Ad converter

An analog-digital (AD) converter for performing AD conversion on measurement target voltages for a plurality of channels, comprising:

• an analog processing part configured to select one of the measurement target voltages and a plurality of reference voltages for each of the channels, to output an analog voltage signal corresponding to the selected voltage;
• a first selection part configured to select one of a plurality of analog voltage signals for the plurality of channels output from the analog processing part;
• a first AD conversion part configured to perform AD conversion on the analog voltage signal selected by the first selection part to generate a first original digital signal;
• a second selection part configured to select one of the plurality of analog voltage signals;
• a second AD conversion part configured to perform AD conversion on the analog voltage signal selected by the second selection part to generate a second original digital signal;
• a digital processing part configured to receive the first original digital signal and the second original digital signal;
• and
• a controller configured to control contents selected in the analog processing part, the first selection part, and the second selection part,
• wherein the plurality of reference voltages include a first reference voltage and a second reference voltage different from each other, and
• wherein the digital processing part includes:
• a first filter block having a first filter configured to generate a first corrected digital signal from the first original digital signal based on a first parameter, and configured to set the first parameter based on the first original digital signal obtained when the first reference voltage is selected by the analog processing part and the first original digital signal obtained when the second reference voltage is selected by the analog processing part;
• a second filter block having a second filter configured to generate a second corrected digital signal from the second original digital signal based on a second parameter, and configured to set the second parameter based on the second original digital signal obtained when the first reference voltage is selected by the analog processing part and the second original digital signal obtained when the second reference voltage is selected by the analog processing part;
• and
• an error determination part configured to output a predetermined error determination signal based on the first corrected digital signal and the second corrected digital signal.