Patent ID: 6400092
Filing Date: 2002-06-04
Classification: H05B,Y02B

Abstract:
An apparatus for driving an electro-luminescent device, characterized by: a transformer including a ferrite core and a first primary winding, a second primary winding and a secondary winding wound onto said core without an air gap; one end of each of the first and second primary windings being connected together; an electrical circuit arranged to drive said one ends of the first and second primary windings; a feed back circuit connected between the electrical circuit and the other end of the second primary winding to control operation of said electrical circuit; one end of the secondary winding being connected to said other end of the second primary winding; and the other end of the secondary winding being connected to the electro-luminescent device, wherein the secondary primary winding is wound onto said core first, then said second primary winding and finally said first primary winding, the turns ratio between the first and second primary windings being from 1:14 to 1:12, the turns ratio between the second primary winding and secondary winding being from 1:100 to 1:250; and wherein said electrical circuit includes a transistor and said feed back circuit comprises a resistor and a capacitor provided in series between said other end of the second primary winding and the base of the transistor.