TPA3110D2

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SLOS528E – JULY 2009 – REVISED NOVEMBER 2015

9.3.7 Thermal Protection

Thermal protection on the TPA3110D2 prevents damage to the device when the internal die temperature

exceeds 150°C. There is a ±15°C tolerance on this trip point from device to device. Once the die temperature

exceeds the thermal set point, the device enters into the shutdown state and the outputs are disabled. This is not

a latched fault. The thermal fault is cleared once the temperature of the die is reduced by 15°C. The device

begins normal operation at this point with no external system interaction.

Thermal protection faults are NOT reported on the FAULT terminal.

9.3.8 DC Detect

TPA3110D2 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. To clear the DC Detect it is necessary to cycle the PVCC supply. Cycling S D will

NOT clear a DC detect fault.

A DC Detect Fault is issued when the output differential duty-cycle of either channel exceeds 14% (for example,

+57%, -43%) for more than 420 msec at the same polarity. 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.

The minimum differential input voltages required to trigger the DC detect are show in table 2. The inputs must

remain at or above the voltage listed in the table for more than 420 msec to trigger the DC detect.

Table 3. DC Detect Threshold

AV(dB)

Vin (mV, differential)

20

112

26

56

32

28

36

17

9.3.9 Short-Circuit Protection and Automatic Recovery Feature

TPA3110D2 has protection from overcurrent conditions caused by a short circuit on the output stage. The short

circuit protection fault is reported on the FAULT pin as a low state. The amplifier outputs are switched to a Hi-Z

state when the short circuit protection latch is engaged. The latch can be cleared by cycling the SD pin through

the low state.

If automatic recovery from the short circuit protection latch is desired, connect the FAULT pin directly to the SD

pin. This allows the FAULT pin function to automatically drive the SD pin low which clears the short-circuit

protection latch.

9.4 Device Functional Modes

9.4.1

SD Operation

minimum level during periods of nonuse for power conservation. The SD input terminal should be held high (see

specification table for trip point) during normal operation when the amplifier is in use. Pulling SD low causes the

outputs to mute and the amplifier to enter a low-current state. Never leave SD unconnected, because amplifier

operation would be unpredictable.

For the best power-off pop performance, place the amplifier in the shutdown mode prior to removing the power

supply voltage.

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