Current and voltage signal detection port multiplexing circuit

Abstract

The present invention discloses a current and voltage signal detection port multiplexing circuit, comprising a signal input port for inputting a detection signal; the detection signal comprising a current signal or a voltage signal; a switch control circuit for generating a level control signal based on the detection signal; a first switch for enabling and controlling a transconductance loop of an operational amplifier circuit based on the level control signal; a third switch for selecting a bias voltage for the operational amplifier circuit based on the level control signal; and an operational amplifier circuit that, after enabling and controlling the switching and bias voltage selection, operationally amplifies the detection signal and outputs a voltage signal. By using two switches to change the enable and control switching of the transconductance loop of the operational amplifier circuit and the gain of the bias circuit, a single front-end signal processing circuit can process two different input signals, thus achieving multiplexing of the signal detection port processing circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of front-end circuit processing of a signal detection circuit, and in particular to a current and voltage signal detection port multiplexing circuit. Background Art

[0002] In traditional industrial applications, when input signals are of different types, such as current or voltage, separate front-end processing circuits are typically required to convert the current and voltage signals into the input range required by the ADC. Consequently, current and voltage signal detection typically require different physical input ports. This results in inconsistent numbers of voltage and current detection ports within the signal detection circuit, making it difficult to allocate channels for both signal detection when designing universal data acquisition cards. Therefore, a port processing circuit capable of multiplexing two different input signals is needed. Summary of the Invention

[0003] The purpose of the present invention is to provide a current and voltage signal detection port multiplexing circuit. By changing the enable control switching of the transconductance loop of the operational amplifier circuit and the gain of the bias circuit through two switches, different processing circuits can be converted to realize the processing of the input current signal or voltage signal; one signal port processing circuit can process two different input signals, thereby realizing the multiplexing of the signal detection port processing circuit.

[0004] The present application provides a current and voltage signal detection port multiplexing circuit, including:

[0005] A signal input port, used to input a detection signal; the detection signal includes a current signal or a voltage signal;

[0006] a switch control circuit, configured to generate a level control signal according to the detection signal;

[0007] A first switch, configured to enable and control switching of a transconductance loop of the operational amplifier circuit according to the level control signal;

[0008] a third switch, configured to select a bias voltage for the operational amplifier circuit according to the level control signal;

[0009] The operational amplifier circuit performs operational amplification on the detection signal and outputs a voltage signal after the enable control switching and the bias voltage selection.

[0010] Furthermore, the first switch is an analog switch K1A, and the third switch is a two-choose-one analog switch K2.

[0011] Furthermore, the operational amplifier circuit includes a transconductance operational amplifier U1, a resistor R0, a resistor R1, a resistor R2, a resistor R3, a resistor R6, and a resistor R7; wherein, one end of R1 is connected to the signal input port and the other end is connected to the inverting input of U1, one end of R0 is connected to the signal input port and the other end is connected to one end of K1A, the other end of K1A is grounded, one end of R2 is connected to the inverting input of U1 and the other end is connected to one end of R3, and the other end of R3 is connected to the output of U1; one end of R7 is connected to the non-inverting input of U1 and the other end is grounded, one end of R6 is connected to the non-inverting input of U1, and the other end is connected to the output of K2; the input of K2 is respectively connected to different reference input voltages.

[0012] Furthermore, the resistance of the resistor R7 is equal to that of the resistor R1.

[0013] Furthermore, it also includes:

[0014] The second switch is configured to change a feedback loop of the operational amplifier circuit according to the level control signal.

[0015] Furthermore, the second switch adopts an analog switch K1B, and the operational amplifier circuit includes resistors R4 and R5, wherein one end of R4 is grounded and the other end is connected to one end of R5, and the other end of R5 is connected to the output end of K2, and one end of K1B is connected to R2 and R3, and the other end is connected to R4 and R5.

