Electronic ballast based on class E amplifier with a capacitive inverter and dimming for photovoltaic applications

In this paper, the design and construction of an electronic ballast based on a class E amplifier with a capacitive impedance inverter and with dimming features is presented. The ballast is intended to supply instant-start fluorescent lamps from a DC 12 V source. The use of class E amplifiers in fluorescent lamps ballasts presents large advantages such as: high power density; simple structure (only one transistor); high efficiency; and optimum lamp driving. The class E amplifier uses a capacitive impedance inverter as the resonant tank and one diode in antiparallel with the switch; these elements allow the implementation of a dimming feature for the ballast. One of the main applications of this ballast is the supply of fluorescent lamps from solar cells. The design process has been simplified obtaining several characteristics and using mathematical programs. The designed electronic ballast drives a 21 W lamp and operates at a switching frequency of 400 kHz. Dimming is implemented using a SG3524 in a VCO fashion.