Method and apparatus for digitizing a voltage

A method of digitizing a voltage comprises the following steps: A capacitor ( 80 ) is charged, through an impedance, to a voltage value (Um) dependent on the voltage to be digitized; that one of a plurality of voltage ranges in which, i.e. the limits between which, said voltage value (Um) lies, is ascertained, and the two limits of that voltage range are defined as a first limit and second limit; the voltage at the capacitor ( 80 ) is modified to the first limit by means of a charge modification circuit containing an impedance ( 84 ), and a first time interval (T1) needed therefor is identified; the voltage at the capacitor ( 80 ) is modified to the second limit; the voltage at the capacitor ( 80 ) is modified from the second to the first limit via the charge modification circuit. A second time interval (T2) needed therefor is identified. Based on values of the first time interval (T1) and second time interval (T2), a digital value (LSB) is calculated, which serves as an indication of how much the voltage value (Um) at the capacitor ( 80 ) differs from one of said two limits. A device for carrying out this method, and its use in an electronically commutated motor, are also described.