CN116799752A - Circuit turn-off device - Google Patents

Circuit turn-off device Download PDF

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Publication number
CN116799752A
CN116799752A CN202210267360.2A CN202210267360A CN116799752A CN 116799752 A CN116799752 A CN 116799752A CN 202210267360 A CN202210267360 A CN 202210267360A CN 116799752 A CN116799752 A CN 116799752A
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CN
China
Prior art keywords
interface
circuit
capacitor
effect transistor
field effect
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210267360.2A
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Chinese (zh)
Inventor
叶树德
同伟锋
张国柱
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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Filing date
Publication date
Application filed by Huawei Technologies Co Ltd filed Critical Huawei Technologies Co Ltd
Priority to CN202210267360.2A priority Critical patent/CN116799752A/en
Priority to PCT/CN2023/079189 priority patent/WO2023174061A1/en
Publication of CN116799752A publication Critical patent/CN116799752A/en
Pending legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H11/00—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The embodiment of the application provides a circuit shutoff device, which comprises: the device comprises an input interface, an output interface, a first capacitor, a control component and a field effect transistor. The first interface of the input interface is connected with the positive electrode of the external circuit, and the second interface is connected with the negative electrode of the external circuit; the first end of the first capacitor is connected with the first interface, and the second end of the first capacitor is connected with the second interface; the field effect transistor is arranged between the first capacitor and the first interface or between the first capacitor and the second interface; the control component is used for controlling the field effect transistor to break the circuit when the short circuit between the first interface and the second interface is detected. The embodiment of the application realizes the reduction of the power consumption of the circuit breaking device by utilizing the field effect transistor to turn off the circuit when the short circuit occurs.

Description

Circuit turn-off device
Technical Field
The embodiment of the application relates to the technical field of electronics, in particular to a circuit turn-off device.
Background
At present, buck (buck) circuits are widely used in circuit design, and in order to stabilize the circuit structure, the buck circuit is generally connected in parallel with a filter capacitor. However, once the short circuit occurs, energy in the filter capacitor flows to the short circuit point to form energy backflow, the whole circuit is burnt out, and in some special working environments, such as coal mine oil gas and other working scenes, combustible and explosive gas can be generated in the scenes at any time, and the energy backflow can even cause explosion. Therefore, a circuit-breaking device is generally provided in the circuit.
At present, a diode is generally adopted as a circuit switching-off device in the industry, and the forward conduction and reverse non-conduction characteristics of the diode can be utilized to effectively prevent energy from flowing backwards during short circuit. However, the diode drop is large and the power supply will generate excessive power consumption on the diode.
Therefore, how to reduce the consumption of the circuit shutdown device under the premise of ensuring that the safe use is satisfied is a problem to be solved.
Disclosure of Invention
The embodiment of the application provides a circuit turn-off device, which can effectively reduce power consumption on the circuit turn-off device.
In a first aspect, there is provided a circuit-switching-off device, characterized in that the circuit-switching-off device comprises: the device comprises an input interface, an output interface, a first capacitor, a field effect transistor and a control component; the input interface comprises: the first interface is used for being connected with the positive electrode, and the second interface is used for being connected with the negative electrode; the first end of the first capacitor is connected with the first interface, and the second end of the first capacitor is connected with the second interface; the field effect transistor comprises a source electrode, a grid electrode and a drain electrode, wherein the source electrode is connected with the first interface, the drain electrode is connected with the first end of the first capacitor, the grid electrode is connected with the output end of the control component, or the drain electrode is connected with the second interface, the source electrode is connected with the second end of the first capacitor, and the grid electrode is connected with the output end of the control component; the control component is used for controlling the switching-off of the field effect transistor by detecting the flow direction of current when the first port and the second port are in short circuit.
In the application, when the first interface and the second interface are not in short circuit, the first capacitor plays a role of filtering, so that the stability of the voltage of the output interface is ensured, and part of energy is also stored; when the first interface and the second interface are in short circuit, the first capacitor can release stored energy to generate energy to flow backward, a large amount of energy is gathered at a short circuit point, the control component sends an instruction to the field effect transistor through the direction of detecting current, and the field effect transistor can turn off the circuit in time, so that safety is ensured. The application uses the field effect transistor turn-off circuit, because the internal resistance of the field effect transistor is constant (milliohm level) and the response time is fast, the application can not only timely process the energy backward flow caused by the filter capacitor when short circuit occurs, but also reduce the power consumption of the turn-off device of the circuit.
