A circuit (10) for powering a halogen lamp (20) comprises an inverter (100) and an output circuit (300). During operation, the inverter (100) and output circuit (300) provide a magnitude-limited current to the halogen lamp such that the lamp power during an initial period is substantially less than the lamp power during a steady-state operating period. Preferably, output circuit (300) is a non-isolated circuit that includes a current-limiting inductance, and inverter (100) includes a frequency control circuit (R2,C4,C7,Q3,R3,R5,C8) for operating the inverter at a higher frequency during the initial period so as to reduce stress upon the lamp filament and preserve the operating life of the lamp. The circuit (10) is especially suitable for powering low voltage halogen lamps.