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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 or by togging the ON/OFF signal for one second.
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(+)
Trim
Vo(-)
Figure 16: 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:
222
−
=
Rtrim
down
Ex. When trim-down –10% (12V X 0.9 =10.8V)
222
−
=
Rtrim
down
DS_s48SS12001_06082006
R
trim-down
−
∆
[ ]
.
732
248
4 .
Vo
−
ΚΩ
. 3
32
∆
+
12
Vo
. 0
07
−
×
.
732
248
4 .
0
1 .
−
=
. 3
32
152
×
+
12
0
1 .
. 0
07
Figure 17: 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:
−
Rtrim
up
Ex. When trim-up +10% (12V X 1.1 = 13.2V)
−
Rtrim
up
Care should be taken to ensure that the maximum
output power of the module remains at or below the
maximum rated power.
Remote ON/OFF
The remote on/off feature on the module can be either
negative or positive logic. Negative logic turns the
module on during a logic low and off during a logic high.
Positive logic turns the modules on during a logic high
and off during a logic low. Remote on/off can be
controlled by an external switch between the on/off
terminal and the Vi(-) terminal. The switch can be an
open collector or open drain. If the remote on/off feature
is not used, please short the on/off pin to Vi(-) for
negative logic and let the pin open for positive logic.
[ ]
ΚΩ
.
50
Figure 18: Circuit Configuration for Remote ON/OFF
Vo(+)
Trim
Vo(-)
[ ]
25
.
668
=
−
ΚΩ
. 3
32
∆
−
12
Vo
. 0
07
25
.
668
=
−
=
. 3
32
19
.
39
×
−
12
0
1 .
. 0
07
Vi(+)
ON/OFF
Vi(-)
R
trim-up
[ ]
ΚΩ
Vo(+)
Trim
Vo(-)
8
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