Successive-approximation type a/d conversion circuit

A successive-approximation type A/D conversion circuit that converts an analog signal into digital data, comprising:

• a selection signal input terminal configured to receive a selection signal which is active or non-active;
• a clock input terminal configured to receive a clock signal;
• a main circuit configured to generate the digital data in synchronization with the clock signal during an active period in which the selection signal is active;
• a data output terminal;
• a data output circuit configured to output the digital data as a serial signal synchronized with the clock signal from the data output terminal during the active period;
• and
• a level adjustment circuit,
• wherein the data output circuit outputs the serial signal by setting a signal level of the data output terminal to a first level in response to switching of the selection signal from the non-active to the active and subsequently, setting the signal level of the data output terminal to the first level or a second level during the active period, and
• wherein when the signal level of the data output terminal has the second level at a time of switching from the active period to a non-active period in which the selection signal is non-active, the level adjustment circuit changes the signal level of the data output terminal from the second level to the first level after switching to the non-active period.