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:
May. 25, 1993
Filed:
Oct. 25, 1991
George Melnyk, Endicott, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A coil is connected to a voltage source by a switch enabled by a drive signal of fixed duration. Drive current in a coil is terminated by a chopper circuit if it reaches a predetermined peak level before the end of preselected rise time interval. The chopper circuit is inhibited from operation until the end of the rise time interval during which time the drive current is allowed to decay. The chopper circuit is enabled at the end of the rise time interval for chopping the drive current at an average peak current value for the duration of the preselected time. The total amount of energy supplied to the actuator is adjusted by allowing the current to decay if the peak current is reached before the end of the predetermined rise time interval and then by chopping the current at a predetermined switching rate for the duration of the preselected time of the drive signal. Short circuit protection is also provided during the predetermined rise time interval.