Sensor conversion acquisition circuit

Abstract

The utility model relates to the technical field of acquisition or monitoring circuits for industrial control or new energy charging, and discloses a sensor conversion acquisition circuit, which comprises a current acquisition end, a voltage acquisition end and a signal processing circuit, the voltage acquisition end comprises a CON1 interface used for being connected with a measured voltage, and the CON1 interface is connected with the input end of the voltage converter through a resistor matrix; the signal processing circuit comprises an operational amplifier chip. According to the utility model, through the converter and the sensor, the measurement of large voltage and large current is converted according to a certain proportion and is output to the analog quantity I / O port of the MCU at the rear stage, and the device can be applied to a hundred-volt-level voltage and hundred-ampere-level current measurement monitoring module for accurate detection.

Description

Technical Field

[0001] The utility model relates to the technical field of acquisition or monitoring circuits for industrial control or new energy charging, in particular to the field of acquisition circuits for sensor signal conversion, and specifically relates to a sensor conversion acquisition circuit. Background Art

[0002] In a new energy charging module, an equipment management system needs to monitor the magnitudes of voltage and current in real time and upload them to a control chip. Currently, in the art, the methods of using resistor ratio voltage division and resistor sampling current are generally adopted to collect voltage and current signals, which cannot sensitively reflect the changes of real-time current and voltage, and the influence of temperature will affect the resistance value of the sampling resistor, thus affecting the sampling accuracy. In the prior art, there is also an improvement of low loss type for the sensor acquisition circuit through an MCU. Refer to the Chinese utility model patent with the publication number: CN203070014U, which provides a control circuit for multi-channel acquisition and single-channel conversion based on a current sensor. This circuit controls the signal acquisition and signal power-on time of multiple sensors to achieve single-channel control conversion. The input end of the sensor power-on control circuit is the power-on control IO port of the MCU, and the output end is the power supply end of the sensor. The function of the sensor power-on control circuit is to realize the on-off control of the power supply of multiple sensors by the MCU. The input end of the sensor multi-channel acquisition circuit is the signal output end of multiple sensors, and the output end of the circuit is a general IO port of the MCU. The function of the multi-channel acquisition circuit is to sequentially convert the output current signals of multiple sensors into voltage signals. The converted voltage signals are transmitted to an A / D conversion circuit, and the signals after A / D conversion are digital signals, which are directly transmitted to the IO port of the MCU. The control circuit of the utility model can control the power-on of the sensor, effectively improve the service life of lossy sensors, and reduce the later maintenance cost. Nevertheless, in pursuit of sensitivity and accuracy, the above-mentioned technology still cannot meet the requirements. Therefore, the present invention is provided. Summary of the Utility Model

[0003] In order to solve the problems such as the precise and sensitive monitoring of the magnitudes of voltage and current in a new energy charging module mentioned in the background art, the present application provides a sensor conversion acquisition circuit to replace the existing resistor sampling technology, thereby improving the sensitivity and accuracy of acquisition.

[0004] In order to achieve the above purpose, the technical solution adopted in the present application is as follows:

[0005] A sensor conversion and acquisition circuit includes a current acquisition terminal, a voltage acquisition terminal, and a signal processing circuit. The current acquisition terminal includes a CT interface for connecting to the signal output terminal of a current sensor. The voltage acquisition terminal includes a CON1 interface for connecting to the voltage to be measured. The CON1 interface is connected to the input terminal of a voltage converter through a resistor matrix. The signal processing circuit includes an operational amplifier chip, a voltage input circuit unit electrically connected to the operational amplifier chip and used to calibrate the voltage output signal, a voltage signal output circuit unit, a current input circuit unit used to calibrate the output current signal, and a current signal output circuit unit. The CT interface is electrically connected to the current input circuit unit to provide a current signal input, and the CON1 interface is electrically connected to the voltage input circuit unit to provide a voltage signal input.

