistor R9 is connected to the signal transmission module 5 and grounded through the tenth resistor R10.

[0051] In a specific embodiment, the ninth resistor R9 and the tenth resistor R10 perform voltage division sampling on the positive voltage.

[0052] Further, the second sampling module 3 includes a second resistor R2, a third resistor R3, a fourth resistor R4, a first operational amplifier OP1, a first crystal diode D1, a second crystal diode D2, a fifth resistor R5, a sixth resistor R6, a second operational amplifier OP2, a seventh resistor R7 and an eighth resistor R8;

[0053] Specifically, the inverting end of the first operational amplifier OP1 is connected to one end of the third resistor R3 and one end of the fourth resistor R4 and is connected to the second power supply end of the anti-electromagnetic interference DC measurement amplifier through the second resistor R2, the other end of the third resistor R3 is connected to the anode of the first crystal diode D1 and is connected to one end of the sixth resistor R6 and the inverting end of the second operational amplifier OP2 through the fifth resistor R5, the other end of the fourth resistor R4 is connected to the cathode of the second crystal diode D2 and the in-phase end of the second operational amplifier OP2, the output end of the first operational amplifier OP1 is connected to the cathode of the first crystal diode D1 and the anode of the second crystal diode D2, the in-phase end of the first operational amplifier OP1 is grounded, the output end of the second operational amplifier OP2 is connected to the other end of the sixth resistor R6 and is connected to the signal transmission module 5 and the first end of the eighth resistor R8 through the seventh resistor R7, and the second end of the eighth resistor R8 is grounded.

[0054] In a specific embodiment, the first operational amplifier OP1 and the second operational amplifier OP2 may both use OP07 operational amplifiers, and cooperate with the second resistor R2, the third resistor R3, the fourth resistor R4, the first operational amplifier OP1, the first crystal diode D1, the second crystal diode D2, the fifth resistor R5 and the sixth resistor R6 to perform absolute value processing on the input negative voltage value; the seventh resistor R7 and the eighth resistor R8 perform voltage division sampling on the absolute value obtained signal.

[0055] Further, the signal transmission module 5 includes a first comparison device A1, a first inverter INV1 and a first switch IC1;

[0056] Specifically, the inverting end of the first comparison device A1, the third end and the first end of the first switching switch IC1 are all connected to the second end of the ninth resistor R9, the inverting end of the first comparison device A1, the eighth end and the tenth end of the first switching switch IC1 are all connected to the first end of the eighth resistor R8, the output end of the first comparison device A1 is connected to the input end of the first inverter INV1, the fifth end and the sixth end of the first switching switch IC1, and the output end of the first inverter INV1 is connected to the twelfth end and the thirteenth end of the first switching switch IC1.

[0057] In a specific embodiment, the first comparison device A1 may be a LM358 comparison device; the first switch IC1 may be a CD4066 chip; and the first inverter INV1 may be a NOT gate chip.

[0058] Further, the difference detection module 6 includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14 and a third operational amplifier OP3;

[0059] Specifically, the in-phase end of the third operational amplifier OP3 is connected to one end of the eleventh resistor R11 and is grounded through the twelfth resistor R12, the other end of the eleventh resistor R11 is connected to the fourth end and the eleventh end of the first switching switch IC1, the inverting end of the third operational amplifier OP3 is connected to the first end of the fourteenth resistor R14 and is connected to the second end and the ninth end of the first switching switch IC1 through the thirteenth resistor R13, and the output end of the third operational amplifier OP3 is connected to the second end of the fourteenth resistor R14 and the voltage abnormality judgment module 7.

[0060] In a specific embodiment, the third operational amplifier OP3 may be an OP07 operational amplifier, and cooperates with the eleventh resistor R11, the twelfth resistor R12, the thirteenth resistor R13 and the fourteenth resistor R14 to perform subtraction processing on the input signal.

[0061] Further, the connection status detection module 4 includes a second comparison device A2 and a third inverter INV3;

[0062] Specifically, the inverting end of the second comparison device A2 is connected to the second power supply end of the anti-electromagnetic interference DC measurement amplifier, the non-inverting end of the second comparison device A2 is grounded, the output end of the second comparison device A2 is connected to the input end of the third inverter INV3, and the output end of the third inverter INV3 is connected to the voltage abnormality judgment module 7.

