High pressure discharge lamp control system and method

A method for supplying a controllable current to a high intensity discharge lamp, comprising:

• providing the controllable current to the high intensity discharge lamp, wherein the controllable current includes at least one portion that varies exponentially with time.

A system for providing a controllable current to a high intensity discharge lamp, comprising:

• a current controller configured to receive input power and to provide an output current waveform as the controllable current to the lamp to cause discharge of light therefrom, the output current waveform including an absolute value amplitude in each half cycle thereof that is generally constant during a first portion thereof and that increases non-linearly from the generally constant amplitude to a peak amplitude during a second portion thereof;
• and
• a lamp voltage sensor adapted to sense a voltage across the high intensity discharge lamp and to provide feedback to the current controller to alter the controllable current based upon the sensed voltage.

A system for driving a high intensity discharge lamp, comprising:

• means for providing a controllable current to the high intensity discharge lamp via a current controller, wherein the controllable current comprises an absolute value amplitude in each half cycle thereof that is generally constant during a first portion thereof and that increases non-linearly from the generally constant amplitude to a peak amplitude during a second portion thereof.

A controllable current waveform for use as an input current for a high intensity discharge lamp, comprising:

• an absolute value amplitude in each half cycle thereof that is generally constant during a first portion thereof and that increases non-linearly from the generally constant amplitude to a peak amplitude during a second portion thereof.

A method for controlling flicker of light emitted from a high intensity discharge lamp, comprising:

• controlling at least a vaporization or a deposition of electrode material on at least one electrode disposed within the high intensity discharge lamp in a closed loop manner to control changes in shape of the at least one electrode over time.

A method for reducing changes in morphology of at least one electrode disposed within a high intensity discharge lamp, comprising:

• sensing a voltage between a pair of electrodes of the high intensity discharge lamp;
• and
• supplying a controllable current to the high intensity discharge lamp to increase temperature at tip of the at least one electrode based upon the sensed voltage.

A system for driving a high intensity discharge lamp, comprising:

• means for controlling at least a vaporization or a deposition of electrode material on at least one electrode disposed within the high intensity discharge lamp in a closed loop manner to control changes in shape of the at least one electrode over time.

A system for driving a high intensity discharge lamp, comprising:

• means for supplying a controllable current to the high intensity discharge lamp to increase temperature at tip of at least one electrode based upon a voltage sensed between a pair of electrodes of the high intensity discharge lamp.