A high-current output intrinsically safe power supply circuit

Abstract

This invention relates to the field of electronic circuit technology, and more particularly to an intrinsically safe power supply circuit with high current output, comprising a power input circuit, an output protection circuit, an overvoltage protection circuit, an overcurrent protection circuit, and a current sampling circuit. The power input circuit limits the overall operating power of the power supply circuit, providing first-level voltage and current limiting protection. The current sampling circuit provides second-level current limiting protection. When either the overvoltage or overcurrent protection value exceeds a set value, the corresponding operational amplifier outputs a high level, which can turn on the thyristor in the output protection circuit, providing third-level protection. The overvoltage, overcurrent, and output protection circuits can limit the output to a safe value, allowing the load to operate continuously. In the event of overvoltage, overcurrent, or short circuit at the load side, the circuit can be instantly shut down with low instantaneous energy, resulting in superior safety.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and in particular to an intrinsically safe power supply circuit with high current output. Background Technology

[0002] With the advancement of intelligent technology, the power of equipment used in specialized industries is increasing. Therefore, researching intrinsically safe power supply circuits with high current output is crucial to meet the needs of applications in special environments such as coal mines. Currently, intrinsically safe power supply circuits mainly suffer from the following shortcomings:

[0003] 1. A circuit that uses a current-limiting resistor for current protection and a Zener diode for voltage-limiting protection has a high safety factor, but is not suitable for high-voltage, high-current applications.

[0004] 2. An integrated circuit surge suppressor with current limiting function is used, but the maximum power of this type of circuit does not exceed 20W and the transient energy is relatively large. At the moment the circuit cuts off the protection, the high voltage and current will appear on the load side instantly, causing the transient energy to exceed 260uJ, which cannot meet the requirements of the shunt short (sudden short circuit) protection circuit in section 10.1.5.3 of the national standard GB3836-4. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing an intrinsically safe power supply circuit with high current output.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An intrinsically safe power supply circuit with high current output includes a power input circuit, an output protection circuit, an overvoltage protection circuit, an overcurrent protection circuit, and a current sampling circuit. The power input circuit includes an operational amplifier U1, which limits the overall operating power of the power supply circuit, ensuring that its output voltage and current do not exceed the electrical parameters of the operational amplifier U1, thus providing first-level voltage and current limiting protection. The current sampling circuit samples the resistor R2 at the output side of the operational amplifier U1. By sampling the current value at the output side of the operational amplifier U1, the overcurrent protection value at the output side of the operational amplifier U1 is adjusted using a reference voltage. When the overcurrent protection value exceeds a set value... When the overvoltage protection circuit and the overcurrent protection circuit are in operation, the output of the operational amplifier U1 can be controlled to provide the second-level current limiting protection. The overvoltage protection circuit and the overcurrent protection circuit collect the voltage value on the output side of the operational amplifier U1 and compare it with the reference voltage to determine the protection value. If the protection value is greater than the set value, it can be adjusted by voltage division through resistors. The overvoltage protection circuit is output through the operational amplifier U3B and the overcurrent protection circuit is output through the operational amplifier U3A. When either the overvoltage protection value or the overcurrent protection value is higher than the set value, the corresponding operational amplifier outputs a high level, which can turn on the thyristor V1 in the output protection circuit to provide the third-level protection.

[0008] Preferably, the power input circuit includes an operational amplifier U1. Pin 1 of operational amplifier U1 is a non-inverting input pin, connected to resistor R6, and the other end is connected to the ReferenceVoltage 2.5V terminal. A capacitor C2 and a resistor R7 are connected in sequence between resistor R6 and the ReferenceVoltage 2.5V terminal. The other ends of capacitor C2 and resistor R7 are grounded. Pin 2 of operational amplifier U1 is an inverting input pin, connected to the CUR-OVER terminal. Pin 5 is the positive power supply pin, pin 4 is the negative power supply pin, and pin 7 is connected to the Enab... The enable port is pin 1. Pin 3 is connected to resistor R8, and the other end is connected to pin 4, which can pull the level low. Pin 6 is the output pin. Pin 6 is connected in series with resistors R2, R3, R4, and R5, and the other end is connected to the V-OUT terminal. The input terminal of resistor R2 is connected to the I-TEST1 port, and the output terminal of resistor R2 is connected to the I-TEST2 port. I-RES1 port is connected between resistors R3 and R4, and I-RES2 port is connected between resistors R4 and R5. Resistor R1 and capacitor C1 are connected in parallel between pin 2 and pin 6 to form a closed-loop negative feedback circuit.

