An intrinsically safe power supply
Patent Information
- Application Number
- CN202521566954.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-25
- Publication Date
- 2026-08-18
- Estimated Expiration
- 2035-07-25
AI Technical Summary
[0003]有鉴于此，有必要提供一种本安电源，用以解决现有技术因模块功率不能满足昏暗环境照明需求的技术问题
[0014]本实用新型的有益效果是：本实用新型提供的一种本安电源，通过反激电路将外接电源输入的电压进行转换从而为负载供能，本实用新型在反激电路与负载之间依次设置了恒流电路、限流限压模块以及快速放电电路，通过恒流电路以及光耦对反激电路的输出限制，可以有效维持电源内的电流和电压水平，同时，在短路发生时，限流限压模块内的比较器通过切断限流限压模块内部与反激电路之间的第一开关实现过流过压保护，限制能量输出，并且，通过闭合快速放电电路上的第二开关，可以将负载上的电能转移到快速放电电路上，消除了短路能量，在限制短路输出和抵消负载短路电火花的多重保护机制下，本实用新型可以在稳定通过火花实验的情况下提供更大且更可靠的功率，进而增加照明亮度，解决现有技术因模块功率不能满足昏暗环境照明需求的技术问题。
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Figure CN224653393U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of mining electrical equipment technology, and in particular to an intrinsically safe power supply. Background Technology
[0002] Existing intrinsically safe power supplies are modularly packaged, resulting in low efficiency, low power output, opaque technology, and high cost, hindering industry development and promotion. Especially when applied to intrinsically safe lighting, the module's power limitations lead to low illuminance, failing to meet the lighting needs of dimly lit underground environments. This paper presents a design for a high-power intrinsically safe power supply for coal mines. In application, this circuit can be integrated into the control board, replacing the intrinsically safe power supply module. Utility Model Content
[0003] In view of this, it is necessary to provide an intrinsically safe power supply to solve the technical problem that the module power of the existing technology cannot meet the lighting needs of dim environments.
[0004] To address the above problems, this utility model provides an intrinsically safe power supply, comprising: Flyback circuit, constant current circuit, current limiting and voltage limiting module and fast discharge circuit; The flyback circuit is electrically connected to the current limiting and voltage limiting module and to the constant current circuit, and is used to convert the voltage of the external power supply into a DC voltage of a preset voltage level and then transmit it to the constant current circuit and the current limiting and voltage limiting module respectively. The flyback circuit includes at least: a flyback control chip; The constant current circuit includes a first comparator and an optocoupler. The non-inverting input of the first comparator is electrically connected to the output of the flyback circuit, and the inverting input is electrically connected to the current limiting and voltage limiting module. The output of the first comparator is electrically connected to the input of the optocoupler, and the output of the optocoupler is electrically connected to the pin on the flyback control chip used to enable the chip. The current limiting and voltage limiting module is equipped with a first switch and a second comparator. One end of the first switch is electrically connected to the output terminal of the second comparator, and the other end is electrically connected to an external load. The non-inverting input terminal and the inverting input terminal of the second comparator are electrically connected to the output terminal of the flyback circuit through different voltage divider circuits. The constant current circuit is used to drive the optocoupler to turn off the enable of the flyback control chip when the DC voltage value is greater than a preset voltage threshold. The current limiting and voltage limiting module is used to turn off the first switch when the DC voltage value is greater than a preset voltage threshold and / or the current value in the circuit is greater than a preset current threshold. The current limiting and voltage limiting module is electrically connected to the external load, and a fast discharge circuit is also connected between the current limiting and voltage limiting module and the external load. The fast discharge circuit is electrically connected to the negative terminal through a second switch, and is used to transfer electrical energy in the external load to the negative terminal when the second switch is closed.
