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. 12, 2005
Filed:
Oct. 25, 2001
Richard James Jales, East Leigh, GB;
Barnaby Norman Wilmott, Bognor Regis, GB;
Richard James Jales, East Leigh, GB;
Barnaby Norman Wilmott, Bognor Regis, GB;
Raymarine Limited, Hampshire, GB;
Abstract
A fluorescent lamp driver circuit has regulator (SR); primary circuit of transformer (TF); electronic switches (TRA and TRB) and current sensing device (Rsense) connected successively in series across power supply (PSF). Controller (CTRL) is connected to create a feed back loop. The secondary circuit of transformer (TF) is coupled to fluorescent lamps (Uand U) via ballast capacitors (Cand C). Diode (D) creates unidirectional current flow, so current sensing device (Rsense) indicates only energy input to lamps (Uand U). Capacitors (Cand C) are placed physically very close to their respective lamps, enabling good matching of currents through lamps (Uand U). Pulse width modulator (PM) with predetermined input is connected to regulator (SR) and, via delay circuit (TD) to controller (CTRL), thus permitting a larger dimming ratio, and further control of input power. Overvoltage detector (OVD) is connected to sense the voltage across inductor (L) and transformer (TF) giving further control in the event of excess voltage.