[0009] Preferably, the output protection circuit includes a transistor VT1 and a thyristor V1. The base (B) of transistor VT1 is connected in series with a resistor R10 and connected to the THY1-CTR terminal. The base (C) of transistor VT1 is connected in parallel with capacitors R14 and R15. The other end of capacitor R15 is connected to the cathode (K) of the thyristor, and the cathode (K) of the thyristor is connected to ground. The other end of capacitor R14 is connected to the gate (G) of the thyristor. The base (E) of transistor VT1 is connected to the anode (A) of the thyristor. The anode (A) of the thyristor is connected between resistors R3 and R4. A resistor R9 is connected between the base (B) and the base (E) of transistor VT1. Resistor R9 can act as a pull-up resistor, so that the base (B) and base (E) remain in a stable state.

[0010] Preferably, the overvoltage protection circuit includes an operational amplifier U3B. Pin 3 of the operational amplifier U3B is a non-inverting input pin, connected to the ReferenceVoltage 2.5V terminal. Pin 4 of the operational amplifier U3B is an inverting input pin, connected in parallel with resistors R16, R13, R12, and capacitor C3. The other end of resistor R16 is connected to the V-OUT terminal, and the other ends of resistors R13, R12, and capacitor C3 are connected to the ground terminal. Pin 5 of the operational amplifier U3B is connected to the THY1-CTR terminal. The V-OUT terminal of the overvoltage protection circuit is connected to the V-OUT terminal of one end of resistor R5. The THY1-CTR terminal of the overvoltage protection circuit is connected to the THY1-CTR terminal of the output protection circuit.

[0011] Preferably, the overcurrent protection circuit includes an operational amplifier U3A. Pin 1 of the operational amplifier U3A is a non-inverting input pin. A resistor R36 is connected in series with pin 1 of the operational amplifier U3A. The negative terminal of the resistor R36 is grounded. The other end of the resistor R36 is connected to a resistor R33. The other end of the resistor R33 is connected to a resistor R26. The other end of the resistor R26 is connected to port I-RES2. A capacitor C9 is connected across the two ends of the resistor R33. A resistor R37 is connected across the two ends of the resistor R36. Resistors R33, C9, R36, and R37 form a parallel circuit. The output of this parallel circuit is connected to a resistor R34. A resistor R35 is connected in parallel across the two ends of the resistor R34. The output of the resistor R35 is connected to... Connected to port P1-2.5V, pin 8 of operational amplifier U3A is the inverting input pin. Pin 8 of operational amplifier U3A is connected in parallel with resistors R17, R19, capacitor C5, and resistor R20. The other ends of resistors R17 and R19 are connected to ground, and the other ends of capacitor C5 and resistor R20 are connected to port I-RES1. Pin 7 of operational amplifier U3A is connected to the THY1-CTR terminal. The I-RES1 terminal of the overcurrent protection circuit is connected to the I-RES1 port between resistors R3 and R4, the I-RES2 terminal is connected to the I-RES2 port between resistors R4 and R5, and the THY1-CTR terminal is connected to the THY1-CTR terminal of the output protection circuit.

[0012] Preferably, the current sampling circuit includes operational amplifiers U2A and U2B. Pin 3 of operational amplifier U2A is a non-inverting input pin. Resistors R25 and R29 are connected in parallel to pin 3 of operational amplifier U2A. The other end of resistor R25 is connected to the I-TEST1 port, and the other end of resistor R29 is connected to ground. Pin 2 of operational amplifier U2A is an inverting input pin. Resistor R22 is connected to pin 2 of operational amplifier U2A, and the other end of resistor R22 is connected to the I-TEST2 port. Pin 8 of operational amplifier U2A is a positive power supply pin, and pin 4 of operational amplifier U2A is a negative power supply pin. A decoupling capacitor C7 is connected between pins 8 and 4 of operational amplifier U2A. Pin 1 of operational amplifier U2A is an output pin. Resistor R23 is connected to pin 1 of operational amplifier U2A. The other end of resistor R23 is connected to pin 5 of operational amplifier U2B, which is a non-inverting input pin. A resistor R18 and a capacitor C4 are connected in parallel between pins 1 and 2 of operational amplifier U2A to form a closed-loop negative feedback circuit. Pin 6 of operational amplifier U2B is the inverting input pin. Pin 6 of operational amplifier U2B is connected in parallel with resistors R27 and R30 and capacitor C8. The other end of resistor R27 is connected to the ADJ-Reference Voltage port, and the other ends of resistor R30 and capacitor C8 are connected to ground. Pin 7 of operational amplifier U2B is the output pin and is connected to the CUR-OVER port. The I-TEST1 port of the current sampling circuit is connected to the I-TEST1 port of the R2 input terminal, the I-TEST2 port of the current sampling circuit is connected to the I-TEST2 port of the R2 output terminal, and the CUR-OVER port of the current sampling circuit is connected to the CUR-OVER port of the power input circuit.

[0013] The beneficial effects of this invention are:

[0014] 1. Overvoltage protection circuit, overcurrent protection circuit and output protection circuit can be used in the same circuit in intrinsically safe power supply circuit with high current output to limit the output to a safe value, thereby allowing the load to operate continuously.

[0015] 2. After using this circuit, the circuit can be shut down instantly when there is overvoltage, overcurrent or short circuit on the load side. The instantaneous energy is low and the safety is better. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the power input circuit and output protection circuit of an intrinsically safe power supply circuit with high current output proposed in this invention.

[0017] Figure 2 This is a schematic diagram of an overvoltage protection circuit for an intrinsically safe power supply circuit with high current output proposed in this invention.

[0018] Figure 3 This is a schematic diagram of an overcurrent protection circuit for an intrinsically safe power supply circuit with high current output proposed in this invention.

[0019] Figure 4 This is a schematic diagram of a current sampling circuit for an intrinsically safe power supply circuit with high current output proposed in this invention.

[0020] In the diagram: 1-Power input circuit, 2-Output protection circuit, 3-Overvoltage protection circuit, 4-Overcurrent protection circuit, 5-Current sampling circuit. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Reference Figure 1 A high-current output intrinsically safe power supply circuit includes a power input circuit 1, an output protection circuit 2, an overvoltage protection circuit 3, an overcurrent protection circuit 4, and a current sampling circuit 5.

[0023] The power input circuit 1 includes an operational amplifier U1. Pin 1 of operational amplifier U1 is a non-inverting input pin, connected to resistor R6, with the other end connected to the ReferenceVoltage 2.5V terminal. A capacitor C2 and a resistor R7 are connected in sequence between resistor R6 and the ReferenceVoltage 2.5V terminal, with the other ends of capacitor C2 and resistor R7 grounded. Pin 2 of operational amplifier U1 is an inverting input pin, connected to the CUR-OVER terminal. Pin 5 is the positive power supply pin, pin 4 is the negative power supply pin, pin 7 is connected to the Enable port, and pin 3 is connected to resistor R8, with the other end connected to pin 4, which can be used to pull the level low. Pin 6 is an output pin, connected in series with resistors R2, R3, R4, and R5, with the other end connected to the V-OUT terminal. The input terminal of resistor R2 is connected to the I-TEST1 port, and the output terminal of resistor R2 is connected to the I-TEST2 port. The I-RES1 port is connected between resistors R3 and R4, and the I-RES2 port is connected between resistors R4 and R5. A resistor R1 and a capacitor C1 are connected in parallel between pins 2 and 6 to form a closed-loop negative feedback circuit.

[0024] Operational amplifier U1 can continuously output up to 3A and peak output up to 5A. Its output can be controlled via the Enable port, or via CUR-OVER and ReferenceVoltage2.5V. CUR-OVER is connected to current sampling circuit 5. By comparing CUR-OVER and ReferenceVoltage2.5V, the output of operational amplifier U1 can be controlled according to its characteristics, thus providing power-off protection for the load-side circuit. Operational amplifier U1 can limit the overall operating power of the power supply circuit, ensuring its output voltage and current do not exceed its electrical parameters, providing first-level voltage and current limiting protection for intrinsically safe power supply circuits with high current output.

[0025] Output protection circuit 2 includes transistor VT1 and thyristor V1. The base (B) of transistor VT1 is connected in series with resistor R10 and connected to the THY1-CTR terminal. The base (C) of transistor VT1 is connected in parallel with capacitors R14 and R15. The other end of capacitor R15 is connected to the cathode (K) of the thyristor, and the cathode (K) of the thyristor is connected to the ground terminal. The other end of capacitor R14 is connected to the gate (G) of the thyristor. The base (E) of transistor VT1 is connected to the anode (A) of the thyristor. The anode (A) of the thyristor is connected between resistors R3 and R4. Resistor R9 is connected between the base (B) and the base (E) of transistor VT1. Resistor R9 can act as a pull-up resistor to keep the base (B) and base (E) in a stable state.

[0026] In output protection circuit 2, the output of transistor VT1 is controlled by the THY1-CTR terminal, which synchronously controls the output state of thyristor V1. Thyristor V1 only conducts when protected by overvoltage protection circuit 3 and overcurrent protection circuit 4. After thyristor V1 conducts, it is not affected by the output value protected by overvoltage protection circuit 3 and overcurrent protection circuit 4. Damage to the operational amplifiers of overvoltage protection circuit 3 and overcurrent protection circuit 4 will not affect the output of thyristor V1, thus ensuring the stability of the output power supply. After thyristor V1 conducts, the power supply on the load side will be directly pulled low, which can provide a second level of protection for intrinsically safe power supply circuits with high current output.

[0027] Reference Figure 2The overvoltage protection circuit 3 includes operational amplifier U3B. Pin 3 of operational amplifier U3B is a non-inverting input pin, connected to the ReferenceVoltage 2.5V terminal. Pin 4 of operational amplifier U3B is an inverting input pin, connected in parallel with resistors R16, R13, R12, and capacitor C3. The other end of resistor R16 is connected to the V-OUT terminal, and the other ends of resistors R13, R12, and capacitor C3 are connected to ground. Pin 5 of operational amplifier U3B is connected to the THY1-CTR terminal. The V-OUT terminal of the overvoltage protection circuit 3 is connected to the V-OUT terminal of one end of resistor R5.

[0028] Reference Figure 3 The overcurrent protection circuit 4 includes an operational amplifier U3A. Pin 1 of the operational amplifier U3A is a non-inverting input pin. Pin 1 of the operational amplifier U3A is connected in series with a resistor R36. The negative terminal of the resistor R36 is grounded. The other end of the resistor R36 is connected to a resistor R33. The other end of the resistor R33 is connected to a resistor R26. The other end of the resistor R26 is connected to port I-RES2. In addition, a capacitor C9 is connected across the two ends of the resistor R33, and a resistor R37 is connected across the two ends of the resistor R36. The resistors R33, C9, R36, and R37 form a parallel circuit. The output of this parallel circuit is connected to a resistor R34. A resistor R35 is connected in parallel across the two ends of the resistor R34. The output of the resistor R35 is connected to port P1-2.5V. Pin 8 of operational amplifier U3A is the inverting input pin. Pin 8 of operational amplifier U3A is connected in parallel with resistors R17 and R19, capacitor C5, and resistor R20. The other ends of resistors R17 and R19 are connected to ground, and the other ends of capacitor C5 and resistor R20 are connected to port I-RES1. Pin 7 of operational amplifier U3A is connected to the THY1-CTR terminal.

[0029] The I-RES1 terminal of the overcurrent protection circuit 4 is connected to the I-RES1 port between resistors R3 and R4, and the I-RES2 terminal of the overcurrent protection circuit 4 is connected to the I-RES2 port between resistors R4 and R5. The THY1-CTR terminals of the overvoltage protection circuit 3 and the THY1-CTR terminals of the overcurrent protection circuit 4 are connected in parallel to the THY1-CTR terminal of the output protection circuit 2.

[0030] Overvoltage protection circuit 3, overcurrent protection circuit 4, and sampling resistor R2 on the output side of power input circuit 1 are used to acquire the current value on the output side through operational amplifier U3A. By adjusting the resistance values ​​of R16, R12, and R13, the voltage at the inverting input terminal of operational amplifier U3A can be compared with the voltage at the non-inverting input terminal, and the output value is fed back to the input side of transistor VT1 to control the output state of thyristor V1. Similarly, by adjusting the voltage at the non-inverting input terminal and the inverting input terminal of operational amplifier U3B, the output state of thyristor V1 can also be controlled.