[0063] In a specific embodiment, the second comparison device A2 may be a LM358 comparison device; and the third inverter INV3 may be a NOT gate chip.

[0064] Further, the voltage abnormality judgment module 7 includes a second transistor V2, a third transistor V3, a fifteenth resistor R15, a sixteenth resistor R16, a second inverter INV2 and a fourth crystal diode D4;

[0065] Specifically, the collector of the second transistor V2 is connected to the collector of the third transistor V3, the emitter of the second transistor V2 is connected to one end of the sixteenth resistor R16 and the cathode of the fourth crystal diode D4 through the fifteenth resistor R15, the other end of the sixteenth resistor R16 is connected to the emitter of the third transistor V3, the base of the second transistor V2 is connected to the output end of the second inverter INV2, the input end of the second inverter INV2 is connected to the base of the third transistor V3 and the output end of the third inverter INV3, and the anode of the fourth crystal diode D4 is connected to the protection control module 8.

[0066] In a specific embodiment, the second transistor V2 and the third transistor V3 can both be NPN transistors, which respectively control the connection status of the fifteenth resistor R15 and the sixteenth resistor R16, wherein the fifteenth resistor R15 cooperates with the fourth crystal diode D4 to provide a first voltage threshold, and the sixteenth resistor R16 distributes power to the fourth crystal diode D4 to provide a second voltage threshold, the first voltage threshold is the maximum difference between the absolute values ​​of the positive voltage and the negative voltage, and the second voltage threshold is the maximum value of the allowed positive voltage; the second inverter INV2 can use a NOT gate chip.

[0067] Further, the protection control module 8 includes a fifth crystal diode D5, a sixth crystal diode D6, a seventeenth resistor R17, a second constant voltage source VCC2 and a first logic device J1;

[0068] Specifically, the anode of the fifth crystal diode D5 is connected to the anode of the fourth crystal diode D4, the cathode of the fifth crystal diode D5 is connected to the A terminal of the first logic device J1 and the cathode of the sixth crystal diode D6, the anode of the sixth crystal diode D6 is connected to the F terminal of the first logic device J1 and the base of the first transistor V1, and the B terminal of the first logic device J1 is connected to the second constant voltage source VCC2 through the seventeenth resistor R17.

[0069] In a specific embodiment, the first logic device J1 can be an AND gate chip, which cooperates with the fifth crystal diode D5, the sixth crystal diode D6, the seventeenth resistor R17 and the second constant voltage source VCC2 to self-lock the input high-level state signal.

[0070] In the anti-electromagnetic interference DC measuring amplifier detection protection circuit of the present embodiment, the first constant voltage source VCC2 triggers the first thyristor S1 and the second thyristor S2 to turn on through the first resistor R1. When the power interface is connected to the positive voltage source and the negative voltage source, the first end of the power interface provides a positive voltage to the first end of the anti-electromagnetic interference DC measuring amplifier interface, and the second end of the power interface provides a negative voltage to the second end of the anti-electromagnetic interference DC measuring amplifier interface. At this time, the first comparison device A1 outputs a high level, the third inverter INV3 outputs a low level, and the second inverter INV2 controls the second triode V2 to turn on. The first operational amplifier OP1 and The second operational amplifier OP2 cooperates with the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the first crystal diode D1 and the second crystal diode D2 to process the absolute value of the input negative voltage, and then the seventh resistor R7 and the eighth resistor R8 perform voltage sampling and output the second sampling signal, and the ninth resistor R9 and the tenth resistor R10 perform voltage sampling on the positive voltage and output the first sampling signal. Since there is a certain error in the input voltage, when the first sampling signal is greater than the second sampling signal, the third terminal and the fourth terminal of the first switching switch IC1 are turned on, and the eighth terminal and The ninth terminal is turned on so that the third operational amplifier OP3 cooperates with the eleventh resistor R11, the twelfth resistor R12, the thirteenth resistor R13 and the fourteenth resistor R14 to perform subtraction processing. Since the absolute value of the required negative voltage is equal to the positive voltage, when the difference between the first sampling signal and the second sampling signal exceeds the first voltage threshold set by the fifteenth resistor R15 and the fourth crystal diode D4, the fourth crystal diode D4 is broken down, and the first logic device J1 cooperates with the fifth crystal diode D5, the sixth crystal diode D6, the seventeenth resistor R17 and the second constant voltage source VCC2 to perform high-level self-locking and control the first transistor V 1 is turned on, the first thyristor S1 and the second thyristor S2 are turned off. Similarly, when the first sampling signal is greater than the second sampling signal, when the difference between the second sampling signal and the first sampling signal exceeds the first voltage threshold, the first thyristor S1 and the second thyristor S2 are turned off. When the second end of the power interface is connected to the ground, the second comparison device A2 will output a low level to control the third triode V3 to be turned on. The sixteenth resistor R16 cooperates with the fourth crystal diode D4 to provide a second voltage threshold. When the signal obtained by subtraction calculation is greater than the second voltage threshold, the first triode V1 will also be triggered to be turned on, and the first thyristor S1 and the second thyristor S2 will be turned off.

