JPH1188166A - A/d converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drastically reduce difference in a conversion result by outputting a value where a conversion value is corrected by means of a correction value based on difference between a theoretical value and the conversion value or the theoretical value corresponding to the conversion value as an A/D conversion result. SOLUTION: An analog signal is inputted to an A/D converter 1 so as to be A/D converted and the obtained conversion value is stored in a register 2. A control circuit 4 reads the correction value stored in a non-volatile memory 3 in accordance with the conversion value. The correction value is given to an arithmetic circuit 5 and added to the conversion value which is given from the register 2 so that the conversion value of the A/D converter 1 is corrected. The corrected value is outputted from the arithmetic circuit 5 as the A/D conversion result of the inputted analog signal. Thus, the conversion value of the A/D converter 1 is corrected by the correction value which is obtained based on difference between the conversion value and the theoretical value so as to obtain the A/D conversion result. Or the theoretical value corresponding to the conversion value is previously stored in the non-volatile memory 3 and outputted as the conversion result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an A / D converter, and more particularly to error correction of an A / D converter.

[0002]

2. Description of the Related Art In recent years, the devices around us have been replaced from analog to digital at surprising speed.
It goes without saying that the technology of the A / D converter and the D / A converter is utilized in these backgrounds. At present, the range of application is expanding to AV equipment, measuring instruments, car electronics for vehicles, and the like, and the importance of A / D converters is increasing more and more.

In such an environment, there are absolute errors (offset errors, gain errors, non-linear errors, quantization errors, errors due to noise) as indices for measuring the performance of the A / D converter. Conventionally, each manufacturer has surpassed the development of a highly accurate A / D converter by reducing such errors. As a result, recently, for example, 16
Although high-precision bit A / D converters are increasing, A / D converters that eliminate the above error have not yet been developed.

[0004]

As described above,
In the conventional A / D converter, various errors exist, and attempts have been made to reduce these errors, and high-precision A / D converters have been developed. However, higher accuracy is required. Was.

Accordingly, the present invention has been made in view of the above, and an object of the present invention is to greatly reduce or eliminate various errors to achieve an A / D having higher accuracy. To provide a converter.

[0006]

According to a first aspect of the present invention, there is provided an A / D converter for converting an input analog signal into a digital signal, and the A / D converter.
A register for storing a conversion value of the digital signal obtained by the D converter, a memory for storing a correction value for correcting an error between a theoretical value of the conversion value and the conversion value, and a conversion stored in the register. A control circuit for reading a correction value corresponding to a value from the memory, a conversion value stored in the register and a correction value read from the memory by the control circuit, and calculating the calculation result by the input analog signal. An arithmetic circuit which outputs a signal as a conversion result is provided.

According to a second aspect of the present invention, there is provided an A / D converter for converting an input analog signal into a digital signal,
A register for storing a conversion value of the digital signal obtained by the A / D converter, a memory for storing a theoretical value (theoretical value) of the conversion value, and a logic corresponding to the conversion value stored in the register A control circuit that reads a value from the memory and outputs the read value as a conversion result of the input analog signal.

[0008]

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

FIG. 1 is a diagram showing a configuration of an A / D converter according to an embodiment of the present invention.

In FIG. 1, the A / D converter of this embodiment is obtained by an A / D converter 1 for converting an input analog signal into a digital signal (A / D conversion) and an A / D converter 1. A register 2 for receiving and storing the conversion value of the digital signal, and a correction value for correcting an error between a theoretical value (theoretical value) of the conversion value in the A / D conversion and the conversion value obtained by the A / D converter 1 A non-volatile memory 3 such as a flash memory for storing, a control circuit 4 for reading out a correction value corresponding to the converted value stored in the register 2 from the non-volatile memory 3, a converted value stored in the register 2 and the control circuit 4 And a calculation circuit 5 that calculates a correction value read from the nonvolatile memory 3 and outputs the calculation result as an A / D conversion result of the input analog signal.

