Appeal No. 1998-1225
Application 08/542,884
examiner.
The disclosed invention pertains to the field of
sensorless motor drives. More particularly, the invention is
directed to a circuit for driving such a motor having a rotor
and a plurality of excitation coils for the rotor.
Representative claim 6 is reproduced as follows:
6. A sensorless motor driving circuit, for driving a
motor having a rotor and a plurality of excitation coils for
the rotor, comprising:
detection means for detecting a reference position for
the rotating rotor based on an excitation coil induction
voltage;
differential pulse generating means, coupled to an output
of said detection means, for generating a differential pulse
using a detection means output signal;
a phase-locked loop circuit for generating a clock pulse,
having a phase comparator for comparing the deferential pulse
with the clock pulse after the clock pulse has been frequency
divided; and
an activation pulse generator for counting the clock
pulses and generating an activation pulse when the
differential pulse is not generated within the duration of a
prescribed number of counts.
The examiner relies on the following references:
Kaneda 5,396,159 Mar. 07, 1995
(filed Sep. 09,
2
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