[0005] In some embodiments of this utility model, the flyback circuit includes at least: an isolation transformer and a first MOSFET; The isolation transformer includes a first primary winding, a second primary winding, and a secondary winding; The flyback control chip includes at least: a power input pin, a drive output pin, and a compensation pin; The power input pin is electrically connected to an external power supply, the drive output pin is electrically connected to the gate of the first MOS transistor, and the compensation pin is electrically connected to the photosensitive device of the optocoupler. One end of the first primary winding is electrically connected to the external power supply, and the other end is electrically connected to the drain of the first MOS transistor. One end of the second primary winding is electrically connected to the power input pin through the first diode and the filter circuit in sequence, and the other end is grounded. The cathode of the first diode is electrically connected to one end of the second primary winding, and the anode is electrically connected to the filter circuit. The secondary winding is electrically connected to the cathode of the light-emitting diode of the optocoupler, the constant current circuit, and the input terminal of the current-limiting and voltage-limiting module. The anode of the light-emitting diode is electrically connected to the output terminal of the constant current circuit.
[0006] In some embodiments of this utility model, the flyback control chip is an MP3910 chip.
[0007] In some embodiments of this utility model, the isolation transformer uses a ferrite core, is wound with pure copper enameled wire, has a withstand voltage of ≥3500VAC between different coils, and has a thermal insulation class of B.
[0008] In some embodiments of this utility model, the flyback circuit further includes: a first fuse, a second fuse, and a third fuse; The second fuse and the third fuse are connected in parallel, with one end of the parallel connection electrically connected to one end of the first fuse and the other end electrically connected to the power input pin. The other end of the first fuse is electrically connected to the external power supply.
[0009] In some embodiments of this utility model, the constant current circuit includes at least: a first sampling resistor and an operational amplifier chip; An operational amplifier chip includes at least: a sampling input pin and a signal output pin; One end of the first sampling resistor is electrically connected to the sampling input pin, and the other end is electrically connected to the input terminal of the current limiting and voltage limiting module, for sampling the voltage input from the flyback circuit to the current limiting and voltage limiting module; The signal output pin is electrically connected to the light-emitting diode of the optocoupler.
[0010] In some embodiments of this utility model, the operational amplifier chip is GS8552.
[0011] In some embodiments of this utility model, the current limiting and voltage limiting module includes two current limiting and voltage limiting circuits connected in series and having the same structure; The current limiting and voltage limiting circuit includes: Sampling resistor, comparator, second MOSFET, third MOSFET, and switching circuit; The sampling resistor is electrically connected to the sampling input pin of the comparator and is used to sample the voltage and current flowing into the current limiting and voltage limiting circuit. The drain of the second MOS transistor is electrically connected to the output terminal of the flyback circuit, the source is electrically connected to the switching circuit, and the gate is electrically connected to the output pin of the comparator. The source of the third MOS transistor is electrically connected to the output terminal of the flyback circuit, the gate is electrically connected to the switching circuit, and the drain serves as the output terminal of the voltage and current limiting circuit. The switching circuit includes at least: a reference voltage source and a transistor; The base of the transistor is electrically connected to the output terminal of the reference power supply and the output terminal of the flyback circuit, the collector is electrically connected to the output terminal of the flyback circuit, and the emitter is electrically connected to the source of the second MOS transistor.
[0012] In some embodiments of this utility model, the fast discharge circuit includes at least: a second switch and an inductor; One end of the inductor is electrically connected to the output terminal of the voltage and current limiting module, and the other end is grounded through the second switch.
[0013] In some embodiments of this utility model, the fast discharge circuit further includes: The second diode has its cathode electrically connected to the other end of the inductor and its anode electrically connected to the second switch.
[0014] The beneficial effects of this utility model are as follows: This utility model provides an intrinsically safe power supply that converts the voltage input from an external power source through a flyback circuit to power the load. This utility model sequentially sets a constant current circuit, a current-limiting and voltage-limiting module, and a fast discharge circuit between the flyback circuit and the load. By limiting the output of the flyback circuit through the constant current circuit and optocoupler, the current and voltage levels within the power supply can be effectively maintained. Simultaneously, in the event of a short circuit, the comparator within the current-limiting and voltage-limiting module achieves overcurrent and overvoltage protection by cutting off the first switch between the current-limiting and voltage-limiting module and the flyback circuit, limiting energy output. Furthermore, by closing the second switch on the fast discharge circuit, the electrical energy on the load can be transferred to the fast discharge circuit, eliminating short-circuit energy. With multiple protection mechanisms that limit short-circuit output and cancel short-circuit sparks, this utility model can provide greater and more reliable power while stably passing spark tests, thereby increasing lighting brightness and solving the technical problem in existing technologies where the module power cannot meet the lighting needs of dimly lit environments. Attached Figure Description
[0015] Figure 1 A schematic diagram of the structure of an embodiment of the intrinsically safe power supply provided by this utility model; Figure 2 A schematic diagram of an embodiment of the flyback circuit provided by this utility model; Figure 3 A schematic diagram of an embodiment of the constant current circuit provided by this utility model; Figure 4 A schematic diagram of an embodiment of the voltage limiting and current limiting circuit provided by this utility model; Figure 5 A schematic diagram of an embodiment of the fast discharge circuit provided by this utility model. Detailed Implementation
[0016] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.
