Tait TB9100, Installation And Operation Manual

Page: 110 / 144

110 Technical Description TB9100 Installation and Operation Manual
© Tait Electronics Limited May 2006
The PA also has four internal power supplies located on the control board
which produce –3, + 2.5, + 5 and + 10VDC.
Boost Regulator
5 and 50 W 12V PAs are fitted with a boost regulator board. Figure 8.12 on
page 111 shows the configuration for a 50W 12V PA, along with the main
inputs and outputs for power, RF and control signals. Note that the 60 W
board is only fitted to the 50W PA.
The boost regulator board accepts an input of 12VDC nominal. The input
is firstly fed through the DC input filter, and then through an output filter
and switch which is controlled by a battery control circuit. This output is
fed to the reciter, which operates from 12VDC instead of the standard
28VDC provided when a PMU is used. The output from the DC input
filter is also fed to the power stage where the voltage is boosted to 28VDC,
and is then fed through an output filter to provide the 28VDC output for
the PA circuit boards.
The battery control circuitry monitors the DC input voltage from the
battery. Protection is provided against the wrong input voltage being
supplied. Reverse polarity protection is provided by a diode between
positive and ground, and requires a user-provided fuse or circuit breaker in
series with the DC input line. The fuse or circuit breaker should be rated at
15A to 18A at 30VDC.
The startup voltage is 12VDC or higher. Once started, the boost regulator
will operate down to 10.25VDC +0.25V before it shuts down to prevent
deep discharge of the battery.