阅读说明：本技术 本安型供电电路及本安型通信网络设备 (Intrinsic safety type power supply circuit and intrinsic safety type communication network equipment ) 是由 熊伟 李耀军 张剑 钱小涛 李文成 于 2020-04-24 设计创作，主要内容包括：本发明公开一种本安型供电电路及本安型通信网络设备,本安型供电电路包括：本安型电源处理电路；多路DC-DC电路,多路DC-DC电路的输入端分别与本安型电源处理电路的输出端连接；次级电压保护电路,次级电压保护电路与多路DC-DC电路连接,次级电压保护电路用于在检测到多路DC-DC电路任意一路输出的电压过压时,输出触发信号；本安型电源处理电路,还用于在接收到触发信号时,停止电源输出。本发明有利于提高本安型供电电路的稳定性和安全性。(The invention discloses an intrinsic safety type power supply circuit and intrinsic safety type communication network equipment, the intrinsic safety type power supply circuit includes: an intrinsic safety type power supply processing circuit; the input ends of the multi-path DC-DC circuit are respectively connected with the output end of the intrinsic safety type power supply processing circuit; the secondary voltage protection circuit is connected with the multi-path DC-DC circuit and is used for outputting a trigger signal when detecting that the voltage output by any one path of the multi-path DC-DC circuit is overvoltage; the intrinsic safety type power supply processing circuit is also used for stopping power supply output when receiving the trigger signal. The invention is beneficial to improving the stability and the safety of the intrinsic safety type power supply circuit.)

1. An intrinsically safe power supply circuit, comprising:

an intrinsic safety type power supply processing circuit;

the input ends of the DC-DC circuits are respectively connected with the output end of the intrinsic safety type power supply processing circuit;

the secondary voltage protection circuit is connected with the multiple paths of DC-DC circuits and is used for outputting a trigger signal when detecting that the voltage output by any one path of the multiple paths of DC-DC circuits is overvoltage;

the intrinsic safety type power supply processing circuit is also used for stopping power supply output when receiving the trigger signal.

2. The intrinsically safe power supply circuit of claim 1, wherein the secondary voltage protection circuit comprises:

the secondary voltage detection control circuit is used for outputting a trigger control signal when detecting that the voltage output by any one of the DC-DC circuits is overvoltage;

the controlled end of the overvoltage protection trigger circuit is connected with the control end of the secondary voltage detection control circuit; and the overvoltage protection trigger circuit is used for disconnecting the voltage output of the intrinsic safety type power supply processing circuit when receiving the trigger control signal and outputting a trigger signal so as to trigger the intrinsic safety type power supply processing circuit to stop the power supply output.

3. The intrinsically safe power supply of claim 2, wherein the secondary voltage sense control circuit comprises a plurality of secondary voltage sense control branches, each of the secondary voltage sense control branches coupled to an output of one of the DC-DC circuits.

4. The intrinsically safe power supply circuit of claim 3, wherein each secondary voltage detection control branch comprises a voltage detection circuit and a switch controller, a detection terminal of the voltage detection circuit is connected with an output terminal of the corresponding DC-DC circuit, and an output terminal of the voltage detection circuit is connected with a voltage feedback terminal of the switch controller; the control end of the switch controller is connected with the controlled end of the overvoltage protection trigger circuit;

the voltage detection circuit is used for detecting the voltage output by the DC-DC circuit and outputting a voltage detection signal;

and the switch controller is used for triggering the overvoltage protection trigger circuit to disconnect the voltage output of the intrinsic safety type power supply processing circuit when the voltage output by the DC-DC circuit is determined to be overvoltage according to the voltage value corresponding to the voltage detection signal and a preset voltage threshold.

5. The intrinsically safe power supply circuit of claim 4, wherein the voltage detection circuit comprises a first resistor and a second resistor, a first terminal of the first resistor is a detection terminal of the voltage detection circuit, the first resistor is grounded via the second resistor, and a common terminal of the first resistor and the second resistor is an output terminal of the voltage detection circuit.

