Patent ID: 7015668

Claim:
A method of commutating an electronically commutated motor ( 20 ), which motor comprises a positive connecting lead ( 34 ) and a negative connecting lead ( 36 ); a stator having at least one winding phase ( 22 ); a permanent-magnet rotor ( 26 ); a rotor position sensor ( 28 ) for producing at least one rotor position signal (u 1 , u 2 ) dependent on the position of that rotor ( 26 ); a full bridge circuit ( 78 ), associated with the at least one winding phase ( 22 ) and controllable by means of the rotor position sensor ( 28 ), said full bridge circuit having upper transistors ( 70 , 72 ), implemented as MOSFETs, that control the connection of the at least one winding phase ( 22 ) to the positive connecting lead ( 34 ), and lower transistors ( 74 , 76 ), implemented as MOSFETs complementary to the upper transistors ( 70 , 72 ), that control the connection of the at least one winding phase ( 22 ) to the negative connecting lead ( 36 ), two complementary MOSFET transistors (e.g. 70 , 74 ) being connected in series in each bridge arm, and a comparator ( 90 , 90 ′, 92 , 92 ′) being associated with each MOSFET transistor of the full bridge circuit ( 78 ) in order to control that transistor, comprising the steps of: in the context of a predetermined change in the rotor position signal (u 1 , u 2 ), switching OFF the MOSFET transistor of a bridge arm to be switched off, in a manner controlled by that signal change, by means of the comparator associated with that transistor; while the MOSFET transistor to be switched off is being switched off, monitoring the gate potential of the MOSFET transistor to be switched off by means of a comparator associated with the MOSFET transistor of a bridge arm that is to be switched on; and once that gate potential has reached a value that is characteristic of a switching off of the MOSFET transistor to be switched off, switching ON the MOSFET transistor to be switched on by means of the comparator associated with it.