Datasheet

DS_
T48SR3R307_10162012
9
FEATURES DESCRIPTIONS (CON.)
This limit includes any increase in voltage due to
remote sense compensation and output voltage set
point adjustment (trim).
Vi(-)
Vi(+)
Vo(-)
Vo(+)
Sense(+)
Sense(-)
Resistance
Contact
Contact and Distribution
Losses
Figure 20: Effective circuit configuration for remote sense
operation
If the remote sense feature is not used to regulate the
output at the point of load, please connect SENSE(+) to
Vo(+) and SENSE(–) to Vo(–) at the module.
The output voltage can be increased by both the
remote sense and the trim; however, the maximum
increase is the larger of either the remote sense or the
trim, not the sum of both.
When using remote sense and trim, the output voltage
of the module is usually increased, which increases the
power output of the module with the same output
current.
Care should be taken to ensure that the maximum
output power does not exceed the maximum rated
power.
Output Voltage Adjustment (TRIM)
To increase or decrease the output voltage set point,
the modules may be connected with an external
resistor between the TRIM pin and either the
SENSE(+) or SENSE(-). The TRIM pin should be left
open if this feature is not used.
Figure 21: Circuit configuration for trim-down (decrease
output voltage)
If the external resistor is connected between the TRIM
and SENSE (-) pins, the output voltage set point
decreases (Fig.18). The external resistor value
required to obtain a percentage of output voltage
change △% is defined as:
() Ω−
∆
=− KdownRtrim 2.10
511
Ex. When Trim-down -20 %( 3.3V×0.8=2.64V)
()
Ω=−=− KdownRtrim 4.152.10
20
511
Figure 22: Circuit configuration for trim-up (increase output
voltage)
If the external resistor is connected between the TRIM
and SENSE (+) the output voltage set point increases
(Fig. 19). The external resistor value required to obtain
a percentage output voltage change △% is defined
as:
Rtrim_up
865.7
∆
3.547+




K
Ω
Ex. When Trim-up +10%(3.3V×1.1=3.63V)
Rtrim_up
865.7
10
3.547+ 90.117K
Ω
The output voltage can be increased by both the remote
sense and the trim, however the maximum increase is
the larger of either the remote sense or the trim, not the
sum of both.
When using remote sense and trim, the output voltage
of the module is usually increased, which increases the
power output of the module with the same output
current.
Care should be taken to ensure that the maximum
output power of the module remains at or below the
maximum rated power.