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:
Dec. 30, 1997
Filed:
Jan. 21, 1997
Applicant:
Inventor:
Yoshifumi Yamamichi, Kyoto, JP;
Assignee:
Rohm Co., Ltd., Kyoto, JP;
Primary Examiner:
Int. Cl.
CPC ...
H02H / ; H03K / ;
U.S. Cl.
CPC ...
318492 ; 318501 ; 318519 ; 388903 ; 361 33 ;
Abstract
Between one end of a motor coil and the ground, a drive transistor is connected. When the drive transistor is turned off, and in particular at the moment when a current flowing through the motor coil drops to zero, a back electromotive force is induced at said one end of the motor coil. The back electromotive force is clamped by a pnp-type transistor with its base supplied with a constant voltage and its emitter connected to said one end of the motor coil.