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:
Sep. 18, 2007
Filed:
Oct. 07, 2005
Yuequan HU, Morrisville, NC (US);
Milan M. Jovanović, Cary, NC (US);
Yuan Chao Niu, Taipei, TW;
Colin Weng, Taipei, TW;
Yuequan Hu, Morrisville, NC (US);
Milan M. Jovanović, Cary, NC (US);
Yuan Chao Niu, Taipei, TW;
Colin Weng, Taipei, TW;
Delta Electronics, Inc., Taipei, TW;
Abstract
A ballast according to the present invention operates in an ignition state, a warm-up state, and a steady state for igniting and powering a lamp. The ballast comprises an igniter that ignites the lamp during the ignition state and a switching power inverter, for example, a full bridge DC-AC inverter implemented with MOSFET switching transistors, that powers the lamp during the warm-up and steady states. The switching power inverter, which drives the igniter, operates at a first switching frequency during the ignition state and operates at a second switching frequency during the steady state. Preferably, the first switching frequency, which in one exemplary embodiment is in the kHz range, is higher than the second switching frequency.