Patent ID: 6456028
Filing Date: 2002-09-24
Classification: H02P

Abstract:
A pulse generating circuit for driving a DC motor, comprising:a ripple pulse forming circuit for forming and outputting a ripple pulse from a ripple component in an electric current for driving the DC motor; a first signal generating means for outputting a first signal corresponding to a rotational number of the DC motor based on the electric current for driving the DC motor or on a voltage for driving the DC motor; a judging circuit for calculating a frequency ratio between the ripple pulse and the first signal and judging whether a deviation of the frequency ratio is greater than a predetermined value compared to a predetermined fixed value; and a correcting circuit for correcting the outputted ripple pulse when the deviation of the frequency ratio is judged to be greater than the predetermined value and maintaining the outputted ripple pulse when the deviation of the ratio is judged to be equal to or less than the predetermined value.