2017 · 26 citations · 0 references
EngineeringElectrical EngineeringAnalog ElectronicsSensorsSystem-on-chip DesignAnalog Integrated CircuitsAnalog IntegrationCmos Circuit DesignDigital Integrated CircuitsMixed-signal Integrated Circuit DesignMixed-signal IntegrationAnalog Readout CircuitsAnalog-to-digital Converter DesignCmos Analog Circuit DesignCmos Analog Integrated CircuitsInput ImpedanceReadout Integrated CircuitsSensor Readout CircuitsVoltage Sensors
A VCO-based sensor readout circuit is presented. It comprises a VCO-based integrator with counters, and a capactively-coupled feedback DAC, to form a 1 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">st</sup> -order DSM with high input impedance and wide dynamic range for voltage sensors. Chopping is applied to suppress the flicker noise. The time-domain approach relaxes the voltage swing requirement compared to that of a Gm-C integrator, and thus area efficiency is achieved. The prototype is implemented in 40nm CMOS. It consumes 21μA under 1.2V supply. With a 100mVpp sinusoidal input, it achieves 74.9dB SNDR over 2 kHz BW and the THD is -82dB. This readout circuit is also measured with a Hall sensor to demonstrate its operation. The FoM and distortion achieves the state-of-the-art performance of VCO-based sensor readout circuits.