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TPA3116D2, TPA3118D2, TPA3130D2
SLOS708G – APRIL 2012 – REVISED DECEMBER 2017
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Copyright © 2012–2017, Texas Instruments Incorporated
7.3.8 Device Protection System
The TPA31xxD2 family contains a complete set of protection circuits carefully designed to make system design
efficient as well as to protect the device against any kind of permanent failures due to short circuits, overload,
over temperature, and under-voltage. The FAULTZ pin will signal if an error is detected according to
Table 4. Fault Reporting
FAULT
TRIGGERING CONDITION
(typical value)
FAULTZ
ACTION
LATCHED/SELF-
CLEARING
Over Current
Output short or short to PVCC or GND
Low
Output high impedance
Latched
Over Temperature
T
j
> 150°C
Low
Output high impedance
Latched
Too High DC Offset
DC output voltage
Low
Output high impedance
Latched
Under Voltage on
PVCC
PVCC < 4.5V
–
Output high impedance
Self-clearing
Over Voltage on
PVCC
PVCC > 27V
–
Output high impedance
Self-clearing
7.3.9 DC Detect Protection
The TPA31xxD2 family has circuitry which will protect the speakers from DC current which might occur due to
defective capacitors on the input or shorts on the printed circuit board at the inputs. A DC detect fault will be
reported on the FAULT pin as a low state. The DC Detect fault will also cause the amplifier to shutdown by
changing the state of the outputs to Hi-Z.
If automatic recovery from the short circuit protection latch is desired, connect the FAULTZ pin directly to the
SDZ pin. This allows the FAULTZ pin function to automatically drive the SDZ pin low which clears the DC Detect
protection latch.
A DC Detect Fault is issued when the output differential duty-cycle of either channel exceeds 60% for more than
420 msec at the same polarity. Table x below shows some examples of the typical DC Detect Protection
threshold for several values of the supply voltage. This feature protects the speaker from large DC currents or
AC currents less than 2Hz. To avoid nuisance faults due to the DC detect circuit, hold the SD pin low at power-
up until the signals at the inputs are stable. Also, take care to match the impedance seen at the positive and
negative inputs to avoid nuisance DC detect faults.
lists the minimum output offset voltages required to trigger the DC detect. The outputs must remain at or
above the voltage listed in the table for more than 420 ms to trigger the DC detect.
Table 5. DC Detect Threshold
PV
CC
(V)
V
OS
- OUTPUT OFFSET VOLTAGE (V)
4.5
0.96
6
1.3
12
2.6
18
3.9
7.3.10 Short-Circuit Protection and Automatic Recovery Feature
The TPA31xxD2 family has protection from over current conditions caused by a short circuit on the output stage.
The short circuit protection fault is reported on the FAULTZ pin as a low state. The amplifier outputs are switched
to a high impedance state when the short circuit protection latch is engaged. The latch can be cleared by cycling
the SDZ pin through the low state.
If automatic recovery from the short circuit protection latch is desired, connect the FAULTZ pin directly to the
SDZ pin. This allows the FAULTZ pin function to automatically drive the SDZ pin low which clears the short-
circuit protection latch.
In systems where a possibility of a permanent short from the output to PVDD or to a high voltage battery like a
car battery can occur, pull the MUTE pin low with the FAULTZ signal with a inverting transistor to ensure a high-
Z restart, like shown in the figure below: