Datasheet

GND
IOUTADJ
REFRTN
GND
LM3463
V
0V - 2.5V
External
voltage source
0 1 2 3 4 5 6 7
0.00
0.05
0.10
0.15
0.20
0.25
V
SEn
(V)
V
IOUTADJ
(V)
LM3463
SNVS807A –MAY 2012–REVISED MAY 2013 www.ti.com
The above equations apply when V
IOUTADJ
is equal to or below V
REF
(2.5V). Generally the V
IOUTADJ
should not be
set higher than V
REF
. Applying a voltage high than V
REF
to the IOUTADJ pin could result in inaccurate LED
driving currents which fall out of the specification. Figure 19 shows the relationship of V
IOUTADJ
and V
SEn
.
Figure 19. V
SEn
versus V
IOUTADJ
Since the analog dimming control interface is designed for slow brightness control only, the rate of change of the
voltage at the IOUTADJ pin must not be higher than 1.25V/sec to allow good tracking of the output current and
changing of the V
IOUTADJ
. The voltage at the IOUTADJ pin can be provided by an external voltage source as
shown in Figure 20.
Figure 20. Adjust V
SEn
by external voltage
To secure high accuracy and linearity of dimming control, the voltage of the IOUTADJ pin can be provided by a
voltage divider connecting across the VREF and REFRTN pins as shown in Figure 21.
14 Submit Documentation Feedback Copyright © 2012–2013, Texas Instruments Incorporated
Product Folder Links: LM3463