User Manual
Airbridge cBTS3612 CDMA Base Station
System Description
2 Hardware Architecture
2-50
2.5 Power Supply Subsystem
2.5.1 Overview
BTS built-in power supply module converts -48V DC into +27V for the BTS, forming
the power supply subsystem together with power distribution, lightning protection
and power monitoring.
According to the requirement of BTS overall design, each site can be configured
with multiple cabinets as required. Different cabinets are interconnected so that
different network configurations can be implemented with flexibility, convenience and
reliability. Therefore the power supply subsystem also needs flexible, convenient
and reliable distribution monitoring solution such as centralized lightning protection,
distributed DC power (i.e. the power supply subsystem of each cabinet is an
integrated system and each power supply module has its own built-in monitoring
unit). These units are connected on the backplane, and information is report to
BTRM through the universal monitoring bus to implement power management and
monitoring.
The -48V power input is filtered by EMI filter and connected to the wiring terminal on
the cabinet top, and then connected to the power backplane input bus bar in the
secondary power supply subrack. The +27V power is output to the output bus bar of
power subrack backplane, then led out from the bus bar, the power cable goes up
along the wiring trough to the distribution copper bar in the DC switchbox on top of
the cabinet. The distribution copper bars in the switchbox dist27V DC power
to different modules (the power passes the over-current protection devices for each
power consumption unit and is connected to the output terminals at the back of the
distribution box). In this way, it is ensured that when the power supply to a unit fails
due to over-current, other units will not be affected.
The structure of the whole power supply subsystem is shown in Figure 2-25.
Lightning protection
power distribution
DC/DC
module
DC/DC
module
DC/DC
module
EMI
filter
-48V
+27VDC OUT
Load
.....
Monitoring
serial port
Figure 2-25
BTS power supply subsystem