DN06040/D - Universal Input, 20W, LED Ballast Design Note

DN06040/D, Design Note for the NCP1351 controller provides for a low cost, variable frequency, flyback converter. It incorporates a very low quiescent current allowing for high value resistors to be used as a start-up circuit direct from the HV rail. The design comprises and input filter, bridge rectifier (using low cost 1N4007 diodes), bulk capacitors and line inductor in filter arrangement, the power stage, rectifier diode and smoothing capacitors. Feedback is CVCC, constant current drive for the LED's with a constant voltage in the event of an open circuit output. In order not to need PFC the input power is capped at 25W, so assuming 80% efficiency the maximum output power is 20W