[0071] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0072] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An electromagnetic interference resistant DC measurement amplifier detection protection circuit, characterized in that: The anti-electromagnetic interference DC measurement amplifier detection protection circuit comprises: an amplifier power interface module, a first sampling module, a second sampling module, a connection state detection module, a signal transmission module, a difference detection module, a voltage anomaly judgment module and a protection control module; The amplifier power interface module is connected to the protection control module, and is used to be connected to the anti-electromagnetic interference DC measurement amplifier, to the positive voltage source, and to the negative voltage source or the ground terminal, and transmits the positive voltage provided by the positive voltage source to the connected anti-electromagnetic interference DC measurement amplifier, and transmits the negative voltage provided by the negative voltage source to the connected anti-electromagnetic interference DC measurement amplifier, and stops transmitting the positive voltage and the negative voltage when receiving the protection signal output by the protection control module; The first sampling module is connected to the amplifier power interface module and is used to perform voltage sampling on the positive voltage and output a first sampling signal; The second sampling module is connected to the amplifier power interface module, and is used to perform absolute value processing and voltage sampling on the negative voltage and output a second sampling signal; The connection status detection module is connected to the amplifier power interface module, and is used to detect the connection status between the amplifier power interface module and the negative voltage source or the ground terminal, and output a first control signal when the amplifier power interface module is detected to be connected to the ground terminal; The signal transmission module is connected to the first sampling module and the second sampling module, and is used to compare the voltages of the first sampling signal and the second sampling signal, and when the voltage of the first sampling signal is greater than the voltage of the second sampling signal, transmit the first sampling signal and the second sampling signal to the difference detection module, and when the voltage of the second sampling signal is greater than the voltage of the first sampling signal, switch the signal transmission path; The difference detection module is connected to the signal transmission module, and is used to perform difference calculation on the first sampling signal and the second sampling signal and output the first difference signal, and perform difference calculation on the second sampling signal and the first sampling signal and output the second difference signal; The voltage anomaly judgment module is connected to the difference detection module and the connection state detection module, and is used to set a first voltage threshold when the first control signal is not received, and output a second control signal when the first difference signal or the second difference signal is greater than the first voltage threshold, and to set a second voltage threshold when the first control signal is received, and output a third control signal when the first difference signal is greater than the second voltage threshold; The protection control module is connected to the voltage anomaly judgment module, and is used to perform signal self-locking processing on the second control signal or the third control signal and output a protection signal.

2. The electromagnetic interference resistant DC measurement amplifier detection protection circuit according to claim 1, characterized in that: The amplifier power interface module includes a power interface, a first thyristor, a second thyristor, a first constant voltage source, a first resistor, a first triode and an anti-electromagnetic interference DC measurement amplifier interface; The first end of the power interface is connected to the anode of the first thyristor, the second end of the power interface is connected to the cathode of the second thyristor, the cathode of the first transistor is connected to the first power supply end of the anti-electromagnetic interference DC measurement amplifier, the anode of the second thyristor is connected to the second power supply end of the anti-electromagnetic interference DC measurement amplifier, the control end of the first thyristor and the control end of the second thyristor are both connected to the collector of the first triode and connected to the first power supply through the first resistor, the emitter of the first triode is grounded, and the base of the first triode is connected to the protection control module.

3. The electromagnetic interference resistant DC measurement amplifier detection protection circuit according to claim 2 is characterized in that: The first sampling module includes a ninth resistor and a tenth resistor; The first end of the ninth resistor is connected to the first power supply end of the anti-electromagnetic interference DC measurement amplifier, and the second end of the ninth resistor is connected to the signal transmission module and grounded through the tenth resistor.

4. The electromagnetic interference resistant DC measurement amplifier detection protection circuit according to claim 3 is characterized in that: The second sampling module includes a second resistor, a third resistor, a fourth resistor, a first operational amplifier, a first crystal diode, a second crystal diode, a fifth resistor, a sixth resistor, a second operational amplifier, a seventh resistor and an eighth resistor; The inverting end of the first operational amplifier is connected to one end of the third resistor and one end of the fourth resistor and is connected to the second power supply end of the anti-electromagnetic interference DC measurement amplifier through the second resistor, the other end of the third resistor is connected to the anode of the first crystal diode and is connected to one end of the sixth resistor and the inverting end of the second operational amplifier through the fifth resistor, the other end of the fourth resistor is connected to the cathode of the second crystal diode and the in-phase end of the second operational amplifier, the output end of the first operational amplifier is connected to the cathode of the first crystal diode and the anode of the second crystal diode, the in-phase end of the first operational amplifier is grounded, the output end of the second operational amplifier is connected to the other end of the sixth resistor and is connected to the signal transmission module and the first end of the eighth resistor through the seventh resistor, and the second end of the eighth resistor is grounded.

5. The electromagnetic interference resistant DC measurement amplifier detection protection circuit according to claim 4, characterized in that: The signal transmission module includes a first comparison device, a first inverter and a first switch; The inverting end of the first comparison device, the third end and the first end of the first switching switch are all connected to the second end of the ninth resistor, the inverting end of the first comparison device, the eighth end and the tenth end of the first switching switch are all connected to the first end of the eighth resistor, the output end of the first comparison device is connected to the input end of the first inverter, the fifth end and the sixth end of the first switching switch, and the output end of the first inverter is connected to the twelfth end and the thirteenth end of the first switching switch.

6. The electromagnetic interference resistant DC measurement amplifier detection protection circuit according to claim 5, characterized in that: The difference detection module includes an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor and a third operational amplifier; The in-phase end of the third operational amplifier is connected to one end of the eleventh resistor and is grounded through the twelfth resistor, the other end of the eleventh resistor is connected to the fourth end and the eleventh end of the first switching switch, the inverting end of the third operational amplifier is connected to the first end of the fourteenth resistor and is connected to the second end and the ninth end of the first switching switch through the thirteenth resistor, and the output end of the third operational amplifier is connected to the second end of the fourteenth resistor and the voltage abnormality judgment module.

7. The electromagnetic interference resistant DC measurement amplifier detection protection circuit according to claim 6, characterized in that: The connection status detection module includes a second comparison device and a third inverter; The inverting end of the second comparison device is connected to the second power supply end of the anti-electromagnetic interference DC measurement amplifier, the non-inverting end of the second comparison device is grounded, the output end of the second comparison device is connected to the input end of the third inverter, and the output end of the third inverter is connected to the voltage abnormality judgment module.

8. The electromagnetic interference resistant DC measurement amplifier detection protection circuit according to claim 7, characterized in that: The voltage abnormality judgment module includes a second triode, a third triode, a fifteenth resistor, a sixteenth resistor, a second inverter and a fourth crystal diode; The collector of the second transistor is connected to the collector of the third transistor, the emitter of the second transistor is connected to one end of the sixteenth resistor and the cathode of the fourth crystal diode through the fifteenth resistor, the other end of the sixteenth resistor is connected to the emitter of the third transistor, the base of the second transistor is connected to the output end of the second inverter, the input end of the second inverter is connected to the base of the third transistor and the output end of the third inverter, and the anode of the fourth crystal diode is connected to the protection control module.

9. The electromagnetic interference resistant DC measurement amplifier detection protection circuit according to claim 8, characterized in that: The protection control module includes a fifth crystal diode, a sixth crystal diode, a seventeenth resistor, a second constant voltage source and a first logic device; The anode of the fifth crystal diode is connected to the anode of the fourth crystal diode, the cathode of the fifth crystal diode is connected to the A end of the first logic device and the cathode of the sixth crystal diode, the anode of the sixth crystal diode is connected to the F end of the first logic device and the base of the first transistor, and the B end of the first logic device is connected to the second constant voltage source through the seventeenth resistor.

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