SEMICONDUCTOR DEVICE, ANALOG-TO-DIGITAL CONVERSION METHOD, ONBOARD SYSTEM, AND MEASUREMENT METHOD

There is provided a semiconductor device including: an integrator that repeats integrating a first reference voltage after integrating an analog signal; a comparator that compares an output of the integrator and a second reference voltage; a counter circuit that counts a first integration time determined to integrate the analog signal, and a second integration time until the output of the integrator reaches the second reference voltage from start of integration of the first reference voltage; a calculation circuit that calculates a digital value of the analog signal based on the first and the second integration times; a control circuit that performs control so that the analog signal is input to the integrator while the counter circuit counts the first integration time; and an integration time update circuit that updates the first integration time counted by the counter circuit based on the second integration time counted thereby.