阅读说明：本技术 一种模拟电阻的电路 (Circuit for simulating resistor ) 是由 尹成义 高飞 蒲申申 于 2019-09-18 设计创作，主要内容包括：本发明公开了一种模拟电阻的电路,属于模拟电阻技术领域,包括取样电阻电路,取样电阻电路串联连接有模数转换电路,模数转换电路串联连接有控制电路,控制电路串联连接有数模转换电路,数模转换电路串联连接有电压输出电路,取样电阻电路对外部设备输入的激励电流I进行取样放大并提供给模数转换电路将电流值转换成数字量,控制电路根据要模拟电阻的值R和激励电流值I计算出所需输出的电压值U,控制数模转换电路输出电压值,进而控制电压输出电路输出设定的电阻值。本发明通过模数转换电路和数模转换电路,实现了电阻的数字化设置,取样电路和模数转换电路,实现了对激励电流的实时测量,在不同激励电流的情况下,依旧能保证输出的准确性。(The invention discloses a circuit of an analog resistor, which belongs to the technical field of analog resistors and comprises a sampling resistor circuit, wherein the sampling resistor circuit is connected with an analog-digital conversion circuit in series, the analog-digital conversion circuit is connected with a control circuit in series, the control circuit is connected with a digital-analog conversion circuit in series, the digital-analog conversion circuit is connected with a voltage output circuit in series, the sampling resistor circuit samples and amplifies an excitation current I input by external equipment and provides the excitation current I for the analog-digital conversion circuit to convert a current value into a digital value, and the control circuit calculates a voltage value U required to be output according to the value R of the analog resistor and the excitation current value I, controls the digital-analog conversion circuit to output the voltage value and further controls the voltage output circuit. The invention realizes the digital setting of the resistor, the sampling circuit and the analog-to-digital conversion circuit through the analog-to-digital conversion circuit and the digital-to-analog conversion circuit, realizes the real-time measurement of the excitation current, and can still ensure the accuracy of the output under the condition of different excitation currents.)

1. The utility model provides a circuit of analog resistor, its characterized in that, including the sampling resistor circuit of being connected with external equipment, sampling resistor circuit series connection has analog-to-digital conversion circuit, analog-to-digital conversion circuit series connection has control circuit, control circuit series connection has digital-to-analog conversion circuit, digital-to-analog conversion circuit series connection has voltage output circuit, sampling resistor circuit samples the excitation current I of external equipment input and amplifies and provide the analog-to-digital conversion circuit with the current value conversion digital quantity, control circuit calculates the voltage value U of required output according to the value R and the excitation current value I of wanting analog resistor, control digital-to-analog conversion circuit output voltage value, and then control voltage output circuit outputs the resistance value of settlement.

2. The circuit for simulating resistors as claimed in claim 1, wherein the sampling resistor circuit comprises R4, a filter circuit composed of R2 and C1 connected in series with R4, and an amplifier circuit composed of U2B connected in series with R2 and R6 and R5 connected in parallel, wherein R4 is a sampling resistor.

3. The circuit for simulating resistors as claimed in claim 1, wherein the analog-to-digital conversion circuit includes a filter circuit composed of R3 and C2 and a control circuit U1, the filter circuit being connected in series with the PD5 in the control circuit U1.

4. The circuit for simulating the resistance as claimed in claim 3, wherein the control circuit U1 is a single chip with analog-to-digital conversion function, and the control circuit U1 has program codes stored therein.

5. The circuit of claim 1, wherein the digital-to-analog converter circuit comprises U3, and U3 is a 16-bit analog-to-digital converter chip.

6. A circuit for modelling a resistor as claimed in claim 5 wherein the voltage output circuit comprises U2A connected in parallel with the voltage feedback and voltage output pins of the digital to analogue conversion circuit U3 and R1, Q1 connected in series with the voltage signal output pin of U2A.

7. A circuit for simulating a resistor as claimed in claim 4 or claim 5, characterized in that the PD2 of the control circuit U1 is connected to the data input 7 of the D/A converter U3, the PD3 of the control circuit U1 is connected to the clock signal 6 of the D/A converter U3, and the PD4 of the control circuit U1 is connected to the synchronous control input 5 of the D/A converter U3.

8. A circuit for simulating a resistor according to claim 1, wherein the voltage value U to be output is calculated according to ohm's law:

U＝I*R。

9. a circuit for modeling a resistance as claimed in claim 1, wherein the output resistance R is calculated by the formula:

R＝U/I。

Technical Field

The invention relates to a circuit, in particular to a circuit for simulating a resistor, and belongs to the technical field of simulated resistors.

