Amplifier and signal processing device

摘要

When a switch is set to off, and a switch is set to on, the voltage of a SigOut terminal is stabilized with a reference voltage, and a bias voltage is applied to a capacitor. Changing the switch from on to off, with the bias voltage retained in the capacitor, a detection signal which is input via a SigIn terminal is amplified with the reference voltage as a reference, and an amplified signal is output from the SigOut terminal.

主权项

1. An amplifier comprising:
a first resistor; a first operational amplifier into which an input signal is input into an inverting input terminal via the first resistor from a signal input terminal; a second resistor, one end of which is connected to the inverting input terminal of the first operational amplifier and the other end of which is connected to the output terminal of the first operational amplifier; a second operational amplifier into which a prescribed reference voltage is input into the non-inverting input terminal and the output terminal is connected to the non-inverting input terminal of the first operational amplifier; a first capacitor, one end of which is connected to the inverting input terminal of the second operational amplifier and the other end of which is connected to the output terminal of the second operational amplifier; a first switch, one end of which is connected to the inverting input terminal of the second operational amplifier and the other end of which is connected to the output terminal of the second operational amplifier; a third resistor and a second switch connected in series, one end of which is connected to the output terminal of the first operational amplifier and the other end of which is connected to the inverting input terminal of the second operational amplifier; and, a control circuit for receiving input of amp control signals and switching the first switch and the second switch on and off in a prescribed order based on the amp control signals; wherein through the control circuit switching the first switch and the second switch on and off in the prescribed order, the first operational amplifier amplifies the input signal with the prescribed reference voltage as a reference and an amplified signal is output from a signal output terminal connected to the output terminal of the first operational amplifier.