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:
Jun. 20, 1989
Filed:
Aug. 24, 1987
Neil G Cheyne, St. Helens, NZ;
Fisher & Paykel, Auckland, NZ;
Abstract
The method uses at least one power switch having 'on' and 'off' states for providing, respectively, low and high impedance paths between an inductive load and a source of power and thereby controls current flow through the inductive load during a sequence of regular reoccurring time periods. The at least one power switch is switched, if in the 'off' state, to the 'on' state substantially at the beginning of at least some of the time periods. The method is operative during any one of a plurality of the 'on' duty periods and switches the at least one power switch from the 'on' state to the 'off' state when a predetermined level of current flow has been reached in one of the inductive load and the at least on power switch, and switches the at least one power switch back to the 'on' state independent of the occurrence of the beginning of a time period.