Vicor VIPAC 28 Vdc MIL-COTS - Manual (Page 8)

7 v i c o r p o w e r . c o m
T
ECHNICAL
O
VERVIEW
Overview
Vicor’s 28 Vdc for MIL-COTS VIPAC front-end section
utilizes either Vicor’s M-FIAM5B or M-FIAM9 input module to
provide EMI filtering, transient protection, inrush current limit-
ing and rectification as appropriate. The front end also con-
tains input connectors, fusing and control circuitry to which
the user can interface discrete circuitry.
Up to three Maxi, Mini, Micro Series DC-DC converters are
combined with the front end in an integrated mechanical as-
sembly providing a high efficiency power supply delivering up
to 400 W of output power.
Circuit Operation
The VIPAC utilizes either the M-FIAM5B or M-FIAM9 module
which provides inrush current limiting, transient protection
and EMI filtering. The DC voltage is applied via an agency ap-
proved 3-pin connector; a fuse in the the “+” lead protects the
VIPAC from damage due to internal shorts. At start up, inrush
current is limited by a FET. This FET serves as both an inrush
current limiter at power up and a voltage limiting device in
the event of an input transient over voltage condition.
The FET, driven by a DC bus voltage sense circuit, is brought to
a low impedance after initial power up.
The 28 V is applied to one or more Vicor Maxi, Mini, Micro DC-
DC converters which deliver the selected output voltage and
current levels. TheDC-DC converters provide output over volt-
age protection, output current limiting, voltage regulation trim
capability and input to output isolation.
Vicor’s VCAD configuration tool selects standard 24 V in Maxi,
Mini, and Micro modules for use within the VIPAC based on
the application requirements. The modules are
chosen based on the input and output requirements and the
closest, but higher power level that is available to that
specified. Specifications for these can be found on their re-
spective data sheets.
DC-DC
Converter
Output #1
M-FIAM5B / M-FIAM9
+DC
-DC
+
PC
PR
–
+
PC
PR
–
+
PC
PR
–
+
SC
–
DC-DC
Converter
Output #2
+
SC
–
Line Filter
Transient Protection
Inrush Current Limiting
Reverse Polarity Protection
Logic Control
– Master Disable (Local mode)
– Output Sequencing
– Module Status
– BUS-OK
Control 1
Control 2
Control 3
DC-DC
Converter
Output #3
+
SC
–
+
_
Remote
RS232
Local Control
OR
User
Interface
Output
18 – 36 Vdc
Input
VIPAC BLOCK DIAGRAM - DC INPUT
J1
J3
GND