[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.
[0018] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.
[0019] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.
[0020] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the present invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0021] like Figure 1 As shown, also combined Figure 2 A specific embodiment of this utility model discloses an intrinsically safe power supply 10, comprising: The circuit includes a flyback circuit 110, a constant current circuit 120, a current limiting and voltage limiting module 130, and a fast discharge circuit 140.
[0022] The flyback circuit 110 is electrically connected to the current limiting and voltage limiting module 130 and the constant current circuit 120, and is used to convert the voltage of the external power supply into a DC voltage of a preset voltage level and transmit it to the constant current circuit 120 and the current limiting and voltage limiting module 130.
[0023] The flyback circuit includes at least: a flyback control chip U21; The constant current circuit 120 includes a first comparator and an optocoupler. The non-inverting input of the first comparator is electrically connected to the output of the flyback circuit, and the inverting input is electrically connected to the current limiting and voltage limiting module. The output of the first comparator is electrically connected to the input of the optocoupler, and the output of the optocoupler is electrically connected to the flyback control chip. The current limiting and voltage limiting module 130 is internally equipped with a first switch and a second comparator. One end of the first switch is electrically connected to the output terminal of the second comparator, and the other end is electrically connected to an external load. The non-inverting input terminal and the inverting input terminal of the second comparator are electrically connected to the output terminal of the flyback circuit through different voltage divider circuits. The constant current circuit 120 is used to drive the optocoupler U22 to cut off the flyback circuit when the DC voltage value is greater than the preset voltage threshold.
[0024] The current limiting and voltage limiting module 130 is used to turn off the first switch when the DC voltage value is greater than a preset voltage threshold and / or the current value in the circuit is greater than a preset current threshold.
[0025] The current limiting and voltage limiting module 130 is electrically connected to the external load, and a fast discharge circuit is also connected between the current limiting and voltage limiting module 130 and the external load. The fast discharge circuit is electrically connected to the negative terminal through the second switch and is used to transfer the electrical energy in the external load to the negative terminal when the second switch is closed.
[0026] It should be noted that the flyback circuit 110 consists of a control regulator MP3910 and supporting circuitry. The circuit design incorporates dual-channel voltage regulation and current limiting measures to handle extreme adverse conditions that may occur in practical applications, ensuring that the system can promptly trigger protection settings in such situations. The supporting isolation transformer is a self-designed wire-wound transformer. It features a ferrite core, pure copper enameled wire winding, a withstand voltage ≥3500VAC between different coils, and a thermal insulation class of B. Furthermore, the circuit includes a self-resetting fuse to prevent overheating of the transformer under extreme conditions. During maximum 12V / 3.6A discharge, the transformer temperature rise is ≤80℃.
[0027] like Figure 2 In some embodiments of this utility model, the flyback circuit 110 includes at least: an isolation transformer T1 and a first MOSFET Q3; The isolation transformer T1 includes a first primary winding, a second primary winding, and a secondary winding; The flyback control chip U21 uses the MP3910 chip and includes at least: a power input pin VIN, a drive output pin GATE, and a compensation pin COMP; the power input pin VIN is electrically connected to an external power supply, the drive output pin GATE is electrically connected to the gate of the first MOSFET Q3, and the compensation pin COMP is electrically connected to the photosensitive device of the optocoupler U22; one end of the first primary winding is electrically connected to the external power supply, and the other end is electrically connected to the drain of the first MOSFET Q3; one end of the second primary winding is electrically connected to the power input pin VIN through the first diode D16 and the filter circuit, and the other end is grounded, wherein the cathode of the first diode D16 is electrically connected to one end of the second primary winding, and the anode is electrically connected to the filter circuit; the secondary winding is electrically connected to the cathode of the light-emitting diode of the optocoupler U22, the input terminal of the constant current circuit 120, and the current limiting and voltage limiting module 130; the anode of the light-emitting diode is electrically connected to the output terminal of the constant current circuit 120.
