CN213243526U

CN213243526U - Proximity switch output protection circuit

Info

Publication number: CN213243526U
Application number: CN202022263350.0U
Authority: CN
Inventors: 陈朝林
Original assignee: Mianyang Qianlong Technology Co ltd
Current assignee: Mianyang Qianlong Technology Co ltd
Priority date: 2020-10-13
Filing date: 2020-10-13
Publication date: 2021-05-18
Anticipated expiration: 2030-10-13

Abstract

The utility model discloses a proximity switch output protection circuit, which comprises a proximity switch output circuit, a second triode, a comparator, a single chip microcomputer, a third resistor, a fourth resistor and a fifth resistor, wherein a first triode emitter of the proximity switch output circuit is grounded after being connected with the third resistor, the inverting end of the comparator is connected between the first triode emitter and R9, the inverting end of the comparator is connected between the fourth resistor and the fifth resistor, the fourth resistor is connected with a power supply after the fourth resistor is connected with the fifth resistor in series, the fifth resistor is grounded, the power supply end and the ground end of the comparator are respectively connected with the power supply and the ground, the output end of the comparator is connected with the input port of the single chip microcomputer, the output port of the single chip microcomputer is connected with the base level of the second triode, the collector electrode of the second triode is connected with the base level of the first triode, the emitter of the second triode is grounded, the single chip microcomputer is connected with the power supply, the output current of the triode, thereby protecting the triode from being burnt.

Description

Proximity switch output protection circuit

Technical Field

The utility model belongs to the technical field of proximity switch, concretely relates to proximity switch output protection circuit.

Background

The proximity switch is a position switch which does not need to be in direct mechanical contact operation with a moving part, and the switch can be operated when the sensing surface of the object proximity switch reaches the action distance, so that a direct current electric appliance is driven or a control instruction is provided for a computer (plc) device. The proximity switch is a switch type sensor (i.e. a non-contact switch), has the characteristics of a travel switch and a microswitch, has sensing performance, reliable action, stable performance, quick frequency response, long service life, strong anti-interference capability and the like, and has the characteristics of water resistance, corrosion resistance and the like. The product has inductance type, capacitance type, Hall type, AC type and DC type.

The proximity switch is also called contactless proximity switch, and is an ideal electronic switching value sensor. When the metal detection body approaches to the induction area of the switch, the switch can accurately reflect the position and the stroke of the motion mechanism without contact, pressure and spark, and an electric command, even if the metal detection body is used for general stroke control, the positioning precision, the operation frequency, the service life, the convenience of installation and adjustment and the applicability to severe environment of the metal detection body are incomparable with those of a general mechanical stroke switch. The method is widely applied to machine tools, metallurgy, chemical engineering, light spinning and printing industries. The automatic control system can be used as the links of limiting, counting, positioning control, automatic protection and the like.

The inventor finds that the prior arts have at least the following technical problems in the practical use process:

the proximity switch output circuit comprises a triode, if no protective measures are taken, the output line and a power supply are short-circuited, so that the output current of the triode is very large, the triode is burnt, and the proximity switch is damaged.

Disclosure of Invention

For overcoming the not enough of above-mentioned existence, the utility model discloses an inventor constantly reforms transform and innovate through long-term exploration attempt and many times's experiment and effort, provides a proximity switch output protection circuit, and it can prevent triode output current when output line and power VCC short circuit to the protection triode can not burnt.

