Data Sheet

WLMDU9456001JT / 172946001
MagI
3
C Power Module
LDHM - LED Step Down High Current Module
We-online.com Würth Elektronik eiSos GmbH & Co. KG – Data Sheet Rev. 1.0
© May 2016 12/35
DESIGN FLOW
Step 1 Program the LED driver module current
The LED driver module requires no external current sensing resistor for LED current regulation. If the default LED current of
350mA is desired, no external resistor is necessary. It is enough to connect the IFIX pin to GND and to leave the ISET pin
open, as shown in the picture below:
C
IN
LED+
DIM
PGND
ISET
IFIX
LED-
Module
AGND
1
3
EP
6
V
IN
2
LED+
7
5
4
High Power LED String
C
OUT
Setup for fixed 350mA LED current
If a different LED current is required, it can be adjusted from 300 mA to 450 mA by varying the value of the resistor R
IADJ
,
connected between ISET pin and GND, leaving the IFIX pin open, according to the following equation and as shown in the
picture on the next page:
I

=
V

∙

k
R

=
1
,
25V
∙
840
R





(
1
)
where V
REF
is the internal voltage reference and k is the current mirror ratio between the LED current and the current flowing
through R
IADJ
. The factor k is fixed by design to 840.