CN220691090U

CN220691090U - Voltage transmitting circuit

Info

Publication number: CN220691090U
Application number: CN202321190173.5U
Authority: CN
Inventors: 许赵武; 周吉昌; 许良
Original assignee: GUANGZHOU HAIGU ELECTRONIC TECHNOLOGY CO LTD
Current assignee: GUANGZHOU HAIGU ELECTRONIC TECHNOLOGY CO LTD
Priority date: 2023-05-17
Filing date: 2023-05-17
Publication date: 2024-03-29
Anticipated expiration: 2033-05-17

Abstract

The utility model relates to a voltage transmitting circuit, which comprises an MCU singlechip, wherein the input end of the MCU singlechip is connected with a reference voltage source, the DA output end of the MCU singlechip is connected with an AD conversion low-pass filter circuit, the AD output end of the MCU singlechip is connected with a voltage output matching drive circuit, and the output end of the AD conversion low-pass filter circuit is connected with the input end of the voltage output matching drive circuit; the reference voltage source is used for inputting voltage and transmitting the input voltage to the input end of the MCU singlechip; the MCU singlechip is used for receiving the input voltage transmitted by the reference voltage source, the MCU singlechip transmits the digital signal to the AD conversion low-pass filter circuit through the DA output end, and the MCU singlechip transmits the analog signal to the voltage output matching drive circuit through the AD output end. The circuit structure of the utility model solves the problem that errors occur in the output current or voltage reflecting the measured physical quantity in the prior manual mode, and realizes the automatic calibration of the output voltage or current of the transmitter.

Description

Voltage transmitting circuit

Technical Field

The utility model relates to the technical field of transmitting circuits, in particular to a voltage transmitting circuit.

Background

The output current (4 mA-20 mA) of the current output type transformer reflects the measured physical quantity. The voltage output type transducer uses voltage (0-10V or 0-5V) to reflect the measured physical quantity. Errors in the output current or voltage in response to the measured physical quantity may occur due to parameters of the current or voltage output circuit device and errors in the DAC reference voltage source. To eliminate this error, calibration must be performed before the transmitter is shipped. The calibration is usually performed manually, and the manual calibration has low working efficiency, which is unfavorable for practical use, so the utility model provides a circuit technical implementation scheme for automatically calibrating output current or output voltage based on the functions of AD and DA of a singlechip.

Disclosure of Invention

In view of the foregoing problems of the prior art, it is a primary object of the present utility model to provide a current or voltage transmitter circuit.

The technical scheme of the utility model is as follows: the voltage transmitting circuit comprises an MCU singlechip, wherein the input end of the MCU singlechip is connected with a reference voltage source, the DA output end of the MCU singlechip is connected with an AD conversion low-pass filter circuit, the AD input end of the MCU singlechip is connected with a voltage output matching drive circuit, and the output end of the AD conversion low-pass filter circuit is connected with the input end of the voltage output matching drive circuit;

the reference voltage source is used for inputting voltage and transmitting the input voltage to the input end of the MCU singlechip;

the MCU singlechip is used for receiving the input voltage transmitted by the reference voltage source, transmitting a digital signal to the AD conversion low-pass filter circuit through the DA output end, and transmitting an analog signal to the voltage output matching drive circuit through the AD input end;

the voltage output matching driving circuit is used for connecting the MCU singlechip and the AD conversion low-pass filter circuit;

the AD conversion low-pass filter circuit is used for receiving signals transmitted by the MCU singlechip, performing feedback sampling on voltage generated by DA conversion, and measuring the voltage generated by DA conversion.

As a preferred embodiment, the reference voltage source is a reference voltage source IC, wherein the output voltage is 2.5V-3.3V, and the maximum error voltage is less than or equal to 2%.

As a preferred implementation mode, the MCU singlechip is internally provided with a 12-bit ADC and a 12-bit DAC circuit.

As a preferred implementation manner, the AD conversion low-pass filter circuit is a low-pass active filter circuit formed by operational amplifiers, and the offset voltage inside the AD conversion low-pass filter circuit is less than 0.25mV; the input current of the paranoid is less than 10PA; positive supply voltage > 24V. The accuracy of the parameters of the internal resistance and capacitance of the AD conversion low-pass filter circuit is 0.1%.