In order to realize the purpose, the utility model adopts the technical scheme that: a proximity switch output protection circuit is provided. The proximity switch output circuit comprises a first resistor, a second resistor, a diode, a first triode, an output line and a power supply, wherein the second resistor is connected with the positive electrode of the diode after being connected with the power supply, the negative electrode of the diode is connected with the collector electrode of the first triode, the emitter electrode of the first triode is grounded, the first resistor is connected with the base level of the first triode, and the output line is connected on a circuit between the diode and the first triode. Proximity switch output protection circuit includes proximity switch output circuit, the second triode, the comparator, a single-chip microcomputer, the third resistance, the fourth resistance, the fifth resistance, ground connection behind proximity switch output circuit's the first triode projecting pole connection third resistance, comparator inverting terminal is connected on the circuit between first triode projecting pole and the third resistance, the comparator homophase end is connected on the circuit between fourth resistance and the fifth resistance, fourth resistance connection power behind fourth resistance and the series connection of fifth resistance, fifth resistance ground connection, power and ground connection are connected respectively to comparator power end and ground terminal, the comparator output inserts the singlechip input port, the base level of second triode is connected to the singlechip output port, the base level of first triode is connected to the collecting electrode of second triode, the projecting pole ground connection of second triode, the singlechip is connected.

According to the utility model discloses a proximity switch output protection circuit, its further preferred technical scheme is: and a capacitor is arranged on a grounding circuit of the singlechip power supply.

According to the utility model discloses a proximity switch output protection circuit, its further preferred technical scheme is: and the power supply connected with the singlechip and the output of the proximity switch share a circuit or are independent circuits.

Compared with the prior art, the technical scheme of the utility model have following advantage beneficial effect:

1. be provided with protection circuit, can effectively prevent that the triode in the middle of the proximity switch from being burnt, played the effect that the protection proximity switch can not be burnt because of too big electric current when output line and power VCC short circuit.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic structural diagram of an output protection circuit of a proximity switch according to the present invention.

Fig. 2 is a schematic diagram of a conventional proximity switch output circuit.

Detailed Description

To make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention. Thus, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but is merely representative of selected embodiments of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it may not be further defined and explained in subsequent figures.

Example 1:

the preceding stage output signal refers to a switch signal (but the driving capability is low) output after detection and processing, the output signal is a switch signal (the driving capability is strong), the proximity switch output circuit converts the preceding stage output signal into the output signal, so that the loading capability of the signal is enhanced, and the proximity switch output protection circuit protects the circuit on the basis, so that the situation that the output current of the triode is too large due to the fact that the output line and a power supply are short-circuited, the triode is burnt, and the damage of the proximity switch is caused is prevented.

As shown in fig. 2, the conventional proximity switch output circuit is not provided with a protection circuit, and the proximity switch output circuit includes a first resistor R7, a second resistor R8, a diode D3, a first triode Q3, an output line, and a power supply (VCC), the second resistor R8 is connected with the power supply and then connected with the anode of the diode, the cathode of the diode is connected with the collector of the first triode, the emitter of the first triode is Grounded (GND), the first resistor R7 is connected with the base of the first triode, the output line is connected on the line between the diode and the first triode, the other end of the first resistor R7 is the input end of the preceding stage output signal, and the output line is the output end of the output signal.

As shown in fig. 1, the circuit comprises a proximity switch output circuit, a second triode Q4, a comparator, a single chip microcomputer, a third resistor R9, a fourth resistor R10 and a fifth resistor R11, wherein an emitter of a first triode of the proximity switch output circuit is connected with the third resistor R9 and then grounded, an inverting terminal of the comparator is connected to a line between an emitter of the first triode Q3 and the R9, and the comparator samples current in the line through the line; the in-phase end of the comparator is connected between a fourth resistor R10 and a fifth resistor R11, after the fourth resistor R10 is connected with the fifth resistor R11 in series, the fourth resistor R10 is connected with a power supply, the fifth resistor R11 is grounded, the fourth resistor R10 and the fifth resistor R11 are combined to determine the reference voltage of the comparator, the power supply end and the ground end of the comparator are respectively connected with the power supply and the ground, the output end of the comparator is connected to the input port P0 of the single chip microcomputer, the output port P1 of the single chip microcomputer is connected with the base level of a second triode Q4, the collector of the second triode Q4 is connected with the base level of a first triode Q3, the emitter of the second triode Q4 is grounded, the single chip microcomputer is connected with the power supply, the power supply of the single chip microcomputer can be shared by a switch output line or an independent line, and.