6. The intrinsically safe power supply circuit of claim 2, wherein the over-voltage protection trigger circuit comprises a switching circuit, a zener diode, and a thyristor, wherein the controlled terminal of the switching circuit is the controlled terminal of the over-voltage protection trigger circuit, wherein the input terminal of the switching circuit is interconnected with the output terminal of the intrinsically safe power processing circuit and the anode of the thyristor, and the output terminal of the switching circuit is connected with the cathode of the zener diode; the anode of the voltage stabilizing diode is grounded and is connected with the control electrode of the thyristor; the cathode of the thyristor is grounded.

7. The intrinsically safe power supply circuit of claim 6, wherein the over-voltage protection trigger circuit further comprises a pull-down resistor and a current-limiting resistor, wherein a first end of the current-limiting resistor is interconnected with the zener diode and a first end of the pull-down resistor, and a second end of the current-limiting resistor is connected with the control electrode of the thyristor; the second end of the pull-down resistor is grounded.

8. An intrinsically safe supply circuit as claimed in claim 6, wherein the switching circuit comprises any one or more of a triode, a MOS transistor, an optocoupler and a relay.

9. The intrinsically safe power supply circuit of any one of claims 1 to 8, further comprising a primary voltage protection circuit, wherein the detection terminal and the input terminal of the primary voltage protection circuit are connected to the output terminal of the intrinsically safe power processing circuit, and the output terminal of the primary voltage protection circuit is grounded;

the primary voltage protection circuit is used for detecting the output voltage of the intrinsically safe power supply processing circuit, disconnecting the voltage output of the intrinsically safe power supply processing circuit when detecting the overvoltage of the output voltage of the intrinsically safe power supply processing circuit, and triggering the intrinsically safe power supply processing circuit to stop the power supply output.

10. An intrinsically safe communication network device comprising a switching chip and an intrinsically safe power supply circuit as claimed in any one of claims 1 to 9;

the intrinsic safety type power supply circuit is connected with the multi-path power supply input end of the exchange chip.

Technical Field

The invention relates to the technical field of power supplies, in particular to an intrinsic safety type power supply circuit and intrinsic safety type communication network equipment.

Background

In special industries such as coal or mines, the requirement on safety performance in products is high, and the whole product cannot have ignition risk due to high temperature or sparks under any condition. When the DC-DC circuit is short-circuited to the ground or two or more DC-DC circuits having different output voltages are short-circuited to exceed the withstand voltage of the load, such as a chip or other devices, is easily damaged to generate high temperature and even spark, and the safety of the product is poor.

Disclosure of Invention

The invention mainly aims to provide an intrinsic safety type power supply circuit and intrinsic safety type communication network equipment, and aims to improve the stability and safety of the intrinsic safety type power supply circuit.

To achieve the above object, the present invention provides an intrinsically safe power supply circuit, including:

an intrinsic safety type power supply processing circuit;

the input ends of the DC-DC circuits are respectively connected with the output end of the intrinsic safety type power supply processing circuit;

the secondary voltage protection circuit is connected with the multiple paths of DC-DC circuits and is used for outputting a trigger signal when detecting that the voltage output by any one path of the multiple paths of DC-DC circuits is overvoltage;

the intrinsic safety type power supply processing circuit is also used for stopping power supply output when receiving the trigger signal.

Optionally, the secondary voltage protection circuit comprises:

the secondary voltage detection control circuit is used for outputting a trigger control signal when detecting that the voltage output by any one of the DC-DC circuits is overvoltage;

the controlled end of the overvoltage protection trigger circuit is connected with the control end of the secondary voltage detection control circuit; and the overvoltage protection trigger circuit is used for disconnecting the voltage output of the intrinsic safety type power supply processing circuit when receiving the trigger control signal and outputting a trigger signal so as to trigger the intrinsic safety type power supply processing circuit to stop the power supply output.

Optionally, the secondary voltage detection control circuit includes multiple secondary voltage detection control branches, and each secondary voltage detection control branch is connected to an output terminal of one of the DC-DC circuits.

