10

10

Tyco Electronics Corp.

18 Vdc to 36 Vdc Input, 3.3 Vdc Output; 165 W

FC250F1 Power Module: dc-dc Converter;

Data Sheet

July 2000

Output Voltage Set-Point Adjustment (Trim)

(continued)

With an external resistor connected between the TRIM

The following equation determines the required exter-

nal-resistor value to obtain a percentage output voltage

change of

∆%.

The test results for this configuration are displayed in

Figure 16.

must not exceed the minimum value of the output over-

voltage protection as indicated in the Feature Specifi-

cations table. This limit includes any increase in voltage

due to remote-sense compensation and output voltage

set-point adjustment (trim). See Figure 12.

Although the output voltage can be increased by both

the remote sense and by the trim, the maximum

increase for the output voltage is not the sum of both.

The maximum increase is the larger of either the

remote sense or the trim. Consult the factory if you

need to increase the output voltage more than the

above limitation.

The amount of power delivered by the module is

defined as the voltage at the output terminals multiplied

by the output current. When using remote sense and

trim, the output voltage of the module can be

increased, which at the same output current would

increase the power output of the module. Care should

be taken to ensure that the maximum output power of

the module remains at or below the maximum rated

power.

8-748 (C).b

Figure 13. Circuit Configuration to Decrease

Output Voltage

8-2883 (F)

Figure 14. Resistor Selection for Decreased Output

Voltage

8-715 (C).b

Figure 15. Circuit Configuration to Increase

Output Voltage

8-2884 (F)

Figure 16. Resistor Selection for Increased Output

Voltage

∆%

100

----------

+

–

()

1.225

∆%

()

------------------------------------------------------------------------- 205

2.255

–









k

Ω

=

ON/OFF

CASE

SENSE(+)

TRIM

SENSE(–)

1M

0

% CHANGE IN OUTPUT VOLTAGE (

∆%)

10k

1k

10

20

40

30

100k

ON/OFF

CASE

SENSE(+)

TRIM

SENSE(–)

1M

100k

0

% CHANGE IN OUTPUT VOLTAGE (

∆%)

10k

24

10

6

8