Ac Module; Figure 12.3 Pmu Ac Module Block Diagram - Tait TB8100 Service Manual

12.2

AC Module

Figure 12.3 PMU AC module block diagram
AC I/P
115/230V
EMC Filter,
50/60Hz
Protection,
& AC Switch
DC
Interface to
DC Module
Control &
Monitor
EMC Filter,
Protection, and AC
Switch
Power Factor
Correction (PFC)
206 Power Management Unit Circuit Description
The AC module accepts an input of 115/230VAC 50/60Hz nominal, and
provides two regulated 28VDC outputs: high current for the PA, and low
current for the reciter.
The main circuit blocks are shown in
in more detail in the paragraphs which follow.
Power Factor
Correction
(PFC)
PFC Control
Microprocessor
The AC input is fed first to an EMC filter consisting of two common-mode
and two differential-mode filters. The input voltage is monitored, and if it
is within the specified voltage range, a "mains OK" signal is sent to the
microprocessor via an opto-coupler. If the mains input voltage is outside the
specified range, the power factor stage is inhibited to protect the AC
converter from damage.
An MOV is fitted between line and phase to clamp low energy noise on the
line. A 10A fuse is also fitted for additional safety. If the fuse blows, it
disconnects the PMU from the mains. Inrush current control is provided by
a high power resistor, which is bypassed by a relay when the PMU is
powered up.
The filtered AC input is fed to this boost power supply where the active
power factor correction circuit converts it to the regulated 400VDC output.
This stage is fully protected from overload and short circuit by the power
supply control circuitry.
Figure 12.3 below, and are described
High Voltage Current Sense
to DC
(HVDC) Output Filter
HVDC Control
Power Supply*
Fan Control
*optional (mounted on DC module)
© Tait Electronics Limited September 2006
28VDC O/P
(PA)
and
28VDC O/P
(Reciter)
DC O/P
13.65/27.3/54.6V
Auxiliary
System
Control Bus
System
Interface
and
Fan
TB8100 Service Manual