Background

A resistor is a linear element, and under certain conditions, the current flowing through a resistor is proportional to the voltage across the resistor, i.e. ohm's law: r ═ U ÷ I, the unit of resistance is ohm, denoted by the symbol "Ω".

As a most basic electronic component, a resistor is widely applied to an analog circuit, and in practical application, the resistance value of the resistor is often required to be adjusted, generally, a resistor box, a sliding resistor and a digital potentiometer are adopted, the resistor box changes the resistance value and the number of series resistors by switching a gear switch to obtain an electrical instrument with a certain resistance value, the volume is large, the price is relatively expensive, the electrical instrument is generally used as a standard resistor in a laboratory or a precision circuit measurement, the resistance value of a mechanical potentiometer is adjustable, the price is relatively cheap compared with the resistor box, and the defects are that the resistance value can be read only by measuring through a universal meter, the resolution is low, and the resistance value drift is large.

With the popularization of digital circuits, a mechanical potentiometer is gradually replaced by a digital potentiometer, the digital potentiometer controls an output resistor through digital input, but at present, the digital potentiometer still has large resistance value and low resolution, and is not suitable for fine adjustment of low resistance value.

Disclosure of Invention

The invention mainly aims to provide a circuit for simulating a resistor, which realizes the digital setting of the resistor by adopting an analog-to-digital conversion circuit and a digital-to-analog conversion circuit, realizes the real-time measurement of an excitation current by adopting a sampling circuit and the analog-to-digital conversion circuit, and can still ensure the accuracy of output under the condition of different excitation currents.

The purpose of the invention can be achieved by adopting the following technical scheme:

the utility model provides a circuit of analog resistor, including the sampling resistor circuit of being connected with external equipment, the sampling resistor circuit series connection has analog-to-digital conversion circuit, analog-to-digital conversion circuit series connection has control circuit, control circuit series connection has digital-to-analog conversion circuit, digital-to-analog conversion circuit series connection has voltage output circuit, the sampling resistor circuit samples the excitation current I of external equipment input and amplifies and provide the analog-to-digital conversion circuit with the current value conversion digital quantity, control circuit calculates the voltage value U of required output according to the value R and the excitation current value I of wanting analog resistor, control digital-to-analog conversion circuit output voltage value, and then control voltage output circuit output set resistance value.

Preferably, the sampling resistor circuit comprises R4, a filter circuit which is connected with R4 in series and is composed of R2 and C1 in series, and an amplifying circuit which is connected with R2 in series and is composed of U2B and R6 and R5 in parallel, wherein R4 is a sampling resistor.

Preferably, the analog-to-digital conversion circuit comprises a filter circuit composed of R3 and C2 and a control circuit U1, wherein the filter circuit is connected with the PD5 in the control circuit U1 in series.

Preferably, the control circuit U1 is a single chip with analog-to-digital conversion function, and program codes are stored in the control circuit U1.

Preferably, the digital-to-analog conversion circuit comprises a U3, and the U3 is a 16-bit analog-to-digital conversion chip.

Preferably, the voltage output circuit comprises a U2A connected in parallel with a voltage feedback pin and a voltage output pin of the digital-to-analog conversion circuit U3, and R1 and Q1 connected in series with a voltage signal output pin of the U2A.

Preferably, the PD2 pin of the control circuit U1 is connected to the data input 7 pin of the digital-to-analog conversion circuit U3, the PD3 pin of the control circuit U1 is connected to the clock signal 6 pin of the digital-to-analog conversion circuit U3, and the PD4 pin of the control circuit U1 is connected to the synchronous control input 5 pin of the digital-to-analog conversion circuit U3.

Preferably, the voltage value U to be output is calculated according to ohm's law:

U＝I*R。

preferably, the formula for calculating the output resistance R is:

R＝U/I。

the invention has the beneficial technical effects that: the digital setting of the resistor is realized by adopting the analog-digital conversion circuit and the digital-analog conversion circuit, the real-time measurement of the exciting current is realized by adopting the sampling circuit and the analog-digital conversion circuit, and the accuracy of the output can be still ensured under the condition of different exciting currents.

Drawings

FIG. 1 is a circuit diagram of a preferred embodiment of a circuit for simulating a resistance according to the present invention;

fig. 2 is a schematic diagram of circuit signals of a preferred embodiment of a circuit for simulating a resistance according to the present invention.

