A switch quantity detection circuit compatible with both empty nodes and potential signals

Abstract

This utility model discloses a switch quantity detection circuit compatible with both no-node and potential signals, comprising: an optocoupler U1, a constant current source module, an auxiliary power supply, a diode D2, a switch quantity input terminal A, a switch quantity input terminal COM, and a signal output terminal Kin. The input terminal of the optocoupler U1 is connected to the switch quantity input terminal A, and the other input terminal of the optocoupler U1 is connected to the input terminal of the constant current source module. The output terminal of the optocoupler U1 is connected to the signal output terminal Kin. The control terminal of the constant current source module is connected to the auxiliary power supply, and the positive terminal of the auxiliary power supply is also connected to the switch quantity input terminal COM through the diode D2. Due to the use of constant current source technology, the current flowing through the optocoupler remains constant regardless of changes in external potential voltage. This prevents the optocoupler from failing to conduct completely due to excessively low voltage, and also prevents damage to the optocoupler due to excessively high voltage, thus broadening the potential detection range and improving versatility and compatibility.

Description

Technical Field

[0001] This utility model relates to the field of switch quantity detection technology, and in particular to a switch quantity detection circuit compatible with both empty nodes and potential signals. Background Technology

[0002] The continuous advancement of electronic technology and the improvement of its intelligence level have led to increasingly higher performance requirements for industrial monitoring systems, such as those in the power sector. Real-time monitoring of the operating status of various devices has become one of the core aspects of modern industry. The operating status information of these devices can all be characterized through switching signals.

[0003] Conventional switching signals mainly include no-node signals, potential signals, and switching signals output by NPN transistors (or NMOS transistors).

[0004] Currently, most commonly used methods for detecting switch signals are based on the principle of optocoupler isolation. Different dedicated circuits are required for detecting different types of switch signals. This approach has significant limitations: poor circuit versatility and compatibility, inability to use both empty node signals and potential signals, and a narrow potential range. Utility Model Content

[0005] This application provides a switch quantity detection circuit that is compatible with both empty nodes and potential signals, thereby solving the technical problems of poor versatility and narrow potential range in existing switch quantity detection circuits.

[0006] This application provides a switch quantity detection circuit compatible with both empty nodes and potential signals, including: Optocoupler U1, constant current source module, auxiliary power supply, diode D2, digital input terminal A, digital input terminal COM, signal output terminal Kin; The input terminal of the optocoupler U1 is connected to the switch input terminal A, the other input terminal of the optocoupler U1 is connected to the input terminal of the constant current source module, and the output terminal of the optocoupler U1 is connected to the signal output terminal Kin. The control terminal of the constant current source module is connected to the auxiliary power supply; The positive terminal of the auxiliary power supply is also connected to the switch input terminal COM through the diode D2, and the diode D2 is used to protect the auxiliary power supply.

[0007] The beneficial effects of the above embodiments are as follows: Due to the use of constant current source technology, the conduction current flowing through optocoupler U1 remains constant regardless of changes in external potential voltage. This prevents optocoupler U1 from failing to conduct completely due to low voltage or from being damaged due to high voltage, thus broadening the potential detection range, improving versatility and compatibility, and effectively ensuring the reliability and stability of the circuit. This circuit can reliably detect any changes in external switching signals. The circuit structure uses general-purpose electronic components, which have the advantages of low cost, strong compatibility, wide application range, and stable and reliable operation.

[0008] Based on the above embodiments, the embodiments of this application can be further improved as follows: In one embodiment of this application: the constant current source module includes: resistor R1, resistor R2, transistor Q1, transistor Q2 and diode D1, resistor R1 is used to provide base current to transistor Q2, the emitter of transistor Q2 is used to provide conduction voltage to transistor Q1, resistor R2 is used to adjust the constant current value, and diode D1 is used to protect the constant current source module.

[0009] In one embodiment of this application: pin 1 of the optocoupler U1 is connected to the switch input terminal A, pin 2 is connected to the constant current source circuit, pin 3 is grounded, and pin 4 is connected to the signal output terminal Kin.

[0010] In one embodiment of this application, it further includes a status indication module, which is connected to the output terminal of the optocoupler U1 and is used to indicate the on / off status of the switch signal.

