White LED Driver Circuits for Off-Line Applications using Standard PWM Controllers White LED Driver Circuits for Off-Line Applications using Standard PWM Controllers Application Note February 12, 2009 AN1387.0 Introduction The LED Ballast As high-efficiency ultra-bright white LEDs come down in Fortunately, there are many power supply topologies suitable cost, they are approaching cost parity with conventional for this application. Virtually any topology having a series mercury vapour, HID quartz……