Patent ID: 8917043

Claim:
A method of driving a multi-phase motor having a plurality of motor windings, the method comprising: generating a zero current signal indicative of a zero crossing of a current though at least one of the plurality of motor windings; generating a position reference signal indicative of a reference position of an angular rotation of the motor; comparing a phase of the zero current signal with a phase of the position reference signal to generate a phase comparison signal; generating a plurality of modulation signals, each having a phase related to a value of the phase comparison signal; and generating a plurality of motor drive signals to the plurality of motor windings in accordance with the plurality of modulation signals, wherein the generating the plurality of modulation signals comprises: providing a look up table in which modulation values are stored corresponding to a shape of at least one of the plurality of modulation signals; generating a first continuous sawtooth ramp signal having a smallest value and a largest value and a plurality of values between the smallest and largest values; adding to the first continuous sawtooth ramp signal a value related to the phase comparison signal to generate a second continuous sawtooth ramp signal having the smallest value and the largest value and the plurality of values between the smallest and largest values, wherein the smallest and largest values of the second continuous sawtooth ramp signal are shifted in time by an adjustment time from the smallest and largest values of the first continuous sawtooth ramp signal, wherein the adjustment time is related to the phase comparison signal; using the adjusted continuous sawtooth ramp signal to sequentially look up values in the look up table to generate the at least one of the plurality of modulation signals; and generating at least one other modulation signal at a predetermined phase relationship to the at least one of the plurality of modulation signals.