JP2606813B2 - Ideal output processor for operational amplifier - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ideal output processing device of an operational amplifier that can obtain an ideal output obtained by performing optimum gain adjustment and offset adjustment for an arbitrary input voltage.

[Conventional technology]

FIG. 2 is a block diagram specifically showing a conventional ideal output processing device of an operational amplifier. In the figure, reference numeral 1 denotes an operational amplifier, 2 denotes a signal input terminal of the operational amplifier 1, 3 denotes a common terminal, and R ₁ denotes a common terminal. , R ₂ is an external impedance that sets the ideal output of the operational amplifier 1, VR ₁ is the gain adjustment knob, R _3, R _4, R ₅ is the resistance for the gain setting, VR ₂ is offset adjustment knob, 4 operation An A / D converter connected to the output side of the amplifier 1.

 Next, the operation will be described.

In the above circuit, the offset adjustment volume VR ₂
No, the external impedance R ₂ is connected to the output terminal of the operational amplifier 1, the case of applying an arbitrary input signal Ei to the signal input terminal 2, ideally the operational amplifier 1 outputs E
Is And the output characteristics are as shown in FIG.

However, in practice, an ideal output cannot be obtained due to variations in circuit elements or errors in resistors, and any input signal Ei =
The output E and the slope R ₂ ′ / R ₁ ′ at 0 change, and the output characteristics change as shown in FIG.

Therefore, conventionally connects the offset adjusting volume VR ₂ to an external impedance R ₂ in series as shown in FIG. 2, when the offset adjustment is short-circuited the second input terminal 2 and 3, these Input potential difference between the zero,
Offset adjustment volume VR ₂ so that the output becomes zero
Adjusting operation.

Next, when performing gain adjustment, a constant voltage (for example, 10 V) is applied to the signal input terminal 2, and the ideal output of the operational amplifier 1 determined by the values of the external impedances R ₁ and R ₂ (in this case, 10 × R ₂ / R ₁ V) so obtained, to perform the output adjustment by the gain adjustment knob VR _1.
As described above, conventionally, offset adjustment and gain adjustment are individually performed by external impedance adjustment.

[Problems to be solved by the invention]

Since the conventional ideal output processing device of the operational amplifier is configured as described above, its own expensive volumes VR ₁ and VR ₂ are required for the offset adjustment and the gain adjustment performed to obtain the ideal output. Becomes Therefore,
In a device that requires many circuits for such ideal output processing,
Increases the number of use of the volume VR _1, VR _2, except that the adjustment operation described above becomes cumbersome, a problem with requiring a sufficiently large installation space for the volume installation, unavoidable significant cost increase There was a point.

The present invention has been made in order to solve the above-mentioned problems, and automatically executes offset adjustment and gain adjustment without using a volume to easily and inexpensively obtain a desired ideal output for an arbitrary input. It is an object to obtain an ideal output processing device of an operational amplifier that can be obtained.

[Means for solving the problem]

An ideal output processing device for an operational amplifier according to the present invention includes:
An operational amplifier having a signal input terminal and a common terminal as two input terminals, an external impedance for adjusting the output of the operational amplifier, and an offset output E _{0 of} the operational amplifier obtained by short-circuiting the two input terminals; The output E _{2 of the} operational amplifier obtained by applying a full-scale voltage between the input terminals, the ideal output E ₃ of the operational amplifier determined based on the external impedance obtained by applying the full-scale voltage,
A non-volatile memory for storing E ₀ , E ₂ , E ₃ in advance, and the respective outputs E ₀ ,
E ₂ , E ₃ and any input voltage applied between the two input terminals
Based on the output E _{01 of the} operational amplifier for Ei, the ideal output E ₀₀ for the arbitrary input voltage Ei And a computer that computes

[Action]

