Sensor device

A sensor device, comprising:

• a voltage detection type sensor for converting a physical quantity into a voltage value and outputting a voltage signal indicating the voltage value;
• a chopper amplifier for generating a modulation signal by chopping the voltage signal output from the sensor with a predetermined chopping frequency, amplifying the modulation signal into an amplification signal, then demodulating the amplification signal and outputting the demodulated amplification signal as an output signal including noise components having the chopping frequency and odd number multiples frequency of the chopping frequency;
• an integrator including an operational amplifier for amplifying a voltage difference between a voltage at a non-inverting input terminal and a voltage at an inverting input terminal, an input resistor connected to the inverting input terminal of the operational amplifier and a capacitor connected between the inverting input terminal and an output terminal of the operational amplifier and adapted to sample the output signal output from the chopper amplifier at a predetermined sampling frequency and integrate the sampled output signal;
• a sampling frequency adjuster that reduces the noise components that pass the integrator by adjusting the sampling frequency so that the chopping frequency is an n-fold of the sampling frequency, where n is a natural number equal to or greater than 1;
• the integration controller executes a control to generate the output signal integrated by the integrator by causing the operational amplifier to charge the capacitor by inputting the output signal output from the chopper amplifier to the inverting input terminal during a predetermined sampling period in every sampling cycle which is an inverse of the sampling frequency and causing the capacitor to discharge after the lapse of the sampling period;
• and
• a digital converter for converting the output signal integrated by the integrator into a digital signal.