Patent ID: 6384543
Filing Date: 2002-05-07
Classification: H05B,Y10S

Abstract:
A switching device for powering a lamp, includinginput terminals for connection to a supply voltage source, an inverter for generating a high-frequency lamp current which includes switching means which are coupled to the input terminals, an external drive circuit which is coupled to the switching means in order to generate a control signal of frequency f for controlling the switching means so as to be alternately conductive and non-conductive, a dimming circuit which is coupled to the control circuit in order to adjust the frequency f, and a load circuit which is coupled to the switching means and includes a series connection of an inductive element and lamp connection terminals which are connected by a circuit which includes a first capacitive element, characterized in that the inductive element is proportioned such that L20/L max&lE;0.7, wherein Lmax is the instantaneous value of the inductance of the inductive element when the amplitude of the current in the inductive element is maximum and the lamp power has its maximum value, and L20 is the instantaneous value of the inductance of the inductive element when the amplitude of the current in the inductive element is maximum and the lamp power amounts to 20% of its maximum value.