With reference to the first aspect, in certain implementation manners of the first aspect, the circuit shutdown device further includes: the first diode is connected in parallel with the field effect transistor, and the conducting direction of the first diode is the same as that of the field effect transistor.
The application can effectively prevent the field effect transistor from being burnt out by connecting the diode in parallel with the field effect transistor, and improves the reliability of the circuit turn-off device.
With reference to the first aspect, in certain implementations of the first aspect, the control assembly includes: the first comparator, the sampling resistor, the operational amplifier, the second capacitor and the reference power supply; the output end of the first comparator is connected with the field effect transistor, the positive input end of the first comparator is connected with the output end of the operational amplifier, and the negative input end of the first comparator is connected with the reference power supply through the second capacitor; the positive input end of the operational amplifier is connected with the second end of the first capacitor, the negative input end of the operational amplifier is connected with the second interface, the output end of the operational amplifier is connected with the positive input end of the first comparator circuit, or the positive input end of the operational amplifier is connected with the first interface, the negative input end of the operational amplifier is connected with the first end of the first capacitor, and the output end of the operational amplifier is connected with the positive input end of the first comparator; one end of the sampling resistor is connected with the positive input end of the operational amplifier, and the other end of the sampling resistor is connected with the negative input end of the operational amplifier; the voltage of the reference power supply is less than the absolute value of the output voltage of the operational amplifier.
With reference to the first aspect, in certain implementations of the first aspect, the first comparator outputs a first voltage or a second voltage, the first voltage being greater than a turn-on voltage of the field effect transistor, the second voltage being less than the turn-on voltage of the field effect transistor.
In the application, when the circuit normally operates, the operational amplifier outputs forward voltage which is larger than the voltage provided by the reference power supply, the first comparator outputs first voltage, the field effect transistor is conducted, and the whole circuit is conducted; when the first interface and the second interface are in short circuit, the first capacitor releases energy to cause the energy to flow backward to a short circuit point, the current on the sampling resistor flows reversely, the operational amplifier outputs reverse voltage, the first comparator outputs second voltage, the field effect transistor is turned off, the whole circuit is turned off, and the energy backflow is prevented. In the application, the operational amplifier is used for amplifying the current change on the sampling resistor, so that the voltage change in the short circuit is more obvious.
It should be understood that the resistance of the sampling resistor in the present application should be as small as possible. The sampling resistor with a small resistance value can reduce the power consumed by the sampling resistor and improve the effective utilization rate of the power supply.
Illustratively, the sampling resistor has a resistance value on the order of milliohms.
With reference to the first aspect, in certain implementation manners of the first aspect, the circuit shutdown device may be applied to a downhole operation environment such as coal mine oil gas.
The circuit turn-off device can effectively avoid safety accidents caused by energy backflow caused by circuit short circuit.
In a second aspect, there is provided a circuit-switching-off device, characterized by comprising: the device comprises an input interface, an output interface, a first capacitor, a field effect transistor and a control component; the input interface comprises: the first interface is used for being connected with the positive electrode, and the second interface is used for being connected with the negative electrode; the first end of the first capacitor is connected with the first interface, and the second end of the first capacitor is connected with the second interface; the field effect transistor comprises a source electrode, a grid electrode and a drain electrode, wherein the source electrode is connected with the first interface, the drain electrode is connected with the first end of the first capacitor, the grid electrode is connected with the output end of the control component, or the drain electrode is connected with the second interface, the source electrode is connected with the second end of the first capacitor, and the grid electrode is connected with the output end of the control component; the control component is used for controlling the turn-off of the field effect transistor by detecting the falling speed of the voltage on the control component when the first port and the second port are in short circuit.
In the application, when the first interface and the second interface are not in short circuit, the first capacitor plays a role of filtering, so that the stability of the voltage of the output interface is ensured, and part of energy is also stored; when the first interface and the second interface are in short circuit, the first capacitor can release stored energy to generate energy to flow backward, a large amount of energy is gathered at a short circuit point, the control component sends an instruction to the field effect transistor by detecting the falling speed of the voltage of the two input ends of the control component, and the field effect transistor can turn off the circuit in time, so that safety is ensured. The application uses the field effect transistor turn-off circuit, because the internal resistance of the field effect transistor is constant (milliohm level) and the response time is fast, the application can not only timely process the energy backflow caused by the filter capacitor, but also reduce the power consumption of the circuit turn-off device.
With reference to the second aspect, in certain implementations of the second aspect, the circuit shutdown device further includes: the first diode is connected in parallel with the field effect transistor, and the conducting direction of the first diode is the same as that of the field effect transistor.