[0028] Preferably, the filter circuit is composed of Figure 2 It is composed of R224, C156, C82 and C213.
[0029] In some embodiments of this utility model, the flyback circuit 110 further includes: a first fuse F1, a second fuse F2, and a third fuse F3; the second fuse F2 and the third fuse F3 are connected in parallel, one end of which is electrically connected to one end of the first fuse F1, and the other end is electrically connected to the power input pin VIN; the other end of the first fuse F1 is electrically connected to an external power supply.
[0030] Understandably, fuses F1, F2, and F3 constitute the self-resetting fuse mechanism of the flyback circuit 110, which can effectively prevent the transformer from overheating under extreme conditions. like Figure 3 The constant current circuit 120 includes at least: a first sampling resistor and an operational amplifier chip U23; The operational amplifier chip used is the GS8552 chip, which includes at least: Sampling input pins INA+, INA-, INB+, INB- and signal output pins OUTA, OUTB; The sampling input pin is electrically connected to the first sampling resistor, and the other end is electrically connected to the input terminal of the current limiting and voltage limiting module 130, which is used to sample the voltage input from the flyback circuit to the current limiting and voltage limiting module. The signal output pin is electrically connected to the light-emitting diode of the optocoupler.
[0031] It should be noted that the constant current circuit 120 is composed of the GS8552 chip and its auxiliary circuitry. It samples the voltage on the output circuit through a sampling resistor. When the voltage exceeds the design value, it drives the isolation optocoupler to operate, disables the MP3910 enable, and limits the circuit's energy.
[0032] Specifically, the optocoupler U22 is used to lower the voltage of the COMP pin on the MP3910, thereby disabling the MP3910's enable.
[0033] Additionally, it should be noted that the output power of the intrinsically safe power supply can be adjusted by adjusting the voltage threshold of the constant current circuit 120.
[0034] like Figure 4 In some embodiments of this utility model, the current limiting and voltage limiting module 130 includes two current limiting and voltage limiting circuits connected in series and having the same structure. Taking one of the current-limiting and voltage-limiting circuits as an example, it specifically includes: The circuit consists of a second sampling resistor Rs, a comparator REF88-1, a second MOSFET Q4, a third MOSFET U24, and a switching circuit. The second sampling resistor Rs is electrically connected to the sampling input pin IN+ of the comparator REF88-1, and is used to sample the voltage and current flowing into the current limiting and voltage limiting circuit.
[0035] The drain of the second MOSFET Q4 is electrically connected to the output terminal of the flyback circuit 110, the source is electrically connected to the switching circuit, and the gate is electrically connected to the output pin IN- of the comparator REF88-1. The source of the third MOSFET U24 is electrically connected to the output of the flyback circuit 110, the gate is electrically connected to the switching circuit, and the drain serves as the output of the voltage and current limiting circuit.
[0036] It should be noted that the current-limiting and voltage-limiting circuit determines the current and voltage in the circuit through a sampling resistor connected in series in the circuit. When the current and voltage exceed the design value, the MOSFET in the circuit will be turned off, thereby cutting off the output. This utility model uses two current-limiting and voltage-limiting circuits connected in series to form a current-limiting and voltage-limiting module. This design can cope with various foreseeable extreme situations. If either current-limiting and voltage-limiting circuit fails, the other current-limiting and voltage-limiting circuit can still effectively limit the circuit energy, ensuring the safe operation of the equipment in the underground gas environment.
[0037] Furthermore, such as Figure 4 The switching circuit includes at least: a reference voltage source and a transistor Q6; The base of transistor Q6 is electrically connected to the output terminal of the reference power supply and the output terminal of the flyback circuit 110, the collector is electrically connected to the output terminal of the flyback circuit 110, and the emitter is electrically connected to the source of the second MOSFET Q4.
