Features descriptions – Delta Electronics S48SR User Manual
Page 9
DS_S48SR12001_07052006
9
Ex. When Trim-down –10% (12V X 0.9 = 10.8V)
[ ]
ΚΩ
=
−
+
Ч
Ч
−
=
−
50
.
152
32
.
3
07
.
0
1
.
0
12
1
.
0
4
.
248
732
.
222
down
Rtrim
Vo(+)
Vo(-)
Trim
R
trim-up
Figure 19:
Circuit configuration for trim-up (increase
output voltage)
If the external resistor is connected between the
TRIM and Vo- the output voltage set point increases.
The external resistor value required to obtain a
percentage output voltage change △Vo% is defined
as:
[ ]
ΚΩ
−
−
∆
=
−
32
.
3
07
.
0
Vo
12
668
.
25
up
Rtrim
Ex. When Trim-up +10% (12V X 1.1 = 13.2V)
[ ]
ΚΩ
=
−
−
×
=
−
39
.
19
32
.
3
07
.
0
1
.
0
12
668
.
25
up
Rtrim
Care should be taken to ensure that the maximum
output power of the module remains at or below the
maximum rated power.
FEATURES DESCRIPTIONS
Over-Current Protection
The modules include an internal output over-current
protection circuit, which will endure current limiting for
an unlimited duration during output overload. If the
output current exceeds the OCP set point, the modules
will automatically shut down (hiccup mode).
The modules will try to restart after shutdown. If the
overload condition still exists, the module will shut down
again. This restart trial will continue until the overload
condition is corrected.
Over-Voltage Protection
The modules include an internal output over-voltage
protection circuit, which monitors the voltage on the
output terminals. If this voltage exceeds the over-
voltage set point, the module will shut down and latch
off. The over-voltage latch is reset by cycling the input
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 Vo+ or Vo -. The
TRIM pin should be left open if this feature is not used.
Vo(+)
Vo(-)
Trim
trim-down
R
Figure 18:
Circuit configuration for trim-down (decrease
output voltage)
If the external resistor is connected between the TRIM
and Vo+ pins, the output voltage set point decreases.
The external resistor value required to obtain a
percentage of output voltage change △Vo% is defined
as:
[ ]
ΚΩ
−
+
∆
∆
−
=
−
32
.
3
07
.
0
Vo
12
Vo
4
.
248
732
.
222
down
Rtrim