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:
Aug. 05, 1997
Filed:
Dec. 07, 1995
Nippondenso Co., Ltd., Kariya, JP;
Abstract
A lamp current i.sub.L flows through a first resistor. Electric current I, which is the output current of a voltage-current converter which converts a lamp voltage V.sub.L to a lamp current I, flows through a second resistor. Feedback control is executed to make V.sub.-, which is the voltage of one terminal of the second resistor, equal a reference voltage V.sub.ref. The power applied to the lamp during start-up is controlled to be the same as the power applied to the lamp during its stable lighting for a predetermined lamp voltage range. Using the following two linear equations, the electric current I is set as I=aV.sub.L +b (where a and b are positive constants) when the lamp voltage V.sub.L is lower than a first predetermined voltage V.sub.a which is less than the lamp voltage during the normal stable lighting period of the lamp, and as I=cV.sub.L +d (where c and d are positive constants with c<a and d>b), when the lamp voltage V.sub.L is greater than or equal to the first predetermined value V.sub.a.