Patent ID: 7667549

Claim:
A semiconductor device comprising: a transmission and reception control circuit configured to receive a first signal from an outside and transmit a second signal to the outside; a ring oscillator; a ring oscillator control circuit operationally connected to the ring oscillator and the transmission and reception control circuit, and configured to detect an edge included in the first signal and control an operation of the ring oscillator; a clock generation circuit operationally connected to the ring oscillator and the ring oscillator control circuit, and configured to generate a clock signal based on the operation of the ring oscillator; and a logic circuit operationally connected to the transmission and reception control circuit, the ring oscillator control circuit, and the clock generation circuit, and configured to perform an operation in accordance with the clock signal, wherein the operation of the ring oscillator is started and the clock signal is output from the clock generation circuit when the ring oscillator control circuit detects the edge included in the first signal, and wherein the operation of the ring oscillator is stopped and an output of the clock signal from the clock generation circuit is stopped when a transmission of the second signal from the transmission and reception control circuit to the outside is terminated.