Patent ID: 6987363
Filing Date: 2006-01-17
Classification: H02J,Y02B

Abstract:
1. A fluorescent type emergency lighting ballast including circuit means for emergency operation of a fluorescent lamp having a cathode heater with power supplied by a battery, when power normally supplied to said fluorescent lamp from a standard fluorescent AC ballast, powered by normal AC power mains is interrupted and the lamp's standard fluorescent ballast is disabled, comprising: a) a rectifier charging circuit adapted to be connected to be powered by the normal AC power supply to the standard fluorescent ballast during normal operation of the normal AC power supply, said charging circuit disconnectably connected to said battery while the normal AC power supply is providing AC power to the lamp; b) an inverter disconnectably connected to said battery upon disenabling of said rectifier charging circuit charging said battery, the output of said inverter switchably oscillating a voltage of said battery to create an AC output current, and including a transformer to step up said inverter created AC voltage to a predetermined level to operate the fluorescent lamp, said inverter disconnectably connected to the fluorescent lamp during a period said inverter is powered by said battery; wherein c) a battery charging control circuit connected to the rectifier charging circuit and the battery, the control circuit including a temperature sensitive switch disposed adjacent the battery, said switch disconnecting the charging circuit from the battery when the temperature sensed by the switch is below a predetermined level; whereby the battery is charged only when it is at or above the temperature sensed by the switch.