Patent ID: 6072282
Filing Date: 2000-06-06
Classification: H05B,Y02B

Abstract:
An electronic ballast for supplying power to one or more gas discharge lamps comprising:a) a rectifier circuit connecting the ballast to a source of AC power for converting received AC power to a form of DC voltage:b) a voltage boosting circuit connected to receive the converted DC voltage for increasing the level thereof to the operating levels required by the lamps;c) a control circuit connected between said boosting circuit and the lamps for controlling the application of boosted voltage to the lamps;d) a power factor correction circuit for adjusting the power factor of the power drawn by the ballast close to unity, said power factor correction circuit connected to said rectifier circuit to receive the converted DC voltage and be turned on thereby in the first half cycle of operation and to said boosting circuit to turn it on and enable in-phase voltage boosting and the ballast once it has been started;e) a voltage limiting and divider circuit connected between said rectifier circuit and said power factor correction circuit for maintaining the voltage applied to said power factor correcting circuit at a proper value regardless of the value of the AC voltage received by the ballast;f) wherein said voltage limiting and divider circuit is adapted through selection of the values of its components to apply sufficient voltage to turn on said power factor correcting circuit at the value of the lowest value of AC voltage that could be received by the ballast;g) an in-rush current limiting circuit connected to said voltage limiting and divider circuit for limiting the start-up current to said power factor correcting circuit to a predetermined appropriate level; andwherein said in-rush current limiting circuit is operationally bypassed by said voltage limiting and divider circuit once said voltage limiting and divider circuit reaches the proper value of voltage to be applied to said power factor correcting circuit.