cui.com
date 06/11/2015 │ page 6 of 7CUI Inc │ SERIES: VSK-S20 │ DESCRIPTION: AC-DC POWER SUPPLY
APPLICATION NOTES
1. Output voltage trimming
Leave open if not used.
Application Circuit for Trim pin
(part in broken line is the interior of models) Formula for Trim Resistor
Note: Value for R1, R2, R3, and Vref refer to Table 3
R
T
: Trim Resistor
a: User-dened parameter, no actual meanings
Vo': The trim up/down voltage
Figure 3
Table 3
Vout
(Vdc)
R1
(kΩ)
R2
(kΩ)
R3
(kΩ)
Vref
(V)
3.3 3.3 1.98 1 1.24
5 3.3 3.3 1 2.5
9 7.5 2.87 1 2.5
12 3.83 1 1 2.5
15 7.5 1.5 1 2.5
24 8.66 1 1 2.5
0V
R
2
R
1
R
3
V
re f
R
T
Trim
0V
R
2
R
1
R
3
V
ref
R
T
Tr
Tr im up
-a
2
a
R 1
R2
-a
R1
-R3
-R3
: a=
Vo’ - Vref
Vo’ - Vref
R
R=
T
:
a=
R
R=
T
up
n
Notes: 1. Output ltering capacitor C2 is an electrolytic capacitor, It is recommended to use high frequency and low impedance electrolytic capacitors. For capacitance and current
of capacitor please refer to manufacture’s datasheet. Voltage derating of capacitor should be 80% or above. C1 is used to lter high frequency noise. TVS is
recommended component to protect post-circuits (when converter fails).
2.
All specications measured at Ta=25C, humidity <75%, nominal input voltage, and rated output load, unless otherwise specied.
For more information, please visit the product page.