As a preferred implementation manner, the voltage output matching driving circuit is an operational amplifier constant current circuit; the voltage output matching driving circuit can also be an operational amplifier in-phase amplifier. The internal offset voltage of the voltage output matching driving circuit is less than 0.25mV; the input current of the paranoid is less than 10PA; positive supply voltage > 24V.

As a preferred embodiment, the DA output is a digital-to-analog conversion output, and the AD input is an analog-to-digital conversion output.

Compared with the prior art, the utility model has the advantages and positive effects that based on the precision of a reference voltage source, the 12-bit AD and DA circuit of the MCU singlechip of the current or voltage output transmitter is utilized, so that the AD conversion is realized to carry out high-precision sampling measurement on the DA conversion output voltage of the transmitter, and the voltage generated by DA conversion is further adjusted, so that the DA conversion output voltage finally reaches the voltage value consistent with the expected calibration, and the automatic calibration of the output voltage or current of the transmitter is realized.

Drawings

FIG. 1 is a schematic block diagram of a voltage transmitter circuit according to the present utility model;

FIG. 2 is a schematic diagram of an automatic calibration output circuit of a current output type transducer of a voltage transducer circuit according to the present utility model;

FIG. 3 is a schematic diagram of an automatic calibration output circuit of a voltage output type transmitter of the voltage transmitting circuit;

FIG. 4 is a schematic diagram of a reference voltage source circuit of a voltage transmitter circuit according to the present utility model;

FIG. 5 is a schematic diagram of an MCU monolithic circuit of the voltage transmitter circuit of the present utility model;

FIG. 6 is a schematic diagram of an AD conversion low-pass filter circuit of a voltage transmitter circuit according to the present utility model;

FIG. 7 is a schematic diagram of an operational amplifier constant current circuit of the voltage transmitting circuit;

FIG. 8 is a schematic diagram of an operational amplifier in-phase amplifying circuit of a voltage transmitting circuit.

Detailed Description

The utility model will be further described with reference to the drawings and the specific embodiments

Example 1

As shown in fig. 1 to 8, the present utility model provides a technical solution: the device comprises an MCU singlechip, wherein the input end of the MCU singlechip is connected with a reference voltage source, the DA output end of the MCU singlechip is connected with an AD conversion low-pass filter circuit, the AD input end of the MCU singlechip is connected with a voltage output matching drive circuit, and the output end of the AD conversion low-pass filter circuit is connected with the input end of the voltage output matching drive circuit;

the MCU singlechip is used for receiving the input voltage transmitted by the reference voltage source, transmitting the digital signal to the AD conversion low-pass filter circuit through the DA output end, and transmitting the analog signal to the voltage output matching driving circuit through the AD output end;

the voltage output matching driving circuit is used for receiving the MCU singlechip and the AD conversion low-pass filter circuit and outputting the MCU singlechip and the AD conversion low-pass filter circuit;

the AD conversion low-pass filter circuit is used for receiving signals transmitted by the MCU singlechip, carrying out feedback sampling on voltage generated by DA conversion, and measuring the voltage generated by DA conversion.

Through the embodiment, based on the precision of the reference voltage source, the 12-bit AD and DA circuits of the MCU single-chip microcomputer of the current or voltage output transmitter are utilized, so that the AD conversion is realized to carry out high-precision sampling measurement on the DA conversion output voltage of the transmitter, the voltage generated by the DA conversion is further adjusted, the DA conversion output voltage finally reaches the voltage value consistent with the expected calibration, and the automatic calibration of the output voltage or current of the transmitter is realized.

Example 2

As shown in fig. 1-4, the reference voltage source adopts a reference voltage source IC, wherein the output voltage is 2.5V-3.3V, and the maximum error voltage is less than or equal to 2%.

