CN215580367U - Intrinsic safety power supply protection circuit - Google Patents
Intrinsic safety power supply protection circuit Download PDFInfo
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- CN215580367U CN215580367U CN202121584767.5U CN202121584767U CN215580367U CN 215580367 U CN215580367 U CN 215580367U CN 202121584767 U CN202121584767 U CN 202121584767U CN 215580367 U CN215580367 U CN 215580367U
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Abstract
The utility model discloses an intrinsic safety power supply protection circuit, which comprises two groups of sub-circuits for simultaneously monitoring the power supply voltage state of a power supply and the current state of a load; the two groups of sub-circuits are respectively provided with a current detection circuit, a voltage detection circuit, a power failure protection circuit and a delay circuit for receiving indication signals of the current detection circuit and/or the voltage detection circuit, the delay circuit is connected with a driving circuit through a logic control circuit, and the driving circuit is used for driving a switching circuit to act; and the two groups of sub-circuits are also connected with a sampling circuit and a current limiting circuit, the sampling circuit is connected with a current detection circuit, and the current limiting circuit is connected with a power failure protection circuit. The design has the advantages of small volume, light weight, quick protection in failure, no need of a radiator, safety, reliability and the like, ensures the safe operation of the connected load in an explosive environment, and effectively prevents the safety threat formed by electric sparks or heat effect.
Description
Technical Field
The utility model relates to the technical field of power supplies, in particular to an intrinsic safety power supply protection circuit.
Background
Natural gas is one kind of combustible gas, and has wide application, small minimum ignition energy, fast combustion speed and strong diffusion capacity. With the continuous development of the natural gas filling industry, electronic devices installed in a natural gas filling station for communication, detection, control and the like are increasing day by day, and explosive gas mixtures may exist in the working environment of the devices, so that the potential danger is high.
One of the factors that may cause the risk of explosion is the amount of energy released by the ignition source, which, when the amount of energy released by the circuit installed in the explosive gas environment is above a certain threshold, can ignite the surrounding explosive gas. For safety reasons, the relevant national standards require that the devices for these special applications have the specified safety and explosion-proof characteristics, and restrict various electrical parameters in the electronic circuit, and at the same time, require the necessary protection measures to limit the spark energy and heat energy generated when the circuit fails, so as to prevent the occurrence of explosion accidents.
An intrinsically safe power supply, hereinafter referred to as an intrinsically safe power supply; the energy supply component plays an important role in the special application occasions, is an energy supply component of electronic equipment for a plurality of filling stations, and is a key component for determining the explosion-proof performance of other electronic equipment. As an intrinsically safe device, its output is required to be such that any electrical or thermal spark or effect produced under specified conditions, including normal operation and specified fault conditions, cannot ignite a specified explosive gas.
In order to meet the explosion-proof standard, one of the conventional processing methods is to isolate the non-intrinsic-safety input of the power supply, and add a double protection circuit after voltage is converted so as to limit the output energy of the power supply.
Specifically, a common intrinsic safety power protection circuit generally adopts a zener protection circuit or a field effect transistor current limiting circuit, and the zener protection circuit has limited output current and needs to consider the problems of heating and voltage drop. When the current limiting circuit of the field effect transistor has a fault, the field effect transistor works in a cut-off state or a constant current state. When the field effect transistor works in a cut-off state, the power output and the rear stage are thoroughly cut off, most protection circuits of the type are generally provided with two stages of high-level switches, and when a fault occurs, only the positive pole of the power supply is cut off, and the negative pole of the power supply is not cut off.
When the field effect transistor works in a saturation region, the power supply output enters a constant current state, the field effect transistor generates heat obviously when the output is short-circuited, the element performance changes in the heating state, the risk of a heat effect is increased, and at the moment, a radiator is often needed, but the size is increased. And when the output voltage of the intrinsic safety power supply is lower and the output power is larger, the loss of the whole protection circuit becomes non-negligible, and the reduction of the voltage drop loss of the protection circuit is very necessary.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide an intrinsically safe power supply protection circuit for output protection of an intrinsically safe power supply at ib level, which has the advantages of no need of a radiator, small volume, quick protection, safety, reliability, wide adaptive power supply voltage, capability of protecting the positive and negative electrodes of power supply output and the like, and can improve the safety of the intrinsically safe power supply.
