The invention relates to a method for operating an electronically commutated synchronous machine with multiple phases, in particular three phases. An actuation circuit (1) is provided for operating the synchronous machine, said actuation circuit having at least two switches (5) for each phase and being used to periodically ascertain a degree of actuation for each phase. In order to ascertain the degree of actuation, an activation duration is determined during which the respective phase is supplied with a supply voltage via the paired switch (5). The following steps are carried out: - measuring a current by means of a single measurement resistor (3) in at least two measurement windows (M1, M2; 20, 22) and - displacing one or more of the activation durations of the different phases relative to one another as soon as the difference between activation points of at least two phases falls below a minimum duration (td) or as soon as the difference between the activation durations of at least two phases falls below double the minimum duration (td*2). The invention additionally relates to an actuation circuit.