The computer according to the present invention stores the offset output measured by the offset adjustment and the gain adjustment automatically performed, the output at the time of applying the full-scale voltage, and the ideal output, and based on the data, rapidly outputs an arbitrary input signal. The calculation acts to obtain an ideal output and acts to suppress each of the adjustment errors.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 5 denotes a computer, which is connected to the output side of the A / D converter 4. Reference numeral 6 denotes a nonvolatile memory connected in a circuit connecting the A / D converter 4 and the computer 5. 7 is a computer 5 for offset adjustment
Are full scale instruction switches for instructing the computer 5 to perform gain adjustment, and the operation of these instruction switches 7 and 8 automatically calculates the offset and gain of the operational amplifier 1; The offset output E _{0 of} the operational amplifier obtained by short-circuiting two input terminals, the output E _{2 of the} operational amplifier obtained by applying a full-scale voltage between the two input terminals, and the output E ₂ obtained by applying the full-scale voltage E ₀ , E ₂ , E ₃ of the ideal output E ₃ of the operational amplifier determined based on the external impedance
Is stored in the nonvolatile memory 6. The same components as those shown in FIG. 2 are denoted by the same reference numerals, and the description thereof will not be repeated.

 Next, the operation will be described.

First, when adjusting the offset, two input terminals 2,
3, the input voltage is reduced to zero, and the offset instruction switch 7 is turned on. Therefore, the computer 5 outputs the offset output E ₀ of the operational amplifier 1 to the A / D converter 4.
Read through. This offset output E ₀ is the input voltage
E ₁ is to zero, the output is considered to shift the output of the operational amplifier 1 where must be zero, the deviation, i.e. the offset amount is stored in the nonvolatile memory 6.

Then, when the gain adjustment is applied with a full-scale input E ₁ between 2 input terminals 2 and 3, turns on the full scale indication switch 8. The output of the operational amplifier 1 at this time is E _2, and the with the computer 5 reads the output E _2, the nonvolatile memory 6 stores the output E _2. Note that the ideal output E ₃ of the operational amplifier 1 is In is determined, the ideal output E ₃ also previously taught in advance microcomputer and stored in the nonvolatile memory 6.

The computer 5 automatically executes offset adjustment and gain adjustment of the operational amplifier 1 based on the outputs E ₀ and E ₂ . When an arbitrary input signal voltage Ei is applied between the two input terminals 2 and 3 after this adjustment, the computer outputs the output E ₀₁ obtained by the operational amplifier 1 at this time.
Based on the above outputs E ₀ , E ₂ , E ₃ , an ideal output E _{00 is} derived, Conceivable. That is, Therefore, That is, in this embodiment, the calculated value of the ideal output determined by the measured value of the offset data and the gain data and the external impedance automatically obtained by the computer, and the output value with respect to the actual input value of the operational amplifier are nonvolatile. Since the data is stored in the memory, and thereafter, the arithmetic processing is performed based on the data stored in the nonvolatile memory, the optimum ideal output of the operational amplifier can be obtained at high speed.

〔The invention's effect〕

As described above, according to the present invention, the computer automatically performs the optimal offset adjustment and gain adjustment processing based on the offset output and the gain output, and performs the offset output, the gain output, A configuration in which an ideal output set by an external impedance is stored in a nonvolatile memory, and thereafter, an ideal output for each operational amplifier output for an arbitrary input signal voltage is obtained based on data stored in the nonvolatile memory. As a result, it is possible to omit the cumbersome operations of offset adjustment and gain adjustment using the volume as in the past, simplify the configuration by avoiding the use of a volume,
Effects such as reduction in cost can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an ideal output processing device of an operational amplifier according to one embodiment of the present invention, FIG. 2 is a block diagram showing a conventional ideal output device of an operational amplifier, FIG.
FIG. 4 is an output characteristic diagram of the operational amplifier for an arbitrary input signal. 1 is an operational amplifier, 2 is a signal input terminal, 3 is a common terminal,
5 is a computer. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-37826 (JP, A) JP-A-58-43031 (JP, A)

Claims (1)

(57) [Claims] An operational amplifier having a signal input terminal and a common terminal as two input terminals, an external impedance for adjusting the output of the operational amplifier, and an offset output of the operational amplifier obtained by short-circuiting the two input terminals. E ₀ , the output E _{2 of the} operational amplifier obtained by applying a full-scale voltage between the two input terminals, and the ideal of the operational amplifier determined based on the external impedance obtained by applying the full-scale voltage A non-volatile memory for storing E ₀ , E ₂ , E ₃ of the output E ₃ in advance, and the output E ₀ , E ₂ , E ₃ read from the non-volatile memory and applied between the two input terminals based on the output E ₀₁ of the operational amplifier for any input voltage Ei, the ideal output E with respect to the given input voltage Ei ₀₀ An ideal output processing device for an operational amplifier comprising: