JPH084213B2 - Non-linear two terminal circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a non-linear two-terminal circuit used in an electric circuit and capable of simulating the non-linear characteristic of voltage-current with a high degree of approximation. It is a thing.

(Prior Art) Conventionally, when a non-linear characteristic of voltage-current (VI) in an electric circuit, for example, the characteristic shown in FIG. 2 is simulated by a two-terminal circuit, as shown in FIG. Switch 21
And a resistor 31 connected in series between the two terminals 10 and 11, and a level detector 41 connected between the two terminals 10 and 11, and a switch 22, 23 and resistors 32, 33 and level detectors 42, 43. Is constructed in the same manner as above and is connected in parallel between the two terminals 10 and 11. Where the level detector 41,4
In 2, 43, when the voltage applied between the two terminals 10 and 11 exceeds the respective voltage set for each level detector, the switches 21, 22 and 23 corresponding to the respective level detectors are closed. . Therefore, the characteristic of the two-terminal circuit having such a configuration is a linear approximation of the nonlinear characteristic of FIG.
In addition, in the case of FIG.

However, in the conventional two-terminal circuit shown in FIG. 3, if the approximation of the polygonal line approximation is increased, that is, the non-linear characteristic of the voltage-current is approximated in detail, the above-mentioned switch, resistance, level detector and There is a problem in that a large number of branches consisting of must be used, and the degree of approximation cannot be so high.

(Problems to be Solved by the Invention) As described above, in the conventional two-terminal circuit, it is necessary to use a large number of circuit elements such as switches and resistors in order to approximate the non-linear characteristic of voltage-current in detail. There is a problem that the structure becomes complicated and the degree of approximation of the polygonal line approximation cannot be increased.

The present invention has been made to solve the above-described problems, and its object is to provide a voltage-current nonlinear characteristic with a high degree of approximation with a simple configuration without adding circuit elements such as switches and resistors. It is to provide a nonlinear two-terminal circuit that can be simulated.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the nonlinear two-terminal circuit of the present invention is obtained by amplifying a voltage applied between two terminals or the voltage. Input voltage, the absolute value circuit that calculates the absolute value of the input voltage and outputs it as a voltage value signal,
An analog / digital converter that converts the voltage value signal output from the absolute value circuit into a digital signal and outputs the digital signal, and a desired voltage-current nonlinear characteristic are stored in advance, and analog / digital conversion is performed according to the voltage-current nonlinear characteristic. Processing means for reading out and outputting a current value signal corresponding to the voltage value signal output from the container, and digital / output for converting the current value signal output from the storage processing means into an analog signal and outputting the analog signal.
Between the analog converter and the current value signal output from the digital / analog converter, the constant current circuit that outputs the current corresponding to the current value signal, and the current output from the constant current circuit between the two terminals. And a diode bridge circuit supplied between the two terminals so as to have the same polarity as that of the voltage.

Here, in particular, as the storage processing means, the unipolar voltage-current non-linear data of the desired voltage-current non-linear characteristic has a point at which the voltage axis is equally divided as an address, and the current value is previously stored as data in the content of the address. It is assumed to be remembered.

(Operation) Therefore, in the non-linear two-terminal circuit of the present invention, the voltage applied between the two terminals can be obtained by dividing the curve of the desired voltage-current non-linear characteristic into fine divisions and storing them in the storage means. Is detected through an operational amplifier and an absolute value circuit, the current value corresponding to the detected voltage is read from the storage processing means, and the current corresponding to the current value is supplied from the constant current circuit to the voltage between the two terminals through the diode bridge circuit. The voltage is supplied between the two terminals to which the above voltage is applied so that they have the same polarity.

(Embodiment) The present invention configures a circuit that detects a voltage applied between terminals of a two-terminal circuit and feeds back the voltage using the voltage value. The gist is to provide a non-linear two-terminal circuit having a characteristic of supplying a current therebetween.

