EFFICIENT SAFETY CIRCUIT FOR ELECTRONIC BALLAST
Original Publication Date: 1998-Mar-01
Included in the Prior Art Database: 2002-Jun-25
In electronic ballast circuits for fluorescent lamps, the self oscillant circuit, commonly used in the low cost half bridge converter, is prone to thermal runaway when the fluorescent lamp does not strike. As a consequence, either the switches are oversized to sustain such a fault condition, or the circuit includes a safety network to avoid this risk. Although several solutions are known which perform such a function, the one described in this paper is easy to implement and does not influence the normal operation of the converter.