[0006] Preferably, the high potential MX1+ of the CON1 interface in the voltage acquisition terminal is connected to the high potential input terminal HT+ of the voltage converter through a resistor matrix, and the low potential MX1- of the CON1 interface is connected to the low potential input terminal HT- of the voltage converter. Among them, the model of the voltage converter is LV25-P. The resistor matrix includes multiple groups of matrix units connected in series between the high potential MX1+ and the high potential input terminal HT+. Any matrix unit includes at least two resistors connected in parallel.

[0007] Further preferably, the voltage input circuit unit and the current input circuit unit have the same structure, and both include two groups of RC filtering units. An adjustment resistor is connected in series between the two groups of RC filtering units, and a DTVS transient voltage diode for protecting the circuit is connected in parallel. Among them, the operational amplifier chip uses a TLE2072 operational amplifier chip. A potentiometer RP for calibrating the output signal is also provided on one group of RC filtering units connected to the operational amplifier chip. The CT interface is connected to the signal output terminal of the current sensor to collect a current signal, and the equally scaled-down current signal IM is collected. IM is converted into a level through a resistor R4 and then output through an operational amplifier U1, that is, it is carried out using a TLE2072 operational amplifier chip, as Figure 3 shown. Among them, capacitors C6 and C7 play a filtering role, DTVS2 plays a protecting role, and potentiometer RP2 is used to calibrate the output signal. Similarly, for the voltage terminal CON1 interface connected to the voltage to be measured, it is converted into a small current through a resistor matrix R10 - R17 and input into a voltage sensor U2, that is, it is carried out using a LV25-P voltage converter. The sensor outputs a current signal VM, and VM is converted into a level through a resistor and then output through an operational amplifier U1, as Figures 2 - 3As shown in the figure. Among them, capacitors C4 and C8 play a filtering role, DTVS1 plays a protection role, and potentiometer RP1 is used to calibrate the output signal. The finally converted voltage signal and current signal are respectively output through the Iout interface and 2out interface of operational amplifier U1, and RC filter circuits and adjusting resistors R18 / R19 are respectively provided on the output interface pins.

[0008] Beneficial effects:

[0009] The utility model converts the measurement of large voltage and large current through a converter and a sensor in a certain proportion and outputs it to the analog I / O port of the subsequent MCU, and can be applied to the measurement and monitoring module of hundreds of volts of voltage and hundreds of amps of current for accurate detection. Description of the drawings

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0011] Figure 1 It is the CT interface circuit of the current acquisition end.

[0012] Figure 2 It is the CON1 interface circuit of the voltage acquisition end.

[0013] Figure 3 It is the signal processing circuit. Specific implementation manners

[0014] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0015] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application to be protected, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0016] Embodiment 1:

[0017] Refer to the specification Figures 1 - 3A sensor conversion and acquisition circuit as shown. Since the present utility model is directed to a sensor conversion and acquisition circuit with practicality and effectiveness as the main purposes, therefore, in this embodiment, the preferred embodiments of this application will be elaborated in detail. Specifically, the circuit structure includes a current acquisition terminal, a voltage acquisition terminal, and a signal processing circuit. The current acquisition terminal includes a CT interface for connecting to the signal output terminal of a current sensor, as shown in Figure 1 ; the voltage acquisition terminal includes a CON1 interface for connecting to the voltage to be measured, as shown in Figure 2 . The CON1 interface is connected to the input terminal of a voltage converter through a resistor matrix; the signal processing circuit includes an operational amplifier chip, and a voltage input circuit unit, a voltage signal output circuit unit, a current input circuit unit, and a current signal output circuit unit that are electrically connected to the operational amplifier chip and are used to calibrate the voltage output signal and the output current signal respectively; the CT interface is electrically connected to the current input circuit unit to provide a current signal input, and the CON1 interface is electrically connected to the voltage input circuit unit to provide a voltage signal input. It is worth noting that using the method of resistor array can reduce the failure rate and improve the stability compared with a single resistor. Even if any one or more of the resistors in the resistor array are short-circuited / opened, it will not cause the entire resistor array to fail, and it can still achieve the purpose of converting small current, which is more stable than an equivalent single resistor.