Optionally, each secondary voltage detection control branch comprises a voltage detection circuit and a switch controller, a detection end of the voltage detection circuit is connected with an output end of the corresponding DC-DC circuit, and an output end of the voltage detection circuit is connected with a voltage feedback end of the switch controller; the control end of the switch controller is connected with the controlled end of the overvoltage protection trigger circuit;

the voltage detection circuit is used for detecting the voltage output by the DC-DC circuit and outputting a voltage detection signal;

and the switch controller is used for triggering the overvoltage protection trigger circuit to disconnect the voltage output of the intrinsic safety type power supply processing circuit when the voltage output by the DC-DC circuit is determined to be overvoltage according to the voltage value corresponding to the voltage detection signal and a preset voltage threshold.

Optionally, the voltage detection circuit includes a first resistor and a second resistor, a first end of the first resistor is a detection end of the voltage detection circuit, the first resistor is grounded via the second resistor, and a common end of the first resistor and the second resistor is an output end of the voltage detection circuit.

Optionally, the overvoltage protection trigger circuit includes a switching circuit, a zener diode, and a thyristor, a controlled end of the switching circuit is a controlled end of the overvoltage protection trigger circuit, an input end of the switching circuit is interconnected with an output end of the intrinsically safe power processing circuit and an anode of the thyristor, and an output end of the switching circuit is connected with a cathode of the zener diode; the anode of the voltage stabilizing diode is grounded and is connected with the control electrode of the thyristor; the cathode of the thyristor is grounded.

Optionally, the overvoltage protection trigger circuit further includes a pull-down resistor and a current-limiting resistor, a first end of the current-limiting resistor is interconnected with the zener diode and a first end of the pull-down resistor, and a second end of the current-limiting resistor is connected with the control electrode of the thyristor; the second end of the pull-down resistor is grounded.

Optionally, the switching circuit includes any one or a combination of a triode, a MOS transistor, an optocoupler, and a relay.

Optionally, the intrinsically safe power supply circuit further includes a primary voltage protection circuit, a detection end and an input end of the primary voltage protection circuit are connected to an output end of the intrinsically safe power supply processing circuit, and an output end of the primary voltage protection circuit is grounded;

the primary voltage protection circuit is used for detecting the output voltage of the intrinsically safe power supply processing circuit, disconnecting the voltage output of the intrinsically safe power supply processing circuit when detecting the overvoltage of the output voltage of the intrinsically safe power supply processing circuit, and triggering the intrinsically safe power supply processing circuit to stop the power supply output.

The invention also provides intrinsic safety type communication network equipment which comprises a switching chip and the intrinsic safety type power supply circuit;

the intrinsic safety type power supply circuit is connected with the multi-path power supply input end of the exchange chip.

The intrinsic safety type power supply circuit is provided with the intrinsic safety type power supply processing circuit, the multi-path DC-DC circuit and the secondary voltage protection circuit, wherein the secondary voltage protection circuit is connected with the multi-path DC-DC circuit, and the secondary voltage protection circuit outputs a trigger signal when detecting that the voltage output by any one path of the multi-path DC-DC circuit is overvoltage, so that the intrinsic safety type power supply processing circuit stops power supply output when receiving the trigger signal, and secondary voltage overvoltage protection is realized. The invention can avoid the problem that the chip or the device exceeds the maximum withstand voltage, or the overvoltage occurs due to the short circuit between the voltage and the ground or the short circuit between high voltage and low voltage. The stability and the safety of the intrinsic safety type power supply circuit are improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a functional block diagram of an embodiment of the intrinsically safe power supply circuit of the present invention;

FIG. 2 is a schematic diagram of functional modules of another embodiment of the intrinsically safe power supply circuit of the present invention;

FIG. 3 is a circuit diagram of an embodiment of the present invention;

FIG. 4 is a circuit diagram of another embodiment of the intrinsically safe power supply circuit of the present invention.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				10	Intrinsic safety type power supply processing circuit	31	Secondary voltage detection control circuit
20	DC-DC circuit	32	Overvoltage protection trigger circuit
				30	Secondary voltage protection circuit	40	Primary voltage protection circuit

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The invention provides an intrinsic safety type power supply circuit.

