Motorola ATCA-717 - Manual (Page 126)

Devices’ Features and Data Paths Power Supply Module
126 PENT/ATCA−717
Power Supply Module
The blade is fed via two redundant −48V inputs. Both are converted via a DC/DC
converter to an intermediate voltage of +12V. This voltage, in turn, is converted via
further DC/DC converters to on−board voltages which are used by the on−board devices.
A −48V/+3.3V DC/DC converter converts the −48V input voltage to +3.3V which is used
to feed the IPMC and power−up logic.
The blade ′s power up and power down cycles are under full control of the IPMC. It
controls both the −48V/+12V DC/DC converter as well as power−up logic which controls
the remaining on−board DC/DC converters. If the IPMC detects a failure on any of the
local on−board voltages, it shuts off the entire blade power.
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The blade ′s power supply structure is shown in the following figure. a
DC
DC
−48V_A
−48V_B
Return_A
Return_B
DC
DC
DC
DC
DC
DC
...
DC
DC
IPMC
Status Control
Power−Up
Logic
DC
DC
−48V_A
−48V_B
Return_A
Return_B
+3.3V
+12V
DC/DC
Enable
+5V
+3.3V
+2.5V
CPU Core
Voltage
Power Good
Figure 39: Blade Power Supply Structure