Granted Patent B2

US 6,972,525 · App. 10/483,862 · Granted Dec 6, 2005

Abstract

Claims (40)

1. A switching arrangement for operating at least one LED, which switching arrangement is provided with

input terminals for connecting a supply source,

output terminals for connecting the LED to be operated,

a first series circuit between one of the input terminals and one of the output terminals including at least a self-inductance, a capacitor and a diode,

a second series circuit between the input terminals, including at least said self-inductance and a switching element which is alternatively switched to a conducting state and a non-conducting state at high frequency,

a third series circuit between the output terminals, including at least said diode and an inductive winding,

characterized in that the inductive winding forms a secondary winding of a transformer which has a primary winding which forms part of both the first and the second series circuits.

2. A switching arrangement as claimed in claim 1 , characterized in that a bypass capacitor is arranged between the input terminals.

3. A switching arrangement for operating at least one LED, said switching arrangement comprising:

input terminals for connecting a supply source;

output terminals for connecting the LED;

a first series circuit between one of the input terminals and one of the output terminals including at least a self-inductance, a capacitor and a diode;

a second series circuit between the input terminals, including at least said self-inductance and a switching element which is alternatively switched to a conducting state and a non-conducting state; and

a third series circuit between the output terminals, including at least said diode and an inductive winding,

wherein said inductive winding forms a secondary winding of a transformer which has a primary winding which forms part of both the first and the second series circuits; and

wherein the switching arrangement is configured in accordance with the relation

2π[(L 1 +Ls) C 3 ] 1/2 >δ,

wherein:

L 1 is the magnitude of the self-inductance in H,

Ls is the magnitude of the self-inductance of the secondary winding in H,

C 3 is the capacitance of the capacitor in F, and

δ is the fraction in s of each switching period of the switching element during which the switching element is switched in its non-conductive state.

4. A switching arrangement as claimed in claim 1 , characterized in that the secondary winding is made up of a first winding and a second winding, which second winding is incorporated in said first series circuit and which also has a connection point with the first winding.

5. A switching arrangement comprising:

a first circuit connected between a first input and a first output of said switching arrangement, said first circuit having a diode;

a second circuit connected between said first input and a second input of said switching arrangement, said second circuit including a switching element;

a third circuit connected between said first output and a second output of said switching arrangement, said third circuit including said diode and an inductive winding; and

a transformer having a primary winding, wherein said inductive winding forms a secondary winding of said transformer;

said diode having an input connected to said primary winding and said secondary winding.

6. The switching arrangement of claim 5 , further comprising a bypass capacitor arranged between said first input and said second input of said switching arrangement.

7. The switching arrangement of claim 5 , said first circuit further comprises a self-inductance and a capacitor.

8. The switching arrangement of claim 7 , wherein said switching arrangement is configured in accordance with the relation

2π[(L 1 +Ls)C 3 ] 1/2 >δ,

wherein:

L 1 is the magnitude of the self-inductance in H;

Ls is the magnitude of a self-inductance of the secondary winding in H;

C 3 is the capacitance of the capacitor in F; and

δ is a fraction in s of each switching period of the switching element during which the switching element is switched in its non-conductive state.

9. The switching arrangement of claim 5 , wherein the secondary winding includes a first winding and a second winding.

10. The switching arrangement of claim 5 , wherein the secondary winding includes a first winding and a second winding, said second winding being incorporated in said first circuit and having a connection point with said first winding.

Assignments (8)