Voltage output module with line loss compensation and voltage and current integrated output device

Abstract

The present invention relates to a voltage output module with line loss compensation, which is used to output a voltage control signal to a load, and includes: a voltage conversion circuit, which is used to receive a PWM signal and convert the PWM signal into a voltage control signal; and a voltage stabilization compensation circuit, which is used to receive the voltage control signal and a line loss feedback signal, and output the voltage control signal to the load after compensating the voltage control signal according to the line loss feedback signal; wherein the voltage stabilization compensation circuit includes a first operational amplifier, the first input end of the first operational amplifier is connected to the output end of the voltage conversion circuit, and the output end of the first operational amplifier is used to output the voltage control signal to the load; and the first input end of the first operational amplifier is connected to the negative line loss feedback terminal, and the second input end of the first operational amplifier is connected to the positive line loss feedback terminal. The voltage output module provided by the present invention has better control accuracy and faster response speed.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial automation and instrumentation, and in particular to a voltage output module with line loss compensation and a voltage-current integrated output device. Background Art

[0002] In the field of industrial control, analog control signal output devices are core devices in control systems and are widely used in control scenarios of field instruments. Analog control signals usually include voltage control signals and current control signals. In some situations where high control accuracy is required, the voltage control signal output by the analog control signal output device needs to have high accuracy. However, when the analog control signal output device is far away from the load, because the wire connecting the analog control signal output device and the load is too long, the impedance of the wire itself cannot be ignored. The voltage control signal generates a voltage drop after flowing through the wire, making the actual voltage value obtained at the load end lower than the preset voltage value, that is, line loss is generated. This phenomenon will affect the control accuracy of the load, and in severe cases, it will even affect the normal operation of the load.

[0003] In view of the above problems, the existing line loss compensation method usually samples and feeds back the voltage at both ends of the load, and then raises the voltage output by the analog control signal output device through software processing based on the feedback signal to compensate for the voltage loss on the long wire. However, in actual applications, the line loss compensation method that relies on software implementation has a slow response speed, and the real-time performance of line loss compensation is poor, which affects the stability of load operation. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a voltage output module with line loss compensation and a voltage-current integrated output device, which solves the technical problems of slow response speed and poor real-time performance of the existing line loss compensation method.

[0006] (II) Technical solution

[0007] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0008] In a first aspect, an embodiment of the present invention provides a voltage output module with line loss compensation, which is used to output a voltage control signal to a voltage-driven load in an industrial control system. The voltage output module includes:

[0009] A voltage conversion circuit, used for receiving a PWM (Pulse-width modulation) signal and converting the PWM signal into a voltage control signal; and a voltage stabilization compensation circuit, used for receiving the voltage control signal and a line loss feedback signal, and compensating the voltage control signal according to the line loss feedback signal and then outputting it to the load;

[0010] The voltage stabilization compensation circuit includes a first operational amplifier, a first input end of the first operational amplifier is connected to the output end of the voltage conversion circuit, and the output end of the first operational amplifier is used to output a voltage control signal to the load; and the first input end of the first operational amplifier is connected to the negative end line loss feedback terminal, and the second input end of the first operational amplifier is connected to the positive end line loss feedback terminal;

[0011] The negative-end line loss feedback terminal is used to connect to the negative end of the load, and provide a line loss feedback signal of the negative end of the load to the first operational amplifier; the positive-end line loss feedback terminal is used to connect to the positive end of the load, and provide a line loss feedback signal of the positive end of the load to the first operational amplifier;

[0012] When the load is a load that requires line loss compensation, the positive-end line loss feedback terminal is connected to the positive end of the load through a wire, and the negative-end line loss feedback terminal is connected to the negative end of the load through a wire; when the load is a load that does not require line loss compensation, the positive-end line loss feedback terminal is short-circuited to the output end of the first operational amplifier, and the negative-end line loss feedback terminal is grounded.

[0013] The voltage output module proposed in the embodiment of the present invention converts the PWM signal into a voltage control signal based on a voltage conversion circuit and then inputs the converted signal into a voltage stabilizing compensation circuit. The first operational amplifier in the voltage stabilizing compensation circuit compensates the voltage control signal according to the line loss feedback signal and then outputs the signal to the load. For the load requiring line loss compensation, the positive line loss feedback terminal and the negative line loss feedback terminal feed back the voltage drop on the wire to the input end of the first operational amplifier, so that the first operational amplifier also compensates for the voltage loss on the wire when compensating the voltage control signal, thereby ensuring the accuracy of the voltage control signal transmitted to the load end. For the load requiring line loss compensation, compared with the existing line loss compensation method based on software processing, the voltage stabilizing compensation circuit in the embodiment of the present invention is a pure hardware circuit constructed based on an operational amplifier, which is theoretically only related to the speed of the operational amplifier, and thus can make the voltage stabilizing compensation circuit have a faster response speed, thereby ensuring the real-time performance of the line loss compensation, and further ensuring the stable operation of the load.

[0014] Optionally, the negative-end line loss feedback terminal is connected to the output end of the voltage conversion circuit through a ninth resistor and a seventh resistor connected in series in sequence, and the first input end of the first operational amplifier is connected between the ninth resistor and the seventh resistor; the positive-end line loss feedback terminal is grounded through an eighth resistor and a sixth resistor connected in series in sequence, and the second input end of the first operational amplifier is connected between the eighth resistor and the sixth resistor; wherein the resistance values ​​of the sixth resistor, the seventh resistor, the eighth resistor, and the ninth resistor are all equal.

[0015] Optionally, the voltage conversion circuit includes a second operational amplifier, a first input terminal of the second operational amplifier is used to receive a PWM signal, a second input terminal of the second operational amplifier is used to receive a reference voltage signal, and the second operational amplifier is used to amplify the PWM signal into a voltage control signal based on the reference voltage signal, and then output it from the output terminal of the second operational amplifier to the voltage stabilization compensation circuit.