[0018] In this embodiment, as shown in Figure 2 , the high potential MX1+ of the CON1 interface in the voltage acquisition terminal is connected to the high potential input terminal HT+ of the voltage converter through a resistor matrix, and the low potential MX1- of the CON1 interface is connected to the low potential input terminal HT- of the voltage converter. Among them, the model of the voltage converter is LV25-P, and the resistor matrix includes multiple groups of matrix units connected in series between the high potential MX1+ and the high potential input terminal HT+. Any matrix unit includes at least two resistors connected in parallel.

[0019] In this embodiment, as shown in Figure 3 , the voltage input circuit unit and the current input circuit unit have the same structure, both including two groups of RC filtering units. An adjusting resistor is connected in series between the two groups of RC filtering units, and a DTVS transient voltage diode for protecting the circuit is connected in parallel. Among them, the operational amplifier chip uses a TLE2072 operational amplifier chip, and a potentiometer RP for calibrating the output signal is also provided on a group of RC filtering units connected to the operational amplifier chip.

[0020] Circuit principle description:

[0021] The CT interface is connected to the signal output end of the current sensor for collecting current signals. The collected current signal IM, which is a proportionally reduced current signal, is converted into a level through resistor R4 and then output through operational amplifier U1, i.e., using the TLE2072 operational amplifier chip, as Figure 3 shown. Among them, capacitor C6 and capacitor C7 play a filtering role, DTVS2 plays a protection role, and potentiometer RP2 is used to calibrate the output signal. Similarly, for the voltage terminal, the CON1 interface is connected to the voltage to be measured, which is converted into a small current through the resistor matrix R10 - R17 and input to the voltage sensor U2, i.e., using the LV25 - P voltage converter. The sensor outputs the current signal VM, and VM is converted into a level through a resistor and then output through operational amplifier U1, as Figures 2 - 3 shown. Among them, capacitors C4 and C8 play a filtering role, DTVS1 plays a protection role, and potentiometer RP1 is used to calibrate the output signal. The finally converted voltage signal and current signal are respectively output through the Iout interface and 2out interface of operational amplifier U1, and RC filtering circuits and adjusting resistors R18 / R19 are respectively provided on the output interface pins.

[0022] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A sensor conversion and acquisition circuit, comprising a current acquisition terminal, a voltage acquisition terminal and a signal processing circuit, characterized in that: The current acquisition end includes a CT interface for connecting to the signal output end of the current sensor, and the voltage acquisition end includes a CON1 interface for connecting to the measured voltage, and the CON1 interface is connected to the input end of the voltage converter through a resistor matrix; the signal processing circuit includes an operational amplifier chip, and a voltage input circuit unit electrically connected to the operational amplifier chip and used to calibrate the voltage output signal, a voltage signal output circuit unit, a current input circuit unit and a current signal output circuit unit for calibrating the output current signal; the CT interface is electrically connected to the current input circuit unit for providing current signal input, and the CON1 interface is electrically connected to the voltage input circuit unit for providing voltage signal input.

2. A sensor conversion and acquisition circuit according to claim 1, characterized in that: The high potential MX1+ of the CON1 interface in the voltage acquisition end is connected to the high potential input terminal HT+ of the voltage converter through a resistor matrix, and the low potential MX1- of the CON1 interface is connected to the low potential input terminal HT- of the voltage converter, wherein the model adopted by the voltage converter is LV25-P, and the resistor matrix includes a plurality of matrix units arranged in series between the high potential MX1+ and the high potential input terminal HT+, and any matrix unit includes at least two parallel resistors.

3. A sensor conversion and acquisition circuit according to claim 1 or 2, characterized in that: The voltage input circuit unit and the current input circuit unit have the same structure, both including two groups of RC filter units, an adjustment resistor is connected in series between the two groups of RC filter units, and a DTVS transient voltage diode for protecting the circuit is arranged in parallel, wherein the operational amplifier chip adopts the TLE2072 operational amplifier chip, and a potentiometer RP for calibrating the output signal is also arranged on a group of RC filter units connected to the operational amplifier chip.

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