Then, in order to realize this, an absolute value circuit connected between two terminals of the constant current circuit, an analog / digital converter,
By comprising the memory processing means, the digital / analog converter, and the constant current circuit, the current flowing through the constant current circuit is the voltage applied between the two terminals, which is the voltage of the memory processing means that has been given in advance. This makes it possible to obtain a characteristic in which the current has a magnitude according to the non-linear characteristic of the current.

Hereinafter, the present invention will be described with reference to an embodiment shown in the drawings.

FIG. 1 shows a configuration example of a non-linear two-terminal circuit according to the present invention, and the same parts as those in FIG. 3 are designated by the same reference numerals. In FIG. 1, 1 is two terminals 10,11
An operational amplifier 2 for detecting the voltage V applied between the two is an absolute value circuit for obtaining the absolute value of the voltage V detected by the operational amplifier 1, and 3 is a digital voltage value signal output from the absolute value circuit 2. It is an analog / digital (A / D) converter that encodes and converts it into a digital signal. Further, 5 is a RAM as a storage processing unit connected to a computer not shown.
And a desired voltage-current non-linear characteristic is stored in advance, that is, the unipolar voltage-current non-linear characteristic data of the voltage-current non-linear characteristic shown in FIG. A current value is stored as data in the content of the address, and a current value signal 9 as a data signal corresponding to a voltage value signal 8 as an address signal output from the analog / digital converter 3
Is output. Further, 4 is a digital / analog (D / A) converter for converting the current value signal 9 output from the memory 5 into an analog signal, and 6 is an output signal from the digital / analog converter 4, The constant current circuit supplies a current I corresponding to an input signal value between the two terminals 10 and 11 via a diode bridge 7.

Next, the operation of the nonlinear two-terminal circuit configured as described above will be described.

In FIG. 1, the voltage V applied between the two terminals 10 and 11 is detected by the operational amplifier 1 and given to the absolute value circuit 2. In the absolute value circuit 2, this operational amplifier 1
The absolute value of the voltage V detected by is calculated and output to the analog / digital converter 3 in the subsequent stage. Then, the analog / digital converter 3 digitally encodes the voltage value signal input from the absolute value circuit 2 and sends the voltage value signal 8 to the memory 5 as an address signal. Then, in the memory 5, a point obtained by equally dividing the voltage axis of the unipolar voltage-current nonlinear characteristic data of the voltage-current nonlinear characteristic shown in FIG. 2 is stored as an address, and the current value is stored as data in the content of the address. Therefore, with respect to the voltage value signal 8 output as an address signal from the analog / digital converter 3, the current value signal 9 corresponding to the voltage is output to the digital / analog converter 4 as a data signal. Then, the digital / analog converter 4 converts the current value signal 9 input from the memory 5 into an analog signal and supplies it to the constant current circuit 6. This constant current circuit 6
Then, a current I corresponding to (matching with) the input signal value from the digital / analog converter 4 is passed to the diode bridge 7. This current becomes the current value I with respect to the voltage value V on the voltage-current nonlinear characteristic of FIG. Then, in the diode bridge 7, the current I given from the constant current circuit 6 is supplied between the two terminals 10 and 11. The reason why the diode bridge 7 is used in the above is to store only one polarity of the voltage-current non-linear characteristic in the memory 5, and the two terminals 10 and 1
This is because the current I having the same polarity as the polarity of the voltage V applied during 1 is supplied.

As described above, in the non-linear two-terminal circuit of the present embodiment, the second configuration has a simple structure without adding circuit elements such as a switch, a resistor and a level detector as in the conventional case.
It is possible to simulate the voltage-current non-linear characteristic in the figure with an extremely high degree of approximation. To be more specific, if the analog / digital conversion is now 12 bits, the voltage can be divided into 1 / (2 ¹² −1) = 1/4095. That is, the unipolar portion of the voltage-current nonlinear characteristic can be approximated by the 4095 broken line. Furthermore, by rewriting the stored data in the memory 5, the voltage-current non-linear characteristic can be arbitrarily and easily changed.

The present invention is not limited to the above-described embodiments, but can be implemented in the same manner as described below.

