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:
Apr. 09, 2013
Filed:
Oct. 17, 2008
Fujio Kurokawa, Nagasaki, JP;
Fujio Kurokawa, Nagasaki, JP;
Nagasaki University, Nagasaki, JP;
Abstract
Provided is a discharge lamp lighting device, which can control a load precisely while improving the practicability. When the difference of a count number (Nn) becomes a predetermined threshold value or less, a predictor circuit () predicts the timing, at which a current value (iQ) becomes a peak value, on the basis of the rate of change of the difference. A switch selecting circuit (), which is driven with a clock frequency higher than the sampling frequency of a first converter unit (), turns off a field effect transistor (Q) at the turn-off timing, and turns on a field effect transistor (Q). A plurality of A/D converters () are subjected to a multi-rate control, thereby to correct the threshold value of the predictor circuit () on the basis of the peak value of a lamp current (iOUT). Even if the peak values of current values (iQand iQ) are positioned for the sampling period of the first converter unit (), the turn-off timings can be precisely set according to the current values (iQand iQ) without increasing the sampling frequency more than the necessary value. As a result, it is possible to improve the practicability and to control the lighting of a fluorescent lamp precisely.