Method and arrangement for controlling the electricity supply of an electronically commutated motor

Abstract

A control circuit () for controlling the current supplied to a winding strand () in an electric motor (). The control circuit comprises at least one semiconductor switch () and a control unit () for controlling the semiconductor switch(es). Each semiconductor switch () is connected to a respective winding strand (), in order to control the current in said winding strand. The control unit () comprises an output () for applying a control signal (CTRL) to the semiconductor switch (), and is configured to set the output (), at least upon switch-off of the semiconductor switch (), to high impedance in order to prevent a voltage at the control unit output from influencing, during the switch-off operation, a signal input at the semiconductor switch (). The improved control circuit increases motor efficiency and reduces commutation noise.