Referring to fig. 1 to 4, in an embodiment of the present invention, the intrinsically safe power supply circuit includes:

an intrinsically safe power supply processing circuit 10;

the input ends of the multiple DC-DC circuits 20 are respectively connected with the output end V-out of the intrinsic safety type power supply processing circuit 10;

the secondary voltage protection circuit 30, the secondary voltage protection circuit 30 is connected to the multiple DC-DC circuits 20, and the secondary voltage protection circuit 30 is configured to output a trigger signal when detecting that the voltage output by any one of the multiple DC-DC circuits 20 is overvoltage;

the intrinsically safe power supply processing circuit 10 is further configured to stop power supply output when receiving the trigger signal.

In this embodiment, the intrinsically safe power processing circuit 10 may be a power supply controller or an intrinsically safe power supply (intrinsically safe. by limiting the energy in the electrical circuit and incorporating the structural design of the electrical device, it is not possible to generate or meet the conditions required to ignite the source in the circuit in both normal and accident situations). The intrinsic safety type power supply processing circuit 10 can be internally provided with an input protection safety circuit connected with an external power supply, an isolation transformer, a rectifier module, a battery switch and a battery management unit, wherein the input end of the input protection safety circuit is connected with an external power supply, the output end of the input protection safety circuit is connected with the isolation transformer, the output end of the isolation transformer is connected with the input end of the rectifier module, and the output end of the rectifier module is connected with an electric switch. In other embodiments, the intrinsically safe power supply may also include a battery module, a battery switch, a battery management unit, and other mobile power supplies capable of wirelessly supplying power.

The multiple DC-DC circuits 20 may be buck DC-DC circuits 20, and each of the multiple DC-DC circuits 20 may output the same supply voltage, for example, 5V. For example, each DC-DC circuit 20 may sequentially include a DC-DC circuit 20 outputting 3.3V, a DC-DC circuit 20 outputting 5V, a DC-DC circuit 20 outputting 1.1V, a DC-DC circuit 20 outputting 0.9V, and the like. The DC-DC circuit 20 may be implemented by a buck chip and its peripheral circuits. The DC-DC circuit 20 may be a single-stage DC-DC voltage step-down or a multi-stage DC-DC voltage step-down, for example, in some loads requiring a smaller voltage, a voltage of 5V output by the single-stage DC-DC circuit 20 may be further reduced to 1.1V or 0.9V by the two-stage DC-DC circuit 20 to adapt to different load supply voltages.

It should be noted that in special industries such as coal or mine, the requirement for safety performance in the product is high, and the whole product cannot have ignition risk due to high temperature or spark under any condition. When the DC-DC circuit 20 is short-circuited to the ground, or when two or more DC-DC circuits 20 having different output voltages are short-circuited, for example, the DC-DC circuit 20 having an output of 1.1V is short-circuited with the output of the DC-DC circuit 20 having an output of 0.9V, so that the output of the DC-DC circuit 20 having an output of 0.9V is 1.1V and exceeds the withstand voltage of the load thereof, the load, such as a chip or other devices, is easily damaged to generate high temperature and even spark. At present, the intrinsically safe power supply circuit is usually provided with a primary voltage protection circuit 40 at the output end of the power supply processing circuit, and when the voltage abnormality of the output end of the power supply processing circuit is detected, the output end of the power supply processing circuit is conducted to the ground. The power supply processing circuit, such as a power supply controller or an intrinsic safety power supply, closes the output after detecting the voltage abnormality (the current becomes larger than a preset current limiting value) of the circuit, thereby realizing overvoltage protection. However, the primary voltage protection circuit 40 can only perform primary voltage overvoltage protection, i.e., overvoltage protection on the voltage at the input of the DC-DC circuit 20, but cannot perform protection when the secondary voltage is overvoltage.

