Successive approximation ad converter and successive approximation ad conversion method

A successive approximation AD converter, comprising:

• a DA converter that converts a higher conversion data greater than an approximate value into an analog higher converted voltage and converts a lower conversion data less than the approximate value into an analog lower converted voltage;
• a sample-and-hold circuit that samples and holds voltage differences between an input voltage input from an outside and each of the higher converted voltage and the lower converted voltage;
• a comparator that outputs, based on the voltage differences output from the sample-and-hold circuit, a first comparison result indicating whether the input voltage is greater or less than the higher converted voltage and a second comparison result indicating whether the input voltage is greater or less than the lower converted voltage;
• and
• an operation unit that changes the approximate value based on the first comparison result and the second comparison result, changes a next higher conversion data and a next lower conversion data based on the changed approximate value, and outputs the changed next higher conversion data and next lower conversion data to the DA converter,
• wherein the successive approximation AD converter is configured such that operations of the DA converter, the sample-and-hold circuit, the comparator, and the operation unit are repeated to obtain a final approximate value that is output as AD converted data;
• and
• wherein the operation unit determines a next order in which the next higher conversion data and the next lower conversion data are output to the DA converter based on the first comparison result, the second comparison result, and a previous order in which the higher conversion data and the lower conversion data have been output.