US Patent 7911159 Robust driver for high intensity discharge lamp

A circuit arrangement and a method for operating a high intensity discharge lamp driver, which assure long-lasting stable operation of a high intensity discharge lamp regardless of the type or the age of the lamp. This is achieved by the determination of a correctional setpoint signal for a given time period based on the a difference signal between a principal setpoint signal and the actual output current signal for a given time period. The principal setpoint signal is then adjusted by the determined correctional setpoint signal.