Patent ID: 7733040

Claim:
A brushless motor comprising: a coil array having m phase magnet coil groups, where m is an integer equal to 3 or greater; a magnet array having a plurality of permanent magnets; n magnetic sensors associated with n phase magnet coil groups among the m phase magnet coil groups, where n is an integer equal to 2 or greater but less than m, wherein the n magnetic sensors are used for detecting relative position of the magnet array and the coil array; and a drive control circuit that utilizes the sensor outputs of the n magnetic sensors to drive the coil array; wherein the drive control circuit includes: a simulated sensor output generator that, based on computation using one or more of the sensor outputs of the n magnetic sensors as a variable, generates (m−n) simulated sensor outputs for the (m−n) phase magnet coil groups not associated with the n magnetic sensors; and a drive signal generator that generates m sets of drive signals for the m phase magnet coil groups, in response to m sensor outputs inclusive of the sensor outputs of the n magnetic sensors and the (m−n) simulated sensor outputs, and wherein the drive control circuit: generates n sets of drive signals for the n phase magnet coil groups associated with the n magnetic sensors using the respective sensor outputs of the n magnetic sensors; and generates (m−n) sets of drive signals for the (m−n) phase magnet coil groups not associated with the n magnetic sensors, using one or more of the sensor outputs of the n magnetic sensors in generation of each of the (m−n) sets of drive signals.