Patent ID: 7508258

Claim:
A chopper amplifier circuit, comprising: a chopper circuit for chopping an input signal based on a pulse having a predetermined frequency so as to modulate the input signal; an amplifier for amplifying the input signal thus modulated; a first sample hold circuit; and a second sample hold circuit, wherein: the chopper amplifier circuit demodulates the modulated signal thus amplified, and outputs the signal thus amplified as an output signal; the chopper circuit chops the input signal by a first pulse and a second pulse shifted from each other in phase by a half cycle, switches a relation of connection between an input terminal pair and an output terminal pair at a timing of the chopping, and outputs the input signal as a modulated signal; the amplifier amplifies the modulated signal and outputs the modulated signal thus amplified as an amplified signal; the first sample hold circuit holds the amplified signal at the first pulse and outputs the amplified signal at the second pulse; and the second sample hold circuit holds the amplified signal at the second pulse and outputs the amplified signal at the first pulse, and further wherein: the first sample hold circuit and the second sample hold circuit each include: a first switch pair into which the amplified signal is inputted; a hold circuit for holding a voltage level of the amplified signal inputted from the first switch pair; and a second switch pair for controlling an output of the amplified signal held by the hold circuit, and one of the first switch pair and the second switch pair is turned off while the other one of the first switch pair and the second switch pair is turned on.