An electronic control circuit for intelligently controlling a gas
discharge lamp associated with an HVAC system. The circuit includes a
microcontroller having a memory containing instructions executable by the
microcontroller to process a plurality of dynamic lamp state signals and
dynamically generate control signals in at least partial dependence on a
plurality of pre-established control parameters to maintain the gas
discharge lamp in a minimum operable state defined by the pre-established
control parameters. The gas discharge lamp is coupled to an electronic
ballast circuit configured to dynamically control a current flow through
the gas discharge lamp in dependence on the dynamically generated control
signals sent by the microcontroller. The executable instructions cause
the microcontroller to iteratively determine the minimum operable state
of the gas discharge tube in at least partial dependence on a voltage
excursion included as one of the plurality of dynamic lamp state signals.