In order to solve the above problem, the detection terminal of the secondary voltage protection circuit 30 of the present embodiment may be disposed at any one of the multiple DC-DC circuits 20, for example, to output a smaller voltage (0.9V), or may be disposed at each of the detection DC-DC circuits 20 to detect the respective circuit voltage outputs of the multiple DC-DC circuits 20. In addition, the secondary voltage protection circuit 30 is further provided with a preset voltage protection threshold, and the preset voltage protection threshold can be adjusted and set according to the magnitude of the output voltage of the DC-DC circuit 20. For example, when the secondary voltage protection circuit 30 detects a voltage across the DC-DC circuit 20 outputting a voltage of 0.9V, the preset voltage protection threshold may be set to any value of 0.7 to 0.8V. The secondary voltage protection circuit 30 outputs a trigger signal when detecting that the voltage of any one of the multiple DC-DC circuits 20 exceeds a preset voltage protection threshold thereof.

It is understood that the intrinsically safe power processing circuit 10 is also provided with a controller, such as a power controller, which may be a TOPjx series chip, UC3844, or the like, in which a voltage limiting function may be provided. When the secondary voltage has an overvoltage condition, the secondary voltage protection circuit 30 outputs an overvoltage trigger signal to the intrinsically safe power supply processing circuit 10, so that the trigger power supply controller stops outputting the PWM signal, and the intrinsically safe power supply processing circuit 10 stops outputting the power supply.

The intrinsic safety type power supply circuit is provided with an intrinsic safety type power supply processing circuit 10, a plurality of DC-DC circuits 20 and a secondary voltage protection circuit 30, wherein the secondary voltage protection circuit 30 is connected with the plurality of DC-DC circuits 20, and the secondary voltage protection circuit 30 outputs a trigger signal when detecting that the voltage output by any one of the plurality of DC-DC circuits 20 is overvoltage, so that the intrinsic safety type power supply processing circuit 10 stops power supply output when receiving the trigger signal, and secondary voltage overvoltage protection is realized. The invention can avoid the problem that the chip or the device exceeds the maximum withstand voltage, or the overvoltage occurs due to the short circuit between the voltage and the ground or the short circuit between high voltage and low voltage. The stability and the safety of the intrinsic safety type power supply circuit are improved.

Referring to fig. 1 to 4, in an embodiment, the secondary voltage protection circuit 30 includes:

a secondary voltage detection control circuit 31, a detection end of which is connected to the multiple DC-DC circuits 20, wherein the secondary voltage detection control circuit 31 is configured to output a trigger control signal when detecting that the voltage output by any one of the multiple DC-DC circuits 20 is overvoltage;

an overvoltage protection trigger circuit 32, a controlled end of which is connected with a control end of the secondary voltage detection control circuit 31; the overvoltage protection trigger circuit 32 is configured to disconnect the voltage output of the intrinsically safe power processing circuit 10 when receiving the trigger control signal, and output a trigger signal to trigger the intrinsically safe power processing circuit 10 to stop the power output.

In this embodiment, the secondary voltage detection control circuit 31 is configured to detect a voltage on any one of the multiple paths of DC-DC circuits 20, and output a trigger control signal to control the overvoltage protection trigger circuit 32 to operate when detecting that the voltage on any one of the multiple paths of DC-DC circuits 20 exceeds a preset voltage protection threshold. The overvoltage protection trigger circuit 32 is based on the control of the secondary voltage detection control circuit 31, and the input end of the overvoltage protection trigger circuit 32 is arranged at the output end V-out of the intrinsically safe power supply processing circuit 10, and the output end of the overvoltage protection trigger circuit 32 is grounded. When receiving the trigger control signal of the secondary voltage detection control circuit 31, the overvoltage protection trigger circuit 32 works and conducts the output end of the power supply processing circuit to the ground, so that the power supply processing circuit closes the output after detecting that the voltage of the circuit is abnormal (the current becomes larger and exceeds a preset current limit value), and overvoltage protection is realized.