[0038] Preferably, the reference voltage source is composed of a CJ431 and its matching circuit.
[0039] It should be noted that the switching circuit can also control the current-limiting and voltage-limiting circuit. Specifically, by adjusting the resistance values of resistors R1 and R2 connected to CJ431, the reference voltage of CJ431 is controlled. As the reference voltage changes, the gate voltage of transistor Q6, which serves as the turn-on voltage point, will also change. When the output of the flyback circuit 110 is overvoltage, Q6 turns on and pulls the level on the control pin of Q4 high, thereby causing Q4 to turn off, achieving voltage and current limiting.
[0040] In some embodiments of this utility model, such as Figure 5 The fast discharge circuit 140 includes at least: The second switch S2, inductor L, and second diode D2 are configured such that one end of inductor L is electrically connected to the output terminal of voltage and current limiting module 130, and the other end is grounded through the second switch S2. The cathode of D2 is electrically connected to the other end of inductor L, and the anode is electrically connected to the second switch S2.
[0041] Specifically, when the load is short-circuited, the current-limiting and voltage-limiting module shuts off its output. Simultaneously, the fast discharge circuit 140 connects to the negative terminal, dissipating the energy on the load capacitor. Furthermore, the presence of inductor L in the fast discharge circuit causes oscillation with the load capacitor, generating a voltage of -2V to -5V depending on the capacitance value, further eliminating energy from the load capacitor.
[0042] Compared with existing technologies, this utility model provides an intrinsically safe power supply that converts the voltage input from an external power source through a flyback circuit to power the load. This utility model sequentially incorporates a constant current circuit, a current-limiting and voltage-limiting module, and a fast discharge circuit between the flyback circuit and the load. By limiting the output of the flyback circuit through the constant current circuit and optocoupler, the current and voltage levels within the power supply can be effectively maintained. Simultaneously, in the event of a short circuit, the comparator within the current-limiting and voltage-limiting module disconnects the first switch between the module and the flyback circuit, achieving overcurrent and overvoltage protection and limiting energy output. Furthermore, by closing the second switch on the fast discharge circuit, electrical energy from the load can be transferred to the fast discharge circuit, further eliminating short-circuit energy. With these multiple protection mechanisms, this utility model can provide greater and more reliable power even after passing a spark test. This design meets the relevant requirements of GB / T 3836.4 and can pass the spark test. The circuit output power is adjustable and controllable, providing technical support for high-power intrinsically safe electrical equipment. This solution can be integrated into the control board of intrinsically safe electrical equipment, or you can purchase finished intrinsically safe power supply components from our company. The solution is open and transparent.
[0043] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model should be included within the protection scope of the present utility model.
Claims
1. An intrinsically safe power supply, characterized in that, include: Flyback circuit, constant current circuit, current limiting and voltage limiting module, and fast discharge circuit; The flyback circuit is electrically connected to the current limiting and voltage limiting module and the constant current circuit, and is used to convert the voltage of the external power supply into a DC voltage of a preset voltage level and then transmit it to the constant current circuit and the current limiting and voltage limiting module respectively. The flyback circuit includes at least: a flyback control chip; The constant current circuit includes a first comparator and an optocoupler. The non-inverting and inverting inputs of the first comparator are electrically connected to the output of the flyback circuit through different voltage divider circuits. The output of the first comparator is electrically connected to the input of the optocoupler. The output of the optocoupler is electrically connected to the enable pin on the flyback control chip. The current limiting and voltage limiting module is equipped with a first switch and a second comparator. One end of the first switch is electrically connected to the output terminal of the second comparator, and the other end is electrically connected to an external load. The non-inverting input terminal and the inverting input terminal of the second comparator are also electrically connected to the output terminal of the flyback circuit through different voltage divider circuits. The constant current circuit is used to drive the optocoupler to turn off the flyback control chip when the first comparator detects that the DC voltage value is greater than a preset voltage threshold. The current limiting and voltage limiting module is used to turn off the first switch when the second comparator detects that the DC voltage value is greater than a preset voltage threshold and / or the current value in the circuit is greater than a preset current threshold. A fast discharge circuit is also connected between the current limiting and voltage limiting module and the external load. The fast discharge circuit is electrically connected to the negative terminal through a second switch and is used to transfer electrical energy from the external load to the negative terminal when the second switch is closed.