In order to solve the above technical problem, the present invention provides an intrinsically safe power protection circuit, which includes a protection circuit connected between a dc power supply and a load; the protection circuit comprises two groups of sub-circuits which are used for monitoring the power supply voltage state of the power supply and the current state of the load at the same time; the two groups of sub-circuits are respectively provided with a current detection circuit, a voltage detection circuit, a power failure protection circuit and a delay circuit for receiving indication signals of the current detection circuit and/or the voltage detection circuit, the delay circuit is connected with a driving circuit through a logic control circuit, and the driving circuit is used for driving a switching circuit to act; and the two groups of sub-circuits are also connected with a sampling circuit and a current limiting circuit, the sampling circuit is connected with a current detection circuit, and the current limiting circuit is connected with a power failure protection circuit.
Further, the power failure protection circuit comprises a voltage stabilizing diode D1, a thyristor Q1, a resistor R1, a resistor R2 and a capacitor C1; cathode of voltage stabilizing diode D1 and T of thyristor Q11The anode of the voltage stabilizing diode D1 is connected with the G pole of the controllable silicon Q1 after passing through the resistor R1; the G pole of the controlled silicon Q1 is respectively connected with one end of a grounding capacitor C1 and one end of a resistor R1, and the other end of the resistor R1 is connected with the negative pole of the power supply through a resistor R2.
Further, the voltage detection circuit includes a comparator U1A, a current source Z1, and resistors R5, R3, R4, R8, R6; the current flowing by the current source Z1 is converted into a voltage drop of R5; one end of the R5 is connected with the voltage to be measured, the other end is connected with the reverse input end of the comparator, then the R3, the R4, the R6 and the R8 form a voltage divider, the voltage dividing output end is connected with the non-inverting input end of the comparator U1A, and the two input ends of the comparator U1A are used for voltage size comparison.
Furthermore, the current detection circuit comprises a comparator U1B and a voltage source Vref, the power supply is connected with the voltage source Vref through a resistor R9 and is connected to the homodromous input end of the comparator U1B, and a detected signal is connected to the inverting input end of the comparator U1B through a resistor R10 by a sampling circuit.
Further, the delay circuit is a monostable circuit HEF 4538.
Further, the logic control circuit is a basic logic judgment circuit HEF4011, and is used for logic judgment of a fault state.
And the voltage stabilizing circuit is a low dropout linear regulator and is used for generating internal stable voltage.
Further, the driving circuits of the two sets of sub-circuits are different;
one of the two groups of sub-circuits comprises a transistor Q11, a transistor Q13, a field effect transistor Q12, a field effect transistor Q14, a capacitor C11 and a plurality of resistors;
the output signal of the logic control circuit connected with the driving circuit is connected with the grid electrode of a field effect transistor Q12 through a resistor R14, the drain electrode of a field effect transistor Q12 is connected with a stabilized power supply through a resistor R12, and the drain electrode of the field effect transistor Q12 is connected with a capacitor C11 and the base electrode of a transistor Q11; the emitter of the transistor Q11 is connected with a regulated power supply through a resistor R11;
meanwhile, the output signal of the logic control circuit connected with the driving circuit is also connected with the grid of a field effect transistor Q14 through a resistor R18, the drain of the field effect transistor Q14 and the emitter of a transistor Q11 are connected with the base of a transistor Q13 through a resistor R16, the emitter of a transistor Q13 is grounded through a resistor R19, the collector of the transistor Q13 is connected with a stabilized power supply through a resistor R15 and a resistor R13, and the output signal is led out from the common connection point of the resistor R13 and the resistor R15.
The other driving circuit in the two groups of sub-circuits comprises a transistor Q20, a transistor Q21, a capacitor C20 and a plurality of resistors; the output signal of the logic control circuit connected with the other drive circuit is connected with the base of a transistor Q20 through a resistor R23, the collector of a transistor Q20 is connected with a resistor R20 and a capacitor C20, and the other end of the resistor R20 is connected with a stabilized power supply; the collector of the transistor Q20 is connected with the collector of the resistor R22 and the collector of the transistor Q21, and the other end of the resistor R22 is connected with the resistor R24;
meanwhile, the output signal of the logic control circuit connected with the other driving circuit is connected with the base of the transistor Q21 through a resistor R25, the emitter of the transistor Q21 is grounded, and the output is led out from the common connection point of the resistor R22 and the resistor R24.
Furthermore, one of the switching circuits in the two sets of sub-circuits comprises a P-channel field effect transistor, and the other switching circuit comprises an N-channel field effect transistor.
