(28V Input, Single Output)
The ARE Series converters utilize a flyback topology with
a nominal switching frequency of 400 kHz. Electrical
isolation and tight output regulation are achieved through
the use of a magnetically coupled feedback.
Output current is limited under any load fault condition to
approximately 165% of rated current. An overload
condition cause the converter output to behave like a
constant current source with the output voltage dropping
below nominal. The converter will resume normal
operation when the load current is reduced below the
current limit point. This protects the converter from both
overload and short circuit conditions. There are no
latching elements included in the load fault protection
circuits to eliminate the possibility of falsely triggering the
protection circuits during single event radiation exposure.
An under-voltage lockout circuit prohibits the converter
from operating when the line voltage is too low to maintain
the output voltage. The converter will not start until the
line voltage rises to approximately 17 volts and will shut
down when the input voltage drops below 16 volts. The
hysteresis reduces the possibility of line noise interfering
with the converter’s start-up and shut down circuitry.
An external inhibit port is provided to control converter
operation. The converter’s operation is inhibited when
this pin is pulled low. It is intended to be driven by an
open collector device. The pin may be left open for
normal operation and has a nominal open circuit voltage
of about 13V.
The ARE Series was developed using a proven
conservative design methodology, which includes
selecting radiation tolerant, and established reliability
components and fully de-rating to the requirements of
MIL-STD-975, MIL-STD-1547, and NASA EE-INST-002.
Conservative de-rating of the radiation-hardened power
MOSFET virtually eliminates the possibility of SEGR and
SEB. A magnetic feedback circuit is utilized instead of
opto-couplers to minimize temperature, radiation and
aging sensitivity. PSPICE was used extensively to predict
and optimize circuit performance for both beginning and
end-of-life. Thorough design analyses include, Worst
Case, Stress, Thermal, Failure Modes and Effects
(FMEA) and Reliability (MTBF).
International Rectifier HiRel Products, Inc.