dc025 Lineage Power, dc025 Datasheet - Page 11

• Manufacturer Part Number: dc025
• Description: Dc025 Dual-output-series Power Modules
• Manufacturer: Lineage Power

March 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 meeting the
requirements of safety extra-low voltage (SELV), the
input must meet SELV requirements.
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
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
Lineage Power
on/off
module output forward biases an
internal diode. Attempting to start the
module under this condition can
damage the module.
during a logic low is 1 mA. The switch
I
(–) terminal (V
on/off
= 0 V to 1.2 V. The
(continued)
on/off
on/off
= 10 V is 50 µA.
on/off
generated by
). The
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.
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.
Grounding Considerations
This code has a built-in isolated case ground pin.
Figure 14. Remote On/Off Implementation
V
I
on/off
on/off
–
+
V
V
ON/OFF
18 Vdc to 36 Vdc Input; 25 W
I
I
(+)
(–)
COM
V
V
O1
O2
LOAD
LOAD
8-754(C)
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