Converter Technology

RD016 Published

Posted: 12 January, 2009

Emergency lighting systems must provide light for a specified length of time if the AC mains supply fails. RD016 is designed as a ‘maintained mode’ light to drive a single high brightness LED at 380mA for upto 4 hours if mains were to fail.

Maintained Mode Emergency Lighting System [Battery and LED not shown]

A front end flyback converter provides an isolated +5V rail from an input voltage of 85 to 265Vac 50/60Hz allowing the ballast to operate on worldwide mains voltages. Whilst powered by mains, an on-board circuit charges the 2.2Ah Li-Ion battery whilst simultaneously running the constant current LED drive stage. When mains fails, the LED driver automatically switches to battery power with no interruption to the LED output.