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US 5,210,470 AGranted
Low power on-off control of electronic ballast
AssigneeAppliance Control Technology, Inc.
InventorWilliam H. Jones
Life of this patent
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Abstract
An electronic ballast for use with fluorescent lamps including an inverter circuit for converting a direct current power source to a high voltage alternating current and starting means to inhibit operation of one of the inverter transistors until such time as fluorescent lamp is turned on. The circuitry taught eliminates substantial drain usually found at start up of inverter circuits due to the large capacitors usually found in such circuitry.
Claims3
A first electronic ballast connected to a fluorescent lamp including:
- an inverter circuit including connections to a direct current power source for converting direct current to high voltage alternating current;
- first and second transistors;
- and a dual toroid coil assembly functioning with said transistors to form said inverter circuit;
- starting means connected between said direct current power source and said second transistor operated to turn said second transistor on thereby initiating operation of said inverter means;
- a low power control circuit;
- connected between said power source and said second transistor;
- operated to inhibit operation of said starting means to prevent operation of said second transistor;
- said low power control circuit including a third transistor connected to said second transistor to ground said second transistor and thereby inhibit operation of said second transistor;
- and switching means manually operated to render said third transistor non-operated whereby said second transistor is conditioned for operation and in response to said starting means said second transistor is rendered operated.
6 more elements
Dependencies are inferred from the claim text.