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8
Tyco Electronics Corp.
Advance Data Sheet
July 2001
18 Vdc to 36 Vdc Input, 28 Vdc Output; 400 W
FC400R1-29 Power Module; dc-dc Converter:
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.,
UL60950, CSA C22.2 No. 60950-00, and VDE
0805 (IEC60950).
If the input source is non-SELV (ELV or a hazardous
voltage greater than 60 Vdc and less than or equal to
75 Vdc), for the module’s output to be considered
meeting the requirements of safety extra-low voltage
(SELV), all of the following must be true:
s
The input source is to be provided with reinforced
insulation from any hazardous voltages, including the
ac mains.
s
One VI pin and one VO pin are to be grounded, or
both the input and output pins are to be kept floating.
s
The input pins of the module are not operator acces-
sible.
s
Another SELV reliability test is conducted on the
whole system, as required by the safety agencies, on
the combination of supply source and the subject
module to verify that under a single fault, hazardous
voltages do not appear at the module’s output.
Note: Do not ground either of the input pins of the
module without grounding one of the output pins.
This may allow a non-SELV voltage to appear
between the output pin and ground.
The power module has extra-low voltage (ELV) outputs
when all inputs are ELV.
The input to these units is to be provided with a maxi-
mum 30 A fast-acting fuse in the ungrounded lead.
Feature Descriptions
Overcurrent Protection
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 unlim-
ited duration. At the point of current-limit inception, the
unit shifts from voltage control to current control. If the
output 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
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 VI(–) terminal (Von/off). The switch can be
an open collector or equivalent (see
Figure 11). A logic
low is Von/off = 0 V to 1.2 V, during which the module is on.
The maximum Ion/off during a logic low is 1 mA. The switch
should maintain a logic-low voltage while sinking 1 mA.
During a logic high, the maximum Von/off generated by
the power module is 15 V. The maximum allowable
leakage current of the switch at Von/off = 15 V is 50 A.
If not using the remote on/off feature, short the
ON/OFF pin to VI(–).
8-580 (F).d
Figure 11. Remote On/Off Implementation
+
Ion/off
–
Von/off
CASE
ON/OFF
VI(+)
VI(–)
SENSE(+)
SENSE(–)
VO(+)
VO(–)