Coulomb counter circuitry operable in a first mode of operation and a second mode of operation, the coulomb counter circuitry comprising: first analog to digital converter (ADC) circuitry configured to generate a first ADC output signal indicative of a current through a load coupled to the coulomb counter circuitry; second analog to digital converter (ADC) circuitry; offset correction circuitry; and accumulator circuitry configured to generate a signal indicative of a cumulative amount of charge transferred to the load, wherein in the second mode of operation, the coulomb counter circuitry is operable to enable the second ADC circuitry and to generate an offset correction factor based at least in part on a second ADC output signal output by the second ADC circuitry, and wherein in subsequent operation of the coulomb counter circuitry in the first mode of operation, the offset correction circuitry applies the offset correction factor to the first ADC output signal.