阅读说明：本技术 一种耐高压隔离的触点检测电路 (High-voltage-resistant isolated contact detection circuit ) 是由 邢素堂 周林春 董玉龙 于 2020-07-16 设计创作，主要内容包括：本公开涉及一种耐高压隔离的触点检测电路,包括依次级联的电源逆变隔离电路(1)、触点动作电路(3)、信号光电隔离电路(4),所述电源逆变隔离电路(1)用于将直流输入电压转换为交流输出电压,并将所述交流输出电压提供到所述触点动作电路(3),所述触点动作电路(3)用于根据触点的动作而对所述信号光电隔离电路(4)提供交流驱动电压,所述信号光电隔离电路(4)包括在受所述交流驱动电压驱动时发光的发光器件(V1)、以及光敏器件(C1),所述光敏器件(C1)用于在感测到所述发光器件(V1)发出的光时,输出第一电平。本公开电路简单,成本低,巧妙地实现了电路供电电源和信号输出与被检测端之间的耐高压隔离要求。(The utility model relates to a contact detection circuit of high pressure resistant isolation, including power contravariant isolating circuit (1), contact action circuit (3), signal optoelectronic isolation circuit (4) that cascade in proper order, power contravariant isolating circuit (1) is used for changing direct current input voltage into interchange output voltage, and will interchange output voltage provides contact action circuit (3), contact action circuit (3) are used for according to the action of contact and to signal optoelectronic isolation circuit (4) provide interchange drive voltage, signal optoelectronic isolation circuit (4) include receive luminous device (V1) and photosensitive device (C1) luminous when interchange drive voltage drives, photosensitive device (C1) are used for sensing the light that luminous device (V1) sent, output first level. The circuit disclosed by the invention is simple and low in cost, and skillfully meets the high-voltage-resistant isolation requirement between the circuit power supply and the signal output and detected end.)

1. A high-voltage-resistant isolated contact detection circuit comprises a power supply inversion isolation circuit (1), a contact action circuit (3) and a signal photoelectric isolation circuit (4) which are sequentially cascaded,

the power supply inversion isolation circuit (1) is used for converting direct current input voltage into alternating current output voltage and providing the alternating current output voltage to the contact action circuit (3),

the contact action circuit (3) is used for providing alternating current driving voltage for the signal photoelectric isolation circuit (4) according to the action of the contact,

the signal photoelectric isolation circuit (4) comprises a light-emitting device (V1) and a light-sensing device (C1) which emit light when driven by the alternating current driving voltage,

the light sensing device (C1) is used for outputting a first level when sensing the light emitted by the light emitting device (V1).

2. The high voltage isolation tolerant contact detection circuit of claim 1, further comprising a standard signal generation circuit (5) located at a subsequent stage of the signal opto-electronic isolation circuit (4) for converting the received first level to a first standard level signal.

3. The high voltage tolerant isolated contact detection circuit of claim 1, wherein the power inverter isolation circuit (1) comprises an isolation transformer (T1) and a control circuit.

4. The high voltage tolerant isolated contact detection circuit according to claim 1, wherein the contact action circuit (3) is composed of a first resistor (R1), a second resistor (R2), a fifth resistor (R5) and a sixth resistor (R5),

wherein the contacts include a first contact and a second contact, the action of the contacts including switching between open and short circuit states of the first and second contacts,

a first resistor (R1) is connected between a first pole and a first contact of the output end of the power inversion isolation circuit (1), a second resistor (R2) is connected between a second pole and a second contact of the output end of the power inversion isolation circuit (1),

a fifth resistor (R5) is connected between the first pole of the output end of the power supply inversion isolation circuit (1) and the first pole of the output end of the contact action circuit (3), and a sixth resistor (R6) is connected between the second pole of the output end of the power supply inversion isolation circuit (1) and the second pole of the output end of the contact action circuit (3).