[0011] In one embodiment of this application: the status indication module includes: a light-emitting diode L1 and a resistor R3, wherein the light-emitting diode L1 and the resistor R3 are connected in series and then connected to the output terminal of the optocoupler U1. Attached Figure Description

[0012] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0013] Figure 1 This is a circuit diagram of a switch quantity detection circuit compatible with empty nodes and potential signals in an embodiment of this application; Figure 2 The equivalent circuit diagram for a switch signal with no node input; Figure 3 This is the power supply equivalent diagram when the switching quantity is a potential signal; Figure 4 The equivalent circuit diagram is for a switching signal that is a potential signal. Detailed Implementation

[0014] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are only for illustrating the present invention and not for limiting the scope of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0015] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0016] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0017] In the description of this utility model, the illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate different embodiments or examples described in this utility model, as well as the features of different embodiments or examples.

[0018] like Figure 1 As shown, a switch quantity detection circuit compatible with empty nodes and potential signals includes: an optocoupler U1, a constant current source module, an auxiliary power supply, a diode D2, a switch quantity input terminal A, a switch quantity input terminal COM, and a signal output terminal Kin. The input terminal of the optocoupler U1 is connected to the switch quantity input terminal A, and the other input terminal of the optocoupler U1 is connected to the input terminal of the constant current source module. The output terminal of the optocoupler U1 is connected to the signal output terminal Kin. The control terminal of the constant current source module is connected to the auxiliary power supply. The positive terminal of the auxiliary power supply is also connected to the switch quantity input terminal COM through the diode D2. The diode D2 is used to protect the auxiliary power supply.

[0019] like Figure 1As shown, the auxiliary power supply has V+ (positive power supply) and V- (negative power supply). V+ and V- are connected to the control terminal and output terminal of the constant current source module, respectively, and are used to provide a stable power supply to the constant current source module. V+ is also connected to the positive terminal of diode D2, and the negative terminal of diode D2 is connected to the COM terminal of the switch input.

[0020] like Figure 1 As shown, the constant current source module includes: resistor R1, resistor R2, transistor Q1, transistor Q2 and diode D1. Resistor R1 is used to provide base current to transistor Q2, the emitter of transistor Q2 is used to provide conduction voltage to transistor Q1, resistor R2 is used to adjust the constant current value, and diode D1 is used to protect the constant current source module.

[0021] like Figure 1 As shown, transistors Q1 and Q2 are both NPN transistors. V+ is connected to one end of resistor R1, and the other end of resistor R1 is connected to the collector of transistor Q1 and the base of transistor Q2, respectively. One end of resistor R2 is connected to the positive terminal of diode D1, and the other end is connected to the base of transistor Q1 and the emitter of transistor Q2, respectively. V- is connected to the emitter of transistor Q1 and the negative terminal of diode D1, respectively. The collector of transistor Q2 is connected to the input terminal of optocoupler U1.

[0022] The working principle of the constant current source module is as follows: the current flows from the switch input terminal A to pin 1 of optocoupler U1, pin 2 of optocoupler U1, transistor Q2 (c) to transistor Q2 (e) to resistor R2, diode D1, and V-. Resistor R1 provides base current to transistor Q2, keeping it in saturation. The voltage across transistor Q2 is Vbe2 = 0.7V. After transistor Q2 is turned on, the voltage across transistor Q1 remains constant at 0.7V. Diode D1 protects the constant current source, and its voltage drop Vd1 is approximately 0.2V. The current I of the constant current source module is I = (Vbe - Vd1) / R2 = (0.7 - 0.2) / R2 = 0.5 / R2. Therefore, adjusting resistor R2 changes the magnitude of the current I.

[0023] like Figure 1 As shown, the input terminals of optocoupler U1 include pin 1 and pin 2, and the output terminals include pin 3 and pin 4. Pin 1 is connected to the switch input terminal A, pin 2 is connected to the collector of transistor Q2, pin 3 is grounded, and pin 4 is connected to the signal output terminal Kin.

[0024] like Figure 1 As shown, this switch quantity detection circuit compatible with empty nodes and potential signals further includes: a status indicator module, which is connected to the output terminal of the optocoupler U1 and is used to indicate the on / off state of the switch quantity signal.