The use principle is as follows: as shown in fig. 1, the emitter of the first output transistor Q3 is not directly grounded, but is grounded through a third resistor R9 with a smaller resistance, and the third resistor R9 is a sampling resistor, so as to know the current of the first transistor Q3, and therefore the resistance of the resistor is smaller. When the output current of the first triode increases, the voltage between the Q3 and R9 of the first triode is output, the voltage is introduced into the reverse phase end of a comparator (U2A), and the reverse phase end of the comparator is connected with a fixed amplitude voltage (the voltage is obtained by dividing the voltage by R10 and R11, and the specific value is determined by the maximum current value allowed to be output by the first triode and the resistance value of R9). When the output current of the first triode is smaller than the allowable current, the voltage of the reverse-phase end of the comparator is smaller than the voltage of the non-phase end, and the comparator outputs high level. On the contrary, when the output current of the first triode is larger than the allowable current, the comparator outputs a low level.

The high level or the low level of comparator output introduces singlechip input port P0, and the input port is IO mouth, and when the singlechip detected that P0 mouth is the high level (output current is less than the current that allows) export P1 outputs the low level, and second triode Q4 ends, and first triode Q3 normal work. When the single chip microcomputer detects that the port P0 is at a low level (the output current is greater than the allowable current), the port P1 outputs a high level, the second triode Q4 is conducted, the current on the port R7 is increased, the base voltage of the first triode Q3 is reduced (the base voltage is less than the triode cut-off voltage), and the first triode Q3 stops working (the output current is zero). Because the single chip microcomputer responds very fast (in microsecond magnitude), the triode can not be burnt down after outputting large current for a short time. When detecting that the input port P0 is at low level, the singlechip starts a delay program (delay 10 ms-100 ms) while outputting high level at the output port P1. During the time delay, the output port P1 always outputs high level, i.e. the first transistor Q3 outputs no current. After the delay time is over, the output port P1 is changed to output low level, the first triode Q3 works normally again, if the output current is still larger than the allowable value, the output of the Q3 is cut off, the cut-off and recovery mechanism of the proximity switch is realized, and the proximity switch is effectively prevented from being burnt by overlarge current.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and to simplify the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. The first feature being "under," "below," and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or merely indicates that the first feature is at a lower level than the second feature.

The above is only a preferred embodiment of the present invention, and it should be noted that the above preferred embodiment should not be considered as limiting the present invention, and the protection scope of the present invention should be subject to the scope defined by the claims. It will be apparent to those skilled in the art that various modifications and enhancements can be made without departing from the spirit and scope of the invention, and such modifications and enhancements are intended to be within the scope of the invention.

Claims

1. A proximity switch output protection circuit comprises a first resistor, a second resistor, a diode, a first triode, an output line and a power supply, wherein the second resistor is connected with the anode of the diode after being connected with the power supply, the cathode of the diode is connected with the collector of the first triode, the emitter of the triode is grounded, the first resistor is connected with the base level of the first triode, and the output line is connected with a circuit between the diode and the first triode, the fourth resistor is connected with a power supply after being connected with the fifth resistor in series, the fifth resistor is grounded, the power supply end and the ground end of the comparator are respectively connected with the power supply and the ground, the output end of the comparator is connected with the input port of the single chip microcomputer, the output port of the single chip microcomputer is connected with the base level of the second triode, the collector electrode of the second triode is connected with the base level of the first triode, the emitter electrode of the second triode is grounded, and the single chip microcomputer is connected with the power supply.

2. The proximity switch output protection circuit as claimed in claim 1, wherein a capacitor is provided on a ground line of the power supply of the single chip microcomputer.

3. The proximity switch output protection circuit according to claim 1, wherein the power supply connected to the single chip microcomputer and the proximity switch output circuit share a line or are independent lines.