5. The high voltage isolation tolerant contact detection circuit of claim 4, further comprising a third resistor (R3) and a fourth resistor (R4) between the power inverter isolation circuit (1) and the contact action circuit (3),

a third resistor (R3) is connected between the first pole of the output end of the power supply inversion isolation circuit (1) and the first pole of the input end of the contact action circuit (3), and a fourth resistor (R4) is connected between the second pole of the output end of the power supply inversion isolation circuit (1) and the second pole of the input end of the contact action circuit (3).

6. The high voltage tolerant isolated contact detection circuit of claim 4 or 5, wherein the light emitting device (V1) emits light when the first and second contacts are open and the light emitting device (V1) does not emit light when the first and second contacts are open and short.

7. The high voltage tolerant isolated contact detection circuit of claim 1, wherein said light sensitive device (C1) is a phototransistor or a photoresistor.

8. The high voltage tolerant isolated contact detection circuit of claim 2, wherein the standard signal generating circuit (5) comprises a comparator (U1A) and a follower (U1B) cascaded in sequence, the first standard level signal being a low level signal.

Technical Field

The invention belongs to the technical field of electronic circuit design of explosion-proof electrical appliances, and particularly relates to a high-voltage-resistant isolated contact detection circuit.

Background

Contact signals are the most common way in signal transmission, and are divided into active contacts and passive contacts, and the passive contacts are usually adopted for signal output. The explosion-proof electrical apparatus is usually designed into different explosion-proof types or type combinations such as explosion-proof type, safety-increasing type, intrinsic safety type, encapsulation protection type and the like according to the requirements of GB3836 explosive environment, wherein an explosion-proof monitoring product usually adopts the intrinsic safety type with the highest safety, high-voltage control equipment such as various explosion-proof switches, control and protection products, electric actuating mechanisms and the like usually adopt the explosion-proof type, the corresponding circuit design is divided into an intrinsic safety circuit and a non-intrinsic safety circuit, different explosion-proof type equipment and circuits need to meet certain isolation voltage-withstand requirements to ensure electrical safety when being electrically connected, and usually, the electrical isolation voltage-withstand between the non-intrinsic safety circuit and the intrinsic safety circuit should meet 2U +1000V (wherein U is the working voltage of the non-intrinsic safety circuit). The explosion-proof high-voltage control equipment usually adopts a passive contact to output a signal to feed back a working state to an explosion-proof monitoring product, such as representing whether a power frequency voltage exists on a load side of the explosion-proof monitoring product. However, the explosion-proof high-voltage control device usually does not perform intrinsic safety design and related authentication on the output signal, and is a non-intrinsic safety circuit, and the intrinsic safety design has a relatively strict limitation on the power consumption of the circuit, so that an explosion-proof monitoring product serving as the detection device needs a suitable circuit to implement the isolation detection of the intrinsic safety circuit on the non-intrinsic safety circuit.

Referring to fig. 1, a conventional passive contact isolation detection principle circuit is generally composed of a photocoupler D1 and a dc power converter D2 as cores, wherein the left and right parts of the dotted line are respectively a non-intrinsic safety circuit and an intrinsic safety circuit, the DC power converter D2 is used for generating power supplies VCC and GND which are isolated from a system power supply VDD and VSS and used as excitation driving power supplies of passive contacts, the power supply isolation of the non-intrinsic safety circuit and the intrinsic safety circuit is realized, the passive contacts are detected by a detection circuit which is formed by a resistor R1 and a light emitting diode part of a photoelectric coupler D1, the photoelectric coupler D1 is used for transmitting the detection signal of the non-intrinsic safety circuit to the intrinsic safety circuit through photoelectric coupling, so that the signal isolation between the non-intrinsic safety circuit and the intrinsic safety circuit is realized, and finally, the detection signal is converted into a standard TTL signal through a signal generating circuit formed by a resistor R2 and a light control transistor part of the photoelectric coupler D1 and is transmitted to the monitoring equipment. The circuit is simple in principle and structure and widely used in electronic circuits.