[0016] Optionally, the voltage conversion circuit further includes a first voltage follower and a second voltage follower;

[0017] The PWM signal is input to the first input terminal of the second operational amplifier through the first voltage follower and the third resistor connected in series in sequence, and the first input terminal of the second operational amplifier is grounded through the fourth resistor;

[0018] The reference voltage signal is input to the second input terminal of the second operational amplifier through the second voltage follower and the second resistor connected in series in sequence, and the second input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier through the fifth resistor;

[0019] Among them, the relationship between the resistance values ​​of the second resistor, the third resistor, the fourth resistor, and the fifth resistor is:

[0020]

[0021] Among them, R 2 , R 3 , R 4 , R 5 Respectively represent the resistance values ​​of the second resistor, the third resistor, the fourth resistor, and the fifth resistor.

[0022] Optionally, the first voltage follower includes a third operational amplifier, the output end of the third operational amplifier is short-circuited to the second input end of the third operational amplifier, the first input end of the third operational amplifier is used to receive the PWM signal, and the output end of the third operational amplifier is connected to the positive end of the third resistor;

[0023] The second voltage follower includes a fourth operational amplifier, the output end of the fourth operational amplifier is short-circuited to the second input end of the fourth operational amplifier, the first input end of the fourth operational amplifier is used to receive the voltage reference signal, and the output end of the fourth operational amplifier is connected to the positive end of the second resistor.

[0024] In a second aspect, an embodiment of the present invention provides a voltage-current integrated output device for outputting a voltage control signal to a voltage-driven load or a current control signal to a current-driven load in an industrial control system, wherein the integrated output device includes an MCU and at least one submodule, wherein:

[0025] The MCU is used to generate an initial PWM signal, a voltage and current gating signal, and an output gating signal; the submodule includes:

[0026] The frequency selection module is used to receive and filter the high-frequency signal in the initial PWM signal and output the PWM signal;

[0027] A voltage and current gating module, used for receiving the PWM signal and the voltage and current gating signal, and outputting the PWM signal from the voltage signal terminal or the current signal terminal according to the voltage and current gating signal;

[0028] A voltage output module, wherein the voltage output module is the voltage output module described in the first aspect, and is used to receive a PWM signal outputted by the voltage signal terminal of the voltage and current gating module, convert the PWM signal into a voltage control signal, and compensate the voltage control signal according to a line loss feedback signal before outputting it to a load;

[0029] A current output module is used to receive the PWM signal output by the current signal terminal of the voltage and current gating module, convert the PWM signal into a current control signal and output it to the load;

[0030] The output gating module is connected to the output ends of the voltage output module and the current output module respectively, and is used to output the voltage control signal output by the voltage output module or the current control signal output by the current output module from the output end according to the output gating signal.

[0031] The voltage-current integrated output device proposed in the embodiment of the present invention is built based on discrete semiconductors, and can output voltage control signals or current control signals according to user needs. It has high signal accuracy, fast response speed, and can realize multi-channel signal output, and can be applied to a wider range of usage scenarios.

[0032] Optionally, the frequency selection module is an RC frequency selection circuit;

[0033] The voltage and current gating module is an analog switch device or a relay switch device;

[0034] The output gating module is an analog switch device, a relay switch device or a PhotoMos (photoelectric coupling) switch device.

[0035] Optionally, the current output module includes: a fifth operational amplifier, a first transistor and a power supply module;

[0036] The first transistor works in an amplification state, the base of the first transistor is connected to the output end of the fifth operational amplifier, and the collector of the first transistor is connected to the output end of the power module through the first resistor;

[0037] The first input terminal of the fifth operational amplifier is used to receive the PWM signal, and the emitter of the first transistor is used to output a current control signal;

[0038] The collector of the first triode is short-circuited to the second input terminal of the fifth operational amplifier, so as to feed back the voltage change at the collector of the first triode to the fifth operational amplifier;

[0039] The power supply module includes a voltage regulating circuit, which is connected to the emitter of the first transistor and is used to receive a voltage feedback signal regarding the voltage change at the positive end of the load, and adjust the voltage at the output end of the power supply module based on the voltage feedback signal to keep the voltage across the first resistor stable.

[0040] Optionally, the first resistor is a precision resistor with low temperature drift.

[0041] Optionally, the voltage regulating circuit includes an SGM61410 chip and a second transistor,

[0042] The second transistor works in an amplification state, the base of the second transistor is connected to the emitter of the first transistor, the emitter of the second transistor is connected to the output end of the power module, and the collector of the second transistor is connected to the FB pin of the SGM61410 chip.

[0043] (III) Beneficial effects

[0044] The voltage output module proposed in the embodiment of the present invention converts the PWM signal into a voltage control signal based on the voltage conversion circuit and then inputs it into the voltage stabilization compensation circuit. The first operational amplifier in the voltage stabilization compensation circuit compensates the voltage control signal according to the line loss feedback signal and then outputs it to the load to ensure the control accuracy. Compared with the existing line loss compensation method based on software processing, the voltage stabilization compensation circuit in the embodiment of the present invention is a pure hardware circuit built based on an operational amplifier, which is theoretically only related to the speed of the operational amplifier, so that the voltage stabilization compensation circuit can have a faster response speed, thereby ensuring the real-time performance of line loss compensation.

[0045] The embodiment provided by the present invention also provides a voltage-current integrated output device, which can output voltage control signals or current control signals according to user needs, has high signal accuracy, fast response speed, and can achieve multi-channel signal output, and can be applicable to a wider range of usage scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A circuit block diagram of a voltage output module with line loss compensation provided in an embodiment;

[0047] Figure 2 A circuit diagram of a voltage output module with line loss compensation provided in an embodiment;

[0048] Figure 3 for Figure 2 Schematic diagram of the connection relationship between the voltage output module and the load in close proximity;

[0049] Figure 4 for Figure 2 Schematic diagram of the connection relationship between the voltage output module and the remote load;

[0050] Figure 5 It is a circuit block diagram of a voltage and current integrated output device;

[0051] Figure 6 It is a circuit diagram of a voltage and current gating module based on the SGM3002 chip;

[0052] Figure 7 The circuit diagram of the output gating module based on the TLP227GA-2 chip;

[0053] Figure 8 It is the circuit diagram of the current output module;

[0054] Fig. 9 It is a voltage regulation circuit based on the SGM61410 chip. DETAILED DESCRIPTION

[0055] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below in conjunction with the accompanying drawings through specific embodiments. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a clearer and more thorough understanding of the present invention and to be able to fully convey the scope of the present invention to those skilled in the art.

