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:
Aug. 06, 1985
Filed:
Dec. 15, 1983
Masuo Kitano, Suwa, JP;
Masahito Yoshino, Suwa, JP;
Kabushiki Kaisha Suwa Seikosha, Tokyo, JP;
Abstract
Circuits are provided for avoiding misdetection of a non-rotated condition after driving the timepiece stepping motor. Voltages induced in the rotor coil by external high frequency magnetic fields, and current produced in the coil by lower frequency AC magnetic fields are detected. When a high frequency or AC magnetic field of sufficient intensity to cause a false indication of motor rotation is detected, the motor is next driven with a pulse having greater width than the normal driving pulse so as to assure operation of the motor. A period is provided, before the normal driving pulse would be applied, to detect AC magnetic fields and a period preceding the period for detection of AC magnetic fields is provided for detection of high frequency magnetic fields. A comparator or inverter is used to determine whether the levels of external magnetic fields are sufficient to cause misdetection of rotor position.