JPH01231431A - A/d converting circuit - Google Patents

Abstract

PURPOSE:To correct the AD conversion without using any programming method by applying correction and calculation to a digital value subject to AD conversion by an AD conversion section based on a digital value representing a reference voltage level at the initial operation stored by a reference voltage level storage section. CONSTITUTION:An analog signal inputted via an analog signal input section 16 is AD-converted by an AD conversion section 10 after the end of the initial operation and its digital value is inputted directly to an arithmetic section 14. The arithmetic section 14 compares the digital value given from the AD conversion section 10 receiving an input analog voltage with a digital value representing a reference voltage level in the initial operation read from a reference voltage level storage section 12, the AD conversion value of the input analog voltage outputted from the AD conversion section 10 is corrected after the end of the initial operation nd its correction value is outputted externally via a digital signal output section 18. Thus, the AD conversion value is corrected without using any programming method.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an AD conversion circuit, and in particular, the present invention relates to an AD conversion circuit, and in particular, A
The present invention relates to an AD conversion circuit that automatically corrects fluctuations in D conversion values.

[Conventional technology]

There are various types of conventional AD conversion circuits, but all of them simply output the digital conversion value in a 1:1 ratio with respect to the input analog voltage based on the reference voltage that is the standard for AD conversion. It was not configured to correct the AD conversion value even if the level of the analog reference voltage fluctuated.

[Problem to be solved by the invention]

As mentioned above, conventional AD conversion circuits are configured to faithfully convert an analog input voltage into a digital value based on the level of the reference voltage and output it, so they are sensitive to fluctuations in the level of the reference voltage. In order to be able to handle this, a programmatic method had to be used, which caused the problem that the program configuration became complicated.

The present invention was made in view of these circumstances, and
It is an object of the present invention to provide an AD conversion circuit capable of correcting an AD conversion value according to fluctuations in a reference voltage that is a reference for AD conversion without using a programming method.

[Means to solve the problem]

In order to achieve the above object, the present invention includes an AD conversion means for AD converting an input analog voltage, and an analog reference voltage that is a reference for AD conversion at the time of initial operation.
A digital value obtained by D conversion is sent to a reference voltage level holding means, and after the initial operation is completed, a digital output from the AD conversion means is received, and this digital value and a digital value indicating a reference voltage level held by the reference voltage level holding means are provided. The present invention is characterized in that it has a calculation means for correcting the AD conversion value of the AD conversion means by performing a comparison calculation with the value.

With this configuration, the AD conversion value for the analog input voltage can be output as a relative value.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of an AD conversion circuit according to the present invention. As shown in the figure, the AD conversion circuit includes an AD conversion section 10 that converts an analog signal inputted from an analog signal input section 16 into a digital signal, and a digital signal of a reference voltage level that is AD-converted by this AD conversion section 10 during initial operation. A reference voltage level holding unit 12 that holds a value, and a reference voltage level holding unit 12 that holds a digital value of a human-powered analog voltage that is AD-converted by the AD conversion unit 10 after the initial operation is completed, and a reference voltage level at the time of initial operation. It is mainly composed of a calculation section 14 that performs correction calculations based on digital values indicating .

In the above configuration, as an initial operation, an analog reference voltage serving as a reference for AD conversion operation in the AD conversion unit IO is input from the analog signal input unit 16 to the AD conversion 910,
The digital value converted by the D conversion section 10 is held in the reference voltage level holding section 12.

Next, after the initial operation is completed, the analog signal input via the analog signal input 816 is AD converted by the AD converter 10, and the digital value thereof is directly input to the arithmetic unit.

The calculation unit 14 compares and calculates the digital value of the input analog voltage output from the AD conversion unit 10 and the digital value indicating the reference voltage level in the initial operation read from the reference voltage level holding unit 12. A.D.
The AD conversion value of the input analog voltage output from the converter 10 is corrected, and the corrected value is sent to the digital signal output unit 18.
output to the outside via.

In this way, according to this embodiment, even if the analog reference voltage level in the AD converter lO fluctuates, the AD conversion value can be corrected based on the reference voltage level at the time of initial operation, without using a programming method. can.

In addition, when the reference voltage level in the AD converter 10 changes significantly, it can be handled by increasing the frequency of initial operations, which simplifies the program configuration compared to the case where a conventional AD converter circuit is used. Since the conversion circuit can be considered as one unit, it is possible to provide versatility.

〔Effect of the invention〕

As explained above, in the present invention, after the initial operation is completed, the digital value AD-converted by the AD converter is converted into the reference voltage level held by the reference voltage level holding unit at the time of the initial operation.
Since the present invention is configured to perform correction calculations based on digital values indicating quasi-voltage levels, the present invention does not require programming techniques even if the reference voltage level, which is the standard for AD conversion in the AD conversion unit, changes. , it is possible to correct the AD conversion value, and it is possible to always output the AD conversion value with respect to analog human power as a relative value.

Therefore, an extremely remarkable effect is exhibited in the processing of analog signals that require high precision, such as the processing of detection outputs from sensors and the like.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of an AD conversion circuit according to the present invention. 10... AD conversion section, 12... Reference voltage level holding section, 14...
...Calculation section, 16...Analog signal input section, 18...
- Digital signal output section.

Claims (1)

[Claims] AD converts input analog voltage from analog to digital
a conversion means, a reference voltage level holding means for holding a digital value obtained by converting an analog reference voltage, which is a reference for AD conversion, into an analog-to-digital value by the AD conversion means at the time of initial operation; A.
1. An AD conversion circuit comprising: calculation means for correcting an AD conversion value of the D conversion means.