Patent ID: 7948318
Filing Date: 2011-05-24
Classification: H03F

Abstract:
1. An amplifying circuit for amplifying an input signal having a waveform that alternates repeatedly between a first section where a signal value varies within a variation range limited by at least one of upper and lower limit values and a second section that is a section other than the first section, comprising: an amplifying unit which amplifies the input signal and applies amplified signal to a designated load; a current detection unit which detects a load current that flows into the designated load upon application of the amplified signal; an estimating unit which calculates, based on a voltage level of the input signal, an estimated value of the load current to be supplied to the load; and an adjusting unit which adjusts an input bias, to be applied to the amplifying unit, in such a manner as to reduce a difference value representing a difference between the estimated value and the load current detected by the current detection unit.