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. 21, 1999
Filed:
Jan. 26, 1998
Douglas M Gustavson, Guilford, CT (US);
Scott O Schweizer, Snohomish, WA (US);
David W Tecklenburg, Mill Creek, WA (US);
Physio-Control Manufacturing Corporation, Redmond, WA (US);
Abstract
A control circuit ideally suited for a capacitor charging circuit (100) that uses an apparent measure of current flow through a circuit line to regulate current drawn from a battery through the circuit line is disclosed. A summing circuit (136) produces a difference voltage (138) of the battery voltage (152) subtracted from a threshold reference voltage (151). The difference voltage (138) is subsequently amplified by an amplifier (140), rectified by a diode (142), and added to a voltage measure (130) from a current-sense resistor (117) by a summing circuit (128). The resulting voltage measure (126) is an apparent measure of current flow and is provided to a charge controller (122) which regulates current flow through a transformer (107) by controlling the operation of a switch (108). As the voltage on the battery (102) decreases below the reference voltage set by voltage source (150), the increasing difference voltage (138) adds bias to the actual measure of current flow (130), thus providing the charge controller (122) with an apparent measure of current flow through the transformer (107) that is higher than the actual level of current flow. The charge controller is thereby deceived and reduces the current drawn from the battery through the transformer.