| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device which operates normally even when a communication distance is extremely short while the maximum communication distance is maintained, and which increases amplitude of a response waveform even when a large amount of electric power is supplied to the semiconductor device and a protection circuit operates.SOLUTION: The semiconductor device includes: a first modulation circuit and a second modulation circuit each of which performs load modulation by an input signal; a detection circuit for determining an output signal by electric power supplied externally; a protection circuit whose operation is controlled by the output signal of the detection circuit; and a modulation selecting circuit for switching selection of the first modulation circuit and the second modulation circuit depending on the output signal of the detection circuit. |