(A) In the above embodiment, it is possible to insert an isolation amplifier in the front stage of the analog / digital converter 3 and in the rear stage of the digital / analog converter 4 to insulate the terminals 10 and 11 from the memory 5 side. is there.

(B) In the above-described embodiment, by biasing the input signal of the analog / digital converter 3, the output of the analog / digital converter 3 at the place where the change of the current with respect to the voltage of the voltage-current non-linear characteristic is small becomes zero. As a result, it is possible to divide the portion where the change in current with respect to voltage is large by 4095. In this case, it becomes possible to approximate the portion of the voltage-current non-linear characteristic in which the change of the current with respect to the voltage is large in more detail.

(C) The analog / digital conversion is the same as that of the embodiment shown in FIG. 1, and the contents of the memory 5 are used for the logarithmic conversion of the voltage-current nonlinear characteristic, and the digital / analog converter 4 is used.
It is also possible to add a logarithmic-linear converter in the latter stage. In this case, it is possible to approximate the portion of the voltage-current non-linear characteristic where the change in current with respect to the voltage is large in more detail than in the above embodiment.

In addition, the present invention can be variously modified and implemented within the scope of the invention.

As described above, according to the present invention, the voltage applied between two terminals or the voltage obtained by amplifying the voltage is used as an input, and the absolute value of the input voltage is calculated to obtain the voltage. An absolute value circuit for outputting as a value signal, an analog / digital converter for converting a voltage value signal output from the absolute value circuit into a digital signal and outputting the digital signal, and a desired voltage-current non-linear characteristic are stored in advance, − According to the current non-linear characteristic,
Storage processing means for reading and outputting a current value signal corresponding to the voltage value signal output from the analog / digital converter, and digital / analog for converting the current value signal output from the storage processing means into an analog signal for output. A converter,
A constant current circuit that inputs the current value signal output from the digital / analog converter and outputs a current corresponding to the current value signal, and the current output from the constant current circuit has the same polarity as the voltage between the two terminals. Since it is configured with a diode bridge circuit that supplies between two terminals so that the voltage-current non-linear characteristic is high with a simple configuration without adding circuit elements such as switches and resistors. An extremely reliable non-linear two-terminal circuit that can be simulated with a degree of approximation can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a nonlinear two-terminal circuit according to the present invention, FIG. 2 is a diagram showing a voltage-current nonlinear characteristic to be approximated, and FIG. 3 is an example of a conventional two-terminal circuit. It is a block diagram. 1 ... Operational amplifier, 2 ... Absolute value circuit, 3 ... Analog / digital converter, 4 ... Digital / analog converter,
5 ... Memory, 6 ... Constant current circuit, 7 ... Diode bridge, 10,11 ... Terminal, 21,22,23 ... Switch, 31,3
2,33 …… Resistance, 41,42,43 …… Level detector.

Claims (2)

[Claims] 1. An absolute value circuit for inputting a voltage applied between two terminals or a voltage obtained by amplifying the voltage and for obtaining an absolute value of the input voltage and outputting the absolute value circuit as a voltage value signal, An analog / digital converter that converts the voltage value signal output from the absolute value circuit into a digital signal and outputs the digital signal, and a desired voltage-current nonlinear characteristic is stored in advance, and the analog / digital converter according to the voltage-current nonlinear characteristic is stored. Storage processing means for reading and outputting a current value signal corresponding to a voltage value signal output from the converter, and a digital / analog converter for converting the current value signal output from the storage processing means into an analog signal for output. A constant current circuit that inputs a current value signal output from the digital / analog converter and outputs a current corresponding to the current value signal; Nonlinear two-terminal circuit, wherein a current output from the road comprising and a supply diode bridge circuit between the two terminals so that the voltage of the same polarity between the two terminals. 2. The storage processing means has a desired voltage-
Unipolar voltage-current nonlinear data of the current nonlinear characteristic is
The nonlinear two-terminal circuit according to claim 1, wherein a point obtained by equally dividing the voltage axis is used as an address, and a current value is previously stored as data in the content of the address.