A method and system include a converter such as an analog-to-digital converter (“ADC”) and a controller. The converter is configured to receive a sensor signal, indicative of a physical measured quantity, and generate an output signal based on the sensor signal and the voltage reference. The converter is further configured to alternately receive a calibration voltage in lieu of the sensor signal and generate the output signal based on the calibration voltage and the voltage reference. The controller is configured to compare the output signal based on the calibration voltage and the voltage reference with an expected value of the output signal based on the calibration voltage and an assumed value of the voltage reference to detect variation of the voltage reference, and to compensate the output signal based on the sensor signal and the voltage reference as a function of the detected variation of the voltage reference.