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. 10, 2001
Filed:
May. 24, 2000
Walter Rolston, Overland Park, KS (US);
Garmin Corporation, , TW;
Abstract
The present invention relates to a circuit for obtaining a wide dimming ratio from a Royer inverter and, more particularly, to a circuit that allows a back light to have wide dimming ratio without having unwanted current spikes that would significantly reduce the life of the back light bulbs. The invention is directed to a DC-to-AC inverter circuit for obtaining a wide dimming ratio in a display back light. The DC-to-AC inverter circuit consists of a voltage source, a Royer inverter circuit and switch circuit to turn on the Royer inverter. The Royer inverter is configured to receive a DC pulse modulated (PWM) signal that is coupled a transformer to produce an output AC PWM signal that is sent to the display back light. The configuration creates an imbalance in the Royer circuit that in turn prevents current spikes that occur when rapidly turning on the Royer inverter.