Differential input A/D converter

A differential input A/D converter which converts a potential difference between two analog input signals from an analog value to a digital value, comprising:

• a first A/D converter which outputs a first conversion result obtained by A/D-converting a first analog input signal;
• a second A/D converter which outputs a second conversion result obtained by A/D-converting a second analog input signal;
• and
• a digital subtracter which outputs a differential conversion result obtained by subtracting the second conversion result from the first conversion result,
• wherein said second A/D converter comprises means for outputting the second conversion result in the form of an analog value, and
• said first A/D converter comprises means for superimposing, on the first conversion result, a result obtained by A/D-converting a difference between an analog value output from said second A/D converter and the second analog input signal.

A differential input A/D converter which converts a potential difference between two analog input signals from an analog value to a digital value, comprising:

• a first A/D converter which outputs a first conversion result obtained by A/D-converting a first analog input signal;
• a second A/D converter which outputs a second conversion result obtained by A/D-converting a second analog input signal;
• and
• a digital subtracter which outputs a differential conversion result obtained by subtracting the second conversion result from the first conversion result,
• wherein said second A/D converter comprises means for outputting the second conversion result in the form of a digital value, and
• said first A/D converter comprises means for obtaining an analog value of the second conversion result by D/A-converting the digital value output from said second A/D converter, and superimposing, on the first conversion result, a result obtained by A/D-converting a difference between the analog value of the second conversion result and the second analog input signal.

A differential input A/D converter which converts a potential difference between two analog input signals from an analog value to a digital value, comprising:

• a first A/D converter which outputs a first conversion result obtained by A/D-converting a first analog input signal;
• a second A/D converter which outputs a second conversion result obtained by A/D-converting a second analog input signal;
• and
• a digital subtracter which outputs a differential conversion result obtained by subtracting the second conversion result from the first conversion result,
• wherein said second A/D converter comprises means for outputting a lower bit side or upper bit side of the second conversion result in the form of a digital value, and D/A-converting the remaining bits, and outputs the D/A conversion result in the form of an analog value, and
• said first A/D converter comprises means for obtaining an analog value of the second conversion result from digital and analog values output from said second A/D converter, and superimposing, on the first conversion result, a result obtained by A/D-converting a difference between the analog value of the second conversion result and the second analog input signal.