The application can effectively prevent the field effect transistor from being burnt out by connecting the diode in parallel with the field effect transistor, and improves the reliability of the circuit turn-off device.
With reference to the second aspect, in certain implementations of the second aspect, the control assembly includes: the second comparator, the first resistor, the second resistor, the third capacitor and the second diode; the output end of the second comparator is connected with the field effect transistor, the positive input end of the second comparator is connected with the first interface, and the negative input end of the second comparator is connected with the negative electrode of the second diode; the resistance value of the first resistor is larger than that of the second resistor, one end of the first resistor is connected with the negative input end of the second comparator, and the other end of the first resistor is connected with the second interface; the third capacitor is connected with the first resistor in parallel, one end of the third capacitor is connected with the negative input end of the second comparator, and the other end of the third capacitor is connected with the second interface; one end of the second resistor is connected with the first interface, and the other end of the second resistor is connected with the anode of the second diode; and the positive electrode of the second diode is connected with the second resistor, and the negative electrode of the second diode is connected with the negative input end of the second comparator.
In the application, the larger the resistance value of the first resistor is, the slower the voltage drop speed of the negative input end of the second comparator is, and the faster the response speed of the control component is. Therefore, the first resistor with a large resistance can rapidly switch off the circuit when a short circuit occurs, so that energy backflow is prevented.
Illustratively, the first resistor has a resistance value on the order of mega ohms.
With reference to the second aspect, in certain implementations of the second aspect, the second comparator outputs a third voltage or a fourth voltage, the third voltage being greater than the turn-on voltage of the field effect transistor, the fourth voltage being less than the turn-on voltage of the field effect transistor.
When the circuit normally operates, the voltage of the positive input end of the second comparator is larger than the voltage of the negative input end, the second comparator outputs a third voltage, the field effect transistor is conducted, and the whole circuit is conducted; when the first interface and the second interface are in short circuit, the first capacitor releases energy to cause the energy to flow backward to a short circuit point, the voltage of the positive input end of the second comparator rapidly drops, the voltage of the negative input end is slower due to the existence of the third capacitor and the first resistor, the voltage of the positive input end of the second comparator is smaller than the voltage of the negative input end in a very short time, the second comparator outputs a fourth voltage, the field effect transistor is turned off, and the whole circuit is turned off to prevent the energy from flowing backward.
With reference to the second aspect, in some implementations of the second aspect, the circuit-breaking device may be applied to a downhole operation environment such as coal mine oil gas.
The circuit turn-off device can effectively avoid safety accidents caused by energy backflow caused by circuit short circuit.
Drawings
Fig. 1 is a schematic diagram of an application scenario according to an embodiment of the present application.
FIG. 2 is a schematic diagram of an embodiment of the present application.
Fig. 3 is a circuit diagram of an embodiment of the present application.
Fig. 4 is a circuit diagram of another embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.
The embodiment of the application provides a circuit turn-off device which can be arranged in electronic equipment.
Fig. 1 is a schematic diagram of an application scenario according to an embodiment of the present application. As shown in fig. 1, the electronic apparatus 100 includes the circuit shutdown device 110 and the buck circuit 120. The circuit shutdown device 110 is connected to the buck circuit 120, and the electronic device 100 is connected to the intrinsically safe power supply 200 and the load device 300, wherein the intrinsically safe power supply 200 is a dc power supply.
In one possible implementation, the intrinsically safe power supply 200 is connected to the circuit shutdown device 110 and the load device 300 is connected to the buck circuit 120.
In another possible implementation, the intrinsically safe power supply 200 is connected to the buck circuit 120 and the load device 300 is connected to the circuit shutdown device 110.
The intrinsically safe power supply 200 supplies power to the load device 300 through the electronic apparatus 100, and the electronic apparatus 100 secures a power supply line. When a short circuit occurs between the intrinsically safe power supply 200 and the electronic device 100, the circuit shutdown device 110 is rapidly turned off to prevent energy from flowing backward to a short circuit point, and a large amount of energy is prevented from being concentrated at the short circuit point; when a short circuit occurs between the electronic device 100 and the load apparatus 300, the buck circuit 120 may reduce the voltage applied to the load apparatus to effectively prevent a large amount of energy from being accumulated at the short circuit point.
In one possible implementation, the intrinsically safe power source 200 and the electronic device 100 and the load device 300 and the electronic device 100 are connected through the phoenix terminals, so that the connection between the devices is ensured to be stable, and the situation that the connection is disconnected due to the severe working environment is avoided.
buck circuit: a buck circuit, a direct current to direct current (direct current to direct current, DC-DC) conversion circuit including an inductor, may implement a buck output.
Intrinsically safe power supply: for short, the intrinsic safety power supply is safe in normal operation and fault state, and the generated electric spark can not ignite explosive mixture in surrounding environment, and is mainly applied to environments containing explosive mixture, such as petroleum, chemical industry, textile, coal mine and the like.
It should be appreciated that the present application is directed to a circuit between an intrinsically safe power supply 200 and a load device 300, and does not involve internal protection of the intrinsically safe power supply and load.
It should be understood that, in the present application, the intrinsically safe power supply 200 and the load device 300 applied to the scenes such as coal mine oil gas have internal short-circuit protection structures, and the present application is not limited to the specific internal short-circuit protection structures.
It should be understood that, in the present application, the electronic device 100 itself is provided with a protection device to ensure that the electronic device 100 can normally operate, and the specific protection device is not a protection key of the present application, which is not described in detail herein, that is, in the present application, a short circuit fault does not occur inside the electronic device 100, and the circuit shutdown device 110, the buck circuit 120 and the connection circuit of the two can all normally operate.
FIG. 2 is a schematic diagram of an embodiment of the present application. As shown in fig. 2, the circuit shutdown device 110 includes a first capacitor 210, a control component 220, a field effect transistor 230, an input interface 240, and an output interface 250. The input interface 240 includes a first interface connected to the positive electrode and a second interface connected to the negative electrode.
When the circuit works normally, the first capacitor plays a role of filtering, the quality of electric energy transmitted from the power supply to the load is improved, and in addition, the first capacitor stores the energy; when the circuit is shorted, the first capacitor acts as a power source, releasing energy outward, causing a change in the electrical signal in the control assembly 220.
The control component 220 receives the detection electrical signal from the circuit and outputs a control signal to the field effect transistor 230.
In one possible implementation, the control component 220 includes a comparator circuit that outputs a first control voltage to the field effect transistor 230 when the circuit is operating normally, such that the field effect transistor 230 is turned on; when the circuit is shorted, the input of the comparator circuit is changed due to the first capacitor 210, and the comparator circuit outputs a second control voltage to the field effect transistor 230, so that the field effect transistor 230 is turned off.
In one possible implementation, the control component 220 further includes a sampling resistor, an operational amplifier, a second capacitor, and a reference power supply, where the sampling resistor is connected to the main loop of the power supply circuit to consume the power supply power; the input end of the operational amplifier is connected with two ends of the sampling resistor, and the output end of the operational amplifier is connected with one input end of the comparator circuit; the other input of the comparator circuit is connected to a reference power supply via a third capacitor.
When the circuit is shorted, the reverse current flow across the sampling resistor causes the op-amp to output a reverse amplified voltage, and one input voltage of the comparator circuit changes, thereby changing the output voltage of the comparator circuit, causing the field effect transistor 230 to turn off. The resistance value of the sampling resistor is small, the milliohm level is achieved, the power consumed by the sampling resistor is guaranteed to be small, and the service efficiency of the power supply is improved.
In one possible implementation, the control component 220 further includes a first resistor, a second resistor, a third capacitor, and a diode. The resistance value of the first resistor is larger than that of the second resistor, the first resistor and the third capacitor are connected in parallel, one end of the first resistor is connected with the cathode of the diode and one input end of the comparator circuit, and the other end of the first resistor is connected with the second interface; one end of the second resistor is connected with the first interface, the other input end of the comparator circuit is connected with the first capacitor 210, and the other end of the second resistor is connected with the anode of the diode; the conducting direction of the diode is from the second resistor to the first resistor.
When the circuit works normally, the voltage of the input end of the comparator circuit connected with the second resistor is larger than that of the input end connected with the first resistor; when the circuit is shorted, the voltage of two input ends of the comparator circuit is reduced, because the first resistor and the third capacitor are connected in parallel to form a micro energy storage structure, the voltage reduction speed of the input end of the comparator circuit connected with the second resistor is larger than that of the input end of the comparator circuit connected with the first resistor, after a certain time, the voltage of the input end of the comparator circuit connected with the second resistor is smaller than that of the input end connected with the first resistor, the output of the comparator circuit is changed, and the field effect transistor 230 is turned off. The larger the difference in the resistance values of the first resistors, the shorter the response time of the capacitor circuit.
