The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 30, 2007
Filed:
Nov. 01, 2004
Yoshihisa Yamada, Shimada, JP;
Yoshihisa Yamada, Shimada, JP;
Yazaki Corporation, Tokyo, JP;
Abstract
A stepper motor driving apparatus, includes a stepper motor; a driven member interlocked with a rotation of a rotor of the stepper motor, a stopper stopping the driven member in a zero position, a controller controlling the excitation state of an excitation coil of the stepper motor, an induced voltage waveform detector detecting an induced voltage waveform generated on the basis of change of magnetic flux in accordance with the rotation of the rotor, and a zero position detector detecting whether the driven member is stopped in the zero position. The zero position detector includes a comparator which compares a time Tin which each induced voltage waveform exceeds a predetermined threshold value with a predetermined contact determining reference time Tref, and a determinant which determines whether the driven member is stopped in the zero position by the stopper based on a result of the comparison by the comparator.