In such a configuration, first, at the time of product evaluation, the A / D converter 1 is evaluated and the input analog signal is A / D converted to obtain a converted value of the digital signal. Theoretical value (theoretical value) is obtained, and the error between the two is obtained. A / D converter 1
In the case where the converted value in the above shows a characteristic as shown in FIG. 2, for example, with respect to the theoretical value, an error as shown in FIG. 2 occurs between the converted value and the theoretical value. Based on this error, a correction value for correcting the conversion value is obtained. When the conversion value is corrected by adding a correction value to the conversion value, if the conversion value and the theoretical value have a relationship of, for example, theoretical value> conversion value as shown in FIG. 2, the correction value is a positive value which is an absolute value of the error. When the conversion value and the theoretical value are in the relationship of the theoretical value <the conversion value,
The correction value is obtained as a negative value of the absolute value of the error. The correction value prepared in advance in this way is stored in the nonvolatile memory 3 together with the corresponding conversion value.

In this state, when an analog signal is input to the A / D converter 1, the analog signal is
The A / D converter 1 performs A / D conversion, and the converted value obtained by the A / D converter 1 is given to the register 2 and stored. The conversion value stored in the register 2 is supplied to the control circuit 4, and the control circuit 4 reads out the correction value stored in the nonvolatile memory 3 from the nonvolatile memory 3 corresponding to the conversion value based on the conversion value. . The correction value read by the control circuit 4 is given to the arithmetic circuit 5, and this correction value and the converted value stored in the register 2 and given from the register 2 are added by the arithmetic circuit 5, whereby the A / D The converted value of the converter 1 is corrected, and the corrected value is output from the arithmetic circuit 5 as an A / D conversion result of the input analog signal.

In such an embodiment, A / A is calculated based on the correction value obtained based on the error between the converted value and the theoretical value.
Since the A / D conversion result is obtained by correcting the conversion value of the D converter 1, the above-described error can be significantly reduced as compared with the conventional A / D converter.

The nonvolatile memory 3 stores only the correction value, and the control circuit 4 stores the correction value corresponding to the converted value in accordance with the converted value given from the register 2. 3 address,
The nonvolatile memory 3 may be accessed based on this address, and the correction value corresponding to the converted value may be read from the nonvolatile memory 3.

FIG. 3 is a diagram showing a configuration of an A / D converter according to an embodiment of the present invention.

In FIG. 3, a feature of this embodiment is that, compared to the embodiment shown in FIG. 1, a theoretical value corresponding to a converted value is stored in advance in the nonvolatile memory 3 in place of the correction value. When the conversion value obtained by the A / D converter 1 and stored in the register 2 is given to the control circuit 4, the control circuit 4 reads the theoretical value from the nonvolatile memory 3 in accordance with the conversion value, and reads the theoretical value. The control circuit 4 converts the theoretical value as an A / D conversion result of the input analog signal.
Output from. In such an embodiment, since the output A / D conversion result is a theoretical value, the above-described error can be eliminated.

[0017]

As described above, according to the present invention, a value obtained by correcting a conversion value by a correction value based on an error between a theoretical value and a conversion value, or a theoretical value corresponding to a conversion value is converted into an A / D signal. Since the conversion result is output, it is possible to significantly reduce or eliminate errors in the conversion result,
A highly accurate A / D converter can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an A / A system according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a configuration of a D converter.

FIG. 2 is a diagram illustrating an example of a relationship between an A / D conversion value and a theoretical value for an analog input signal.

FIG. 3 is a diagram illustrating an A / A control system according to an embodiment of the present invention;
FIG. 3 is a diagram illustrating a configuration of a D converter.

[Explanation of symbols]

 Reference Signs List 1 A / D converter 2 Register 3 Non-volatile memory 4 Control circuit 5 Operation circuit

Claims (2)

[Claims] 1. An A / D converter for converting an input analog signal into a digital signal, a register for storing a converted value of the digital signal obtained by the A / D converter, and a theoretical value of the converted value A memory for storing a correction value for correcting an error between the conversion value and the conversion value, a control circuit for reading a correction value corresponding to the conversion value stored in the register from the memory, a conversion value stored in the register, An A / D converter comprising: a control circuit for calculating a correction value read from the memory by a control circuit, and outputting the calculation result as a conversion result of the input analog signal. 2. An A / D converter for converting an input analog signal into a digital signal, a register for storing a conversion value of the digital signal obtained by the A / D converter, and a theoretical value of the conversion value A memory for storing (theoretical value); and a control circuit for reading a theoretical value corresponding to the converted value stored in the register from the memory, and outputting the read value as a conversion result of the input analog signal. A / D converter characterized by the above-mentioned.