The first resistor adopts a megaohm-level resistor, and the capacitor adopts a microfarad-level capacitor, so that large backward energy generated by short circuit between the first resistor and the capacitor is prevented.
The gate of the field effect transistor 230 is connected to the output terminal of the control component 220, and when the circuit is operating normally, the field effect transistor 230 is turned on; when the circuit is shorted, the field effect transistor 230 turns off.
In one possible implementation, the circuit-switching device 110 further includes a diode connected in parallel to the field-effect transistor 230, and having a conduction direction identical to that of the field-effect transistor 230. The diode may protect the field effect transistor 230 from burning out the field effect transistor 230.
Fig. 3 is a circuit diagram of an embodiment of the present application.
It should be noted that, when the field effect transistor is an N-metal-oxide-semiconductor (NMOS), the first terminal may refer to the drain terminal and the second terminal may refer to the source terminal. When the field effect transistor is a P-metal-oxide-semiconductor (PMOS), the first terminal may be referred to as a source terminal and the second terminal may be referred to as a drain terminal.
In the present application, the voltage value at which the field effect transistor can be turned on is VDD, and the voltage value at which the field effect transistor can be turned off is VSS.
The circuit-switching-off device of fig. 3 comprises a field-effect transistor S31, a sampling resistor R32, a comparator U31, an operational amplifier K31, capacitors C31, C32 and voltage interfaces vin+, vin-, vout+, vout-. The control component comprises a sampling resistor R32, an operational amplifier K31, a comparator U31 and a capacitor C32.
In the circuit shown in fig. 3, the input end of the operational amplifier K31 is connected to both ends of the resistor R32, and the output end is connected to the positive input end of the comparator U31; one end of the resistor R32 is connected with the second end of the field effect transistor, and the other end of the resistor R is connected with the second end of the capacitor C31; the negative input end of the comparator U31 is connected with the ground through a capacitor C32, and the output end is connected with the grid electrode of the field effect transistor; the capacitor C31 is connected between the voltage terminals Vout+ and Vout-, a first end of the capacitor C31 is connected with Vout+, and a second end of the capacitor C31 is connected with Vout-; the first terminal of the field effect transistor is connected to the voltage terminal Vin-, and the second terminal is connected to the resistor R31.
When the circuit works normally, current flows out from the intrinsic safety power supply, flows to Vout+ through a voltage interface Vin+, then flows into a load device, flows to Vin-through a voltage interface Vout-after passing through the load device, and finally returns to the intrinsic safety power supply. When the circuit works normally, the capacitor C31 plays a role of filtering and stores energy flowing into the capacitor, current on the resistor R31 flows from right to left in the figure, the voltage value at the left end of the resistor R31 is smaller than that at the right end, the operational amplifier amplifies the voltage on the sampling resistor R31, the output voltage is V+, the comparator compares V+ with the reference voltage, the output voltage is VDD, the reference voltage is provided by the capacitor C32, and the field effect transistor S31 is conducted.
When a short circuit occurs at the position 1 in the figure, which is equivalent to vin+ and Vin-short circuit, the short circuit current converges to a short circuit point, the capacitor C31 releases stored energy, the current on the resistor R31 flows from left to right, the voltage value at the left end of the resistor R31 is larger than the voltage value at the right end, the voltage output by the operational amplifier is V-, V-is the reverse voltage of V+, the comparator compares the V-with the reference voltage, the output voltage is VSS, and the field effect transistor S31 is turned off, so that energy backflow is avoided, and equipment is protected.
The resistance value of the sampling resistor R31 is small and reaches milliohm level, the power consumed by the sampling resistor R31 is ensured to be small, the utilization rate of an intrinsic safety power supply is improved, and an operational amplifier can convert small current on the sampling resistor R31 into larger voltage, so that the comparator can conveniently identify and compare the voltage.
In one possible implementation, a diode may be connected in parallel to the field effect transistor S31, and the diode may have the same conduction direction as the field effect transistor, and may function to stabilize voltage and prevent the field effect transistor from being burned out.
In the embodiment, the output of the comparator is controlled by detecting the current flow direction of the resistor R31, and the circuit is turned off by utilizing the field effect transistor, so that the situation that the explosion of the coal mine oil gas scene is caused by energy backflow after the short circuit is avoided is ensured.
The characteristics of the field effect transistor in the embodiment of the application are constant internal resistance and are generally in milliohm level, the current in the circuit is generally 2A according to the design of two-stage protection, the power loss caused by the circuit switching-off device is only tens of milliwatts, which occupies one thousandth of the output energy of the power supply, and the utilization efficiency of the energy source is greatly improved.