Furthermore, a shunt resistor with the resistance value of 3 k-10 k is arranged between the source electrode and the drain electrode of the switch circuit, and a dummy load resistor is connected between the switch circuits of the two sub-circuits.
The utility model has the beneficial effects that: the intrinsic safety power supply protection circuit can be suitable for intrinsic safety power supply output protection at ib level, has the advantages of no need of a radiator, small volume, quick protection, safety, reliability, wide adaptive power supply voltage and capability of protecting the positive and negative electrodes of power supply output, and improves the safety of the intrinsic safety power supply.
Drawings
Fig. 1 schematically shows a structural schematic diagram of an intrinsically safe power protection circuit.
Fig. 2 schematically shows a power failure protection circuit of the intrinsically safe power protection circuit.
Fig. 3 schematically shows a voltage detection circuit of the intrinsically safe power protection circuit.
Fig. 4 schematically shows a schematic diagram of a current detection circuit of the intrinsically safe power protection circuit.
Fig. 5 schematically shows a schematic diagram of the driving circuit 1 of the intrinsically safe power protection circuit.
Fig. 6 schematically shows a schematic diagram of the driving circuit 2 of the intrinsically safe power protection circuit.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should also be noted that, unless otherwise explicitly stated or limited, the terms "disposed" and "connected" are to be interpreted broadly, e.g., as meaning directly connected to each other, indirectly connected to each other through an intermediate medium, and communicating between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Referring to fig. 1 to 6, the following description will be made in detail with reference to embodiments, and for the sake of simplicity, the following description omits the technical common sense known to those skilled in the art.
The intrinsic safety power supply protection circuit comprises a protection circuit connected between a direct current power supply and a load, wherein the protection circuit comprises two groups of sub-circuits, and the two groups of sub-circuits are used for monitoring the power supply voltage state of the power supply and the current state of the load at the same time.
Under normal conditions, the intrinsic safety power protection circuit and the direct-current power module are installed in the special explosion-proof box, and the load can be exposed in the environment where flammable and explosive gases are likely to appear.
The two groups of sub-circuits are respectively provided with a current detection circuit, a voltage detection circuit, a power failure protection circuit and a delay circuit, and the delay circuit is used for receiving indication signals of the current detection circuit and/or the voltage detection circuit.
The delay circuit is connected with the drive circuit through the logic control circuit, and the drive circuit is used for driving the switch circuit to act. And the two groups of sub-circuits are also connected with a sampling circuit and a current limiting circuit, the sampling circuit is connected with a current detection circuit, and the current limiting circuit is connected with a power failure protection circuit.
The switch circuits of the two groups of sub-circuits respectively control the positive output end and the negative output end of the direct current power supply, and the current limiting circuit and the sampling circuit are shared by the two groups of sub-protection circuits. Structurally, a direct-current power supply positive end, a current limiting circuit, a switching circuit of one of the sub-protection circuits, a load, a switching circuit of the other sub-protection circuit, a sampling circuit and a direct-current power supply negative end sequentially form a series structure.
When overvoltage and overcurrent faults occur between the direct current power supply module and the load, the intrinsic safety power supply protection circuit limits the current supplied to the load and tries to recover normal power supply after a period of time.
The utility model has the advantages of small volume, light weight, rapid protection in failure, automatic recovery, no need of a radiator, safety, reliability and the like in practical application, ensures the safe operation of the connected load in an explosive environment, and effectively prevents the safety threat formed by electric sparks or heat effect.
In actual operation, two classes of overvoltage fault states can be preset, and when a preset first-stage overvoltage fault state occurs, the voltage detection circuit can act to trigger the driving circuit, so that the two groups of switches are opened simultaneously.
When an overcurrent fault occurs, a signal generated by the sampling circuit triggers the current detection circuit to act, the current detection circuit gives an indication signal to further trigger the driving circuit and the delay circuit simultaneously, so that the two groups of switches are opened simultaneously, the delay circuit is triggered simultaneously, the delay circuit controls the driving circuit again after the switches are kept in an open state for a period of time, so that the switches are restored to a closed state again, if the overcurrent fault state still exists, protection is performed again, and the protection process is repeated until the overcurrent fault is relieved.
When a second-level overvoltage fault state occurs, the power failure protection circuit acts to trigger the current limiting circuit to be disconnected, so that the whole protection circuit is protected and is not damaged.
