ISOLATED DC/DC CONVERTERS
36 Vdc - 75 Vdc Input 12 Vdc /6 A Output
May 17, 2011
Bel Power Inc., a subsidiary of Bel Fuse Inc.
Output Trim Equations
Trim Resistor Calculate
Equations for calculating the trim resistor are shown below. The Trim Down resistor should be connected
between the Trim pin and Sense(-) pin. The Trim Up resistor should be connected between the Trim pin and the
Sense(+) pin. Only one of the resistors should be used for any given application.
Sense(+)
511
Module
Trim
Rtrimdown
10.22
k
delta
Rtrimdown
Rtrimup
Sense(-)
Sense(+)
Trim
(100 delta)Vo5.11 511
Rtrimup (
10.22) k
Module
1.225delta
delta
Sense(-)
Note:
Vo _ req Vo
delta
100
Vo
Vo_req=Desired (trimmed) output voltage [V]
Output voltage Vo=12 V
400
360
320
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
280
240
200
160
120
80
40
0
0
12 12.12 12.24 12.36 12.48 12.6 12.72 12.84 12.96 13.08 13.2
Adjusted output voltage Vo,adj(V)
9.8 10.02 10.24 10.46 10.68 10.9 11.12 11.34 11.56 11.78 12
Adjusted output voltage Vo,adj (V)
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302 Tel 201-432-0463 Fax 201-432-9542 www.belfuse.com
4