dw025 Lineage Power, dw025 Datasheet - Page 11

• Manufacturer Part Number: dw025
• Description: Dw025 Dual Output-series Power Modules Dc-dc Converters
• Manufacturer: Lineage Power

Data Sheet
April 2008
Design Considerations
Safety Considerations
For safety-agency approval of the system in which the
power module is used, the power module must be
installed in compliance with the spacing and separation
requirements of the end-use safety agency standard,
i.e., UL -1950, CSA 22.2-950, EN60950.
For the converter output to be considered to be meet-
ing the requirements of safety extra-low voltage
(SELV), one of the following must be true:
If the input meets extra-low voltage (ELV) require-
ments, then the converter’s output is considered ELV.
The input to these units is to be provided with a maxi-
mum 5 A normal-blow fuse in the ungrounded lead.
Input/Output Voltage Reversal
CAUTION: Applying a reverse voltage across the
Feature Descriptions
Output Overvoltage Clamp
The output overvoltage clamp consists of control
circuitry, independent of the primary regulation loop,
that monitors the voltage on the output terminals. The
control loop of the clamp has a higher voltage set point
than the primary loop (see Feature Specifications
table). This provides a redundant voltage control that
reduces the risk of output overvoltage.
Lineage Power
All inputs are SELV and floating with the output also
floating.
All inputs are SELV and grounded with the output
also grounded.
Any non-SELV input must be provided with rein-
forced insulation from any other hazardous voltages,
including the ac mains, and must have a SELV reli-
ability test performed on it in combination with the
converters.
module input or output forward biases
an internal diode. Attempting to start
the module under this condition can
damage the module.
(continued)
DW025 Dual Output-Series Power Modules: dc-dc Converters;
36 Vdc to 75 Vdc Input; Dual Outputs; 25 W
Current Limit
To provide protection in a fault (output overload) condi-
tion, the unit is equipped with internal current-limiting
circuitry and can endure current-limiting for an unlimited
duration. At the point of current-limit inception, the unit
shifts from voltage control to current control. If the out-
put voltage is pulled very low during a severe fault, the
current-limit circuit can exhibit either foldback or tailout
characteristics (output current decrease or increase).
The unit operates normally once the output current is
brought back into its specified range.
Remote On/Off
Two remote on/off options are available. Positive logic
remote on/off turns the module on during a logic high
voltage on the remote on/off pin, and off during a logic
low. Negative logic remote on/off, code suffix “1,” turns
the module off during a logic high and on during a logic
low.
To turn the power module on and off, the user must
supply a switch to control the voltage between the
on/off terminal and the V
switch can be an open collector or equivalent (see
Figure 14). A logic low is V
maximum I
should maintain a logic-low voltage while sinking 1 mA.
During a logic high, the maximum V
the power module is 10 V. The maximum allowable
leakage current of the switch at V
Figure 14. Remote On/Off Implementation
V
I
on/off
on/off
–
+
on/off
during a logic low is 1 mA. The switch
V
V
ON/OFF
I
I
(+)
(–)
I
(–) terminal (V
on/off
= 0 V to 1.2 V. The
on/off
COM
V
V
on/off
O1
O2
= 10 V is 50 µA.
on/off
generated by
). The
LOAD
LOAD
8-754(C)
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