Linear sinusoidal waveform spindle driver and method for driving a polyphase, brushless DC motor using commutation currents with user controlled rise and fall times

摘要

A circuit and method for providing drive currents to a polyphase dc motor are presented. The circuit (40) includes a circuit for generating a user-defined waveform first. signal in synchronism with a reference frequency signal. A reference frequency signal generator (62) generates pulses of a second signal at a reference frequency. A commutation circuit (56) combines segments of the first and second signals, and a circuit (64) is provided for applying the combined sinusoidal/trapezoidal waveforms to coils of the polyphase dc motor in a commutative sequence. Preferably, the user-defined waveform, when combined with the second signal, has approximately a sinusoidal/trapezoidal waveform.