TPA3100D2-Q1_15 Datasheet, PDF(25/38 Page) Texas Instruments – 20-W STEREO CLASS-D AUDIO POWER AMPLIFIER

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TPA3100D2-Q1

www.ti.com ......................................................................................................................................................................................... SLOS557 â SEPTEMBER 2008

The MUTE terminal can also be used with the FAULT output to automatically recover from a short-circuit event.

When a short-circuit event occurs, the FAULT terminal transitions high indicating a short-circuit has been

detected. When directly connected to MUTE, the MUTE terminal transitions high, and clears the internal fault

flag. This causes the FAULT terminal to cycle low, and normal device operation resumes if the short-circuit is

removed from the output. If a short remains at the output, the cycle continues until the short is removed.

If external MUTE control is desired, and automatic recovery from a short-circuit event is also desired, an OR gate

can be used to combine the functionality of the FAULT output and external MUTE control (see Figure 32).

TPA3100D2

External GPIO

Control

MUTE

FAULT

Figure 32. External MUTE Control

MSTR/SLV and SYNC Operation

The MSTR/SLV and SYNC terminals can be used to synchronize the frequency of the class-D output switching.

When the MSTR/SLV terminal is high, the output switching frequency is determined by the selection of the

resistor connected to the ROSC terminal (see ROSC Resistor Selection). The SYNC terminal becomes an output

in this mode, and the frequency of this output is also determined by the selection of the ROSC resistor. This TTL

compatible, push-pull output can be connected to another TPA3100D2, configured in the slave mode. The output

switching is synchronized to avoid any beat frequencies that could occur in the audio band when two class-D

amplifiers in the same system are switching at slightly different frequencies.

When the MSTR/SLV terminal is low, the output switching frequency is determined by the incoming square wave

on the SYNC input. The SYNC terminal becomes an input in this mode and accepts a TTL compatible square

wave from another TPA3100D2 configured in the master mode or from an external GPIO. If connecting to an

external GPIO, recommended frequencies are 200 kHz to 300 kHz for proper device operation, and the

maximum amplitude is 4 V.

Using Low-ESR Capacitors

Low-ESR capacitors are recommended throughout this application section. A real (as opposed to ideal) capacitor

can be modeled simply as a resistor in series with an ideal capacitor. The voltage drop across this resistor

minimizes the beneficial effects of the capacitor in the circuit. The lower the equivalent value of this resistance,

the more the real capacitor behaves like an ideal capacitor.

Short-Circuit Protection and Automatic-Recovery Feature

The TPA3100D2 has short-circuit protection circuitry on the outputs that prevents damage to the device during

output-to-output shorts, output-to-GND shorts, and output-to-VCC shorts. When a short circuit is detected on the

outputs, the part immediately disables the output drive. This is a latched fault and must be reset by cycling the

voltage on the SHUTDOWN pin or MUTE pin. This clears the short-circuit flag and allows for normal operation if

the short was removed. If the short was not removed, the protection circuitry again activates.

The FAULT terminal can be used for automatic recovery from a short-circuit event, or used to monitor the status

with an external GPIO. For automatic recovery from a short-circuit event, connect the FAULT terminal directly to

the MUTE terminal. When a short-circuit event occurs, the FAULT terminal transitions high indicating a

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