2. The intrinsically safe power supply according to claim 1, characterized in that, The flyback circuit includes at least: an isolation transformer and a first MOSFET; The isolation transformer includes a first primary winding, a second primary winding, and a secondary winding; The flyback control chip includes at least: a power input pin, a drive output pin, and a compensation pin; The power input pin is electrically connected to an external power supply, the drive output pin is electrically connected to the gate of the first MOS transistor, and the compensation pin is electrically connected to the photosensitive device of the optocoupler. One end of the first primary winding is electrically connected to the external power supply, and the other end is electrically connected to the drain of the first MOS transistor. One end of the second primary winding is electrically connected to the power input pin through the first diode and the filter circuit in sequence, and the other end is grounded. The cathode of the first diode is electrically connected to one end of the second primary winding, and the anode is electrically connected to the filter circuit. The secondary winding is electrically connected to the cathode of the light-emitting diode of the optocoupler, the constant current circuit, and the input terminal of the current-limiting and voltage-limiting module. The anode of the light-emitting diode is electrically connected to the output terminal of the constant current circuit.
3. The intrinsically safe power supply according to claim 2, characterized in that, The flyback control chip is the MP3910 chip.
4. The intrinsically safe power supply according to claim 2, characterized in that, The isolation transformer uses a ferrite core, is wound with pure copper enameled wire, has a withstand voltage of ≥3500VAC between different coils, and has a thermal insulation class of B.
5. The intrinsically safe power supply according to claim 2, characterized in that, The flyback circuit also includes: a first fuse, a second fuse, and a third fuse; The second fuse and the third fuse are connected in parallel, with one end of the parallel connection electrically connected to one end of the first fuse and the other end electrically connected to the power input pin. The other end of the first fuse is electrically connected to the external power supply.
6. The intrinsically safe power supply according to claim 1, characterized in that, The constant current circuit includes at least: a first sampling resistor and an operational amplifier chip; An operational amplifier chip includes at least: a sampling input pin and a signal output pin; One end of the first sampling resistor is electrically connected to the sampling input pin, and the other end is electrically connected to the input terminal of the current limiting and voltage limiting module, for sampling the voltage input from the flyback circuit to the current limiting and voltage limiting module; The signal output pin is electrically connected to the light-emitting diode of the optocoupler.
7. The intrinsically safe power supply according to claim 6, characterized in that, The operational amplifier chip used is GS8552.
8. The intrinsically safe power supply according to claim 1, characterized in that, The current limiting and voltage limiting module includes two series-connected current limiting and voltage limiting circuits with identical structures. The current limiting and voltage limiting circuit includes: Sampling resistor, comparator, second MOSFET, third MOSFET, and switching circuit; The sampling resistor is electrically connected to the sampling input pin of the comparator and is used to sample the voltage and current flowing into the current limiting and voltage limiting circuit. The drain of the second MOS transistor is electrically connected to the output terminal of the flyback circuit, the source is electrically connected to the switching circuit, and the gate is electrically connected to the output pin of the comparator. The source of the third MOS transistor is electrically connected to the output terminal of the flyback circuit, the gate is electrically connected to the switching circuit, and the drain serves as the output terminal of the current limiting and voltage limiting circuit. The switching circuit includes at least: a reference voltage source and a transistor; The base of the transistor is electrically connected to the output terminal of the reference voltage source and the output terminal of the flyback circuit, the collector is electrically connected to the output terminal of the flyback circuit, and the emitter is electrically connected to the source of the second MOS transistor.
9. The intrinsically safe power supply according to claim 8, characterized in that, The fast discharge circuit includes at least: a second switch and an inductor; One end of the inductor is electrically connected to the output terminal of the current limiting and voltage limiting circuit, and the other end is grounded through the second switch.
10. The intrinsically safe power supply according to claim 9, characterized in that, The fast discharge circuit also includes: The second diode has its cathode electrically connected to the other end of the inductor and its anode electrically connected to the second switch.