JFW100B Lineage Power, JFW100B Datasheet - Page 15

• Manufacturer Part Number: JFW100B
• Manufacturer: Lineage Power

April 2008
Feature Descriptions
Forced Load Sharing (Parallel Operation)
(continued)
Figure 26. Wiring Configuration for Redundant
Current Monitor
The current monitor (CURMON) pin produces a dc volt-
age proportional to the dc output current of the module.
The voltage is referenced to the secondary SENSE(–)
pin and is typically 4.5 V at rated output current. For
paralleling with Fx300x modules, consult the factory for
the V/A ratio. The output impedance of this pin is
approximately 20 k¾, so customer detection circuitry
must have a high-impedance input.
Overtemperature Protection
These modules feature an overtemperature protection
circuit to safeguard against thermal damage. The cir-
cuit shuts down and latches off the module when the
maximum case temperature is exceeded. The module
can be restarted by cycling the dc input power for at
least 1.0 second or by toggling the primary or second-
ary referenced remote on/off signal for at least
1.0 second.
Lineage Power
Parallel Operation
CASE
ON/OFF
V
V
CASE
ON/OFF
V
V
I
I
I
I
(+)
(–)
(+)
(–)
PARALLEL
PARALLEL
SENSE(+)
SENSE(–)
SENSE(+)
SENSE(–)
dc-dc Converters; 36 Vdc to 75 Input, Vdc 12 Vdc Output; 50 W to 150 W
V
V
V
V
O
O
O
O
(+)
(–)
(+)
(–)
(continued)
8-581 (C).c
Power Good Signal
The power good signal (PWRGOOD pin) is an open-
collector, secondary-referenced pin that is pulled low
when all five of the following conditions are met:
1. The sensed output voltage is greater than half the
2. The overvoltage shutdown latch is not set.
3. The thermal shutdown latch is not set.
4. The unit is not in current limit.
5. Secondary internal bias is present.
There is one situation where the power good signal can
be low even though the module has failed. This can
occur when the module is paralleled with other mod-
ules for additional output power (i.e., the output ORing
diodes would not be used). If one module power train
stops delivering power (fails), the other paralleled mod-
ule(s) would provide a voltage at the output pin of the
failed module. The failed module would then not detect
that its output power is not being delivered. However, in
this situation, the current monitor pins of the paralleled
modules would indicate that current is not being deliv-
ered from one module and that module had failed.
For redundant applications, the ORing diodes would
keep the other module voltages from being applied to
the failed module output and the power good signal
would indicate a failure.
Thermal Warning Signal
The thermal warning (TEMPWARN) pin is a second-
ary-referenced, open-collector output that shorts to
SENSE(–) a few degrees before the module goes into
thermal shutdown. When the module temperature
cools, the thermal warning pin will open, but the unit
will remain latched off until the input power or the pri-
mary or secondary referenced remote on/off is recycled
for 1.0 second.
Thermal Considerations
Introduction
The JFW-Series power modules operate in a variety of
thermal environments; however, sufficient cooling
should be provided to help ensure reliable operation of
the units. Heat-dissipating components inside the units
are thermally coupled to the case. Heat is removed by
conduction, convection, and radiation to the surround-
ing environment. Proper cooling can be verified by
measuring the case temperature. Peak temperature
(T
C
) occurs at the position indicated in Figure 27.
rated nominal output voltage.
15