However, with the improvement of the industrialization level, the power supply voltage of the field device is higher and higher, the load side working voltage of the explosion-proof high-voltage control device generally reaches industrial frequency alternating current 660V, even up to 1140V, the passive contact detection circuit has lower power isolation withstand voltage realized by a direct current power converter, generally below 500V, and the direct current-direct current conversion efficiency is lower, the power consumption of the circuit is higher, the isolation withstand voltage level of the circuit is improved, the cost and the technical complexity for reducing the power consumption are higher, and the requirement of detecting the passive contact by an intrinsic safety circuit with high withstand voltage isolation performance of an explosion-proof monitoring product is not met.

Disclosure of Invention

Aiming at the problem of insufficient voltage-resistant isolation level of the passive contact detection circuit, the invention provides the high-voltage-resistant isolated contact detection circuit which is simple in structure, low in technical complexity, high-voltage-resistant isolation and low in power consumption, and meets the requirements of intrinsic safety detection and high-voltage-resistant isolation on non-intrinsic safety passive contacts in an explosion-proof monitoring product.

According to the embodiment of the invention, the high-voltage-resistant isolated contact detection circuit comprises a power supply inversion isolation circuit (1), a contact action circuit (3) and a signal photoelectric isolation circuit (4) which are sequentially cascaded, the power supply inversion isolation circuit (1) is used for converting direct current input voltage into alternating current output voltage, and supplies the AC output voltage to the contact point action circuit (3), the contact point action circuit (3) is used for supplying AC driving voltage to the signal photoelectric isolation circuit (4) according to the action of the contact point, the signal photoelectric isolation circuit (4) comprises a light-emitting device (V1) and a light-sensing device (C1) which emit light when driven by the alternating current driving voltage, the light sensing device (C1) is used for outputting a first level when sensing the light emitted by the light emitting device (V1).

According to the embodiment of the invention, the high-voltage-resistant isolated contact detection circuit further comprises a standard signal generating circuit (5) which is positioned at the rear stage of the signal photoelectric isolating circuit (4) and is used for converting the received first level into a first standard level signal.

According to the embodiment of the invention, the power supply inversion isolation circuit (1) comprises an isolation transformer (T1) and a control circuit.

According to an embodiment of the present invention, the contact action circuit (3) is composed of a first resistor (R1), a second resistor (R2), a fifth resistor (R5) and a sixth resistor (R5), wherein the contacts include a first contact and a second contact, the action of the contacts includes switching between open and short circuit states of the first contact and the second contact, the first resistor (R1) is connected between a first pole of the output terminal of the power inversion isolation circuit (1) and the first contact, the second resistor (R2) is connected between a second pole of the output terminal of the power inversion isolation circuit (1) and the second contact, the fifth resistor (R5) is connected between a first pole of the output terminal of the power inversion isolation circuit (1) and a first pole of the output terminal of the contact action circuit (3), and the sixth resistor (R6) is connected between a second pole of the output terminal of the power inversion isolation circuit (1) and the contact action circuit: (R6) 3) Between the second poles of the output terminals.

According to the embodiment of the invention, the high voltage resistant isolated contact detection circuit further comprises a third resistor (R3) and a fourth resistor (R4) which are positioned between the power supply inversion isolation circuit (1) and the contact action circuit (3), wherein the third resistor (R3) is connected between a first pole of the output end of the power supply inversion isolation circuit (1) and a first pole of the input end of the contact action circuit (3), and the fourth resistor (R4) is connected between a second pole of the output end of the power supply inversion isolation circuit (1) and a second pole of the input end of the contact action circuit (3).

According to an embodiment of the present invention, the light emitting device (V1) emits light when the first and second contacts are open-circuited, and the light emitting device (V1) does not emit light when the first and second contacts are open-circuited.

According to an embodiment of the present invention, the photosensitive device (C1) is a phototransistor or a photoresistor.

