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:
Oct. 22, 1996
Filed:
Feb. 09, 1995
Bryce L Hesterman, Fort Wayne, IN (US);
MagneTek, Inc., Nashville, TN (US);
Abstract
The present invention provides a low-cost power factor corrected electronic ballast circuit. A preferred embodiment includes a discontinuous conduction mode boost power factor correction circuit that is controlled with a simple pulse-width modulator (PWM) circuit comprising a few discrete components instead of an integrated circuit. The PWM circuit utilizes a reference waveform signal derived from the ballast inverter. The reference waveform is combined with a feedback signal to create a composite signal that is compared with a reference voltage to create a pulse-width-modulated signal. The feedback signal is used to regulate the bulk DC voltage. In an alternative embodiment, a feedforward signal that is proportional to the time-varying level of the rectified line voltage is added to the reference waveform and the feedback signal, and serves to modulate the pulse width of the boost circuit in a manner that reduces the harmonic distortion of the input current. In addition to the boost circuit, the power factor correction circuit can be realized with flyback and buck-boost topologies. The invention can also utilize several different types of inverter circuits.