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. 03, 1984
Filed:
Nov. 27, 1981
John I Daspit, Santa Monica, CA (US);
Data-Design Laboratories, Cucamonga, CA (US);
Abstract
An electronic ballast circuit for operating high intensity gas discharge tubes such as high pressure sodium, high pressure mercury and metal halide tubes, as well as ordinary fluorescent tubes. In the preferred embodiment, an inductance and a capacitance are connected in series with the load across the dc supply, with a solid state switch between the junction of the inductance and capacitance and the other side of the load, and a control circuit for the switch to operate the switch at a high frequency such as 20,000 hertz. Alternative embodiments omitting the capacitance and utilizing a transformer for the inductance are especially suited for less expensive units and for emergency lighting use. Power supply circuits with switching operated in conjunction with the previously mentioned switch provide for regulation of lamp output during start-up and for compensating changes in supply voltage coordinated with lamp aging.