According to the embodiment of the application, a field effect transistor is used for replacing a diode, short circuit rapid protection is realized through voltage/current detection, loss reduction of 10% is realized, precious power supply power can be used for improving key performance under the condition that underground equipment limits power consumption, and the access capability of the equipment is greatly enhanced.
In addition, the response speed of the field effect transistor can reach 100 ns-level action time, and the circuit is rapidly turned off when the circuit is short-circuited, so that energy backflow is inhibited, and energy peaks are avoided.
It should be understood that in the embodiment of the present application, the circuit-breaking device is disposed between the intrinsic safety power source and the load device, and in fact, other circuits or devices may be included between the circuit-breaking device and the intrinsic safety power source, and between the circuit-breaking device and the load device, which is not limited in this aspect of the present application.
Fig. 4 is a circuit diagram of another embodiment of the present application.
It should be noted that, when the field effect transistor is an N-metal-oxide-semiconductor (NMOS), the first terminal may refer to the drain terminal and the second terminal may refer to the source terminal. When the field effect transistor is a P-metal-oxide-semiconductor (PMOS), the first terminal may refer to a source terminal and the second terminal may refer to a drain terminal.
In the present application, the voltage value at which the field effect transistor can be turned on is VDD, and the voltage value at which the field effect transistor can be turned off is VSS.
The circuit shutdown device of fig. 4 includes a field effect transistor S41, resistors R41 and R42, a comparator U41, capacitors C41 and C42, a diode D41, and voltage interfaces vin+, vin-, vout+, vout-, wherein the resistance value of the resistor R42 is smaller than the resistor R41. The control component comprises a resistor R41, a resistor R42, a comparator U41, a capacitor C42 and a diode D41.
In the circuit diagram shown in fig. 4, the positive input end of the comparator U41 is directly connected with the voltage interface vin+, the negative input end is connected with the voltage interface vin+ through the diode D41 and the resistor R42, and the output end is connected with the gate of the field effect transistor S41; one end of the resistor R42 is connected with the voltage end Vin+, and the other end of the resistor R42 is connected with one input end of the comparator U41 through the diode D41; one end of the resistor R41 is connected with the voltage end Vin-, and the other end of the resistor R41 is connected with one input end of the comparator U41; the capacitor C42 is connected with the resistor R41 in parallel, one end of the capacitor C is connected with the voltage end Vin-, and the other end of the capacitor C is connected with the negative input end of the comparator U41; the capacitor C41 is connected between the voltage terminals Vout+ and Vout-, a first end of the capacitor C41 is connected with Vout+, and a second end of the capacitor C41 is connected with Vout-; the first end of the field effect transistor is connected with the voltage end Vin-, and the second end of the field effect transistor is connected with Vout-through another stage of protection circuit; the conduction direction of the diode D41 is from right to left in the figure.
When the circuit is operating normally, one path of current is: the current flows out of the intrinsic safety power supply, flows to Vout+ through a voltage interface Vin+, then flows into a load device, flows to Vin-through a voltage interface Vout-after passing through the load device, and finally returns to the intrinsic safety power supply. Another path of current is: the current flows out of the intrinsic safety power supply, flows to the resistor R42 through the voltage interface Vin+, and then flows to the diode D41, and because the capacitor C42 is equivalent to an open circuit and the internal resistance of the comparator is large, the current flowing in the input end is negligible, so the current flows to the Vin-through the resistor R41 and finally returns to the intrinsic safety power supply.
When the circuit works normally, the capacitor C42 plays a role in filtering and stores energy flowing into the capacitor, in the figure, currents on the resistors R41 and R42 flow downwards from top to bottom, voltage drop occurs on the resistors, so that the voltage value of the positive input end of the comparator is larger than that of the negative input end, the comparator outputs the voltage VDD, and the field effect transistor S41 is conducted.
When a short circuit occurs at the position 1 in the figure, which is equivalent to vin+ and Vin-short circuit, the short circuit current converges to a short circuit point, the capacitors C41 and C42 release stored energy, the voltage at the input end of the comparator U41 is the voltage on the capacitor C41 and the capacitor C42 respectively, along with the release of the energy on the capacitors C41 and C42, the voltage on the capacitor C41 and the capacitor C42 is reduced along with the reduction, the voltage reduction speed on the capacitor C41 is larger than the voltage reduction speed on the capacitor C42 because the resistance value of the resistor R42 is smaller than the resistor R41, the voltage on the capacitor C41 is smaller than the voltage on the capacitor C42 in an extremely short time, namely the voltage at the positive input end of the comparator is smaller than the voltage at the negative input end, the comparator outputs the voltage VSS, and the field effect transistor S41 turns off the circuit, so that energy backflow is avoided, and equipment is protected.