[0025] like Figure 1 As shown, specifically, the status indicator module includes: a light-emitting diode L1 and a resistor R3. The light-emitting diode L1 and the resistor R3 are connected in series and then connected to pin 4 of the optocoupler U1.

[0026] The working principle of this switch quantity detection circuit is as follows: (1) When the switch quantity is an empty node signal When the node is closed (since COM is connected to V+, it is equivalent to COM short-circuiting A), the internal auxiliary power supply V+ is connected to the switch input terminal A. The equivalent circuit is as follows: Figure 2 As shown, at this time, V+ is applied to pin 1 of optocoupler U1 through diode D2, optocoupler U1 is turned on, LED L1 is lit, and the state of signal output terminal Kin changes from high to low. The subsequent signal processing unit (such as CPU or CPLD and other electrical components) obtains the action information and processes it. When the empty node is disconnected, optocoupler U1 is turned off, L1 is turned off, and Kin changes from low to high.

[0027] (2) When the switching quantity is a potential signal, the signal applied to pin 1 of optocoupler U1 is an external switching voltage signal. Since the switching input terminal COM of the potential signal is connected to the V+ of the internal auxiliary power supply through diode D2, this raises the actual voltage of the switching input terminal A by V+. That is, the auxiliary power supply and the switching potential Vd are connected in series. The power supply equivalent diagram is shown below. Figure 3 As shown, even if the potential signal is very small, the connection of V+ can still ensure that the optocoupler U1 can reliably conduct.

[0028] Because of the presence of diode D2, the operating power supply of the constant current source is not affected by the external switching voltage Vd, as shown in the equivalent diagram. Figure 4 As shown.

[0029] (3) When the switching quantity is an NPN transistor (or NMOS) output, the auxiliary power supply can still provide the power conditions for the transistor (NMOS) to conduct.

[0030] Thanks to the use of constant current source technology, the conduction current flowing through pins 1 and 2 of optocoupler U1 remains constant regardless of changes in external potential voltage. This prevents optocoupler U1 from failing to conduct completely due to low voltage or from being damaged due to high voltage, thus improving versatility and compatibility, and effectively ensuring the reliability and stability of the circuit.

[0031] This circuit can reliably detect any changes in the external switching signal, and it uses only general-purpose electronic components. The circuit structure is simple, the cost is low, and it is easy to use.

Claims

1. A switch quantity detection circuit compatible with air node and potential signal, characterized in that, include: Optocoupler U1, constant current source module, auxiliary power supply, diode D2, digital input terminal A, digital input terminal COM, signal output terminal Kin; The input terminal of the optocoupler U1 is connected to the switch input terminal A, the other input terminal of the optocoupler U1 is connected to the input terminal of the constant current source module, and the output terminal of the optocoupler U1 is connected to the signal output terminal Kin. The control terminal of the constant current source module is connected to the auxiliary power supply; The positive terminal of the auxiliary power supply is also connected to the switch input terminal COM through the diode D2, and the diode D2 is used to protect the auxiliary power supply.

2. The switching quantity detection circuit according to claim 1, characterized in that, The constant current source module includes: resistor R1, resistor R2, transistor Q1, transistor Q2 and diode D1. Resistor R1 is used to provide base current to transistor Q2, the emitter of transistor Q2 is used to provide conduction voltage to transistor Q1, resistor R2 is used to adjust the constant current value, and diode D1 is used to protect the constant current source module.

3. The switching quantity detection circuit according to claim 1, characterized by Pin 1 of the optocoupler U1 is connected to the switch input terminal A, pin 2 is connected to the constant current source circuit, pin 3 is grounded, and pin 4 is connected to the signal output terminal Kin.

4. The switching quantity detection circuit according to claim 1, characterized by Also includes: A status indicator module is connected to the output terminal of the optocoupler U1 and is used to indicate the on / off status of the switch signal.

5. The switching quantity detection circuit according to claim 4, characterized in that: The status indication module includes: a light-emitting diode L1 and a resistor R3. The light-emitting diode L1 and the resistor R3 are connected in series and then connected to the output terminal of the optocoupler U1.

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