Rotation-speed circuit for electric motors

摘要

A control circuit (for example Fig. 1) uses (as the criterion for controlling the rotation speed of an electric motor (12)) a defined pulse width (T) of a control-pulse signal (VIN) supplied to it, which control pulse signal is not supplied directly to the motor but is converted into a voltage signal (VOUT) corresponding to the pulse width. For this purpose, the control circuit contains a convertor circuit having a charging/discharging circuit (14, 24) which varies the charging voltage (VC) of a capacitor (32) as a function of differences between the actual rotation speed of the motor and the required rotation speed of the motor defined by the control-pulse signal. The stored value of the charging voltage is used for producing the motor driver voltage. <IMAGE>