In the present application, in particularThe power failure protection circuit of the intrinsic safety power protection circuit comprises a voltage stabilizing diode D1, a thyristor Q1, a resistor R1, a resistor R2 and a capacitor C1. Cathode of voltage stabilizing diode D1 and T of thyristor Q11The anode of the voltage stabilizing diode D1 is connected with the G pole of the controllable silicon Q1 after passing through the resistor R1.
The G pole of the controlled silicon Q1 is respectively connected with one end of a grounding capacitor C1 and one end of a resistor R1, the other end of the resistor R1 is connected with the negative pole of a power supply through a resistor R2, and the T2 pole of the controlled silicon Q1 is grounded. When the second-stage voltage of the positive end of the power supply failure power supply exceeds a preset threshold value, the state is defined as a second-stage overvoltage fault state, at the moment, the voltage-stabilizing diode D1 is conducted, the thyristor Q1 is triggered to be conducted, and then the current-limiting circuit is triggered to be fused. The current limiting circuit may be formed by a fuse.
The voltage detection circuit comprises a comparator U1A, a current source Z1, a resistor R5, a resistor R3, a resistor R4, a resistor R8 and a resistor R6.
The current flowing through the current source Z1 is converted into a voltage drop of R5, one end of R5 is connected with the voltage to be measured, and the other end is connected with the reverse input end of the comparator. Then, the voltage divider is formed by the voltage divider and the R3, R4, R6 and R8, the voltage dividing output end is connected with the non-inverting input end of the comparator U1A, and the two input ends of the comparator U1A are compared in voltage magnitude. Of course, the capacitor C4 may be connected in parallel between the resistor R6 and the resistor R8, and the capacitor C3 may be connected between the resistors R5 and R6.
When the detected voltage exceeds a first-stage preset threshold value, the output of the trigger comparator U1A is turned over, and the sampling circuit can be a precise sampling resistor.
The current sensing circuit includes a comparator U1B, a voltage source Vref, and a resistor R9. The power supply is connected with a voltage source Vref through a resistor R9 and is connected to the homodromous input end of the comparator U1B, and a detected signal is connected to the inverting input end of the comparator U1B through a resistor R10 by a sampling circuit.
When the current flowing through the sampling circuit exceeds a preset value, the output of the comparator U1B is inverted.
The delay circuit of the intrinsic safety power supply protection circuit comprises a conventional monostable HEF4538, and the function of realizing accurate delay and returning to an initial state after entering a transient steady state and keeping a preset time can be realized.
The logic control circuit of the intrinsic safety power supply protection circuit comprises a basic logic judgment circuit HEF4011 used for logic judgment of fault states.
The intrinsic safety power supply protection circuit further comprises a voltage stabilizing circuit used for providing power supply for the two groups of sub-circuits, wherein the voltage stabilizing circuit is a low dropout linear voltage regulator and is used for generating internal stable voltage.
It should be noted that, for the sake of clarity, in the embodiment of the present application, the following reference numerals 1 and 2 are used to respectively denote two sets of sub-circuits, namely, sub-circuit 1 and sub-circuit 2, and the circuits included in the two sets of sub-circuits are also respectively distinguished by reference numerals 1 and 2.
That is, the sub-circuit 1 includes a current detection circuit 1, a voltage detection circuit 1, a power failure protection circuit 1, a delay circuit 1, a logic control circuit 1, a drive circuit 1, and a switch circuit 1.
The sub-circuit 2 comprises a current detection circuit 2, a voltage detection circuit 2, a power failure protection circuit 2, a delay circuit 2, a logic control circuit 2, a drive circuit 2 and a switch circuit 2.
The current limiting circuit and the sampling circuit are shared by two groups of sub-circuits, and structurally, the direct current power supply positive end, the current limiting circuit, the switch circuit 1, the load, the switch circuit 2, the sampling circuit and the direct current power supply negative end sequentially form a series structure.
In practical operation, the current detection circuit includes a voltage comparator LM339 and a precision reference voltage source, and the current detection circuit 1 and the current detection circuit 2 have the same structure. The voltage detection circuit comprises a voltage comparator LM339 and a precision current source, and the voltage detection circuit 1 and the voltage detection circuit 2 have the same structure.
Of course, there are two voltage stabilizing circuits for providing power to the two sets of sub-circuits, namely, the voltage stabilizing circuit 1 and the voltage stabilizing circuit 2, which provide power to the two sets of sub-circuits respectively.
The voltage stabilizing circuit 1 supplies power to the current detecting circuit 1, the voltage detecting circuit 1, the delay circuit 1, the logic control circuit 1, and the driving circuit 1.
