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. 21, 2008
Filed:
May. 25, 2007
Kotaro Matsui, Shizuoka, JP;
Tomoyuki Ichikawa, Shizuoka, JP;
Kotaro Matsui, Shizuoka, JP;
Tomoyuki Ichikawa, Shizuoka, JP;
Koito Manufacturing Co., Ltd., Tokyo, JP;
Abstract
A discharge lamp lighting circuitincludes an electric power supply part and a control part. The control part generates a control signal (Sc) for controlling the magnitude of electric power based on a lamp voltage (VL) of a discharge lamp. The electric power supply part supplies the electric power based on the control signal (Sc) from the control part to the discharge lamp. The control part has a differential computation part for differentiating a lamp voltage corresponding signal (VS) with respect to time and generating a first differential signal Sd(=dVS/dt), and an integral computation part for integrating a second differential signal (Sd) which monotonously increases and decreases as the first differential signal (Sd) increases and decreases with respect to time and generating a first integral signal (Si), and generates the control signal (Sc) so that the electric power decreases with an increase in the first integral signal (Si).