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. 25, 1992
Filed:
Sep. 28, 1990
Alan A Fennema, Tucson, AZ (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A servo positioning system, such as used in an optical disk or other types of disk drives includes focus and positioning servo circuits. When a focus error is detected, then it is desired to stop the operation of the positioning system. Similarly, when a positioning error is detected, such as excessive speed or a non-zero velocity at the end of a seek or positioning motion, the head carriage should also be stopped. The stopping of the head carriage is by dynamic braking through use of a power amplifier which is switched from a transconductance mode used during normal servo positioning operations to a voltage amplifying mode which is set to a zero input for dynamically braking the servo positioning system to a safe speed and thence to a stop condition whereupon further error recovery procedures may be employed.