Gte Products Corporation

Micro Linear Corporation

John B Sampson

Ronald A Lesea

Alland Chee

A method and apparatus for controlling the operation of a gas discharge lamp including regulation of power provided to the lamp for maintaining a preselected illumination intensity, automatic lamp shut down for preventing a catastrophic failure of the lamp, and automatic selection of operating frequencies for increasing efficiency and extending useful life of the lamp. An appropriate quality factor Q is achieved by including a low pass filter followed by a high pass filter in the lamp network so as to allow deep dimming of the lamp. Preferably, the arc power delivered to the lamp network is sensed and regulated. By sensing the arc power instead of only the lamp current, the illumination intensity of the lamp is accurately regulated. Further, the lamp ballast is automatically shut down near the end of the lamp's useful life, before operation in partial rectification. Preferably, power to the lamp is shut off based on the arc power entering the lamp network instead of relying only on the voltage of the lamp to avoid unnecessarily shutting down the lamp. The lamp network is automatically operated at an appropriate frequency selected from among a plurality of predetermined frequencies according to the lamp's present mode of operation including: preheating, starting, and continuous operation. Preferably, each frequency is optimized for the particular lamp and for the particular mode of operation.

Controlling gas discharge lamp intensity with power regulation and end of life protection

For coupling one, or more, gaseous discharge lamps to a high-frequency AC power-source a ballasting (current-limiting) network employs a first capacitor, a second inductor, and a transformer having a primary winding coupled to the high-frequency AC power-source by the first capacitor and a secondary winding coupled to the gaseous discharge lamp by the second inductor.

High-pass t-networks with integral transformer for gaseous discharge

For coupling one, or more, gaseous discharge lamps to a high-frequency AC power-source a ballasting (current-limiting) network employs a first capacitor, a second capacitor, and a transformer having a primary winding coupled to the high-frequency AC power-source by the first capacitor and a secondary winding coupled to the gaseous discharge lamp by the second capacitor.

High-pass T-networks with integral transformer for gaseous discharge

For coupling one, or more, gaseous discharge lamps to a high-frequency AC power-source a ballasting (current-capacitor, and a transformer having a primary winding coupled to the high-frequency AC power-source by the first capacitor and a secondary winding coupled to the gaseous discharge lamp by the second capacitor.

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Morgan Hill, CA, United States of America

John B Sampson