D2800D_15 Datasheet, PDF (2/10 Pages) International Rectifier – HIGH RELIABILITY, RADIATION TOLERANT, LOW POWER, DC-DC CONVERTER

D28XXD-SERIES
(28V Input, Regulated Dual Outputs)
Circuit Description
The D-Series DC-DC converters utilize two-stage
regulation with a flyback topology with a switching
frequency of 250KHz for primary regulation and linear
post regulation in the secondary for each of the
outputs.
Output power is limited under any load fault
condition to approximately 110% of rated output.
An overload condition causes 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 to eliminate the possibility of falsely
triggering the protection circuits during single event
radiation exposure.
An under-voltage protection circuit prohibits the
converter from operating when the line voltage is
too low for safe operation. The converter will not
start until the line voltage rises to approximately 16V.
An inhibit pin is provided to control converter operation.
This inhibit pin is intended for operation with an open
collector transistor drive or a relay closure to the
input return. The pin may be left open for normal
operation and has a nominal open circuit voltage of
4V. Also provided are the individual output on/off
control pins (Pin 10-Output 1 Inhibit and Pin 9-Output
2 Inhibit).
Synchronization input pin is included allowing
multiple converters to operate at a common switching
frequency. Converters can be synchronized to a
common frequency with an external clock. This may
be used to eliminate beat frequency noise or to avoid
generating noise at certain frequencies for noise
sensitive systems.
Design Methodology
The D-Series is developed using a proven conservative
design methodology, which includes selecting
radiation tolerant and established reliability
components and fully derating to the requirements
of EEE-INST-002 and MIL-STD-1547B. Heavy
derating of the radiation-hardened power MOSFET
virtually eliminates the possibility of SEGR and SEB.
2
www.irf.com