[0031] like Figure 4 As shown, the current sampling circuit 5 includes operational amplifiers U2A and U2B. Pin 3 of operational amplifier U2A is a non-inverting input pin. Resistors R25 and R29 are connected in parallel to pin 3 of operational amplifier U2A. The other end of resistor R25 is connected to the I-TEST1 port, and the other end of resistor R29 is connected to ground. Pin 2 of operational amplifier U2A is an inverting input pin. Resistor R22 is connected to pin 2 of operational amplifier U2A, and the other end of resistor R22 is connected to the I-TEST2 port. Pin 8 of operational amplifier U2A is a positive power supply pin, and pin 4 of operational amplifier U2A is a negative power supply pin. A decoupling capacitor C7 is connected between pins 8 and 4 of operational amplifier U2A. Pin 1 of operational amplifier U2A is an output pin. Resistor R23 is connected to pin 1 of operational amplifier U2A. The other end of resistor R23 is connected to pin 5 of operational amplifier U2B, which is a non-inverting input pin. A resistor R18 and a capacitor C4 are connected in parallel between pins 1 and 2 of operational amplifier U2A, forming a closed-loop negative feedback circuit. Pin 6 of operational amplifier U2B is the inverting input pin. A resistor R27, a resistor R30, and a capacitor C8 are connected in parallel between pin 6 of operational amplifier U2B. The other end of resistor R27 is connected to the ADJ-Reference Voltage port, and the other ends of resistor R30 and capacitor C8 are connected to ground. Pin 7 of operational amplifier U2B is the output pin and is connected to the CUR-OVER port.

[0032] The I-TEST1 port of current sampling circuit 5 is connected to the I-TEST1 port of the input terminal of R2, and the I-TEST2 port of current sampling circuit 5 is connected to the I-TEST2 port of the output terminal of R2. The CUR-OVER port of current sampling circuit 5 is connected to the CUR-OVER port of power input circuit 1.

[0033] The current sampling circuit 5 can collect the current value across resistor R2. The output state of operational amplifier U2A can be determined by adjusting resistors R25 and R29, and the output value can be determined by resistor R18. The voltages at the non-inverting and inverting input terminals of operational amplifier U2B are compared, and the output value is fed back to the inverting input terminal of operational amplifier U1. By controlling the output state of operational amplifier U1, the output state on the load side can be controlled, thereby providing a third-level protection for intrinsically safe power supply circuits with high current output.

[0034] Overvoltage protection circuit 3, overcurrent protection circuit 4, and output protection circuit 2 can be used in the same circuit in intrinsically safe power supply circuits with high current output, limiting the output to a safe value, thus allowing the load to operate continuously. If two sets of circuits are used, they can be applied to the IB-level protection circuit specified in GB3836-4-2021; if three sets of circuits are used, they can be applied to the IA-level protection circuit.

[0035] With the above circuit, the input power supply provides a load circuit to the power supply after passing through operational amplifier U1. Operational amplifier U1 can control the power supply output through control logic circuit. A reference voltage is connected to the non-inverting input terminal of operational amplifier U1. This voltage is compared with the output voltage of overcurrent protection circuit 4. This reference voltage is connected to the inverting input terminal of operational amplifier U1. When there is an overcurrent in the output, the output of operational amplifier U1 can be turned off. Overcurrent protection circuit 4 detects the power resistor R2 on the output circuit. The resistance of power resistor R2 is small, and its power should be twice the rated power. Power resistors are connected to the non-inverting and inverting input terminals of operational amplifier U2A. The output state of operational amplifier U2A is controlled through a negative feedback circuit. Then, operational amplifier U2B is used as a comparator circuit to feed the output back to the inverting input side, ultimately controlling the maximum operating current on the load side.

[0036] Overvoltage detection circuit 3 and overcurrent detection circuit 4, through the comparator circuits of operational amplifiers U3A and U3B, control the output value of the operational amplifiers by comparing a reference voltage with a setting resistor, and provide the output value to the control side of thyristor V1, enabling rapid turn-off and clamping of thyristor V1. Using this circuit, the circuit can be instantly turned off when short-term overvoltage, overcurrent, or short circuit occurs on the load side, while the output power can reach 30W, the instantaneous turn-off time can be controlled within 10µs, and the transient energy can be suppressed within 260µJ.