The voltage stabilizing circuit 2 supplies power to the current detection circuit 2, the voltage detection circuit 2, the delay circuit 2, the logic control circuit 2 and the drive circuit 2.
The driving circuit 1 and the driving circuit 2 of the intrinsic safety power protection circuit are different.
Specifically, the driving circuit 1 includes a transistor Q11, a transistor Q13, a field effect transistor Q12, a field effect transistor Q14, a capacitor C11, and a plurality of resistors.
Wherein, the output signal from the logic control circuit 1 is connected with the grid of a field effect transistor Q12 through a resistor R14, the drain of the field effect transistor Q12 is connected with a stabilized power supply through a resistor R12, and the drain of the field effect transistor Q12 is connected with a capacitor C11 and the base of a transistor Q11; the emitter of the transistor Q11 is connected with the regulated power supply through the resistor R11, and the drain of the transistor Q12 is also connected with the resistor R12 and then connected with the regulated power supply.
Meanwhile, the output signal from the logic control circuit 1 is also connected with the gate of a field effect transistor Q14 through a resistor R18, the drain of a field effect transistor Q14 and the emitter of a transistor Q11 are connected with the base of a transistor Q13 through a resistor R16, the emitter of a transistor Q13 is grounded through a resistor R19, the collector of the transistor Q13 is connected with a stabilized power supply through a resistor R15 and a resistor R13, and the output signal is led out from the common connection point of the resistor R13 and the resistor R15. A grounding resistor R17 is connected between the resistor R16 and the base of the transistor Q13.
The driving circuit 2 comprises a transistor Q20, a transistor Q21, a capacitor C20 and a plurality of resistors; the output signal from the logic control circuit 2 is connected with the base of a transistor Q20 through a resistor R23, the collector of the transistor Q20 is connected with a resistor R20 and a capacitor C20, and the other end of the resistor R20 is connected with a stabilized power supply; the collector of the transistor Q20 is connected with the R21, the resistor R22 and the collector of the transistor Q21, and the other end of the resistor R22 is connected with the resistor R24.
Meanwhile, the output signal from the logic control circuit 2 is connected to the base of the transistor Q21 through the resistor R25, the emitter of the transistor Q21 is grounded, and the output is led out from the common connection point of the resistor R22 and the resistor R24.
The switch circuit 1 of the intrinsic safety power supply protection circuit comprises a P-channel field effect transistor, the switch circuit 2 comprises an N-channel field effect transistor, and a shunt resistor with the resistance value of 3 k-10 k is arranged between the source electrode and the drain electrode of each field effect transistor.
Which are a switching circuit 1 and a switching circuit 2, respectively controlling the positive output terminal and the negative output terminal. Of course, the corresponding drive circuit 1 and drive circuit 2 are different. Further, it is preferable that a dummy load resistor is connected between the switching circuit 1 and the switching circuit 2.
When an overvoltage and overcurrent fault occurs between the direct current power supply module and the load, the output protection circuit limits the current supplied to the load and tries to recover normal power supply after a period of time.
The utility model has the advantages of small volume, light weight, rapid protection in failure, automatic recovery, no need of a radiator, safety, reliability and the like in practical application, ensures the safe operation of the connected load in an explosive environment, and effectively prevents the safety threat formed by electric sparks or heat effect.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An intrinsically safe power supply protection circuit includes a protection circuit connected between a direct current power supply and a load; the method is characterized in that: the protection circuit comprises two groups of sub-circuits which are used for monitoring the power supply voltage state of the power supply and the current state of the load at the same time; the two groups of sub-circuits are respectively provided with a current detection circuit, a voltage detection circuit, a power failure protection circuit and a delay circuit for receiving indication signals of the current detection circuit and/or the voltage detection circuit, the delay circuit is connected with a driving circuit through a logic control circuit, and the driving circuit is used for driving a switching circuit to act; and the two groups of sub-circuits are also connected with a sampling circuit and a current limiting circuit, the sampling circuit is connected with a current detection circuit, and the current limiting circuit is connected with a power failure protection circuit.
2. According toThe intrinsically safe power protection circuit of claim 1, wherein: the power failure protection circuit comprises a voltage stabilizing diode D1, a controllable silicon Q1, a resistor R1, a resistor R2 and a capacitor C1; the cathode of the voltage stabilizing diode D1 and the T of the thyristor Q11The anode of the voltage stabilizing diode D1 is connected with the G pole of the controllable silicon Q1 after passing through a resistor R1; the G pole of the controllable silicon Q1 is respectively connected with one end of a grounding capacitor C1 and one end of a resistor R1, and the other end of the resistor R1 is connected with the negative pole of the power supply through a resistor R2.
