Inrush protection circuit

Details Inrush protection circuit Inrush protection circuit

1997-09-29

1999-07-27

Wong, Peter S.

Electric power conversion systems

Current conversion

Including automatic or integral protection means

363 89, 323222, 323282, 323908, 315247, H02H 7125, H02M 542, G05F 110

Patent

active

059301309

ABSTRACT:
A large inrush of electrical current flow occurs during a short interval after switch closure, when power is applied to a conventional electronic ballast commonly used for fluorescent lighting. This inrush current flows as the main filter capacitor in the ballast charges to its steady state value. For a lighting circuit that contains a multiplicity of ballasts, the combined magnitude of the inrush is potentially large enough to cause contact failure of the switching device due to arcing and contact welding. The invention features a circuit for limiting inrush current having a current-limiting resistor that is active for a brief interval during startup. The resistor is subsequently bypassed from the principal current path by a switching transistor. The transistor is controlled by electrical signals normally present in conventional electronic ballasts. The advantage of the inventive circuitry is the use of only two inexpensive components to accomplish inrush current protection.

REFERENCES:
patent: 4631470 (1986-12-01), Bingley
patent: 4769752 (1988-09-01), Rackowe
patent: 4982306 (1991-01-01), Koroncai et al.
patent: 5122724 (1992-06-01), Criss
patent: 5187653 (1993-02-01), Lorenz
patent: 5519289 (1996-05-01), Katyl et al.
patent: 5729062 (1998-03-01), Satoh
Billings, Keith "Switchmode Power Supply Handbook", McGraw-Hill, Chapter 7, 1989.

Affiliated with

Also associated with

Rating

Inrush protection circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Inrush protection circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inrush protection circuit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-886426