[0056] It should be noted that, unless otherwise specified, all modules or circuits in all embodiments of the present invention are grounded. In addition, in order to distinguish the two ends of a load, a resistor or other electronic device, the positive end and the negative end are used to describe them respectively, and the positive end and the negative end are sometimes referred to as the first end and the second end in the art.

[0057] Embodiment 1

[0058] like Figure 1 As shown, this embodiment provides a voltage output module with line loss compensation, which is used to output a voltage control signal to a voltage-driven load in an industrial control system. The voltage output module includes:

[0059] A voltage conversion circuit is used to receive a PWM signal and convert the PWM signal into a voltage control signal; and a voltage stabilization compensation circuit is used to receive the voltage control signal and a line loss feedback signal, and compensate the voltage control signal according to the line loss feedback signal before outputting it to the load.

[0060] Among them, the voltage stabilization compensation circuit includes a first operational amplifier A1, the first input terminal of the first operational amplifier A1 is connected to the output terminal of the voltage conversion circuit, and the output terminal of the first operational amplifier A1 is used to output a voltage control signal to the load; and the first input terminal of the first operational amplifier A1 is connected to the negative end line loss feedback terminal, and the second input terminal of the first operational amplifier A1 is connected to the positive end line loss feedback terminal.

[0061] The negative-end line loss feedback terminal is used to connect to the negative end of the load, and provide a line loss feedback signal of the negative end of the load to the first operational amplifier A1; the positive-end line loss feedback terminal is used to connect to the positive end of the load, and provide a line loss feedback signal of the positive end of the load to the first operational amplifier A1.

[0062] When the load is a load that requires line loss compensation, the positive line loss feedback terminal is connected to the positive end of the load through a wire, and the negative line loss feedback terminal is connected to the negative end of the load through a wire; when the load is a load that does not require line loss compensation, the positive line loss feedback terminal is short-circuited to the output end of the first operational amplifier A1, and the negative line loss feedback terminal is grounded.

[0063] It should be noted that when the voltage output module is connected to a load that requires line loss compensation, the two wires are actually wires of substantially the same length as the wire connecting the first operational amplifier A1 and the positive end of the load, and are used to reflect the voltage drop on the wire connecting the output end of the first operational amplifier A1 and the positive end of the load, so as to provide a more accurate line loss feedback signal to the input end of the first operational amplifier A1. Furthermore, whether the load requires line loss compensation is determined based on factors such as the actual control accuracy, the amplitude of the voltage control signal, the power of the load, and the resistance of the wire, wherein the resistance of the wire is related to the cross-sectional area of ​​the wire and the distance between the load and the voltage output module. For example, when the amplitude of the voltage control signal is 5V, the control accuracy is ±0.1V, and the distance between the load and the voltage output module is too long, so that the impedance on the wire has a practical impact on the above control accuracy, it is necessary to consider the line loss compensation of the wire connecting the two. The above method for determining whether the load requires line loss compensation is well known to those skilled in the art.

[0064] Specifically, in order to ensure the accuracy of the line loss feedback signal, the voltage stabilization compensation circuit in this embodiment also includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9, the negative line loss feedback terminal is connected to the output end of the voltage conversion circuit through the ninth resistor R9 and the seventh resistor R7 connected in series in sequence, and the first input end of the first operational amplifier A1 is connected between the ninth resistor R9 and the seventh resistor R7; the positive line loss feedback terminal is grounded through the eighth resistor R8 and the sixth resistor R6 connected in series in sequence, and the second input end of the first operational amplifier A1 is connected between the eighth resistor R8 and the sixth resistor R6; wherein the resistance values ​​of the sixth resistor R6, the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9 are all equal.

[0065] Generally, the resistance of the sixth resistor R6 to the ninth resistor R9 is much larger than the resistance of the wire, and the specific resistance is set according to the load to be driven. For example, when the rated voltage of the load is ±10V, the input impedance is 1kΩ, the amplitude of the rated control voltage is 5V, and the impedance of the wire is 50Ω, the resistance of the sixth resistor R6 to the ninth resistor R9 is set to 120kΩ, so that the voltage stabilization compensation circuit can accurately compensate for the voltage drop caused by the impedance on the wire.

[0066] Based on the above configuration, in the voltage output module provided by the embodiment of the present invention, the voltage stabilization compensation circuit is equivalent to a differential operational amplifier circuit with a voltage gain of 1, and provides a stable voltage control signal to the load based on a feedback line connected to the first input terminal and the second input terminal of the first operational amplifier A1. However, unlike the traditional differential operational amplifier circuit, when connecting the load that requires line loss compensation, the present embodiment feeds back the voltage at the load end to the input end of the differential operational amplifier circuit through the positive and negative line loss feedback terminals via the wire, rather than feeding back the voltage at the output end of the differential operational amplifier circuit to the input end of the differential operational amplifier circuit. Thus, while forming deep feedback based on the differential operational circuit, the wire connecting the positive and negative ends of the load with the positive and negative line loss feedback terminals is comparable in length to the wire connecting the output end of the operational amplifier with the positive end of the load, and thus their impedances are also comparable. Thus, the voltage drop caused by the wire connecting the output end of the operational amplifier with the load is also fed back to the input end of the operational amplifier through the feedback circuit, and the error of the voltage control signal caused by the voltage drop on the wire is eliminated through the operation of the operational amplifier. Thus, while the voltage output by the above-mentioned voltage stabilization compensation circuit remains stable, the voltage drop caused by the wire is also fed back and compensated, thereby achieving the purpose of line loss compensation.

