page

date

DESCRIPTION: chassis mount dc-dc converter

6 of 11

08/2009

20050

phone

phone 503.612.2300 fax

www.v-infinity.com

fax 503.612.2383

PART NUMBER: VHK50W

9. OUTPUT TRIMMING (OPTIONAL)

The output voltages are preset to nominal values as indicated by the models table at the factory. If desired, the output voltage may

optionally be trimmed to a different value (+/- 10%) with external resistors and/or potentiometer as shown below.

To trim the output voltage with fixed resistors, the output voltage can be calculated as follows.

Trim-Up

Trim-Down

FIGURE 4: TRIM-UP VOLTAGE SETUP

FIGURE 5: TRIM-DOWN VOLTAGE SETUP

Table 1. For example, to trim-up the output voltage of 5.0V

Table 1. For example, to trim-up the output voltage of 5.0V

as follows:

as follows:

R load

10K

Ω

Trimpot

+Vin

-Vin

-Vo

-S

Trim

+S

+Vo

R load

R trim-up

+Vin

-Vin

+Vo

Trim

-Vo

R load

+Vin

-Vin

+Vo

Trim

-Vo

R trim-down

R2 = 3.3 KΩ

R1 = 5.8 KΩ

o

o, nom = 5.4 - 5.0 = 0.4 V

V - V

=

= 11.2 (KΩ)

R

0.4

trim-up

5.8 - 3.3 x 0.4

V

- V

=

= 9.18 (KΩ)

R

0.4

trim-down

5.8 - 5.32 x 0.4

R2 = 5.32 KΩ

R1 = 5.8 KΩ

o

o, nom

= 5.0 - 4.6 = 0.4 V

FIGURE 3. TRIMMING WITH

EXTERNAL POTENTIOMETER

=

(KΩ)

R

o

o, nom

V - V

o

o, nom

trim-up

R1 - R2 x (V - V

)

=

(KΩ)

R

o

o, nom

V

- V

o

o, nom

trim-down

R1 - R2 x (V

- V )

13.3

74.25

48V

173.7

6.977

7.191

4.636

3.3

7.2

Ω

Ω

608.6

25.189

25.189

18.945

5.8

3.168

28V

24V

15V

12V

5V

3.3V

Table 1

306

1638

48V

173.7

120

68

60.1

5.32

15

Ω

Ω

608.6

430

150

86.45

5.8

6.18

28V

24V

15V

12V

5V

3.3V

Table 2