[0016] The present invention has the beneficial effects:

[0017] The present application adds an analog switch K1A to the transconductance loop of the operational amplifier circuit to enable the transconductance circuit, thereby achieving conversion between current and voltage inputs. An analog switch K1B is added to the feedback loop to change the feedback loop of the operational amplifier circuit, thereby changing the gain coefficient of the amplifier circuit and meeting different gain requirements. An analog switch K2 is added to the bias loop of the operational amplifier circuit to select the bias voltage of the amplifier circuit. The switch control circuit outputs high and low level control signals according to the different input signals to open, close, or select the analog switches K1A, K1B, and K2, thereby enabling the same front-end signal processing circuit to process two different input signals and realize the reuse of the signal detection port processing circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the connection of the current and voltage signal detection port multiplexing function circuit of the present invention;

[0019] Figure 2 Provides a schematic diagram of a current and voltage signal detection port multiplexing circuit for an embodiment of the present invention;

[0020] Figure 3A detection port processing circuit provided in an embodiment of the present invention when the input is a current signal;

[0021] Figure 4 The embodiment of the present invention provides a detection port processing circuit when the input is a voltage signal. DETAILED DESCRIPTION

[0022] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Unless otherwise specifically stated, the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0024] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0025] Additionally, descriptions of well-known structures, functions, and configurations may be omitted for clarity and conciseness. Those skilled in the art will recognize that various changes and modifications can be made to the examples described herein without departing from the spirit and scope of the present disclosure.

[0026] Technologies, methods and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods and equipment should be considered part of the authorization specification.

[0027] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0028] Example 1

[0029] like Figure 1 As shown, this embodiment provides a current and voltage signal detection port multiplexing circuit, a signal input port for inputting a detection signal; the detection signal includes a current signal or a voltage signal;

[0030] a switch control circuit, configured to generate a level control signal according to the detection signal;

[0031] A first switch, configured to enable and control switching of a transconductance loop of the operational amplifier circuit according to the level control signal;

[0032] a third switch, configured to select a bias voltage for the operational amplifier circuit according to the level control signal;

[0033] The operational amplifier circuit performs operational amplification on the detection signal and outputs a voltage signal after the enable control switching and the bias voltage selection.

[0034] Specifically, the first switch is an analog switch K1A, and the third switch is an analog switch K2. Figure 2 As shown in the figure, a schematic diagram of a current and voltage signal detection port multiplexing circuit is given; Figure 2 In the example, the operational amplifier circuit includes a transconductance operational amplifier U1, a resistor R0, a resistor R1, a resistor R2, a resistor R3, a resistor R6, and a resistor R7; the operational amplifier circuit includes three loops:

[0035] Loop 1: The transconductance loop is composed of resistor R0 and transconductance operational amplifier U1;

[0036] Loop 2: The feedback loop is composed of resistors R1, R2, R3 and transconductance operational amplifier U1;

[0037] Loop 3: The bias loop is composed of R6, R7, and transconductance operational amplifier U1.

[0038] The resistance values ​​of the resistor R7 and the resistor R1 are equal.

[0039] In one embodiment, in order to meet the requirements of different gains of the operational amplifier circuit and achieve the change of the gain coefficient of the amplifier circuit, the multiplexing circuit is further provided with a second switch for changing the gain change of the operational amplifier circuit according to the level control signal.

[0040] Specifically, the second switch is an analog switch K1B, the operational amplifier circuit includes resistors R4 and R5, and loop 2 also includes R4 and R5. The input terminals of K2 are connected to reference voltages Vref_1.65V and Vref_3.53V, respectively.

[0041] The working principle of the present invention is:

[0042] The signal input interface J1 inputs the detection signal, which can be a current signal or a voltage signal. When the input detection signal is a current signal, the switch control circuit port C / U_CTRL outputs a high level (3.3V); at this time, after the analog switches K1A and K1B receive the high-level control signal, K1A and K1B are both closed, and after K2 receives the high-level control signal, it selects to output the reference voltage Vref_3.3V.

