CURRENT GENERATION

Current-generation circuitry, comprising: a plurality of candidate current sources operable to generate respective candidate currents; an output current source operable to generate an output current; comparator circuitry; and control circuitry operable to control the current sources and the comparator circuitry and connections therebetween to: in an adjustment step, generate an adjustment current by selecting one of the candidate currents or by summing together a plurality of the candidate currents, and calibrate at least a plurality of the candidate current sources including each candidate current source which contributes to that adjustment current by comparing that adjustment current to a comparative current using the comparator circuitry and adjusting control signals applied to the candidate current sources being calibrated to adjust their candidate currents until that adjustment current and the comparative current are brought into a defined relationship; and in a calibration step, following the adjustment step, generate a reference current by selecting one of the candidate currents generated by the candidate current sources calibrated in the adjustment step or by summing together a plurality of the candidate currents generated by those candidate current sources, and calibrate the output current source by comparing its output current to that reference current and adjusting a control signal applied to that output current source to adjust its output current until its output current and that reference current are brought into a defined relationship.