The KA7543 is an advanced lamp current feedback dimming control IC. This ballast control IC provides all of the necessary features to implement wide range dimming control, soft start and constant power consumption for intelligent electronic ballast systems. The KA7543 is optimized for advanced electronic ballast systems requiring minimum board area. External component counts can be reduced by adopting the KA7543. Current feedback control method of the inverter status is one of the most attractive merits in KA7543. Internal soft start circuitry eliminates the need for external soft start discrete components. Voltage controlled soft dimming circuit is built into the IC to control the lighting output in a wide range. Protection circuitry, no lamp protection, abnormal protection, one lamp detection, UVLO, restart on lamp adding , have been added.