[0043] At this time, the circuit connection diagram is as follows Figure 3As shown, therefore, at this time, the operational amplifier amplifies the input current signal i and the output is Vadc:

[0044]

[0045] When the input detection signal is a voltage signal, the switch control circuit port inputs a low level (0V). At this time, after the analog switches K1A and K1B receive the low level control signal, K1A and K1B are both disconnected. After K2 receives the low level control signal, it selects to output the reference voltage Vref_1.65V. At this time, the circuit connection diagram is as follows Figure 4 As shown, the operational amplifier amplifies the input voltage signal Ui and outputs U o :

[0046]

[0047] In the above formula, in order to make the output V adc and U o To meet the input range required for conversion to the ADC processing circuit, appropriate resistance values ​​can be set, that is, R0~R7 select appropriate values ​​to achieve current and voltage signal detection ranges of 4~20mA and -5~5V respectively.

[0048] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Based on the technical essence of the present invention and within the spirit and principles of the present invention, any simple modification, equivalent replacement and improvement of the above embodiment shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. Current and voltage signal detection port multiplexing circuit, characterized in that: include: Signal input port, used for inputting detection signal; The detection signal includes a current signal or a voltage signal; a switch control circuit, configured to generate a level control signal according to the detection signal; A first switch, configured to enable and control switching of a transconductance loop of the operational amplifier circuit according to the level control signal; a second switch, configured to change a feedback loop of the operational amplifier circuit according to the level control signal, thereby changing a gain coefficient of the amplifier circuit; a third switch, configured to select a bias voltage for the operational amplifier circuit according to the level control signal; an operational amplifier circuit, which performs operational amplification on the detection signal and outputs a voltage signal after the enable control switching and the bias voltage selection; The operational amplifier circuit includes a transconductance loop, a feedback loop, and a bias loop; When the input detection signal is a voltage signal, the switch control circuit generates a low level, controls the first switch and the second switch to be disconnected, the feedback loop and the bias loop are both turned on, and the third switch selects to output the reference voltage Vref_1.65V; When the input detection signal is a current signal, the switch control circuit generates a high level, controls the first switch and the second switch to be closed, the transconductance loop, the feedback loop and the bias loop are all turned on, and the third switch selects to output the reference voltage Vref_3.3V.

2. The current and voltage signal detection port multiplexing circuit according to claim 1, characterized in that: The first switch is an analog switch K1A, and the third switch is a two-choose-one analog switch K2.

3. The current and voltage signal detection port multiplexing circuit according to claim 2, characterized in that: The operational amplifier circuit includes a transconductance operational amplifier U1, a resistor R0, a resistor R1, a resistor R2, a resistor R3, a resistor R6, and a resistor R7; wherein, one end of R1 is connected to the signal input port and the other end is connected to the inverting input end of U1, one end of R0 is connected to the signal input port and the other end is connected to one end of K1A, the other end of K1A is grounded, one end of R2 is connected to the inverting input end of U1 and the other end is connected to one end of R3, and the other end of R3 is connected to the output end of U1; one end of R7 is connected to the non-inverting input end of U1 and the other end is grounded, one end of R6 is connected to the non-inverting input end of U1, and the other end is connected to the output end of K2; the input ends of K2 are respectively connected to different reference input voltages.

4. The current and voltage signal detection port multiplexing circuit according to claim 3, characterized in that: The resistance of the resistor R7 is equal to that of the resistor R1.

5. The current and voltage signal detection port multiplexing circuit according to claim 1, characterized in that: The second switch uses an analog switch K1B, and the operational amplifier circuit includes resistors R4 and R5, wherein one end of R4 is grounded and the other end is connected to one end of R5, and the other end of R5 is connected to the output end of K2. One end of K1B is connected to R2 and R3, and the other end is connected to R4 and R5.

6. The current and voltage signal detection port multiplexing circuit according to claim 1, characterized in that: When the detection signal is a current signal, the input range of the current signal is 4 to 20 mA. When the detection signal is a voltage signal, the input range of the voltage signal is -5 to 5V.

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