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:
Oct. 28, 2003
Filed:
Dec. 28, 1999
Martijn Bredius, Santa Clara, CA (US);
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
A current-limited low-impedance return path is provided between an isolated bus system and the primary supply that provides this isolated bus system. In a preferred embodiment, a voltage follower circuit with an input at ground potential supplies a controlled zero-voltage to a center-tap on the load side of an isolation transformer. This voltage follower circuit provides a low-impedance path for unbalanced communications signals, but is configured to present a high-impedance, or current-limited, path to short-circuit currents. In this manner, the commonmode voltage changes that are caused by parasitic currents between the primary supply and the isolated bus system are minimized by providing the low-impedance path for these currents, and the isolation is maintained by providing the high-impedance path for short-circuit currents.