Combination ballast and cold cathode sealed lamp and method

Claim 2

A high frequency, low voltage ballast for a cold cathode tube, comprising in combination: an output transformer having a secondary winding connected to supply power to said tube; said transformer having a center tapped primary winding for inducing voltage across said secondary winding; a pair of feedback windings adjacent the primary winding; an E--E section core, each section comprising first outer leg, a second outer leg and a center leg; a dielectric bobbin carrying said primary winding and said feedback windings all on the center leg of the first E core section; a multi-section dielectric bobbin carrying the secondary winding mounted on the center leg of the other E core section with approximately one half of the secondary winding carried in a first section of the multi-section bobbin, and approximately the other half of the secondary winding carried by a different section of the multi-section bobbin in spaced apart relation to the first section; a pair of switching FETS connected for alternate conduction to establish alternating current in the primary winding for inducing higher voltage alternating current in the secondary winding for operating the tube; means for receiving a low voltage ac or dc supply voltage to operate the ballast; means for biasing the FETS from rectified supply voltage; and means including said feedback windings for establishing said alternate conduction.

Claim 3

A high frequency, low voltage ballast for a cold cathode tube, comprising in combination: an output transformer having a secondary winding connected to supply power to said tube; said transformer having a center tapped primary winding for inducing voltage across said secondary winding; a pair of feedback windings adjacent the primary winding; an E--E section core, each section comprising first outer leg, a second outer leg and a center leg; a dielectric bobbin carrying said primary winding and said feedback windings all on the center leg of the first E core section; a further dielectric bobbin carrying the secondary winding mounted on the center leg of the other E core section; a pair of switching means connected for alternate conduction to establish alternating current in the primary winding for inducing higher voltage alternating current in the secondary winding for operating the tube; means for receiving a low voltage ac or dc supply voltage to operate the ballast; means for biasing the switching means from rectified supply voltage; and means including said feedback windings for establishing said alternate conduction.

Claim 4

A high frequency, low voltage ballast for a cold cathode tube, comprising in combination: an output transformer having a secondary winding connected to supply power to said tube; said transformer having a center tapped primary winding for inducing voltage across said secondary winding; a pair of feedback windings adjacent the primary winding; an E--E section core, each section comprising first outer leg, a second outer leg and a center leg; a dielectric bobbin carrying said primary winding and said feedback windings all on the center leg of the first E core section; a further dielectric bobbin carrying the secondary winding mounted on the center leg of the other E core section; a pair of switching means connected for alternate conduction to establish alternating current in the primary winding for inducing higher voltage alternating current in the secondary winding for operating the tube; means for receiving a low voltage ac or dc supply voltage to operate the ballast; means for biasing the switching means from rectified supply voltage; and means including said feedback windings for establishing said alternate conduction.

Claim 7

A high frequency, low voltage ballast for a cold cathode tube, comprising in combination: an output transformer having a secondary winding connected to supply power to said tube; said transformer having a center tapped primary winding for inducing voltage across said secondary winding; a pair of feedback windings adjacent the primary winding; an E--E section core, each section comprising first outer leg, a second outer leg and a center leg; a dielectric bobbin carrying said primary winding and said feedback windings all on the center leg of the first E core section; a multi-section dielectric bobbin carrying the secondary winding mounted on the center leg of the other E core section with approximately one half of the secondary winding carried in a first section of the multi-section bobbin, and approximately the other half of the secondary winding carried by a different section of the multi-section bobbin in spaced apart relation to the first section; a pair of switching FETS connected for alternate conduction to establish alternating current in the primary winding for inducing higher voltage alternating current in the secondary winding for operating the tube; means for receiving a low voltage ac or dc supply voltage to operate the ballast; means for asymetrically biasing the FETS from rectified supply voltage with a selected FET receiving higher biassing voltage than the non-selected FET to insure that it always conducts first when the FETS are supplied with operating voltage; and means including said feedback windings for establishing said alternate conduction.

Claim 8

A high frequency, low voltage ballast for a cold cathode tube, comprising in combination: an output transformer having a secondary winding connected to supply power to said tube; said transformer having a center tapped primary winding for inducing voltage across said secondary winding; a pair of feedback windings adjacent the primary winding; an E--E section core, each section comprising first outer leg, a second outer leg and a center leg; a dielectric bobbin carrying said primary winding and said feedback windings all on the center leg of the first E core section; a multi-section dielectric bobbin carrying the secondary winding mounted on the center leg of the other E core section with approximately one half of the secondary winding carried in a first section of the multi-section bobbin, and approximately the other half of the secondary winding carried by a different section of the multi-section bobbin in spaced apart relation to the first section; a pair of switching FETS connected for alternate conduction to establish alternating current in the primary winding for inducing higher voltage alternating current in the secondary winding for operating the tube; means for receiving a low voltage ac or dc supply voltage to operate the ballast; means for asymetrically biasing the FETS from rectified supply voltage with a selected FET receiving higher biassing voltage than the non-selected FET to insure that it always conducts first when the FETS are supplied with operating voltage; and means including said feedback windings for establishing said alternate conduction.

Claim 9

A dielectric bobbin for uniquely carrying a winding having substantially equal numbers of turns in each half thereof with a connecting turn extending between said halves comprising in combination; a multi-section cylindrical bobbin having at least three sections and an axial opening there through; said bobbin having a dielectric cylindrical core body and spaced apart dielectric peripheral spacers; substantially half of said turns being wound about the core between a first and an adjacent second spaced apart spacer; said connecting turn being wrapped about said core between said second spacer and a third spacer spaced apart therefrom; and, the other substantial half of said turns being wrapped about said core between said third spacer and a fourth spacer spaced therefrom.

Claim 10

A dielectric bobbin for uniquely carrying a winding having substantially equal numbers of turns in each half thereof with a connecting turn extending between said halves comprising in combination; a multi-section cylindrical bobbin having at least three sections and an axial opening there through; said bobbin having a dielectric cylindrical core body and spaced apart dielectric peripheral spacers; substantially half of said turns being wound about the core between a first and an adjacent second spaced apart spacer; said connecting turn being wrapped about said core between said second spacer and a third spacer spaced apart therefrom; and, the other substantial half of said turns being wrapped about said core between said third spacer and a fourth spacer spaced therefrom.

Claim 11

The method of wrapping the winding of claim 5 on the core of claim 5, comprising the steps of: wrapping the substantially half of said turns about the core between the first and second spacers in a clockwise direction; wrapping the connecting turn about the core in a counter clockwise direction; and, wrapping the other substantial half of said turns about the core in a clockwise direction.

Claim 12

The method of claim 6, wherein: said first mentioned substantially half of said turns penetrates said first spacer at a location adjacent the core to be wrapped between said first and second spacers outwardly of the core to the outer edge of said second spacer; said connection turn extending over the second spacer via a peripheral groove and extending through said third spacer adjacent to the core; and said other substantial half of the winding being wrapped between said third and fourth spacer outwardly from the core.