Synaptics Incorporated
Amplifier flicker noise and offset mitigating systems and methods

Abstract:

A system includes an amplification circuit and offset calibration circuit. The amplification circuit includes a modulation circuit operable to modulate a received signal, an amplifier operable to amplify the modulated signal, and a modulation circuit operable to demodulate the amplified signal. The offset calibration circuit includes a logic circuit operable to set a control signal and adjust the control signal based on an output of the amplification circuit, where the output is based on the demodulated signal, and a compensation signal generator operable to generate a compensation signal based on the control signal to compensate for an offset associated with the amplification circuit, and apply the compensation signal on the amplification circuit to adjust the output of the amplification circuit. The offset calibration circuit in conjunction with the application circuit reduces flicker, offset, and offset drift, and also suppresses the upmodulate ripple due to chopping.