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:
Apr. 06, 1993
Filed:
Sep. 23, 1991
Jeffrey A Krinsky, Renton, WA (US);
Tim R Majoch, Puyallup, WA (US);
The Boeing Company, Seattle, WA (US);
Abstract
Disclosed is an electrical control circuit (10) for controlling current through a furnace coil or other resistive load (14). The control circuit includes a plurality of current control stages (12(1), 12(2), . . . 12(N)), a minimum circuit (16), and a control system (22) which provides feedback from the load. The control circuit utilizes a signal conditioner (20) and a sensor (18) to provide information regarding the load to the minimum circuit. The minimum circuit provides the minimum of inputs from the control system and a limit circuit (24) to the current control stages, thereby controlling the current that is drawn through the load. Each current control stage includes an operational amplifier (30), a pass transistor (34), a sense resistor (R.sub.s), and a feedback resistor (R.sub.f). The sense resistors ensure that there is current sharing through each of the current control stages. The operational amplifiers are a pre-drive to the pass transistors to allow smaller sense resistors to be used. The feedback resistors (R.sub.f) provide degenerative feedback to the operational amplifiers.