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. 21, 2001
Filed:
Feb. 23, 2000
Asmo Co., Ltd., Shizuoka, JP;
Abstract
An ultrasonic motor drive apparatus includes a transformer having a primary coil and a secondary coil which drives a piezoelectric body of an ultrasonic motor. One end and the other end of the primary coil are connected to the drains of MOSFETS. The gates of the MOSFETs are connected to receive switching signals to alternately turn on and off electrical currents which flow in the primary coil. The sources of the MOSFETs are connected to the ground through ferrite beads, respectively. The ferrite bead generates a counter electromotive voltage so that the surge voltage which develops on the drain of the MOSFET at the time of turning off of the MOSFET is suppressed and high frequency oscillations are suppressed.