KFD 6-25-60/060801
5
A jumper across the ON/OFF terminal and the -V
I
terminal can be used to override the Remote ON/OFF
(see Figure 4). Either a user-supplied switch or the override jumper should be wired into the circuit via indi-
vidual PWB current paths not common to the
-V
I
current path. Connect the switch or jumper wire at the
KFD terminals, across the common connection point and the Remote ON/OFF point. This connection will
prevent noise from falsely triggering the Remote ON/OFF.
11.0 OUTPUT VOLTAGE REVERSAL
12.0 ISOLATION
The KFD output is fully isolated from the input. The KFD DC to DC Converter is encapsulated in noncon-
ductive cases that mount on PC boards. The module is rated to full load at 71°C in a natural convection
environment (without a heat sink or external filter).
13.0 PARALLEL OPERATION
The Power Module can be configured for parallel operation with forced load sharing, to provide for redun-
dant operation or to satisfy additional power requirements. For a typical redundant operation, Schottky
diodes or equivalent should be used to protect against a short circuit condition. The forward voltage drops
across the diodes do not affect the set point voltage applied to the load because of the remote sensing
compensation. If multiple units are used to develop combined power, in excess of the rated maximum (to
satisfy additional power requirements), the Schottky diodes are not required.
14.0 FORCED LOAD SHARING
To implement forced load sharing, the following connections must be made at the pins of the KFD unit. In
addition to that the wiring configuration must be arranged in a way that is compatible with good noise
immunity
a) The parallel pins of all the units connected in parallel must be connected together. The paths of
these connections must be as direct as possible.
b) All Remote Sense pins must be connected to the D.C to D.C. Converter bus at the same point. Connect
all Remote Sense (+) terminals to the (+) side of the power bus at the same point, and all Remote Sense
(-) terminals to the (-) side of the power bus at the same point.
CAUTION
Do not apply a reverse polarity voltage across the KFD output terminals. Such an
application will forward bias an internal diode of the Power Module and damage
the KFD unit.
NOTE
CLOSE PROXIMITY AND SHORT CONNECTING WIRES ARE NECESSARY
FOR GOOD NOISE IMMUNITY