[0067] The above-mentioned voltage stabilization compensation circuit is a pure hardware circuit built based on the operational amplifier A1. Theoretically, its response speed is only related to the operation speed of the operational amplifier A1. The faster the operation speed of the operational amplifier A1, the faster the response speed of the voltage stabilization compensation circuit. Therefore, compared with the existing line loss compensation method based on software processing, the voltage stabilization compensation circuit can have a faster response speed, thereby ensuring the real-time performance of line loss compensation.

[0068] Embodiment 2

[0069] In order to better understand the first embodiment, this embodiment is described in detail in conjunction with a specific circuit.

[0070] like Figure 2 As shown, this embodiment provides a voltage output module with line loss compensation, which is used to output a voltage control signal to a load, including:

[0071] A voltage conversion circuit is used to receive a PWM signal and convert the PWM signal into a voltage control signal V7; and a voltage stabilization compensation circuit is used to receive the voltage control signal V7 and the line loss feedback signal fed back by the positive line loss feedback terminal and the negative line loss feedback terminal, and output the voltage control signal from the Vout terminal to the positive end of the load after compensating the voltage control signal according to the line loss feedback signal. The voltage control signal output from the Vout terminal is represented by V12, which has the same voltage value as the output end of the first operational amplifier A1.

[0072] The voltage conversion circuit includes a first voltage follower, a second voltage follower and a second operational amplifier A2; the first input terminal of the second operational amplifier A2 is used to receive a PWM signal, and the second input terminal of the second operational amplifier A2 is used to receive a reference voltage signal Vref. The second operational amplifier A2 is used to amplify the PWM signal into a voltage control signal based on the reference voltage signal Vref, and then output it from the output terminal of the second operational amplifier A2 to the voltage stabilization compensation circuit.

[0073] The PWM signal is input into the first input terminal of the second operational amplifier A2 through the first voltage follower and the third resistor R3 connected in series, and the first input terminal of the second operational amplifier A2 is grounded through the fourth resistor R4; the reference voltage signal is input into the second input terminal of the second operational amplifier A2 through the second voltage follower and the second resistor R2 connected in series, and the second input terminal of the second operational amplifier A2 is connected to the output terminal of the second operational amplifier A2 through the fifth resistor R5;

[0074] The relationship between the resistance values ​​of the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5 is:

[0075]

[0076] Among them, R 2 , R 3 , R 4 , R 5 They respectively represent the resistance values ​​of the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5.

[0077] It should be noted that the first voltage follower and the second voltage follower are used to isolate the input signal and the output signal to ensure the stability of the output signal, and the voltage gain is 1. The first voltage follower and the second voltage follower can adopt existing voltage followers, for example, they can be voltage follower circuits based on triodes or operational amplifiers.

[0078] In a preferred implementation of the present embodiment, the first voltage follower includes a third operational amplifier A3, the output end of the third operational amplifier A3 is short-circuited to the second input end of the third operational amplifier A3, and the first input end of the third operational amplifier A3 is used to receive the PWM signal, and the output end of the third operational amplifier A3 is connected to the positive end of the third resistor R3; the second voltage follower includes a fourth operational amplifier A4, the output end of the fourth operational amplifier A4 is short-circuited to the second input end of the fourth operational amplifier A4, and the first input end of the fourth operational amplifier A4 is used to receive the voltage reference signal Vref, and the output end of the fourth operational amplifier A4 is connected to the positive end of the second resistor R2.

[0079] Based on the above voltage conversion circuit, the voltage V7 at its output end is

[0080]

[0081] Among them, V5 represents the voltage at the output end of the first voltage follower, that is, the voltage of the PWM signal; V6 represents the voltage at the output end of the second voltage follower, that is, the voltage of the reference voltage signal Vref. In the actually constructed voltage output module, Vref, the fifth resistor R5 and the second resistor R2 are all pre-set fixed values, so the voltage of V6 can be changed by adjusting the PWM signal, thereby controlling the voltage of V7 output by the voltage conversion circuit.

[0082] The voltage conversion circuit is used to convert the PWM signal into a voltage control signal V7. In order to ensure that the output voltage control signal V7 is more stable, the voltage conversion circuit in this embodiment is substantially configured as an addition and subtraction circuit with high input impedance and low output impedance based on the second operational amplifier A2. From the output end of the voltage conversion circuit, the voltage conversion circuit is equivalent to a constant voltage source, so the voltage control signal outputted by it has high stability and good driving capability for the rear-end load.

[0083] The voltage stabilization compensation circuit includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a first operational amplifier A1. The negative line loss feedback terminal is connected to the output end of the voltage conversion circuit through the ninth resistor R9 and the seventh resistor R7 connected in series in sequence. The first input end of the first operational amplifier A1 is connected between the ninth resistor R9 and the seventh resistor R7; the positive line loss feedback terminal is connected to ground through the eighth resistor R8 and the sixth resistor R6 connected in series in sequence, and the second input end of the first operational amplifier A1 is connected between the eighth resistor R8 and the sixth resistor R6; wherein the resistance values ​​of the sixth resistor R6, the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9 are all equal. The first input end of the first operational amplifier A1 is connected to the output end of the voltage conversion circuit, and the output end of the first operational amplifier A1 is used to output a voltage control signal to the load. The above-mentioned negative line loss feedback terminal is used to be connected to the negative end of the load, and provide the first operational amplifier A1 with a line loss feedback signal of the negative end of the load; the above-mentioned positive line loss feedback terminal is used to be connected to the positive end of the load, and provide the first operational amplifier A1 with a line loss feedback signal of the positive end of the load.