Referring to fig. 1 to 4, in an embodiment, the secondary voltage detection control circuit 31 includes a plurality of secondary voltage detection control branches (not shown), and each secondary voltage detection control branch is connected to one output terminal of the DC-DC circuit 20.

In this embodiment, the number of the secondary voltage detection control branches corresponds to the number of the DC-DC circuits 20, each secondary voltage detection control branch is configured to detect an output voltage of one DC-DC circuit 20, and when it is detected that the voltage of the DC-DC circuit 20 exceeds a preset voltage protection threshold of the DC-DC circuit 20, output a trigger control signal to control the operation of the overvoltage protection trigger circuit 32.

Referring to fig. 1 to 4, in an embodiment, each of the secondary voltage detection control branches includes a voltage detection circuit 311 and a switch controller U1, a detection terminal of the voltage detection circuit 311 is connected to a corresponding output terminal of the DC-DC circuit 20, and an output terminal of the voltage detection circuit 311 is connected to a voltage feedback terminal of the switch controller U1; the control end of the switch controller U1 is connected with the controlled end of the overvoltage protection trigger circuit 32;

the voltage detection circuit 311 is configured to detect a voltage output by the DC-DC circuit 20 and output a voltage detection signal;

and the switch controller U1 is configured to trigger the overvoltage protection triggering circuit 32 to disconnect the voltage output of the intrinsically safe power processing circuit 10 when the voltage value corresponding to the voltage detection signal and the preset voltage threshold value determine that the voltage output by the DC-DC circuit 20 is overvoltage.

In this embodiment, the voltage detection circuit 311 may be implemented by a voltage division detection circuit composed of a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is the detection end of the voltage detection circuit 311, the first resistor R1 is grounded via the second resistor R2, and the common end of the first resistor R1 and the second resistor R2 is the output end of the voltage detection circuit 311. The first resistor R1 and the second resistor R2 are used for series voltage division to realize voltage detection, and according to the voltage division principle, the larger the ratio of the first resistor R1 to the second resistor R2 is, the larger the voltage divided by the first resistor R1 is. In this way, the detection signal output to the switch controller U1 can be adjusted by adjusting the resistance of the first resistor R1 and/or the second resistor R2 to adjust the sensitivity of the switch controller U1 to voltage detection.

The switch controller U1 may be implemented by a single chip, a microprocessor such as a DSP or an FPGA, and a person skilled in the art can set the voltage threshold of the voltage detection signal by integrating hardware circuits, such as a comparator, an ADC conversion circuit, and a filter, and software programs or algorithms into the switch controller U1, or by integrating software circuits, such as a comparator, an ADC conversion circuit, and a filter, or by analyzing and comparing software programs or algorithms of the received voltage detection signal. The analog voltage detection signal is converted into a digital signal by operating or executing a software program and/or module stored in the switch controller U1 and calling data stored in a memory, and the ADC conversion circuit integrated in the switch controller U1 converts the analog voltage detection signal into a digital signal, and compares, analyzes, and the like the voltage detection signal converted into the digital signal to determine whether the voltage output from the headphone DC-DC circuit 20 is overvoltage.

Referring to fig. 1 to 4, in an embodiment, the overvoltage protection trigger circuit 32 includes a switch circuit 321, a zener diode ZD1, and a thyristor ZD2, a controlled terminal of the switch circuit 321 is a controlled terminal of the overvoltage protection trigger circuit 32, an input terminal of the switch circuit 321 is interconnected with the output terminal V-out of the intrinsically safe power processing circuit 10 and an anode of the thyristor ZD2, and an output terminal of the switch circuit 321 is connected with a cathode of the zener diode ZD 1; the anode of the zener diode ZD1 is grounded and is connected with the control electrode of the thyristor ZD 2; the cathode of the thyristor ZD2 is connected to ground.

