Amplification circuit and integrated circuit having such and controlling method of the amplification circuit

摘要

An amplification circuit includes an amplifying unit to which a signal supplied via an AC coupling capacitor is input, the amplifying unit starting an amplifying operation for the input signal when a potential level at an input portion of the amplifying unit reaches an operating threshold level from a predetermined low level, and a feedback resistor circuit, provided in a feedback line through which electric charge is fed back to the input portion of the amplifying unit, in which feedback resistor circuit a resistance value is controllable by a control signal supplied from an outside thereof.