The LT®1937 is a step-up DC/DC converter specifically
digned to drive white LEDs with a constant current. The
device can drive two, three or four LEDs in seri from a
Li-Ion cell. Seri conneion of the LEDs provid identical
LED currents rulting in uniform brightns and
eliminating the need for ballast ristors. The LT1937
switch at 1.2MHz, allowing the use of tiny external
components. The output capacitor can be as small as
0.22mF, saving space and cost versus alternative solutions.
A low 95mV feedback voltage minimiz power loss
in the current setting ristor for better efficiency.
The LT1937 is available in low profile SC70 and ThinSOT
packag.