[0037] When a large voltage or current is detected, the operational amplifier can output a high level, instantly enabling the thyristor V1 to short-circuit to ground. Due to the characteristics of thyristor V1, even if the semiconductor current-limiting switch operational amplifier is damaged, thyristor V1 can still reliably conduct, ensuring that the output circuit has no output voltage or current, preventing energy from being released into an explosive environment. At the same time, it can also enable the power operational amplifier to shut down its output, achieving dual protection. Thyristor V1 can be controlled through the output of the operational amplifier. Under normal operating conditions, the operational amplifier outputs a low level to reliably cut off thyristor V1.

[0038] Output protection circuit 2, overvoltage protection circuit 3, and overcurrent protection circuit 4 can be reused in intrinsically safe power supply circuits with high current output, enabling these circuits to achieve protection levels of ib and ia, thus making them safer.

[0039] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-current output intrinsically safe power supply circuit, characterized in that, It includes a power input circuit (1), an output protection circuit (2), an overvoltage protection circuit (3), an overcurrent protection circuit (4), and a current sampling circuit (5). The power input circuit (1) includes an operational amplifier U1, which limits the overall operating power of the power circuit. Its output voltage and current do not exceed the electrical parameters of the operational amplifier U1, and it plays the role of first-level voltage and current limiting protection. The current sampling circuit (5) collects the resistance R2 on the output side of the operational amplifier U1. By collecting the current value on the output side of the operational amplifier U1, the overcurrent protection value on the output side of the operational amplifier U1 is adjusted by the adjustment reference voltage. When the overcurrent protection value is greater than the set value, the output of the operational amplifier U1 can be controlled, which plays the role of the second-level current limiting protection. The overvoltage protection circuit (3) and overcurrent protection circuit (4) collect the voltage value of the output side of the operational amplifier U1 and compare it with the reference voltage to determine the size of the protection value. If the protection value is greater than the set value, it can be adjusted by voltage division through resistors. The overvoltage protection circuit (3) is output through operational amplifier U3B, and the overcurrent protection circuit (4) is output through operational amplifier U3A. When any value of overvoltage protection and overcurrent protection is higher than the set value, the corresponding operational amplifier outputs a high level, which can turn on the thyristor V1 in the output protection circuit (2) and play the role of the third level of protection. The power input circuit (1) includes an operational amplifier U1. Pin 1 of the operational amplifier U1 is a non-inverting input pin. Pin 1 is connected to one end of resistor R6. The other end of resistor R6 is connected to the ReferenceVoltage 2.5V terminal. Resistor R6 and the ReferenceVoltage 2.5V terminal are connected in sequence to one end of capacitor C2 and resistor R7. The other ends of capacitor C2 and resistor R7 are grounded. Pin 2 of the operational amplifier U1 is an inverting input pin. Pin 2 is connected to the CUR-OVER terminal. Pin 5 is the positive power supply pin. Pin 4 is the negative power supply pin. Pin 7 is connected to the Enable port. Pin 3 is connected to one end of resistor R8. The other end of resistor R8 is connected to pin 4. The connection can be used to pull the level low; pin 6 is the output pin, with resistors R2, R3, R4, and R5 connected in series on pin 6, and the other end connected to the V-OUT terminal. The input terminal of resistor R2 is connected to the I-TEST1 port, and the output terminal of resistor R2 is connected to the I-TEST2 port. I-RES1 port is connected between resistors R3 and R4, and I-RES2 port is connected between resistors R4 and R5. Resistor R1 and capacitor C1 are connected in parallel between pin 2 and pin 6 to form a closed-loop negative feedback circuit. The output protection circuit (2) includes a transistor VT1 and a thyristor V1. The base of transistor VT1 is connected in series with a resistor R10 and connected to the THY1-CTR terminal. The collector of transistor VT1 is connected in parallel with one end of capacitors R14 and R15. The other end of capacitor R15 is connected to the cathode K of the thyristor. The cathode K of the thyristor is connected to the ground terminal. The other end of capacitor R14 is connected to the gate G of the thyristor. The emitter of transistor VT1 is connected to the anode A of the thyristor. The anode A of the thyristor is connected between R3 and R4. A resistor R9 is connected between the base of transistor VT1 and the emitter of transistor VT1. The resistor R9 can play the role of pulling up the level, so that the base and emitter of transistor VT1 remain in a stable state.

