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US 2010/0134048 A1Published application
HID-Lamp Control Method and Circuit
AssigneePower-One Italy S.p.A.
InventorsEmanuele Pancani, Filippo Vernia
Life of this patent
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Abstract
A method and circuit for controlling an HID lamp powered by an HID ballast during warm-up includes gradually increasing the lamp power as the lamp voltage increases. The method includes the steps of calculating a variable reference signal as a function of the lamp voltage and controlling the lamp operating conditions based on the variable reference signal and a feedback signal, to thereby keep the lamp current within a range around a substantially constant target value during warm-up.
Claims26
An HID lamp control circuit comprising:
- a digital control device having a lamp-voltage input, a feedback-signal input, and a control signal output for driving the HID lamp;
- and
- wherein the digital control device is programmed to
- sample lamp-voltage signals during a warm-up phase,
- calculate a corrected reference signal,
- compare the feedback signal and the corrected reference signal to generate a control signal to drive the HID lamp such that the lamp operating condition is modified to maintain the lamp current within a range around a substantially constant predetermined warm-up current value.
3 more elements
A method for controlling an HID lamp during warm-up comprising the steps of:
- gradually increasing lamp power as lamp voltage increases;
- calculating a variable reference signal as a function of the lamp voltage;
- controlling lamp operating conditions based on the variable reference signal and on a feedback signal, to keep lamp current within a range around a substantially constant target value during warm-up.
Dependencies are inferred from the claim text.