US Patent 7688011 Control circuit for an electronically commutated motor

A control circuit for an electronically commutated motor (120), having a power stage (122) that comprises at least two semiconductor switches (216, 218) to influence the motor current. The semiconductor switches are controllable by way of commutation signals. The control circuit comprises a current measuring element (170) to make available a motor current control variable (I) dependent on the motor current, a base diode (240) that is arranged in series with the current measuring element and between the current measuring element and the at least two semiconductor switches, and a motor current setting element (180) with which the commutation signals can be influenced as a function of the motor current control variable.