Improved half bridge drive for discharge lamps

摘要

The driver utilises a method of half-bridge control stabilisation and a safety switch-off circuit for driving a fluorescent lamp with protection against externally coupled noise. High frequency noise voltages coupled into the circuit are tapped by at least a secondary winding (RKc) of an inductance with a primary winding (RKa) in the lamp's current path (La) and are rectified. The rectified voltage charges a capacitance (C5) and optimally ensures switch-off element (Q7) operation via the safety switch-off circuit (SAK).