Abstract: An adjusting circuit includes: a detection circuit outputting a detection signal indicative of whether a noise occurs in electric power inputted into an integrated circuit operating in synchronization with a clock signal; and a controlling circuit outputting to the integrated circuit a first clock signal having a first frequency, or a second clock signal having a second frequency lower than the first frequency when the detection signal indicates the noise occurs. The detection circuit includes a first circuit outputting a first delayed clock signal obtained by delaying the first clock signal according to an operation voltage of the integrated circuit, a second circuit outputting a second delayed clock signal obtained by delaying the first clock signal according to a threshold voltage lower than the operation voltage, and an output circuit outputting the detection signal based on a result of comparing phases of the first and second delayed clock signals.

Abstract: A semiconductor device includes a clock circuit that outputs a clock signal of a first frequency, a detection circuit that detects occurrence of power supply noise and end of the power supply noise, and a control circuit. The control circuit drops, in a case where the occurrence of the power supply noise is detected, a frequency of the clock signal from the first frequency to a second frequency, determine a frequency return time according to a noise occurrence time from the occurrence of the power supply noise to the end of the power supply noise, and returns the frequency of the clock signal from the second frequency to the first frequency on the basis of the frequency return time.

Abstract: A transmission circuit includes a first drive part capable of switching to one of an on state that is driven by current and an off state, i.e., a high impedance state in accordance the value of a first input signal; and a first termination resistor part connected in series with the first drive part. The resistance values of the first drive part are switched in accordance with the state of the first drive part.