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:
Jul. 11, 2000
Filed:
Jan. 14, 1998
Koito Manufacturing Co., Ltd., Tokyo, JP;
Abstract
A discharge lamp lighting circuit which, in turning on a discharge lamp, when an abnormal condition occurs in a discharge lamp or in the present discharge lamp lighting circuit due to a transient cause, can resume the power supply to the discharge lamp at the time when the present transient abnormal condition cause disappears. The discharge lamp lighting circuit includes lighting control for controlling the lighting of a discharge lamp, an abnormal condition detector for detecting an abnormal condition occurring in the discharge lamp or in the discharge lamp lighting circuit, and a protection circuit which receives a signal from the abnormal condition detector to thereby stop the power supply to the discharge lamp. The protection circuit is composed of first protection unit and second protection unit. When a permanent abnormal condition is detected in the discharge lamp or in the discharge lamp lighting circuit, the power supply to the discharge lamp is cut off by the first protection unit and such cutoff condition of the power supply is also held. Also, when a transient abnormal condition is detected in the discharge lamp or in the discharge lamp lighting circuit, the power supply to the discharge lamp is cut off by the second protection unit and, after then, when the present abnormal condition is no longer detected, the power supply cutoff condition is removed to thereby resume the power supply to the discharge lamp. Further, while the power supply to the discharge lamp is being cut off by the second protection unit, the operation of the first protection unit is prevented from cutting off the power supply to the discharge lamp and holding such power supply cutoff condition.