White LED driver constant current
isolated offline circuit diagram
High brightness white LEDs are becoming a prominent source
of light and often have better efficiency and reliability when
compared to that of conventional light sources. While LEDs can
operate from an energy source as simple as a battery and resistor,
most applications require an efficient energy source not only for
the reduction of losses, but also for the lumen maintenance of the
LED itself. Using integrated off line switching regulators like the
VIPer12A and VIPer22A in a constant current configuration, a low
cost, high efficient LED driver for multiple LEDs has been developed.
This document introduces the isolated and non-isolated offline
constant current LED driver based on the VIPerX2A family.
All three LED driver configurations operate in the extended wide
range input voltage, from 90 to 264V ac.
VIPer12A current selectable LED driver circuit diagram
The circuit diagram is designed to display the full functionality
of VIPer12A and VIPer22A as white LED drivers to drive 1W, 3W as
well as 5W LEDs at wide range input voltage. The components selected
are optimized for 5W LED driver application. The following pages
contain the schematics and bills of materials that reflect the
components used on the boards. Based on this circuit, there are six
different configurations with different output power level that
could be derived by making minor components changes to the
evaluation board. The subsequent pages will show the schematics and
bills of materials for the circuit to drive 1W, 3W and 5W.
Download: VIPower: Offline constant current LED driver using