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. 07, 1992
Filed:
Jul. 03, 1990
Moses Khazam, Lexington, MA (US);
Karl Karash, Berlin, MA (US);
Charles P Smith, Framingham, MA (US);
Anthony J Suto, Leominster, MA (US);
Fadi H Daou, Roslindale, MA (US);
GenRad, Inc., Concord, MA (US);
Abstract
An output circuit (62) for generating a signal in the form of a voltage between an output signal node and an output reference node (60) receives power from a pair of voltage regulators (Q1 and 68, Q2 and 70). The regulators are connected in power-circuit series so as to be powered by the difference between the output potentials of two opposite-polarity supplies without a direct low-impedance connection between the power-supply ground (73) and the output reference node (60). To avoid large current flow in any external path between an output reference node (60) of an electronic circuit and the ground node (73) of its power supply, a current sensor (R1, R2, 86) senses the net current that the power supplies provide to the circuitry that includes the regulators, and it controls variable loads (Q3, Q4) that selectively drive current into and draw current from the reference node (60) so as to drive the net current to zero.