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:
Nov. 08, 1994
Filed:
Sep. 16, 1993
Peter W Shackle, Arlington Heights, IL (US);
Motorola Lighting, Inc., Buffalo Grove, IL (US);
Abstract
A ballast circuit (100) includes a ground fault detector (200). The ballast circuit is arranged for coupling to a power source (101) and a load (135, 137), the power source characterized by a source frequency, the ballast circuit including an electromagnetic interference ('EMI') filter (110) which includes a ground terminal (145). The ground fault detector (200) determines when the load is coupled to a ground fault (141) by detecting the presence of a high-frequency current at the ground terminal, the high-frequency current characterized by a frequency that is substantially greater than the source frequency. When the high-frequency current is detected, the ground fault detector provides an output signal (150) which may be used to disconnect the load from the ballast circuit.