INTERFACE CIRCUIT

摘要

In a calibration circuit (101) of an interface circuit, a control circuit (140) controls a selector (120) so that voltages (V1, VREF) or voltages (V1, V2) are provided to a comparator (130) when executing calibration. The voltages can be switched between the inverting or non-inverting inputs of the comparator (120). Further, in each of these states, the control circuit (140) finds the signal value of the variable resistance control signal (UPCODE, DNCODE) when the output of the comparator (120) has changed, and uses the average value of the signal values that were found to find the calibration data for controlling the resistance value of the termination resistance.