A Calibration Technique of Charge-Pump PLL Readout Circuit for SiC-MOS Capacitor Hydrogen Sensors

A novel calibration technique for a Charge-Pump Phase-Locked Loop (CP-PLL) is proposed. The CP-PLL serves as a readout circuit for MOS capacitor hydrogen sensors, converting the non-linear small-signal capacitance variation into a shift in the PLL error voltage. The readout architecture is improved in order to allow for straightforward calibration, enhancing its accuracy. The effectiveness of the proposed calibration method is demonstrated through simulations, with initial errors of up to nearly 1 V reduced below 20 mV.