Patent ID: 6888331

Claim:
Circuit arrangement for sensorless commutation of a brush-less direct-current motor (dc motor), comprising: an amplifier to provide at least two coils of a rotor or a stator of said motor with supply voltages for driving said motor, a back electromotive force (BEMF) amplifier to output induced voltages of said coils of said motor, respectively, a multiplexer to output alternatively one of said induced voltages, and a state machine connected to said amplifier and said multiplexer to determine, depending on its current state, which of said at least two coils is provided with said supply voltages by said amplifier and which of said induced voltages is selected by said multiplexer, characterized in that a digitizing circuit is provided to digitize said output of said multiplexer, to digitally process said output, and to provide said state machine with a control signal enabling said state machine to correctly determine the state of said motor.