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. 28, 1996
Filed:
Sep. 17, 1993
Donald J Ashley, Endicott, NY (US);
Leonard J Hitchcock, Montrose, PA (US);
Michael J Johnson, Raleigh, NC (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A matched pair of npn transistor configured as emitter followers provide high impedance isolation for input error voltage busses in the current share circuitry used with parallel connected current programmed dc to dc converters. The matched emitter followers offer the bus isolation of buffer amplifiers but do not add the detrimental offset voltage to the input error signals. Trimmable current sinks are connected to the emitters of the transistors to guarantee equal VBE drops. Slight intentional unbalancing can be introduced using the current sources to improve stability. The current share circuitry equalizes main FET switching currents not load currents reducing FET stresses. A programmable differential amplifier is provided which can accommodate different regulator output voltages. Diagnostic circuitry monitors share circuitry operation.