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:
Jun. 13, 2000
Filed:
Apr. 20, 1998
Allan A Nostwick, Huntington, IN (US);
Other;
Abstract
A versatile ballast and method of controlling and operating a high intensity discharge lamp. Lamp ignitor circuitry provides a high frequency alternating current starting voltage that is at least several times the nominal operating voltage of the lamp, thus shortening the starting time. This starting voltage is applied in series with normal operating voltage. After sustained ignition of the lamp has begun and a substantial lamp arc current has developed, the relatively low current supply characteristic of the alternating current starting voltage results in its becoming relatively insignificant. As lamp startup proceeds, the internal arc voltage typically falls to a fraction of its steady-state value; and circuit provision is made to correspondingly change applied current so as to maintain an essentially constant wattage operating power input to the lamp as the arc voltage changes. This automatic control of current also compensates for changes that occur in lamp characteristics as the lamp ages. In addition to the foregoing, provision is also made for adjusting the level of constant power input so as to provide for dimming and also to set the desired constant power level at any desired value over a wide range of from about 10 to 100 percent of lamp rated power.