According to an embodiment of the present invention, the standard signal generating circuit (5) includes a comparator (U1A) and a follower (U1B) which are sequentially cascaded, and the first standard level signal is a low level signal.

The invention has the advantages and beneficial effects that:

1. the invention converts the isolation voltage-resistant design between the input and the output of the direct current converter into the isolation voltage-resistant design of the power inverter transformer through a reasonable circuit structure, the transformer isolation is a common reliable isolation means, a power isolation circuit with high voltage resistance can be easily obtained by adjusting the transformer parameters, and the photoelectric isolation of signals is a common high voltage-resistant isolation technology which can be easily realized, thereby skillfully realizing the high voltage-resistant isolation requirement between a circuit power supply and the signal output and the detected end;

2. according to the invention, the design that the excitation driving power supply is generated by the direct current-direct current isolation conversion is converted into the direct current-alternating current inversion conversion to generate the alternating voltage to drive the passive contact and the detection circuit, so that the power conversion efficiency is improved, and the power consumption of the circuit is reduced, thereby realizing the low-power-consumption operation of the circuit and meeting the requirement of the intrinsic safety design on the low power consumption of the circuit;

3. the invention has simple circuit and low cost, the excitation drive circuit and the contact detection circuit only adopt simple resistance circuits, has extremely high safety, has extremely low requirements on the structure and the power of an inverter circuit, and is suitable for various specific inverter realization circuits;

4. the AC excitation driving mode provided by the invention has the additional beneficial effect of prolonging the service life of a photoelectric coupling device or a light emitting tube.

Drawings

FIG. 1 is a schematic diagram of a passive contact isolation detection circuit in the prior art;

FIG. 2 is a block diagram of a passive contact detection circuit according to an embodiment of the present invention;

fig. 3 is a schematic diagram of the power inverter isolation circuit 1 according to an embodiment of the invention;

FIG. 4 is a schematic diagram of the contact action circuit 3 according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a photo-isolation circuit 4 according to an embodiment of the invention;

FIG. 6 is a schematic diagram of a specific general configuration of a passive contact sensing circuit according to an embodiment of the present invention;

fig. 7 is a schematic structural block diagram of a power inverter circuit according to an embodiment of the present invention.

Detailed Description

The following describes the embodiments in further detail with reference to the accompanying drawings.

It will be appreciated by those skilled in the art that while the following description refers to numerous technical details of embodiments of the present invention, this is by way of example only, and not by way of limitation, to illustrate the principles of the invention. The present invention can be applied to places other than the technical details exemplified below as long as they do not depart from the principle and spirit of the present invention.

In addition, in order to avoid limiting the description of the present specification to a great extent, in the description of the present specification, it is possible to omit, simplify, and modify some technical details that may be obtained in the prior art, as would be understood by those skilled in the art, and this does not affect the sufficiency of disclosure of the present specification.

The principles of the present invention are first summarized.

According to an embodiment of the present invention, a detection circuit includes: the device comprises a power supply inversion isolation circuit, an excitation driving circuit, a contact detection circuit, a signal photoelectric isolation circuit and a standard signal generation circuit. The power supply inversion isolation circuit inverts an intrinsically safe direct current power supply into an alternating current power supply, the alternating current power supply drives a detected passive contact and a contact detection circuit through an excitation driving circuit, the opening and closing state of the detected passive contact is converted into the extinguishing and lighting of a light emitting tube in the signal photoelectric isolation circuit under the excitation of alternating current voltage, the change of a corresponding optical signal excites the on-off of an electric signal at the output end of a transistor in the signal photoelectric isolation circuit, and the electric signal is transmitted to a standard signal generation circuit through the electric-optical-electric conversion and isolation to generate intrinsically safe standard signal output.