Further, the overvoltage protection trigger circuit 32 further includes a pull-down resistor R3 and a current-limiting resistor R4, a first end of the current-limiting resistor R4 is interconnected with first ends of the zener diode ZD1 and the pull-down resistor R3, and a second end of the current-limiting resistor R4 is connected with a control electrode of the thyristor ZD 2; the second terminal of the pull-down resistor R3 is connected to ground.

In this embodiment, the switch circuit 321 may be implemented by any one or a combination of a triode, a MOS transistor, an optocoupler, and a relay. The switch circuit 321 may be implemented by a single electronic switch including a transistor, a MOS transistor, an optocoupler, and a relay, or a switch circuit including the above electronic switches. The overvoltage protection trigger circuit 32 further comprises a capacitor C1, and the capacitor C1 is used as a filter capacitor of the control stage of the thyristor ZD2, so that the influence of external interference on the control stage of the thyristor ZD2 is reduced.

It should be noted that, in general, the power supply voltage of a chip such as a switch chip is small, when the thyristor ZD2 and the zener diode ZD1 are used to realize overvoltage protection, when a certain voltage is lower than the rated voltage of the zener diode ZD1 or lower than the control-level starting voltage of the thyristor ZD2, the circuit is disabled. The multi-path voltage required by many chips at present is not suitable for directly protecting the secondary voltage by using the zener diode ZD1 and the thyristor ZD2 because the multi-path voltage is lower than the reverse breakdown voltage of the zener diode ZD1 or the control-level starting voltage of the thyristor ZD2 (the control-level starting voltage of the thyristor ZD2 on the market is 3V at minimum). For this purpose, the invention arranges the secondary voltage detection control branch on the secondary voltage side, and the overvoltage protection trigger circuit 32 on the primary voltage side, and when the secondary voltage detection control branch detects the overvoltage of the secondary voltage, the overvoltage protection trigger circuit 32 is triggered to carry out turn-off protection on the primary voltage. Meanwhile, the intrinsically safe power supply processing circuit 10 turns off the output after detecting that the voltage of the circuit is abnormal (the current becomes larger than a preset current limiting value), thereby realizing protection.

In this embodiment, two outputs of the DC-DC circuit 20 are taken as an example to explain the working principles of the secondary voltage detection control branch and the overvoltage protection trigger circuit 32, and the outputs of the two outputs of the DC-DC circuit 20 are respectively labeled as V _ a and V _ B. Specifically, the voltage detection circuit 311 detects the output terminal V _ a or V _ B of the two-way DC-DC circuit 20, and outputs a voltage detection signal to the switch controller U1. The switch controller U1 compares the voltage sense signal to a stored reference voltage, i.e., a preset voltage threshold. In a normal state, the voltages output by the output terminals V _ a or V _ B of the two DC-DC circuits 20 are both smaller than the corresponding reference voltages. The switch controller U1 controls the switch circuit 321 to keep non-conducting state, at this time, the zener diode ZD1 is not broken down reversely, the thyristor ZD2 control stage is connected to ground through the current limiting resistor R4 and the pull-down resistor R3, and the thyristor ZD2 is in off state.

In an abnormal state, V _ a or V _ B in the output terminals of the two DC-DC circuits 20 is shorted to ground, and when the DC-DC circuits 20 are shorted between V _ a and V _ B, the voltage value of the lower voltage (assumed to be V _ a) is inevitably increased, and when the switch controller U1 detects that the voltage detection signal is greater than the corresponding reference voltage, the output is changed (for example, signal inversion is performed, high level is output in a normal state, and low level is output in an abnormal state, otherwise, the switching circuit 321 is in a conducting state), the primary voltage is applied to the control electrode of the thyristor ZD2 through the zener diode ZD1 and the pull-down resistor R3, and the thyristor ZD2 is conducted, so that the primary voltage is output to ground, and overvoltage protection is realized. In addition, because the voltage and the current of the path of voltage are increased instantly, the intrinsic safety power supply processing circuit carries out overcurrent protection on the voltage of the path of voltage and turns off the output.

