Gregory M Harper

US Patent:

7327101, Feb 5, 2008

Filed:

Dec 27, 2006

Appl. No.:

11/646138

Inventors:

Timothy Chen - Aurora OH, US
Ajay Karthik Hari - Mayfield Heights OH, US
Gregory Alan Harper - Louisville KY, US

Assignee:

General Electric Company - Schenectady NY

International Classification:

G05F 1/00

US Classification:

315307, 315289, 315290, 315276, 315209 R, 315273, 315DIG 5

Abstract:

Systems and methods are disclosed that facilitate sensing a pulse in a ballast circuit for a lamp when the lamp is in an end-of-life (EOL) stage or when the lamp is experiencing an arcing conduction condition, such as may occur when a contact between the lamp and its holder is compromised. Upon sensing the pulse, a microcontroller may distinguish between EOL and arcing conditions based on detected pulse width(s), and may initiate an appropriate response. For instance, if the pulse is due to an arcing event, the microcontroller may interrupt lamp operation for a brief period before restarting the lamp to mitigate the arcing condition. If the pulse is caused by an EOL condition, the microcontroller may place the lamp in a preheat or restarting mode to hasten lamp failure. In either case, responses to the sensed pulse mitigate the occurrence of dangerously high lamp temperatures that may damage lamp sockets.