Patent ID: 7420404

Claim:
A phase adjuster circuit in minute signal amplification using a reference signal and a phase shift reference signal having a given phase difference with respect to the reference signal, comprising: a chopping wave converter circuit that converts the reference signal into a chopping wave; a chopping wave amplitude control circuit to which the chopping wave is inputted and which outputs an adjustment signal corresponding to a difference of an amplitude value of the chopping wave with respect to an amplitude reference value to the chopping wave converter circuit; and a phase shift circuit that compares the inputted chopping wave with a given threshold value to output the phase shift reference signal, wherein the chopping wave converter circuit adjusts the amplitude value of the chopping wave according to the adjustment signal, wherein the chopping wave converter circuit comprises: a first constant current source circuit that variably controls the amount of current according to the adjustment signal; a capacitor element that is charged or discharged by the first constant current source circuit; and a switch circuit that controls charge and discharge operation with respect to the capacitor element according to the reference signal, wherein in the case where the amplitude value of the chopping wave crosses the amplitude reference value, the amount of current of the first constant current source circuit is decreased according to the adjustment signal, and wherein in the case where the amplitude value of the chopping wave does not cross the amplitude reference value, the amount of current of the first constant current source circuit is increased according to the adjustment signal.