Patent ID: 6919695
Filing Date: 2005-07-19
Classification: H05B,Y02B

Abstract:
1. Device for operating a high-pressure discharge lamp, comprising a switched mode power supply circuit (SMPS) for supplying power to the high pressure discharge lamp from a supply voltage, the power supply circuit comprising a half bridge commutating forward (HBCF) circuit including an inductance (L hbcf ), a capacitor circuit of a first capacitor (C s1 ) and a second capacitor (C s2 ) in series, the lamp (LA) being connectable between the inductance (L hbcf ) and a point (M) between the first and second capacitor (C s1 , C s2 ); wherein overvoltage protection means are connected parallel to the lamp, which switch from an off-state with a high resistance operation to an on-state with a low resistance operation when the voltage difference across the protection means exceeds a breakover voltage (V bo ), the breakover voltage (V bo ) being selected to correspond to a predetermined maximum voltage across the first or the second capacitor (C s1 , C s2 ).