Abstract: For driving unipolarly operated windings of an electronically commutated dc motor, each of the windings has a final power stage allocated to it. The final power stages are driven selectively and in cyclical sequence via an analog multiplexer dependent on rotor position signals. A drive of the final power stages is defined via a control voltage supplied to a common input of the analog multiplexer. The final power stages are referenced to ground via a common intermediate resistor. A comparator having first and second inputs is provided. A current corresponding to a rated value of the motor current and defined by external drive signals is impressed on a control resistor connecting to the second input. The intermediate resistor connects to the first input. At the control resistor and at the intermediate resistor voltages are developed which correspond to the rated value and actual value respectively of the motor current and which are compared in the comparator.