[0084] In fact, in the specific circuit of the above voltage output module, the voltage value of V7 is the design value for driving the load, and V12 is the actual output value of the voltage output module. When the load is close to the voltage output module, the wire connecting the load and the voltage output module is short, and the voltage drop caused by the impedance of the wire can be ignored; when the load is far away from the voltage output module, the voltage drop caused by the impedance of the wire will make the value of V12 significantly smaller than the value of V7, thereby reducing the control accuracy of the voltage output module, and line loss compensation is required.

[0085] like Figure 3 and 4 As shown, the voltage output module provided in this embodiment can be used to directly provide a voltage control signal to a load at a short distance, and can also be used to provide a voltage control signal with line loss compensation to a load at a long distance, and the wiring methods in the two cases are different.

[0086] like Figure 3 As shown, for a close load that does not require line loss compensation, the positive end of the load is connected to the Vout terminal through a short wire, the negative end of the load is grounded through a short wire, and the positive line loss feedback terminal is short-circuited with the Vout terminal, and the negative line loss feedback terminal is grounded. Since the short wire connecting the close load is short, the impedance on the short wire can be ignored, so the above connection method is equivalent to a differential operational amplifier circuit with a voltage gain of 1, which is used to improve the stability of the voltage control signal V12 output by the Vout terminal.

[0087] Specifically, the voltage value V12 at the output terminal of the first operational amplifier A1 is

[0088]

[0089] That is, the voltage V9 output to the positive terminal of the load is equal to the voltage V12 at the output terminal of the first operational amplifier A1, and is equal to the voltage V7 of the voltage control signal output by the voltage conversion circuit.

[0090] like Figure 4 As shown, for a long-distance load that requires line loss compensation, the positive end of the load is connected to the Vout terminal through the wire RL2, the negative end of the load is grounded through the wire RL3, and the positive end line loss feedback terminal is connected to the positive end of the load through the wire RL1, and the negative end line loss feedback terminal is connected to the negative end of the load through the wire RL4. At this time, a total of 4 wires are used, and the resistance values ​​of the wires RL1, RL2, RL3, and RL4 cannot be ignored. Since the lengths of RL1, RL2, RL3, and RL4 are basically the same, their resistance values ​​satisfy the following relationship:

[0091] R L1 =R L2 =R L3 =R L4 <<R6 =R 7 =R 8 =R 9

[0092] The voltages at each point in the figure satisfy the following relationship:

[0093]

[0094] V12-V9=V_RL2=V10 (2)

[0095] V12+V10=2V8 (3)

[0096] According to the virtual short of the operational amplifier,

[0097] V11=V8 (4)

[0098] Where RL 1 , RL 2 RL 3 , RL 4 Respectively represent the resistance values ​​of wires RL1, RL2, RL3, and RL4, R 6 , R 7 , R 8 , R 9 They respectively represent the resistance values ​​of the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, and the ninth resistor R9, V8 represents the voltage value of the second input terminal of the first operational amplifier A1, V9 represents the voltage value of the positive terminal of the load, V10 represents the voltage value of the negative terminal of the load, V11 represents the voltage value of the first input terminal of the first operational amplifier A1, V12 represents the voltage value of the output terminal of the first operational amplifier A1, and V_RL2 represents the voltage on the wire RL2.

[0099] By combining (1) to (4), we can obtain that V9 = V7, that is, the voltage V9 output to the positive terminal of the load is equal to the voltage V7 of the voltage control signal output by the voltage conversion circuit. In other words, the voltage output module provided in the embodiment of the present invention compensates for the voltage drop caused by the impedance of the wire itself, thereby ensuring the accuracy of the voltage control signal output to the load.

[0100] Embodiment 3

[0101] like Figure 5 As shown, this embodiment also provides a voltage-current integrated output device, which is used to output a voltage control signal to a voltage-driven load, or output a current control signal to a current-driven load in an industrial control system. The integrated output device includes an MCU (Microcontroller Unit) and at least one submodule, wherein:

[0102] The MCU is used to generate an initial PWM signal, a voltage and current gating signal, and an output gating signal. The method by which the MCU generates the initial PWM signal, the voltage and current gating signal, and the output gating signal is a prior art. Here, by changing the duty cycle of the initial PWM signal, the amplitude of the output signal can be adjusted to meet the control signal requirements of different amplitudes.

[0103] The submodules include: a frequency selection module, a voltage and current gating module, a voltage output module, a current output module and an output gating module. The connection relationship and functions between the above modules are as follows.

[0104] The frequency selection module is used to receive and filter the high frequency signal in the initial PWM signal and output the PWM signal. Preferably, the frequency selection module is an RC frequency selection circuit, which can be a first-order RC frequency selection circuit or a second-order RC frequency selection circuit.

[0105] The voltage and current gating module is used to receive the PWM signal and the voltage and current gating signal, and output the PWM signal from the voltage signal end or the current signal end according to the voltage and current gating signal. The voltage and current gating module can be an analog switch device or a relay switch device. In fact, the voltage and current gating module is an electronic switch, which is used to input the PWM signal into the voltage output module at the back end, or the current output module at the back end according to the voltage and current gating signal. The voltage and current gating module can use existing technology, such as the SGM3002 dual-channel analog switch chip produced by Shengbang Microelectronics, which has two sets of analog switch circuits. One of the analog switch circuits can be used in the sub-module of this embodiment. Specifically, if Figure 6 As shown, the output end of the frequency selection module can be connected to the COM1 pin of the chip, the pin of the MCU used to output the voltage and current selection signal is connected to the IN1 pin of the chip, the NO1 pin of the chip is connected to the voltage output module as the voltage signal end, and the NC1 of the chip is connected to the current output module as the current signal end; when the voltage and current selection signal received on the IN pin is 0, that is, the pin of the MCU used to output the voltage and current selection signal is at a low level, the COM1 pin is connected to the NC1 pin, the PWM signal is input to the current output module at the back end, and the current output current control signal is output; when the voltage and current selection signal received on the IN pin is 1, that is, the pin of the MCU used to output the voltage and current selection signal is at a high level, the COM1 pin is connected to the NO1 pin, the PWM signal is input to the voltage output module at the back end, and the current submodule outputs the voltage control signal.

