PROTECTING CIRCUIT FOR ARC DISCHARGE LAMP

摘要

Provided is a method to detect an arcing condition in an arc discharge lamp ballasts is disclosed. An AC current signal flows from the lamp load to ground via at least one ring core. The ring core is provided for detecting an arcing condition in AC current signal and the ballast circuit by detecting a current spike along the ring core. When there is a current spike in the primary core, created by the arcing condition, a proportional increase in voltage within a control signal occurs on the secondary core. A rectifier circuit is used for conditioning the increase in voltage within the control signal. A control circuit, responsive to the increase in voltage within the control signal, dynamically adjusts the operating frequency of a resonant inverter so that the arcing condition is extinguished.

主权项

1. An apparatus for detecting an arcing condition in an electronic ballast circuit, the arcing condition producing a current spike, the apparatus comprising:
an inverter for driving a lamp load; wherein the current spike flows from the lamp load to ground via at least one ring core when the arcing condition; wherein the current spike flows through a primary side of the ring core producing a corresponding increase in voltage within a control signal on a secondary side of the core; a rectifier circuit for conditioning the increase in voltage; and a control circuit responsive to the increase in voltage for adjusting an operating frequency of the inverter for extinguishing the arcing condition.