3. The intrinsically safe power protection circuit of claim 1, wherein: the voltage detection circuit comprises a comparator U1A, a current source Z1, resistors R5, R3, R4, R8 and R6; the current flowing by the current source Z1 is converted into a voltage drop of R5; one end of the R5 is connected with the voltage to be measured, the other end is connected with the reverse input end of the comparator, then the R3, the R4, the R6 and the R8 form a voltage divider, the voltage dividing output end is connected with the non-inverting input end of the comparator U1A, and the two input ends of the comparator U1A are used for voltage size comparison.
4. The intrinsically safe power protection circuit of claim 1, wherein: the current detection circuit comprises a comparator U1B and a voltage source Vref, a power supply is connected with the voltage source Vref through a resistor R9 and is connected to the homodromous input end of the comparator U1B, and a detected signal is connected to the inverting input end of the comparator U1B through a resistor R10 by a sampling circuit.
5. The intrinsically safe power protection circuit of claim 1, wherein: the delay circuit is a monostable HEF 4538.
6. The intrinsically safe power protection circuit of claim 1, wherein: the logic control circuit is a basic logic judgment circuit HEF4011 and is used for the logic judgment of the fault state.
7. The intrinsically safe power protection circuit of claim 1, wherein: the voltage stabilizing circuit is a low dropout linear voltage regulator and is used for generating internal stable voltage.
8. The intrinsically safe power protection circuit of claim 1, wherein: the two groups of sub-circuits are different in driving circuit;
one of the two groups of sub-circuits comprises a transistor Q11, a transistor Q13, a field effect transistor Q12, a field effect transistor Q14, a capacitor C11 and a plurality of resistors;
the output signal of the logic control circuit connected with the driving circuit is connected with the grid electrode of a field effect transistor Q12 through a resistor R14, the drain electrode of a field effect transistor Q12 is connected with a stabilized power supply through a resistor R12, and the drain electrode of the field effect transistor Q12 is connected with a capacitor C11 and the base electrode of a transistor Q11; the emitter of the transistor Q11 is connected with a regulated power supply through a resistor R11;
meanwhile, the output signal of the logic control circuit connected with the driving circuit is also connected with the grid of a field effect transistor Q14 through a resistor R18, the drain of the field effect transistor Q14 is connected with the emitter of a transistor Q11, the output signal is connected with the base of a transistor Q13 through a resistor R16, the emitter of a transistor Q13 is grounded through a resistor R19, the collector of the transistor Q13 is connected with a stabilized power supply through a resistor R15 and a resistor R13, and the output signal is led out from the common connection point of the resistor R13 and the resistor R15;
the other driving circuit in the two groups of sub-circuits comprises a transistor Q20, a transistor Q21, a capacitor C20 and a plurality of resistors; the output signal of the logic control circuit connected with the other drive circuit is connected with the base of a transistor Q20 through a resistor R23, the collector of a transistor Q20 is connected with a resistor R20 and a capacitor C20, and the other end of the resistor R20 is connected with a stabilized power supply; the collector of the transistor Q20 is connected with the collector of the resistor R22 and the collector of the transistor Q21, and the other end of the resistor R22 is connected with the resistor R24;
meanwhile, the output signal of the logic control circuit connected with the other driving circuit is connected with the base of the transistor Q21 through a resistor R25, the emitter of the transistor Q21 is grounded, and the output is led out from the common connection point of the resistor R22 and the resistor R24.
9. The intrinsically safe power protection circuit of claim 1, wherein: one of the two sub-circuits comprises a P-channel field effect transistor, and the other one comprises an N-channel field effect transistor.
10. The intrinsically safe power protection circuit of claim 1, wherein: and a 3 k-10 k shunt resistor is arranged between the source electrode and the drain electrode of the switch circuit, and a dummy load resistor is connected between the switch circuits of the two sub-circuits.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202121584767.5U CN215580367U (en) | 2021-07-13 | 2021-07-13 | Intrinsic safety power supply protection circuit |
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| CN202121584767.5U CN215580367U (en) | 2021-07-13 | 2021-07-13 | Intrinsic safety power supply protection circuit |
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| GR01 | Patent grant |