Abstract: A drive circuit for a brushless motor utilizing both phase shift and current shaping to provide for efficient operation of a brushless motor in a servo control system. The circuit includes circuitry for altering the phase of the drive signal as a function of motor velocity to compensate for increased current phase lag due to inductance of the motor at high commutation frequencies corresponding to high motor velocities. In addition to altering the phase shift of the drive signal, the circuitry also alters the commutation signal waveform to compensate for a non-sinusoidal field distribution to produce a nearly sinusoidal torque from each of the brushless motor windings. The compensation of both phase shift and commutation signal waveform is accomplished using digital circuitry. The phase commutation is a non-linear function of motor velocity. The waveform compensation is selected to compensate for a trapezoidal magnetic field distribution in the motor air gap.