Adan V Hernandez

US Patent:

6356027, Mar 12, 2002

Filed:

May 7, 1999

Appl. No.:

09/306910

Inventors:

Michael Y. Zhang - Chicago IL
Adan Hernandez - Naperville IL
Sreeraman Venkitasubrahmanian - Naperville IL

Assignee:

Philips Electronics North America Corporation - New York NY

International Classification:

H05B 3700

US Classification:

315136, 315240, 315362

Abstract:

A 0-10V dimming interface protection circuit generating an indication that line voltage is applied across first and second leads of the dimming interface controlling light output by a lamp, includes a first device for limiting current serially connected between a line voltage source and the first lead of the dimming interface, a second device connected across the first and second leads for detecting application of line voltage to the dimming interface and for generating a control signal, and a third device for switching, operated in response to the control signal, for causing an increase in resistance of the first device to thereby limit current to the dimmer interface and limit light output by the lamp. According to one aspect of the invention, the protection circuit also includes a fourth device for preventing spurious operation of the second device.