Ignition device for discharge lamp - has feedback control through monitors on lamp to vary pulse-width modulator on drive circuit

摘要

The lamp is driven from a DC supply via a DC converter (11) to generate h.v. and a pulse-width modulator to vary the chopped signal. A bridge circuit (14) feeds the lamp (15) as well as providing reference points for the current- and voltage monitoring circuits. These monitored signals are applied and drive the pulse-width modulator. The monitored signals are multiplied together and the resulting signal passed through a comparator which has standard reference signals. The feedback control ensures a constant drive to the lamp during starting even with momentary interruption of the supply. ADVANTAGE - Improved starting sequence, improved efficiency.