The circuit converts intrinsically safe direct-current voltage into alternating-current power supply through the inversion principle, improves the isolation withstand voltage level of the inverter isolation transformer through adjusting transformer parameters, is easy to realize that the phenomena of flashover and flashover do not occur between the input and the output of the circuit under the condition of 4.2kV (AC), and greatly improves the isolation high-voltage resistance of the power circuit. Meanwhile, the tested passive contact is driven by the direct current-alternating current conversion and the alternating voltage excitation, so that the power conversion efficiency is improved, the power consumption of the excitation driving circuit and the contact detection circuit is reduced, the power consumption of the circuit is greatly reduced, and the requirement of the intrinsic safety design on the power consumption is met. The photoelectric isolation of the signal can easily realize the isolation voltage-resistant performance of more than 4.2V (AC).

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 2 is a block diagram of a passive contact detection circuit according to an embodiment of the present invention.

The circuit comprises a power isolation circuit 1, a tested passive contact and a contact action circuit 3 are driven by an excitation driving circuit 2, the contact action circuit 3 transmits a detected signal to a signal photoelectric isolation circuit 4, the isolated output signal is transmitted to a standard signal generating circuit 5, and finally, the standard signal generating circuit generates a standard signal to be output.

Fig. 3 to 5 are schematic circuit structures of main parts provided by an embodiment of the present invention, and fig. 6 is a schematic circuit structure of a passive contact detection circuit provided by an embodiment of the present invention.

Referring to fig. 3, the power inverter isolation circuit 1 converts the intrinsically safe DC power supply DC into the AC voltage AC through the isolation transformer T1 and the control circuit, etc., and the isolation between the AC and the DC is realized through T1, the circuit isolation withstand voltage design is simplified to the transformer isolation withstand voltage design, and the adjustment of the transformer isolation performance parameters easily meets the withstand voltage capability of 4.2v (AC). For example, fig. 7 is a schematic block diagram of a power inverter circuit, and the power inverter isolation circuit 1 may be implemented by any suitable specific circuit structure.

Referring to fig. 4, the resistors R1, R2, R5, R6 and the light emitting tube V1 constitute a passive contact operating circuit 3, the AC voltage AC drives the passive contacts contact1, contact1 to be measured and the passive contact detecting circuit by the excitation driving circuit 2, the light emitting tube V1 is lit when the contacts are open, and the light emitting tube V1 is off when the contacts are closed, so that the light signal indicates the open/closed state of the contacts.

Referring to fig. 5, the optical signal variation is applied to the photosensor C1 in the signal photoelectric isolation circuit 4, and the electrical signal at the output end of the photosensor C1 is switched with the optical signal, thereby realizing the electro-optic-electrical conversion and isolation of the detection signal.

Referring to fig. 6, the present embodiment uses dc 5V power supply, and dc 5V power supply is implemented by 12: the 220 power supply inverter isolation circuit 1 obtains 91.6V alternating current excitation voltage, when a detected passive contact is open-circuited, the excitation voltage is applied to two ends of a light emitting tube V1 in the signal photoelectric isolation circuit 4 through the contact action circuit 3, the light emitting tube V1 is lighted, the signal photoelectric isolation circuit 4 outputs low level, and the low level outputs a standard 0V low level signal after passing through a comparator U1A and a follower U1B in a standard signal generating circuit 5; when the tested passive contact is open-circuited, the alternating-current excitation voltage is applied to the passive contact to directly form a loop, the light-emitting tube V1 is turned off, the signal photoelectric isolation circuit 4 outputs a high level, and the high level outputs a standard 5V high-level signal after passing through the comparator U1A and the follower U1B in the standard signal generating circuit 5.

Through power isolation and signal isolation, the left side and the right side of the dotted line realize better high-voltage-resistant isolation, namely, the high-voltage-resistant isolation between the detection equipment end and the detected passive contact is realized.

From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the scope of the invention. Those skilled in the art will appreciate that the operations and routines depicted in the flowchart steps or described herein may be varied in many ways. More specifically, the order of the steps may be rearranged, the steps may be performed in parallel, the steps may be omitted, other steps may be included, various combinations of routines may be made, or omitted. Accordingly, the invention is not to be restricted except in light of the attached claims.