Datasheet

CH1
(Post DRC)
RMS
Weighting Register (Scale)
. . .
CH2
(Post DRC)
.
.
.
.
.
.
Satallite
Energy Sum
Programmable
Threshold
Comparator
EMO
CH7
(Post DRC)
0xBB–0xBE
Reg 0x10
0xB2
RMS
RMS
0xB3
0xB4
0xB9
CH8
(Post DRC)
0xB2
RMS
0xBA
Sub
Energy Sum
TAS5548
www.ti.com SLES270 –NOVEMBER 2012
6 System Power Controller
6.1 Energy Manager
TAS5548 has an Energy Manager that can be used to monitor/control the overall energy in the system.
The key features are:
1. There are separate controllers for Satellite (EMO1) and Sub (EMO2) channels. If EMO2 is not enabled,
then the EMO1 pin is OR'd with the output of the subwoofer comparator.
2. The satellite channels participating in the energy estimation are selectable. For example, in the 5.1
Mode, the line out channels can be programmed to not participate in the energy estimation.
3. There is a mixer for each channel before mixing. This is for scaling each channel before adding. The
energy of all participating satellite channels are added and compared with a programmable threshold.
If the value crosses the threshold, the satellite_over_power bit in the status register is set. Similarly, if
the overall energy is lower than another programmable register, the satellite_idle bit in the status
register is set. Both these bits are “sticky,” meaning once set, the external controller has to write a “0”
to clear the bit
4. Similar to the satellite channel, the sub channel energy is also estimated and compared against an
upper and lower threshold. If above the upper threshold, the sub_over_power bit is set and if below the
threshold, the sub_idle_bit are set. These are also "sticky" bits. Sub channels also have a disable pin
that bypass energy comparison.
5. An OR of the 4 status bits are available on EMO pin
External controller on the detection of EMO interrupt (pin going high) can read the status register for more
information.
The controller can shutdown the PWM for idle mode and or reduce channel energy to reduce overall
power. The Controller discerns more details on the EMO condition by using the status and enable bits.
Figure 6-1 shows the EMO system for satellite channels. A similar EMO system for the subwoofer channel
also will be implemented. The EMO pin is shared between satellite and sub channels.
Figure 6-1. Energy Manager
Copyright © 2012, Texas Instruments Incorporated System Power Controller 45
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