The resistor R41 has a large value of megaohm level, the capacitor C42 has a small capacitance value of microfarad level, the voltage on the capacitor C42 is ensured to drop slowly when short circuit occurs, and the reaction efficiency is improved.
In one possible implementation, a diode may be connected in parallel to the field effect transistor S31, and the diode may have the same conduction direction as the field effect transistor, and may function to stabilize voltage and prevent the field effect transistor from being burned out.
In the embodiment, the output of the comparator is controlled by detecting the change speed of the voltage drop of the input end of the comparator, and the circuit is turned off by utilizing the field effect transistor, so that the situation that the explosion of the coal mine oil gas scene is caused by energy backflow after the short circuit is avoided is ensured.
The characteristics of the field effect transistor in the embodiment of the application are constant internal resistance and are generally in milliohm level, the current is generally 2A according to the design of two-stage protection, the power loss is only tens of milliwatts, and the power loss accounts for one thousandth of the output energy of the power supply, so that the energy utilization efficiency is greatly improved.
According to the embodiment of the application, a field effect transistor is used for replacing a diode, short circuit rapid protection is realized through voltage/current detection, loss reduction of 10% is realized, precious power supply power can be used for improving key performance under the condition that underground equipment limits power consumption, and the access capability of the equipment is greatly enhanced.
In addition, the response speed of the field effect transistor can reach 100 ns-level action time, and when the power supply voltage is abnormal, the circuit is rapidly turned off, so that energy backflow is inhibited, and energy peaks are avoided.
It should be understood that in the embodiment of the present application, the circuit-breaking device is disposed between the intrinsic safety power source and the load device, and in fact, other circuits or devices may be included between the circuit-breaking device and the intrinsic safety power source, and between the circuit-breaking device and the load device, which is not limited in this aspect of the present application.
It should be understood that the embodiments in fig. 2, fig. 3 and fig. 4 only include a primary circuit, but the number of circuit stages in the circuit shutdown device is not limited in the present application, and the circuit of the embodiment of the present application may be further cascaded on the basis of the embodiment of the present application, where the composition and principle of the circuit are the same or similar, and the disclosure is not repeated herein. In fact, according to the national security level requirements, the circuit shutdown device needs to have protection circuits with different levels according to different production environments.
It will be appreciated that when a multi-stage circuit is included in the circuit-breaking device, the multi-stage circuit may share the first capacitance.
The safety level of the device is required to reach the ib intrinsic safety class safety level of the national standard in the coal mine industry, and the ib intrinsic safety class safety level is required to be protected twice, namely, after a fault point occurs on a link, the circuit can still play a role in protection, no excessive energy is generated, and from the circuit design, a two-stage protection circuit is required to be designed on a circuit shutdown device, and when a problem occurs at one stage, the second stage can still play a role.
In the several embodiments provided in the present application, it should be understood that the circuits and devices disclosed in the embodiments of the present application may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of components is merely a logical functional division, and there may be additional divisions in actual implementation, e.g., multiple components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.
The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (8)

1. A circuit shutdown device, characterized in that the circuit shutdown device comprises:
the device comprises an input interface, an output interface, a first capacitor, a field effect transistor and a control component;
the input interface comprises:
a first interface for connecting with the positive pole of the external circuit,
the second interface is used for being connected with the negative electrode of the external circuit;
the first end of the first capacitor is connected with the first interface, and the second end of the first capacitor is connected with the second interface;
the field effect transistor comprises a source electrode, a grid electrode and a drain electrode, wherein the source electrode is connected with the first interface, the drain electrode is connected with the first end of the first capacitor, the grid electrode is connected with the output end of the control component, or the drain electrode is connected with the second interface, the source electrode is connected with the second end of the first capacitor, and the grid electrode is connected with the output end of the control component;
the control component is used for controlling the switching-off of the field effect transistor by detecting the flow direction of current when the first port and the second port are in short circuit.
2. The circuit interrupting device of claim 1 further comprising:
the first diode is connected in parallel with the field effect transistor, and the conducting direction of the first diode is the same as that of the field effect transistor.
