Patent ID: 7586276

Claim:
An electronically commutated motor ( 10 ) comprising a permanent-magnet rotor ( 16 ) and a stator having at least one stator winding ( 12 , 14 ); a microcontroller ( 36 ) for generating at least one commutation signal (OUT 1 , OUT 2 ) for switching the current (I) in said at least one stator winding ( 12 , 14 ) on and off; and a device ( 36 ) for generating at least one second signal ( 51 ) to influence the magnitude of the current (I) that flows, during operation, through that stator winding ( 12 , 14 ) when and if switched on by the commutation signal (OUT 1 , OUT 2 ); a first field-effect transistor ( 22 ), connected in series with the associated stator winding ( 14 ), and to whose gate (G) the commutation signal (OUT 2 ) is applied, via a voltage divider ( 42 , 46 ), wherein a resistance ( 46 ) of that voltage divider ( 42 , 46 ) is arranged between that gate (G) and a point ( 26 ) having a predetermined electrical potential; and a second field-effect transistor ( 48 ), arranged between the source (S) of the first field-effect transistor ( 22 ) and said point ( 26 ) having the predetermined electrical potential, and to whose gate (G) the second signal ( 51 ) is applied, to modify the voltage drop (U DS ) at the second field-effect transistor ( 48 ) as a function of said second signal ( 51 ), in order to influence a pinch-off voltage (U GS ) of the first field-effect transistor ( 22 ).