30 V, 2 A High Efficiency CVCC LED Driver

This Design Note (DN) is an extension to
ON Semiconductor's Evaluation Board User's Manual
EVBUM2039/D and features a 30 V max, 2 A version of the
off-line, NCL30051 based constant voltage, constant
current (CVCC) high efficiency LED driver. The original
document features a 55 V max, constant current, 1.5 A
(current settable) LED driver with multiple dimming
capabilities and active power factor correction in a
two-stage off-line converter utilizing a resonant half-bridge
in the main conversion stage. This DN presents a similar
version of that design which is suitable for driving LED
strings up to 30 V at a max current of up to 3 A. This design
is suitable for LED street lighting and wall pack lamp
applications. The maximum output voltage and output
current can be adjusted via resistors R28 and R26
respectively, shown in the secondary circuit schematic. The
detailed circuit operational description can be found in the
original mentioned NCL30051 evaluation board user's
manual (EVBUM2039/D) and is essentially identical
circuit-wise with the exception of the component changes
that are indicated in the BOM. The resonant half-bridge
transformer design for this DN was merely ratioed from the
secondary winding on the original 55 V transformer design
to meet the new voltage and current requirements. The
primary winding, required inductances, and overall
construction are essentially the same.