2. The intrinsically safe power supply circuit with high current output according to claim 1, characterized in that, The overvoltage protection circuit (3) includes an operational amplifier U3B. Pin 3 of the operational amplifier U3B is a non-inverting input pin and is connected to the ReferenceVoltage 2.5V terminal. Pin 4 of the operational amplifier U3B is an inverting input pin and is connected to one end of resistors R16, R13, R12, and capacitor C3. The other end of resistor R16 is connected to the V-OUT terminal, and the other end of resistors R13, R12, and capacitor C3 is connected to the ground terminal. Pin 5 of the operational amplifier U3B is connected to the THY1-CTR terminal. The V-OUT terminal of the overvoltage protection circuit (3) is connected to the V-OUT terminal of one end of resistor R5. The THY1-CTR terminal of the overvoltage protection circuit (3) is connected to the THY1-CTR terminal of the output protection circuit (2).

3. The intrinsically safe power supply circuit with high current output according to claim 1, characterized in that, The overcurrent protection circuit (4) includes an operational amplifier U3A. Pin 1 of the operational amplifier U3A is a non-inverting input pin. Pin 1 of the operational amplifier U3A has one end of resistor R36 and one end of resistor R33. The other end of resistor R36 is grounded. The other end of resistor R33 is connected to resistor R26. The other end of resistor R26 is connected to port I-RES2. Capacitor C9 is connected to both ends of resistor R33. Resistor R37 is connected to both ends of resistor R36. Resistor R33, capacitor C9, resistor R36, and resistor R37 form a parallel circuit. The output of this parallel circuit is connected to resistor R34. Resistor R35 is connected in parallel to both ends of resistor R34. The output of resistor R35 is connected to port P1-2.5V. Pin 8 of the operational amplifier U3A is an inverting input pin. Pin 8 of the operational amplifier U3A is connected to resistors R17, R19, capacitor C5, and resistor R20. One end of the resistor R17 and the other end of the resistor R19 are connected to the ground terminal, the other end of the capacitor C5 and the resistor R20 are connected to the port I-RES1, and pin 7 of the operational amplifier U3A is connected to the THY1-CTR terminal. The I-RES1 terminal of the overcurrent protection circuit (4) is connected to the I-RES1 port between resistors R3 and R4, the I-RES2 terminal is connected to the I-RES2 port between resistors R4 and R5, and the THY1-CTR terminal is connected to the THY1-CTR terminal of the output protection circuit (2).

4. The intrinsically safe power supply circuit with high current output according to claim 1, characterized in that... The current sampling circuit (5) includes operational amplifiers U2A and U2B. Pin 3 of operational amplifier U2A is a non-inverting input pin. Pin 3 of operational amplifier U2A is connected to one end of resistors R25 and R29. The other end of resistor R25 is connected to the I-TEST1 port, and the other end of resistor R29 is connected to the ground. Pin 2 of operational amplifier U2A is an inverting input pin. Pin 2 of operational amplifier U2A is connected to one end of resistor R22. The other end of resistor R22 is connected to the I-TEST2 port. Pin 8 of operational amplifier U2A is a positive power supply pin, and pin 4 of operational amplifier U2A is a negative power supply pin. A decoupling capacitor C7 is connected between pins 8 and 4 of operational amplifier U2A. Pin 1 of operational amplifier U2A is an output pin. Connect one end of resistor R23, and connect the other end of resistor R23 to pin 5 of operational amplifier U2B. Pin 5 of operational amplifier U2B is a non-inverting input pin. Resistor R18 and capacitor C4 are connected in parallel between pins 1 and 2 of operational amplifier U2A to form a closed-loop negative feedback circuit. Pin 6 of operational amplifier U2B is an inverting input pin. Pin 6 of operational amplifier U2B is connected to one end of resistor R27, resistor R30 and capacitor C8. The other end of resistor R27 is connected to the ADJ-Reference Voltage port, and the other ends of resistor R30 and capacitor C8 are connected to the ground terminal. Pin 7 of operational amplifier U2B is an output pin and is connected to the CUR-OVER port. The I-TEST1 port of the current sampling circuit (5) is connected to the I-TEST1 port of the input terminal of R2, the I-TEST2 port of the current sampling circuit (5) is connected to the I-TEST2 port of the output terminal of R2, and the CUR-OVER port of the current sampling circuit (5) is connected to the CUR-OVER port of the power input circuit (1).

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