Patent ID: 7944156
Filing Date: 2011-05-17
Classification: H05B,Y02B

Abstract:
1. A control circuit that interconnects a source of AC voltage to a high intensity discharge lamp, for controlling the flow of current through said high intensity discharge lamp, the control circuit comprising: open circuit voltage supply for supplying a predetermined open circuit voltage to said high intensity discharge lamp; breakdown voltage supply for providing high frequency voltage pulses of predetermined magnitude with periodic intervals to said high intensity discharge lamp to create a breakdown of said high intensity discharge lamp to a glow state; arc development current control for providing a controlled current at a controlled frequency into said high intensity discharge lamp, as said high intensity discharge lamp transitions from said glow state to the beginning phase of the arc state, for a stabilization period of no less than one second; frequency transition circuit for increasing the current into said high intensity discharge lamp following said stabilization period to a level that is not more than two times the normal operating current of said high intensity discharge lamp; and power control, responsive to said frequency transition, for switching said high intensity discharge lamp to a low operating frequency at a normal operating current of said high intensity discharge lamp.