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:
Mar. 08, 1994
Filed:
May. 19, 1992
Andrew Bobel, Des Plaines, IL (US);
Motorola Lighting, Inc., Buffalo Grove, IL (US);
Abstract
A circuit (100) for driving an instant-start fluorescent lamp (102) has an inverter (103, 132) and a series-resonant LC oscillator (146, 152). A capacitor (190) begins charging after power-up of the circuit and when its voltage reaches a certain level causes breakdown of a diac (192), which discharges the capacitor into an inverter transistor (132) to trigger operation of the inverter. Re-triggerring of the inverter is prevented by a diode (194) which subsequently discharges the capacitor cyclically, and by a capacitor (186) which enables a transistor (180) at a predetermined time following power-up. The occurrence of a subsequent fault condition causes a capacitor (210) to charge and to enable a transistor (196) which disables the inverter. Charging of the initiating capacitor (190) is prevented by an open circuit between terminal connectors (160, 162) if the lamp is not present.