GE Industrial Solutions QPW025A0F41_H - Manual (Page 7)

Data Sheet
October 5, 2009
QPW025A0F41/QPW025A0F41-H DC-DC Power Module
36-75Vdc Input; 3.3Vdc Output Voltage; 25A Output Current
LINEAGE POWER 7
component failure and fault tests were performed in
the power converters.
ƒ One pole of the input and one pole of the output are
to be grounded, or both circuits are to be kept
floating, to maintain the output voltage to ground
voltage within ELV or SELV limits
.
For all input sources, other than DC MAINS, where the
input voltage is between 60 and 75V dc (Classified as
TNV-2 in Europe), the following must be meet, if the
converter’s output is to be evaluated for SELV:
ƒ The input source is to be provided with reinforced
insulation from any hazardous voltage, including the
ac mains.
ƒ
One Vi pin and one Vo pin are to be reliably earthed,
or both the input and output pins are to be kept
floating.
ƒ
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.
The power module has ELV (extra-low voltage) outputs
when all inputs are ELV.
All flammable materials used in the manufacturing of
these modules are rated 94V-0, or tested to the
UL60950 A.2 for reduced thickness.
The input to these units is to be provided with a
maximum 6A fast-acting (or time-delay) fuse in the
unearthed lead.
Feature Descriptions
Remote On/Off
Two remote On/Off logic options are available. Positive
logic remote On/Off turns the module ON during a logic-
high voltage on the remote On/Off pin, and turns the
module OFF during a logic-low. Negative logic remote
On/Off turns the module OFF during a logic-high and
turns the module ON during logic-low. Negative logic is
specified by suffix “1” at the end of the device code.
To turn the power module on and off, the user must
supply a switch to control the voltage between the
ON/OFF pin and the V
IN
(–) terminal (V
on/Off
). The switch
may be an open collector or equivalent (see Figure 10).
A logic-low is V
on/off
= 0 V to 1.2V. 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 is 50 µA. If not using the
remote on/off feature, do one of the following:
For positive logic, leave the ON/OFF pin open.
For negative logic, short the ON/OFF pin to V
IN
(–).
SENSE(+)
V O (+)
SENSE(–)
V O (–)
V I (-)
+
–
I on/off
ON/OFF
V I (+)
LOAD
V on/off
Figure 10. Circuit configuration for using Remote
On/Off Implementation.
Overcurrent Protection
To provide protection in a fault (output overload) condi-
tion, the module is equipped with internal current-limiting
circuitry, and can endure current limiting continuously.
At the instance of current-limit inception, the output
current begins to tail-out. When an overcurrent
condition exists beyond a few seconds, the module
enters a “hiccup” mode of operation, whereby it shuts
down and automatically attempts to restart.. While the
fault condition exists, the module will remain in this
hiccup mode, and can remain in this mode until the fault
is cleared. The unit