Wherein, the MCU singlechip is internally provided with a 12-bit ADC and a 12-bit DAC circuit. The reference voltage source provides accurate reference power supply (error is less than 2%) for the AD conversion circuit and the DA conversion circuit of the MCU singlechip, so that AD and DA conversion precision of the singlechip is ensured; meanwhile, the MCU singlechip determines DA conversion data corresponding to each standard point according to the AD conversion reference voltage and outputs V1.

The AD conversion low-pass filter circuit is a low-pass active filter circuit formed by operational amplifiers, and the internal offset voltage of the AD conversion low-pass filter circuit is less than 0.25mV; the input current of the paranoid is less than 10PA; positive supply voltage > 24V. The accuracy of the internal resistance-capacitance parameter of the AD conversion low-pass filter circuit is 0.1%. The DA conversion low-pass filter carries out filtering treatment on the conversion output voltage V1 of the singlechip and filters quantization noise output V2.

The voltage output matching driving circuit is an operational amplifier constant current circuit; the voltage output matching driving circuit can also be an operational amplifier in-phase amplifier. The internal offset voltage of the voltage output matching driving circuit is less than 0.25mV; the input current of the paranoid is less than 10PA; positive supply voltage > 24V. The current output matching driver circuit in fig. 2 converts the 0.5-2.5V voltage to a 4-20 mA output. The voltage output matching driver circuit in fig. 3 converts 0-2.5V to 0-10V or 0-5V. The resistor adopts 0.1% precision due to the operational amplifier circuit in which low offset voltage (< 0.25 mV) and low offset input current (< 10 PA) are sampled. The error caused by the output matching driver circuit can be negligible.

The DA output end is a digital-to-analog conversion output end, and the AD input end is an analog-to-digital conversion output end.

Working principle: the single chip microcomputer 12-bit AD conversion circuit samples and measures V2, the measurement error is less than 2% (the 12-bit AD quantization error is far less than 2%, and the error is determined by a reference voltage source). And comparing the sampling voltage with the standard point voltage to obtain an error voltage. And correspondingly adjusting DA (PWM) conversion data according to a certain control algorithm by utilizing the obtained error voltage to generate a new DA output V1 and a new filtering output V2. This process is repeated until the error is 0.

Claims

1. The utility model provides a voltage transmission circuit, includes MCU singlechip, its characterized in that: the input end of the MCU singlechip is connected with a reference voltage source, the DA output end of the MCU singlechip is connected with an AD conversion low-pass filter circuit, the AD input end of the MCU singlechip is connected with a voltage output matching drive circuit, and the output end of the AD conversion low-pass filter circuit is connected with the input end of the voltage output matching drive circuit;

the MCU singlechip is used for receiving the input voltage transmitted by the reference voltage source, transmitting a digital signal to the AD conversion low-pass filter circuit through the DA output end, and transmitting an analog signal to the voltage output matching drive circuit through the AD output end;

2. The voltage transmitter circuit of claim 1 wherein: the reference voltage source adopts a reference voltage source IC, wherein the output voltage is 2.5V-3.3V, and the maximum error voltage is less than or equal to 2%.

3. The voltage transmitter circuit of claim 1 wherein: the MCU singlechip is internally provided with a 12-bit ADC and a 12-bit DAC circuit.

4. The voltage transmitter circuit of claim 1 wherein: the AD conversion low-pass filter circuit is a low-pass active filter circuit formed by operational amplifiers, and the internal offset voltage of the AD conversion low-pass filter circuit is less than 0.25mV; the input current of the paranoid is less than 10PA; positive power supply voltage > 24V; the accuracy of the parameters of the internal resistance and capacitance of the AD conversion low-pass filter circuit is 0.1%.

5. The voltage transmitter circuit of claim 4 wherein: the voltage output matching driving circuit is an operational amplifier constant current circuit; the voltage output matching driving circuit can also be an operational amplifier in-phase amplifier; the internal offset voltage of the voltage output matching driving circuit is less than 0.25mV; the input current of the paranoid is less than 10PA; positive supply voltage > 24V.

6. The voltage transmitter circuit of claim 1 wherein: the DA output end is a digital-to-analog conversion output end, and the AD input end is an analog-to-digital conversion output end.