A/D conversion circuit

An A/D conversion circuit comprising:

• a comparison-reference-signal generator section configured to generate a comparison reference signal, which has a specific waveform, synchronized with a sampling clock signal;
• a comparator configured to compare a voltage of an input signal and a voltage of the comparison reference signal to thereby generate a first trigger signal;
• a first time to digital converter configured to calculate a first time digital value corresponding to a phase difference between a reference clock signal and the first trigger signal;
• and
• a digital-signal generator section configured to generate, based on the first time digital value and a second time digital value corresponding to a phase difference between the reference clock signal and a second trigger signal based on the sampling clock signal, a digital signal corresponding to the voltage of the input signal, wherein
• the first time to digital converter includes:
• a first state transition section configured to start transition of a state based on the first trigger signal and output first state information indicating the state;
• and
• a first weight operation section configured to, in synchronization with the reference clock signal, perform, on a value based on the first state information, weighting corresponding to time elapsing and perform a predetermined arithmetic operation to thereby calculate the first time digital value corresponding to a number of transition times of the state of the first state transition section.