Patent ID: 8638053

Claim:
A circuit for driving a multi-phase brushless DC motor, the motor having a motor shaft and a plurality of motor windings, the circuit comprising: a position signal generator configured to generate a plurality of position signals, each one of the plurality of position signals representative of a rotational position of the motor shaft; a frequency difference processor coupled to receive a signal related to a selected one of the position signals, coupled to receive a reference clock signal, and configured to generate a frequency difference value related to a frequency difference between the signal related to the selected one of the position signals and the reference clock signal; a synchronization control processor coupled to receive the frequency difference value and configured to generate a synchronization selection signal; and a multiplexer having a first input node coupled to receive the signal related to the selected one of the position signals, a second input node coupled to receive the reference clock signal, a control node coupled to receive the synchronization control signal, and an output node at which is generated a multiplexer output signal comprised of either the signal related to the selected one of the position signals or the reference clock signal.