rev.
page
date
3 of 4
1/2009
PART NUMBER:
VLD24-XXX
DESCRIPTION:
constant current dc-dc converter
ANALOG DIMMING CONTROL
A
+Vin
1
6
Cin
VLD24-XXX
5
1 st LED
G ND
R
W
4
2
3
La st LED
ON /OFF /PWM
POT Dim
Cin = 47μF for best performance
Io can be set between 0A and Io(max) with
trim pot Rw. For example, to set the output
current (Io) to 200mA using the VLD24-350,
choose Rw=0.4Ω. The trim pot should be
placed close to pins 1 and 2 with shortest
possible leads.
0.75
0.703
0.657
Io_300
w
0.61
0.563
Io_350
w
0.517
0.47
Io_500
w
0.423
0.377
Io_600
w
0.33
Io_700
w
0.283
0.237
0.19
0.143
0.097
0.05
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3
R
w
Ω
TYPICAL APPLICATION CIRCUITS
+Vin
1
6
Cin
+Vin
1
6
Cin
VLD24-XXX
4
2
3
La st L ED
POT Dim
ON/ OFF /PWM
VLD24-XXX
4
5
2
3
ON/ OF F /PWM
1st LED
La st L ED
POT Dim
GND
5
1st LED
GND
R
W
R
W
Figure 1a. Series Configuration
Figure 1b. Parallel Configuration
EMS FILTER CIRCUITS
700 µ H * 2
+ Vin
1
µ
F
Cera mic
2 .2
µ
F
Fi ter2 T
1
6
Ce ra mic
VLD24-XXX
5
4 2
3
Las t LED
ON/OFF/PWM
G ND
1s t LED
20050
SW
112
th
Ave. Tualatin, Oregon
97062
phone
503.612.2300
fax
503.612.2382
CUI [ CUI INC ]
