The present disclosure provides a signal conversion circuit and fingerprint identification system. The signal conversion circuit is configured to generate a first digital signal according to a first analog signal, and includes a comparator and counter. The comparator includes a first input terminal configured to receive the first analog signal, a second input terminal connected to a reference voltage generator and configured to receive a reference voltage, and an output terminal configured to output a second digital signal. The counter is connected to the output terminal, and is configured to generate a first digital signal. The signal conversion circuit according to the present disclosure has the advantages of simple circuit structure, small circuit area, low cost and low power consumption.

A semiconductor device includes an AD conversion unit that performs AD conversion on an input signal based on a reference voltage to be supplied, a reference voltage detection unit that detects the reference voltage supplied to the AD conversion unit, and a control unit that corrects a result of the AD conversion by the AD conversion unit in accordance with the reference voltage detected by the reference voltage detection unit. Thereby, AD conversion can be performed accurately even when a reference voltage varies.

A semiconductor device includes an AD conversion unit that performs AD conversion on an input signal based on a reference voltage to be supplied, a reference voltage detection unit that detects the reference voltage supplied to the AD conversion unit, and a control unit that corrects a result of the AD conversion by the AD conversion unit in accordance with the reference voltage detected by the reference voltage detection unit. Thereby, AD conversion can be performed accurately even when a reference voltage varies.