[0106] The voltage output module is the voltage output module described in the first or second embodiment, and is used to receive the PWM signal outputted by the voltage signal terminal of the voltage and current gating module, convert the PWM signal into a voltage control signal, and output the voltage control signal to the load after compensating the voltage control signal according to the line loss feedback signal. It should be noted that Figures 2 to 4 GND and Figure 5 The GND terminals in the embodiment are essentially used to provide a ground terminal for the negative end of the load. Therefore, when the voltage output module is applied to the sub-module in this embodiment, there is no need to set a separate GND terminal, or the GND of the voltage output module can be short-circuited with the GND terminal of the sub-module.

[0107] The current output module is used to receive the PWM signal output by the current signal terminal of the voltage and current gating module, convert the PWM signal into a current control signal and output it to the load. The current output module can be implemented by an existing VI conversion module or a self-built circuit.

[0108] The output gating module is connected to the output ends of the voltage output module and the current output module, respectively, and is used to output the voltage control signal output by the voltage output module or the current control signal output by the current output module from the output end according to the output gating signal. The output gating module is an analog switch device, a relay switch device or a PhotoMos switch device. The output gating module is actually also an electronic switch, which is used to output the current control signal Iout output by the current output module to the load, or output the voltage control signal Vout to the load according to the gating signal. The output gating module can be implemented using existing technology. Preferably, in order to isolate the interference signal propagating in the reverse direction from the load end, a PhotoMos switch device can be selected. For example, the TLP227GA-2 optocoupler switch chip produced by Toshiba, the internal circuit diagram of the chip and the circuit connection diagram in the sub-module are shown in the figure below. Figure 7As shown, the chip has two sets of photoelectric coupling switch circuits, among which a set of switch circuits composed of pins 1, 2, 7, and 8 is analyzed as an example. The input of pin 8 is always high level. When pin 2 is low level, the corresponding light emitting diode is turned on, and the output of pin 7 is the same as the input of pin 1; when pin 2 is high level, the corresponding light emitting diode is turned off, and the output of pin 7 is always low level. Based on the above working principle of TLP227GA-2 photoelectric coupling switch chip, the above output selection signal is a two-bit digital control signal, that is, pin 2 of the chip is connected to the pin of the MCU for outputting the first output selection signal, pin 4 of the chip is connected to the pin of the MCU for outputting the second output selection signal, pin 1 is connected to the output terminal Iout of the current output module, pin 3 is connected to the output terminal Vout of the voltage output module, the input of pins 8 and 6 is always high level, and pins 7 and 5 are connected together to the output terminal of the submodule. When the output selection signal output by the MCU is 01, that is, pin 2 is at a low level and pin 4 is at a high level, the control signal output terminal outputs a current control signal Iout; when the output selection signal output by the MCU is 10, that is, pin 2 is at a high level and pin 4 is at a low level, the control signal output terminal outputs a voltage control signal Vout.

[0109] The voltage-current integrated output device proposed in the embodiment of the present invention is based on a pure hardware circuit, and can output a voltage control signal or a current control signal from the control signal output terminal according to the needs of the user. It has high signal accuracy and fast response speed, and can realize multi-channel signal output, so it is suitable for a wider range of usage scenarios. In addition, based on the voltage control module in the submodule, the voltage-current integrated output device can quickly adjust the output voltage control signal according to the line loss feedback signal fed back by the positive line loss feedback terminal and the negative line loss feedback terminal, so that the voltage control signal has a higher control accuracy and a faster response speed for the load, thereby providing a more accurate and stable voltage control signal for the load.

[0110] When using the voltage-current integrated output device proposed in the embodiment of the present invention, if the sub-module is required to provide a current control signal to a current-driven load, the current-driven load can be directly connected between the control signal output terminal and the GND terminal; if a voltage control signal needs to be provided to a voltage-driven load at a short distance and line loss compensation is not required, the voltage-driven load is directly connected between the control signal output terminal and the GND terminal, and the positive-end line loss feedback terminal is short-circuited to the control signal output terminal, and the negative-end line loss feedback terminal is short-circuited to the GND terminal; if a voltage control signal needs to be provided to a voltage-driven load at a long distance and line loss compensation is required, the voltage-driven load is directly connected between the control signal output terminal and the GND terminal, and the positive-end line loss feedback terminal is connected to the positive end of the voltage-driven load, and the negative-end line loss feedback terminal is connected to the negative end of the voltage-driven load.

[0111] like Figure 8 As shown, in a preferred implementation of this embodiment, the above-mentioned current output module is implemented based on a transistor. Specifically, the current output module includes: a fifth operational amplifier A5, a first transistor A and a power supply module.

[0112] The first transistor A works in an amplification state, the base of the first transistor A is connected to the output end of the fifth operational amplifier A5, and the collector of the first transistor A is connected to the output end of the power module through the first resistor R1; the first input end of the fifth operational amplifier A5 is used to receive the PWM signal, and the emitter of the first transistor A is used to output a current control signal; the collector of the first transistor A is short-circuited to the second input end of the fifth operational amplifier A5, and is used to feed back the voltage change at the collector of the first transistor A to the fifth operational amplifier A5; the power module includes a voltage regulation circuit, which is connected to the emitter of the first transistor A, and is used to receive a voltage feedback signal VFB about the voltage change at the positive end of the load, and adjust the voltage at the output end of the power module based on the voltage feedback signal VFB, so that the voltage (V1-V2) across the first resistor R1 is stably maintained at a set value.

[0113] Based on the circuit of the above current output module, it can be known that:

[0114]

[0115] V2=V3=V4

[0116] Among them, V1 represents the output voltage of the power module, V2 represents the collector voltage of the first transistor A, and is also the negative terminal voltage of the first resistor R1, V3 represents the voltage of the second input terminal of the fifth operational amplifier A5, and the fourth operational amplifier A4 represents the voltage of the first input terminal of the fifth operational amplifier A5.

