Data Sheet
EHW015A0A Series Eighth-Brick Power Modules
36–75Vdc Input; 5.0Vdc Output; 15A Output Current
June 29, 2009
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
Feature Description
Remote On/Off
Two remote on/off options are available. Positive logic
turns the module on during a logic high voltage on the
ON/OFF pin, and off during a logic low. Negative logic
remote On/Off, device code suffix “1”, turns the module
off during a logic high and on during a logic low.
power (Maximum rated power = Vo,set x Io,max).
SENSE(+)
SENSE(–)
VI(+)
VI(-)
VO(+)
VO(–)
IO
Vin+
SUPPLY
Vout+
LOAD
II
CONTACT
RESISTANCE
CONTACT AND
DISTRIBUTION LOSSE
Ion/off
ON/OFF
TRIM
Figure 11. Circuit Configuration for remote
sense .
Von/off
Input Undervoltage Lockout
Vout-
Vin-
At input voltages below the input undervoltage lockout
limit, the module operation is disabled. The module will
only begin to operate once the input voltage is raised
above the undervoltage lockout turn-on threshold,
Figure 10. Remote On/Off Implementation.
VUV/ON
.
Once operating, the module will continue to operate
until the input voltage is taken below the undervoltage
To turn the power module on and off, the user must
supply a switch (open collector or equivalent) to control
the voltage (Von/off) between the ON/OFF terminal and
the VIN(-) terminal (see Figure 10). Logic low is
0V ≤ Von/off ≤ 1.2V. The maximum Ion/off during a logic
low is 1mA, the switch should be maintain a logic low
level whilst sinking this current.
turn-off threshold, VUV/OFF
.
Overtemperature Protection
To provide protection under certain fault conditions, the
unit is equipped with a thermal shutdown circuit. The
unit will shutdown if the thermal reference point Tref
(Figure 13), exceeds 130oC (typical), but the thermal
shutdown is not intended as a guarantee that the unit
will survive temperatures beyond its rating. The
module can be restarted by cycling the dc input power
for at least one second or by toggling the remote on/off
signal for at least one second. If the auto-restart option
(4) is ordered, the module will automatically restart
upon cool-down to a safe temperature.
During a logic high, the typical maximum Von/off
generated by the module is 15V, and the maximum
allowable leakage current at Von/off = 5V is 1μA.
If not using the remote on/off feature:
For positive logic, leave the ON/OFF pin open.
For negative logic, short the ON/OFF pin to VIN(-).
Remote Sense
Output Overvoltage Protection
Remote sense minimizes the effects of distribution
losses by regulating the voltage at the remote-sense
connections (See Figure 11). The voltage between the
remote-sense pins and the output terminals must not
exceed the output voltage sense range given in the
Feature Specifications table:
The output over voltage protection scheme of the
modules has an independent over voltage loop to
prevent single point of failure. This protection feature
latches in the event of over voltage across the output.
Cycling the on/off pin or input voltage resets the
latching protection feature. If the auto-restart option (4)
is ordered, the module will automatically restart upon
an internally programmed time elapsing.
[VO(+) – VO(–)] – [SENSE(+) – SENSE(–)] ≤ 0.5 V
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.
Overcurrent Protection
To provide protection in a fault (output overload)
condition, the unit is equipped with internal
current-limiting circuitry and can endure current
limiting continuously. At the point of current-limit
inception, the unit enters hiccup mode. If the unit is
not configured with auto–restart, then it will latch off
following the over current condition. The module can be
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
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