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:
May. 03, 2011
Filed:
Sep. 12, 2008
Yoshinori Imanaka, Kyoto, JP;
Kenichi Fukumoto, Kyoto, JP;
Yoshinori Imanaka, Kyoto, JP;
Kenichi Fukumoto, Kyoto, JP;
Rohm Co., Ltd., , JP;
Abstract
A soft start circuit generates a soft start voltage Vss which changes with time at a starting time of lighting an EEFL. A pulse width modulator generates a PWM signal Vpwm whose duty ratio is feedback-controlled so that a feedback voltage Vfb corresponding to an output voltage Vdrv of an inverter conforms to the soft start voltage Vss. A logical control unit performs switching control of a voltage of a primary coil of a transformer on the basis of the PWM signal Vpwm from the pulse width modulator. The soft start circuit executes at least one striking operation in which the soft start voltage Vss is raised with time, lowered when being reached to a first voltage level VH, and raised again when being lowered to a second voltage level VL lower than the first voltage level VH.