[0117] Among them, the power module can adjust the output voltage V1 according to the voltage feedback signal VFB at the positive end of the load: when the impedance of the load increases, the voltage value of VFB decreases, and V1 increases accordingly; when the impedance of the load decreases, the voltage value of VFB increases, and V1 decreases accordingly, thereby ensuring that the voltage (V1-V2) across the first resistor R1 is stably maintained at the set value, thereby achieving a stable output of Iout, and at the same time reducing the electrical stress on the first transistor A, preventing the first transistor from failing due to excessive power consumption, and preventing the first transistor A from being broken down by transient overcurrent, thereby ensuring the reliability of the current output module. It should be noted that the voltage feedback signal VFB is used to directly feedback the voltage change on the load to the power module, so that the power module can quickly adjust its output voltage V1 according to the voltage feedback signal VFB; in addition, directly collecting the voltage feedback signal VFB from the output end Iout of the current output module can also eliminate the signal interference that may be caused by the current output module itself, and improve the accuracy of the voltage feedback signal VFB.

[0118] In particular, it can be seen from formula (5) that the output accuracy of Iout is directly related to the first resistor R1, so the first resistor R1 can be selected as a precision resistor with low temperature drift to ensure the output accuracy of the current control signal Iout.

[0119] It should be noted that the function of the power module adjusting the output voltage V1 according to the voltage feedback signal VFB can be implemented by using an existing DC / DC module with a voltage regulation circuit, or by building a circuit by yourself, for example. Fig. 9As shown, the voltage regulation circuit is implemented based on the SGM61410 chip produced by Shengbang Microelectronics. The voltage regulation circuit includes the SGM61410 chip and the second transistor B. The second transistor B works in the amplification state. The base of the second transistor B is connected to the emitter of the first transistor A, the emitter of the second transistor B is connected to the output end of the power module, and the collector of the second transistor B is connected to the FB pin of the SGM61410 chip. Among them, the second transistor B is equivalent to an adjustable resistor that can change the equivalent resistance between its collector and emitter according to the voltage input to its base, so the voltage value input to the FB pin can be changed according to the voltage value of VFB, and then the voltage value output by the SW pin is affected based on the SGM61410 chip, so as to achieve the purpose of adjusting the V1 voltage value according to the voltage value of VFB. The peripheral circuits and circuit parameters used to make the SGM61410 chip work normally are built based on the existing technology and will not be repeated here. Furthermore, the voltage regulation circuit based on the SGM61410 chip provided in this embodiment further includes a first feedback resistor Rf1, a second feedback resistor Rf2 and a third feedback resistor Rf3, wherein the first feedback resistor Rf1 is connected in series between the output end of the power module and the emitter of the second transistor B, and the two ends of the second feedback resistor Rf2 and the third feedback resistor Rf3 are connected in parallel between the collector and the emitter of the second transistor B. After receiving the voltage feedback signal VFB, the voltage regulation circuit inputs the second transistor B working in the amplification region, changes the equivalent resistance value between the collector and the emitter of the second transistor B, and then adjusts the voltage division size on the first feedback resistor Rf1, the second feedback resistor Rf2 and the third feedback resistor Rf3, thereby changing the voltage value of the voltage signal input to the FB pin of the SGM61410 chip, so that the voltage value output by the SW pin changes with the voltage feedback signal VFB, thereby achieving the purpose of adjusting the voltage value of V1.

[0120] It should be noted that the network formed by the second transistor B and the second feedback resistor Rf2 and the third feedback resistor Rf3 which are series resistors connected in parallel between the collector and the emitter of the second transistor B can essentially be regarded as an adjustable resistor for adjusting the equivalent resistance value of the network based on the voltage feedback signal VFB. When the voltage value of the voltage feedback signal VFB changes, the equivalent resistance value between the collector and the emitter of the second transistor B changes, thereby changing the equivalent resistance of the network, and further changing the first feedback resistor Rf1 and the voltage divider on the network, thereby changing the voltage value of the voltage signal of the input FB pin.

[0121] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions.

[0122] It should be noted that in the claims, any reference numerals placed between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In the claims enumerating several means, several of these means may be embodied by the same hardware. The use of the words first, second, third, etc., is for convenience of expression only and does not indicate any order. These words may be understood as part of the component name.

[0123] In addition, it should be noted that, in the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0124] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments after knowing the basic creative concept. Therefore, the claims should be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0125] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention should also include these modifications and variations.

Claims

1. A voltage output module with line loss compensation, used to output voltage control signals to voltage-driven loads in industrial control systems. It is characterized in that The voltage output module comprises: a voltage conversion circuit, configured to receive a PWM signal and convert the PWM signal into a voltage control signal; and A voltage stabilization compensation circuit, used for receiving the voltage control signal and the line loss feedback signal, and compensating the voltage control signal according to the line loss feedback signal and then outputting the compensated voltage control signal to the load; The voltage stabilization compensation circuit comprises a first operational amplifier (A1), a first input end of the first operational amplifier (A1) is connected to the output end of the voltage conversion circuit, and the output end of the first operational amplifier (A1) is used to output a voltage control signal to the load; and a first input end of the first operational amplifier (A1) is connected to the negative end line loss feedback terminal, and a second input end of the first operational amplifier (A1) is connected to the positive end line loss feedback terminal; The negative-end line loss feedback terminal is used to be connected to the negative end of the load, and to provide a line loss feedback signal of the negative end of the load to the first operational amplifier (A1); the positive-end line loss feedback terminal is used to be connected to the positive end of the load, and to provide a line loss feedback signal of the positive end of the load to the first operational amplifier (A1); When the load is a load that requires line loss compensation, the positive-end line loss feedback terminal is connected to the positive end of the load through a wire, and the negative-end line loss feedback terminal is connected to the negative end of the load through a wire; When the load is a load that does not require line loss compensation, the positive line loss feedback terminal is short-circuited to the output terminal of the first operational amplifier (A1), and the negative line loss feedback terminal is grounded.

