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. 10, 2012
Filed:
Mar. 16, 2007
Yoshito Otaguro, Kyoto, JP;
Yoshito Otaguro, Kyoto, JP;
Rohm Co., Ltd., , JP;
Abstract
A back electromotive force detection circuit detects a zero-crossing point by comparing a back electromotive force Vu in at least one coil of a motor with a center tap voltage at a common node of the coils, and outputs a back electromotive force detection signal. A switching control circuit controls switching states of multiple switching circuits based upon the back electromotive force detection signal, thereby adjusting the current flowing through the coils. A window generating circuit outputs a window signal at a predetermined level during a period obtained by multiplying the cycle of the back electromotive force detection signal by a predetermined coefficient before the detection of the zero-crossing point. The switching control circuit stops the switching operation during a period in which the window signal is maintained at the predetermined level, thereby setting the state to the high impedance state that corresponds to a non-driving period.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile