Patent ID: 6020691
Filing Date: 2000-02-01
Classification: H05B,Y02B,Y10S

Abstract:
A discharge lamp driving circuit for driving a high intensity discharge lamp, said circuit comprising:a plurality of DC voltage input connections for powering the discharge lamp driving circuit;two lamp-driving connections between which the high intensity discharge lamp is connectible;a bridge circuit connected to said DC voltage input connections, said bridge circuit including high/low frequency driver control circuitry connected to drive switching elements of said bridge circuit, said high/low frequency driver control circuitry igniting the lamp connected between said lamp driving connections by an alternating sinusoidal voltage, biased by an alternating rectangular voltage during starting to aid glow-to-arc transition; anda filter network having at least two filter stages, each of said at least two filter stages being connected to said lamp driving connections and to said switching elements of said bridge circuit to remove acoustic resonance in the lamp during normal operation by filtering an alternating rectangular current driving the lamp.