2. The voltage output module according to claim 1, It is characterized in that The negative-end line loss feedback terminal is connected to the output end of the voltage conversion circuit through a ninth resistor (R9) and a seventh resistor (R7) connected in series in sequence, and the first input end of the first operational amplifier (A1) is connected between the ninth resistor (R9) and the seventh resistor (R7); the positive-end line loss feedback terminal is grounded through an eighth resistor (R8) and a sixth resistor (R6) connected in series in sequence, and the second input end of the first operational amplifier (A1) is connected between the eighth resistor (R8) and the sixth resistor (R6); wherein the resistance values ​​of the sixth resistor (R6), the seventh resistor (R7), the eighth resistor (R8), and the ninth resistor (R9) are all equal.

3. The voltage output module according to claim 1 or 2, It is characterized in that The voltage conversion circuit comprises a second operational amplifier (A2), wherein a first input end of the second operational amplifier (A2) is used to receive a PWM signal, and a second input end of the second operational amplifier (A2) is used to receive a reference voltage signal, and the second operational amplifier (A2) is used to amplify the PWM signal into a voltage control signal based on the reference voltage signal, and then output the amplified voltage control signal from an output end of the second operational amplifier (A2) to the voltage stabilization compensation circuit.

4. The voltage output module according to claim 3, It is characterized in that The voltage conversion circuit also includes a first voltage follower and a second voltage follower; The PWM signal is input into the first input terminal of the second operational amplifier (A2) through a first voltage follower and a third resistor (R3) connected in series in sequence, and the first input terminal of the second operational amplifier (A2) is grounded through a fourth resistor (R4); The reference voltage signal is input into the second input end of the second operational amplifier (A2) through a second voltage follower and a second resistor (R2) connected in series, and the second input end of the second operational amplifier (A2) is connected to the output end of the second operational amplifier (A2) through a fifth resistor (R5); The relationship between the resistance values ​​of the second resistor (R2), the third resistor (R3), the fourth resistor (R4), and the fifth resistor (R5) is: Among them, R 2 , R 3 , R 4 , R 5 Respectively represent the resistance values ​​of the second resistor (R2), the third resistor (R3), the fourth resistor (R4), and the fifth resistor (R5).

5. The voltage output module according to claim 4, It is characterized in that The first voltage follower comprises a third operational amplifier (A3), the output end of the third operational amplifier (A3) is short-circuited to the second input end of the third operational amplifier (A3), the first input end of the third operational amplifier (A3) is used to receive the PWM signal, and the output end of the third operational amplifier (A3) is connected to the positive end of the third resistor (R3); The second voltage follower comprises a fourth operational amplifier (A4), the output end of the fourth operational amplifier (A4) is short-circuited to the second input end of the fourth operational amplifier (A4), the first input end of the fourth operational amplifier (A4) is used to receive the reference voltage signal, and the output end of the fourth operational amplifier (A4) is connected to the positive end of the second resistor (R2).

6. A voltage-current integrated output device for outputting a voltage control signal to a voltage-driven load or a current control signal to a current-driven load in an industrial control system. It is characterized in that The integrated output device includes an MCU and at least one submodule, wherein: The MCU is used to generate an initial PWM signal, a voltage and current gating signal, and an output gating signal; the submodule includes: The frequency selection module is used to receive and filter the high-frequency signal in the initial PWM signal and output the PWM signal; A voltage and current gating module, used for receiving the PWM signal and the voltage and current gating signal, and outputting the PWM signal from the voltage signal terminal or the current signal terminal according to the voltage and current gating signal; A voltage output module, wherein the voltage output module is the voltage output module according to any one of claims 1 to 5, and is used to receive a PWM signal outputted from a voltage signal terminal of a voltage and current gating module, convert the PWM signal into a voltage control signal, and compensate the voltage control signal according to a line loss feedback signal before outputting it to a load; A current output module is used to receive the PWM signal output by the current signal terminal of the voltage and current gating module, convert the PWM signal into a current control signal and output it to the load; The output gating module is connected to the output ends of the voltage output module and the current output module respectively, and is used to output the voltage control signal output by the voltage output module or the current control signal output by the current output module from the output end according to the output gating signal.

7. The voltage-current integrated output device according to claim 6, It is characterized in that The frequency selection module is an RC frequency selection circuit; The voltage and current gating module is an analog switch device or a relay switch device; The output gating module is an analog switch device, a relay switch device or a PhotoMos switch device.

8. The voltage-current integrated output device according to claim 6, It is characterized in that The current output module comprises: a fifth operational amplifier (A5), a first transistor (A) and a power supply module; The first transistor (A) operates in an amplification state, the base of the first transistor (A) is connected to the output end of the fifth operational amplifier (A5), and the collector of the first transistor (A) is connected to the output end of the power module through a first resistor (R1); The first input terminal of the fifth operational amplifier (A5) is used to receive the PWM signal, and the emitter of the first transistor (A) is used to output a current control signal; The collector of the first triode (A) is short-circuited to the second input terminal of the fifth operational amplifier (A5), so as to feed back the voltage change at the collector of the first triode (A) to the fifth operational amplifier (A5); The power supply module includes a voltage regulating circuit, which is connected to the emitter of the first transistor (A) and is used to receive a voltage feedback signal regarding the voltage change at the positive end of the load, and adjust the voltage at the output end of the power supply module based on the voltage feedback signal to keep the voltage across the first resistor (R1) stable.

9. The voltage-current integrated output device according to claim 8, It is characterized in that The first resistor (R1) is a precision resistor with low temperature drift.

10. The voltage-current integrated output device according to claim 8, It is characterized in that The voltage regulating circuit includes an SGM61410 chip and a second transistor (B). The second transistor (B) works in an amplification state, the base of the second transistor (B) is connected to the emitter of the first transistor (A), the emitter of the second transistor (B) is connected to the output end of the power module, and the collector of the second transistor (B) is connected to the FB pin of the SGM61410 chip.

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