3. The circuit shutdown device of claim 1 or 2, wherein the control assembly comprises:
the first comparator, the sampling resistor, the operational amplifier, the second capacitor and the reference power supply;
the output end of the first comparator is connected with the field effect transistor, the positive input end of the first comparator is connected with the output end of the operational amplifier, and the negative input end of the first comparator is connected with the reference power supply through the second capacitor;
the positive input end of the operational amplifier is connected with the second end of the first capacitor, the negative input end of the operational amplifier is connected with the second interface, the output end of the operational amplifier is connected with the positive input end of the first comparator circuit, or the positive input end of the operational amplifier is connected with the first interface, the negative input end of the operational amplifier is connected with the first end of the first capacitor, and the output end of the operational amplifier is connected with the positive input end of the first comparator;
one end of the sampling resistor is connected with the positive input end of the operational amplifier, and the other end of the sampling resistor is connected with the negative input end of the operational amplifier;
the voltage of the reference power supply is smaller than the absolute value of the voltage of the output end of the operational amplifier.
4. A circuit shutdown device according to claim 3, wherein the first comparator outputs a first voltage or a second voltage, the first voltage being greater than the on-voltage of the field effect transistor and the second voltage being less than the on-voltage of the field effect transistor.
5. A circuit shutdown device, characterized in that the circuit shutdown device comprises:
the device comprises an input interface, an output interface, a first capacitor, a field effect transistor and a control component;
the input interface comprises:
a first interface for connecting with the positive pole of the external circuit,
the second interface is used for being connected with the negative electrode of the external circuit;
the first end of the first capacitor is connected with the first interface, and the second end of the first capacitor is connected with the second interface;
the field effect transistor comprises a source electrode, a grid electrode and a drain electrode, wherein the source electrode is connected with the first interface, the drain electrode is connected with the first end of the first capacitor, the grid electrode is connected with the output end of the control component, or the drain electrode is connected with the second interface, the source electrode is connected with the second end of the first capacitor, and the grid electrode is connected with the output end of the control component;
the control component is used for controlling the turn-off of the field effect transistor by detecting the falling speed of the voltage on the control component when the first port and the second port are in short circuit.
6. The circuit interrupting device of claim 5 further comprising:
the first diode is connected in parallel with the field effect transistor, and the conducting direction of the first diode is the same as that of the field effect transistor.
7. The circuit interrupting device of claim 5 or 6, wherein the control assembly comprises:
the second comparator, the first resistor, the second resistor, the third capacitor and the second diode;
the output end of the second comparator is connected with the grid electrode of the field effect transistor, the positive input end of the second comparator is connected with the first interface, and the negative input end of the second comparator is connected with the negative electrode of the second diode;
the resistance value of the first resistor is larger than that of the second resistor, one end of the first resistor is connected with the negative input end of the second comparator, and the other end of the first resistor is connected with the second interface;
the third capacitor is connected with the first resistor in parallel, one end of the third capacitor is connected with the negative input end of the second comparator, and the other end of the third capacitor is connected with the second interface;
one end of the second resistor is connected with the first interface, and the other end of the second resistor is connected with the anode of the second diode;
and the positive electrode of the second diode is connected with the second resistor, and the negative electrode of the second diode is connected with the negative input end of the second comparator.
8. The circuit shutdown device of claim 7, wherein the second comparator outputs a third voltage or a fourth voltage, the third voltage being greater than an on-voltage of the field effect transistor, the fourth voltage being less than the on-voltage of the field effect transistor.
CN202210267360.2A 2022-03-17 2022-03-17 Circuit turn-off device Pending CN116799752A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202210267360.2A CN116799752A (en) 2022-03-17 2022-03-17 Circuit turn-off device
PCT/CN2023/079189 WO2023174061A1 (en) 2022-03-17 2023-03-02 Apparatus for disconnecting circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210267360.2A CN116799752A (en) 2022-03-17 2022-03-17 Circuit turn-off device

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Publication number Priority date Publication date Assignee Title
US6831447B1 (en) * 2003-05-20 2004-12-14 Itt Manufacturing Enterprises, Inc. Surge limiting circuit with optional short circuit detection
CN205160032U (en) * 2015-11-12 2016-04-13 湖北一彰科技有限责任公司 Electric wiring transships and short -circuit protective device(SCPD)
CN205544195U (en) * 2016-03-28 2016-08-31 广州汽车集团股份有限公司 Current foldback circuit and power supply
CN208890354U (en) * 2018-10-26 2019-05-21 成都英特格灵微电子技术有限公司 A kind of feedback short circuit protection circuit for Buck

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