DS_H48SA12025_05052008
FEATURES DESCRIPTIONS
Over-Current Protection
The modules include an internal output over-current
protection circuit. If the output current exceeds the OCP
set point, the modules will automatically shut down, and
enter hiccup mode or latch mode, which is optional.
For hiccup mode, the module 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.
Hiccup mode is default mode.
For latch mode, the module will latch off once it
shutdown. The latch is reset by either cycling the input
power or by toggling the on/off signal for one second.
Over-Voltage Protection
The modules include an internal output over-Voltage
protection circuit. If the output voltage exceeds the OVP
set point, the modules will automatically shut down, and
enter hiccup mode or latch mode, which is optional.
For hiccup mode, the module will try to restart after
shutdown. If the over-voltage condition still exists, the
module will shut down again. This restart trial will
continue until the over-voltage condition is corrected.
Hiccup mode is default mode.
For latch mode, the module will latch off once it
shutdown. The latch is reset by either cycling the input
power or by toggling the on/off signal for one second.
Over-Temperature Protection
The over-temperature protection consists of circuitry
that provides protection from thermal damage. If the
temperature exceeds the over-temperature threshold
the module will shut down, and enter in auto-restart
mode or latch mode, which is optional.
For auto-restart mode, the module will monitor the
module temperature after shutdown. Once the
temperature is within the specification, the module will
be auto-restarted. Auto-restart mode is default mode.
For latch mode, the module will latch off once it
shutdown. The latch is reset by either cycling the input
power or by toggling the on/off signal for one second.
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.
Vo(+)
Vi(+)
Vo(-)
Sense(-)
Sense(+)
Vi(-)
ON/OFF
Trim
R
Distribution resistor
Vo(+)
Vi(+)
Vo(-)
Sense(-)
Sense(+)
Vi(-)
ON/OFF
Trim
R
Distribution resistor
Figure 18:
Remote on/off implementation
Remote Sense
Remote sense compensates for voltage drops on the
output by sensing the actual output voltage at the point
of load. The voltage between the remote sense pins
and the output terminals must not exceed the output
voltage sense range given here:
[Vo(+) – Vo(–)] – [SENSE(+) – SENSE(–)]
≤
10%
×
Vout
This limit includes any increase in voltage due to
remote sense compensation and output voltage set
point adjustment (trim).
Vo(+)
Vi(+)
Vo(-)
Sense(-)
Sense(+)
Vi(-)
ON/OFF
Trim
R
Distribution resistor
Vo(+)
Vi(+)
Vo(-)
Sense(-)
Sense(+)
Vi(-)
ON/OFF
Trim
R
Distribution resistor
Figure 19:
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.
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