7-4
Power Supplies
Coral FlexiCom 6000 Installation Manual
PPS
Peripheral Power Su
pply Unit
7
presents a block diagram of the PPS power supply.
Three separate, switch-mode, DC to DC converters convert the 48VDC input power
to the following outputs: +5VDC, +12VDC, –5VDC, –12VDC.
(One DC-DC converter provides both the –5VDC and –12VDC outputs.)
Filtering circuitry minimizes ripple and noise on the –48VDC feed to the peripheral
cards. The filtering circuitry typically produces an output voltage about 1.5 volts
lower than the input to the PPS.
Monitoring circuitry verifies that each voltage output is within tolerance. Should any
voltage fall out of tolerance, the monitoring circuitry produces an alarm signal to the
system processor, and shuts the PPS down. The green power indicator of a PPS in shut
down condition is still illuminated.
Following a shutdown, and when there is no clear reason for the voltage to drop out
of tolerance, the power ON/OFF switch must be turned to OFF and then to ON in order
to return the power supply to working order.
Figure 7-2
PPS Block
Diagram
...................................................................................................
2
Circuit Description
Turn on the PPS and RPS units only after powering the Main Control Shelf and verifying
that the Main Control Shelf has initialized properly, otherwise the cards in the peripheral
shelves/cages may not initialize.
+5V
+12V
-5V
-12V
-48V
+5V
DC-DC
CONVERTER
+12V
DC-DC
CONVERTER
-48V
FILTER
POWER
SWITCH
48V RTN IN
POWER ON
L.E.D.
T.P.
T.P.
T.P.
T.P.
T.P.
-48V IN
F2
15A
F1
8A
48V RTN
DGND
DGND
DGND
AGND
-5V REG.
-5V & -12V
DC-DC
CONVERTER
-12V REG.