Patent ID: 6954042
Filing Date: 2005-10-11
Classification: H02P

Abstract:
1. A motor driving circuit for a three-phase brushless DC motor having a three-phase-coil and first and second Hall sensors, configured to detect the magnetic field of a rotor, the motor driving circuit comprising: a first comparator, coupled to the first Hall sensor, configured to receive and compare a first pair of Hall signals generated by the first Hall sensor, and configured to output a first Hall signal; a second comparator, coupled to the second Hall sensor, configured to receive and compare a second pair of Hall signals generated by the second Hall sensor, and configured to output a second Hall signal; an adder unit, coupled to the first and second Hall sensors, configured to receive the first pair of Hall signals from the first Hall sensor and a second pair of Hall signals from the second Hall sensor, the adder unit further configured to output a third pair of Hall signals; a third comparator, coupled to the adder unit, configured to compare the third pair of Hall signals of the adder unit and to output a third Hall signal; and a motor driver, coupled to the first, second and third comparators, configured to receive the first, second, and third Hall signals and to change directions of currents flowing through phases of the three-phase coil accordingly.