Robust Driver For High Intensity Discharge Lamp
AssigneeKoninklijke Philips Electronics N.V.
InventorsDolf Henricus Jozef Van Casteren, Robertus Leonardus Tousain
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Abstract
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.
Claims32
Circuit arrangement for operating a high intensity discharge lamp, said circuit arrangement comprising
- regulable converter means adapted to generate a current regulable in magnitude out of a supply voltage,
- commutator means for commutating the current and comprising lamp connection terminals, setpoint signal generator means adapted to generate a principal setpoint signal for said current, correctional setpoint signal generator means adapted to generate a correctional setpoint signal adjusting said principal setpoint signal to form a corrected setpoint signal, said correctional setpoint signal generator means comprising
- memory means,
- output means for said correctional setpoint signal,
- input means adapted to acquire an input signal, and
- calculation means adapted to periodically recalculate said correctional setpoint signal based on said input signal and a signal stored in said memory means,
- and said circuit arrangement furthermore comprising phase synchronization means adapted to synchronize said correctional setpoint signal generator to said principal setpoint signal.
Method for operating a high intensity discharge lamp driver, said method comprising:
- generation of a principal setpoint signal for a given time period;
- acquisition of a signal corresponding to an actual output current for said given time period;
- determination of a difference signal between said principal setpoint signal and said actual output current signal for said given time period;
- determination of a correctional setpoint signal for a subsequent time period of said given time period based on said difference signal;
- adjustment of said principal setpoint signal with said correctional setpoint signal for said subsequent time period.
Dependencies are inferred from the claim text.