Referring to fig. 1 to 4, in an embodiment, the intrinsically safe power supply circuit further includes a primary voltage protection circuit 40, a detection terminal and an input terminal of the primary voltage protection circuit 40 are connected to the output terminal V-out of the intrinsically safe power supply processing circuit 10, and an output terminal of the primary voltage protection circuit 40 is grounded;

the primary voltage protection circuit 40 is configured to detect an output voltage of the intrinsically safe power processing circuit 10, and when detecting that the output voltage of the intrinsically safe power processing circuit 10 is overvoltage, disconnect the voltage output of the intrinsically safe power processing circuit 10, and trigger the intrinsically safe power processing circuit 10 to stop the power output.

In this embodiment, the primary voltage protection circuit 40 can be implemented by using the overvoltage protection trigger circuit 32. Namely, the primary voltage protection circuit 40 is formed by the components of the zener diode ZD3, the thyristor ZD4, the pull-down resistor R3, the current-limiting resistor R4, and the like. Specifically, the cathode of the zener diode ZD3 is connected to the output terminal (positive terminal of the primary voltage) of the intrinsically safe power supply processing circuit, and the anode of the zener diode ZD3 is connected to the ground through the pull-down resistor R5 (kiloohm level); the anode A of the thyristor ZD2 is connected with the anode of the primary voltage, the cathode K is grounded, the control electrode G is connected with the anode of the voltage-stabilizing diode ZD3 through a current-limiting resistor R6, the primary voltage protection circuit 40 further comprises a capacitor C2, and the capacitor C2 is used as a filter capacitor of the control stage of the thyristor ZD4, so that the influence of external interference on the control stage of the thyristor ZD4 is reduced. When the thyristor ZD4G normally works, the voltage resistance of the Zener diode ZD3 is slightly higher than the normal voltage, the Zener diode ZD3 does not work, the pole of the thyristor ZD4G is connected to the ground through the current-limiting resistor R6 and the pull-down resistor R5, and the thyristor ZD4 is not conducted. When the voltage of the output end of the intrinsic safety power supply processing circuit is abnormal and exceeds the voltage withstanding value of the Zener diode ZD3, the Zener diode ZD3 is conducted. The power voltage at the output end of the intrinsically safe power supply processing circuit 10 drives the control electrode G of the thyristor ZD4 through the Zener diode ZD3 and the pull-down resistor R5, the thyristor ZD4 is turned on, and the voltage is conducted to the ground through the thyristor ZD 4. The intrinsically safe power supply processing circuit 10 turns off the output after detecting that the voltage of the circuit is abnormal (the current becomes larger than a preset current limiting value), thereby realizing protection.

The present invention further provides an intrinsically safe communication network device, which includes the switching chip 100 and the intrinsically safe power supply circuit as described above;

the intrinsically safe power supply circuit is connected with the multi-path power supply input end of the switching chip 100.

The detailed structure of the intrinsically safe power supply circuit can refer to the above embodiments, and is not described herein again; it can be understood that, because the intrinsically safe power supply circuit is used in the intrinsically safe communication network device of the present invention, the embodiment of the intrinsically safe communication network device of the present invention includes all technical solutions of all embodiments of the intrinsically safe power supply circuit, and the achieved technical effects are also completely the same, and are not described herein again.

In this embodiment, the intrinsically safe communication network device may be a switch, and may be particularly applied to communication network devices in special industries with high safety requirements, such as coal or mines.

With the rapid development of chip technology and manufacturing process, the integration level of the switching chip 100 is higher and higher, and the chip function is stronger and stronger; accompanying this is a dramatic increase in the chip supply voltage from one or two to three or more, with the chip supply voltage becoming lower (e.g., 0.9V) and the voltage-to-voltage difference becoming smaller (some chips use both 0.9V and 1.1V). In this embodiment, the switch chip 100 has a plurality of power input terminals, and the plurality of power input terminals are respectively connected to corresponding DC-DC circuits in the intrinsically safe power supply circuit.

The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.