cui.com

date 06/11/2015

│ page 6 of 7

CUI 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

a: User-defined 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

+Vo

0V

Trim

0V

Trim

+Vo

Trim up

Trim down

a

-a

a

-a

:

a=

Vref

Vref

Vo’ - Vref

Vo’ - Vref

R=

T

:

a=

R=

T

up

down

Notes:

1. Output filtering 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 filter high frequency noise. TVS is

recommended component to protect post-circuits (when converter fails).

2. All specifications measured at Ta=25C, humidity <75%, nominal input voltage, and rated output load, unless otherwise specified.

For more information, please visit the product page.