Electronic ballast having adaptive frequency shifting

Details Electronic ballast having adaptive frequency shifting Electronic ballast having adaptive frequency shifting

2006-02-13

2009-02-10

Owens, Douglas W. (Department: 2821)

Electric lamp and discharge devices: systems

Current and/or voltage regulation

Automatic regulation

C315S291000, C315S308000

Reexamination Certificate

active

07489090

ABSTRACT:
An electronic ballast for driving a gas discharge lamp avoids mercury pumping in the lamp by adaptively changing an operating frequency of an inverter of the ballast when operating near high-end. The inverter of the ballast generates a high-frequency AC voltage, which is characterized by the operating frequency and an operating duty cycle. The ballast also comprises a resonant tank for coupling the high-frequency AC voltage to the lamp to generate a present lamp current through the lamp, and a current sense circuit for determining the magnitude of the present lamp current. A hybrid analog/digital control circuit controls both the operating frequency and the operating duty cycle of the inverter with closed-loop techniques. The control circuit adjusts the duty cycle of the inverter in response to a target lamp current and the present lamp current. To avoid mercury pumping, the control circuit attempts to maximize the duty cycle of the inverter when operating at high-end. Specifically, the control circuit adjusts the operating frequency of the inverter in response to the target lamp current signal, the duty cycle of the inverter, and a target duty cycle in order to drive the operating duty cycle toward the target duty cycle.

REFERENCES:
patent: 6452344 (2002-09-01), MacAdam et al.
patent: 6642669 (2003-11-01), MacAdam et al.
patent: 6674248 (2004-01-01), Newman et al.
patent: 6982528 (2006-01-01), Cottongin et al.
patent: 7061189 (2006-06-01), Newman et al.
patent: 2003/0052623 (2003-03-01), Muehlschlegel
patent: 2005/0179404 (2005-08-01), Veskovic et al.
patent: 01/69983 (2001-09-01), None
European Patent Office, International Search Report and Written Opinion, Jun. 14, 2007, 11 pages.

Affiliated with

Also associated with

Rating

Electronic ballast having adaptive frequency shifting does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Electronic ballast having adaptive frequency shifting, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electronic ballast having adaptive frequency shifting will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-4118941