Power Supply; Figure 102. .Power Supply Circuit Block Diagram - Alcatel 1850 TSS-320 Technical Handbook

4.1.2 Power Supply

The unit is powered from two completely independent main battery supplies (BATT_A and BATT_B)
having a nominal voltage of -48V.
A single main voltage is generated from the input batteries by means of a +5V/10A DC/DC converter: the
VC5V voltage, used for the Hard Disk Drive and to generate alternate voltages required by the board.
An isolated 9V/100mA DC/DC converter is used to generate the VC9VN (-9V) for housekeeping
interfaces.
A 3,3V/16A step down DC/DC converter is used to generate the VC3V3 voltage, used for LV devices on-
the mother board and the daughter board.
Alternate supply voltages are obtained from VC3V3 by means of DC/DC step down converters or Low
Drop Out (LDO): VC2V5 (+2.5V) and VC1V2 (+1.2V).
A block diagram is shown in Figure 102. on page 160.
VBATT POW320 A
Fuse
Protection
VBATT POW320 B
F_BATT+
F_BATT-
V 3.6 A
V 3.6 B
A Low Drop Out device is used to generate an additional VC3V6 voltage (3.6V), used to power devices
on-board external modules (TRU) related to their remote inventory and alarm interface.
An additional duplicated 3.3VS "service power supply" is received from the back panel: it is used together
with the VC3V3 for powering the circuitry related to the SPI bus interface ("Spider" and its slave devices).
Alcatel 1850 TSS-320 Rel. 1.1
160/270 8DG 07734 AAAA Edition 01
OR-RING
Over Voltage
with
Protection
Diodes
DC/DC
-48V / +5V
10A
DC/DC
+5V / +3.3V
Fuse
Protection

Figure 102. .Power supply circuit block diagram

START-UP
and
INRUSH
Current
Limiting
Circuit
LDO
+5V / +3.6V
DC/DC
+5V / -9V
DC/DC
+5V / +1.2V
LDO
+3.3V / +2.5V
VC 3VS
F_BATT+
EMI
Filter
F_BATT-
VC3V6
VC9VN
VC5V
VC1V2
VC3V3
VC2V5
Technical Handbook Common
Unit Descriptions