Patent ID: 6274987
Filing Date: 2001-08-14
Classification: H05B,Y10S

Abstract:
A protection circuit for at least one gas discharge lamp, the protection circuit sensing at least one failure mode in the lamp(s) and providing a control signal to a ballast circuit powering the lamp(s) to reduce power being supplied to the lamp(s) to prevent overheating of the lamp(s) comprising:a sensor means for detecting the failure mode(s) in the lamp(s), the sensor means providing a sensor signal proportional to the lamp(s) power;a control means coupled to the sensor means, the control means having a control input terminal for receiving the sensor signal and a control output terminal, the control means providing the control signal at the output terminal in response to the sensor means detecting said failure mode;a boost converter connected to the control means output terminal, the boost converter operable to receive the control signal such that upon receipt of the control signal power to the lamp(s) is reduced to prevent overheating of the lamp(s); anda time delay means, The time delay means connected to the control means such that the control means is unresponsive during starting of the lamp(s).