Detailed Description

In order to make the technical solutions of the present invention more clear and definite for those skilled in the art, the present invention is further described in detail below with reference to the examples and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

As shown in fig. 1-2, the circuit of the analog resistor provided in this embodiment includes a sampling resistor circuit connected to an external device, the sampling resistor circuit is connected in series with an analog-to-digital conversion circuit, the analog-to-digital conversion circuit is connected in series with a control circuit, the control circuit is connected in series with a digital-to-analog conversion circuit, the digital-to-analog conversion circuit is connected in series with a voltage output circuit, the sampling resistor circuit samples and amplifies an excitation current I input by the external device and provides the amplified excitation current to the analog-to-digital conversion circuit to convert a current value into a digital value, the control circuit calculates a voltage value U to be output according to a value R of the analog resistor to be simulated and the excitation current value I, controls the digital-to-analog conversion circuit to output a set resistance value, the sampling resistor circuit converts the excitation current I of the, the analog-digital conversion circuit converts the signal into a digital signal, the control circuit calculates a voltage value U to be output according to an ohm law U-I R according to a resistance value R to be simulated, the digital-analog conversion circuit is controlled to output a voltage U, the voltage output circuit automatically follows according to the voltage U output by the digital-analog conversion circuit, so that the voltage of an Out point is U, and the output resistance R is U/I.

In this embodiment, as shown in fig. 1, the sampling resistor circuit includes R4, a filter circuit connected in series with R4 and composed of R2 and C1, and an amplifier circuit connected in parallel with R2 and composed of U2B, R6, and R5, where R4 is a sampling resistor, and converts a current signal into a voltage signal, where R2 and C1 constitute the filter circuit, and filters the voltage signal sampled by R4 to eliminate interference, and U2B, R5, and R6 constitute the amplifier circuit, and amplify the filtered signal to improve accuracy.

In this embodiment, as shown in fig. 1, the analog-to-digital conversion circuit includes a filter circuit composed of R3 and C2 and a control circuit U1, the filter circuit is connected in series with the PD5 in the control circuit U1, and the filter circuit filters the signal output by the sampling resistor circuit to eliminate interference.

In this embodiment, as shown in fig. 1, the control circuit U1 is a single chip with analog-to-digital conversion function, and can convert the voltage signal output by the sampling resistor circuit into digital signal for the control circuit to perform calculation, and the control circuit U1 stores program codes for controlling all circuits to implement the required functions.

In this embodiment, as shown in fig. 1, the digital-to-analog conversion circuit includes U3, U3 is a 16-bit analog-to-digital conversion chip, and outputs a required voltage signal through a control command issued by the control circuit U1.

In this embodiment, as shown in fig. 1, the voltage output circuit includes a U2A connected in parallel with the voltage feedback pin and the voltage output pin of the digital-to-analog conversion circuit U3, and R1 and Q1 connected in series with the voltage signal output pin of U2A, and is configured to follow the voltage output by the digital-to-analog conversion circuit, so as to achieve the function of analog thermal resistance.

In this embodiment, as shown in fig. 1, pin PD2 of the control circuit U1 is connected to pin 7 of the data input of the digital-to-analog conversion circuit U3, pin PD3 of the control circuit U1 is connected to pin 6 of the clock signal of the digital-to-analog conversion circuit U3, and pin PD4 of the control circuit U1 is connected to pin 5 of the synchronization control input of the digital-to-analog conversion circuit U3.

In the present embodiment, as shown in fig. 1, the voltage value U to be output is calculated according to ohm's law:

U＝I*R。

in the present embodiment, as shown in fig. 1, the calculation formula of the output resistance R is:

R＝U/I。

as shown in fig. 1 to 2, the principle of the circuit for simulating the resistor provided in this embodiment is as follows: the sampling resistance circuit converts an excitation current I of external equipment into a voltage signal, the voltage signal is connected to the analog-digital conversion circuit, the analog-digital conversion circuit converts the signal into a digital signal, the control circuit calculates a voltage value U to be output according to an ohm law U-I R according to a resistance value R to be simulated, the digital-analog conversion circuit is controlled to output the voltage U, the voltage output circuit automatically follows the voltage U output by the digital-analog conversion circuit, the voltage at an Out point is U, and therefore the output resistance R-U/I is achieved.

In summary, in this embodiment, according to the circuit for simulating the resistor of this embodiment and the circuit for simulating the resistor provided in this embodiment, the analog-to-digital conversion circuit and the digital-to-analog conversion circuit are adopted in the present invention, so that the digital setting of the resistor is realized, and the sampling circuit and the analog-to-digital conversion circuit are adopted, so that the real-time measurement of the excitation current is realized, and under the condition of different excitation currents, the accuracy of the output can still be ensured.

The above description is only for the purpose of illustrating the present invention and is not intended to limit the scope of the present invention, and any person skilled in the art can substitute or change the technical solution of the present invention and its conception within the scope of the present invention.