Abstract: One aspect of the present invention provides a motor control system that includes a linear control system operative, in a linear mode, to provide a plurality of control signals for driving an associated motor based on an error signal. The system also includes control logic operative, in a pulse-width modulation (PWM) mode, to provide the plurality of control signals for driving the motor, at least some of the plurality of control signals being pulse-width-modulated signals based on the error signal. An error system generates the error signal based on an indication of a sensed electrical characteristic of the motor relative to a predetermined reference signal. A feedback network is coupled across the error system. The feedback configured to have transfer function characteristics that substantially match responses in the linear mode and the PWM mode of motor control system, which facilitates transitions between the linear mode and the PWM mode.

Abstract: A method and circuit (55) are presented for reducing a current spike (9) created after a commutation of a driving current of a polyphase motor (14). The motor (14) has a plurality of coils (40) that are driven by a commutated dc voltage from a power supply. The circuit (55) includes a circuit that produces a signal (DrvENOccurred) for indicating a commutation of the dc voltage and a circuit for PWM modulating the dc voltage (CLK,74) during at least a portion of a time before a current induced in one of the coils (40) reaches a peak value. A counter (57) determines at least a portion of a time that begins a delayed time after the commutation, and ends when the current reaches the peak value.