TPA2015D1_11 Datasheet, PDF (15/28 Pages) Texas Instruments – 2 W Constant Output Power Class-D Audio Amplifier With Adaptive Boost Converter andBattery Tracking SpeakerGuard™ AGC

TPA2015D1
www.ti.com
SLOS638A – NOVEMBER 2011 – REVISED NOVEMBER 2011
SPEAKER LOAD LIMITATION
Speakers are non-linear loads with varying impedance (magnitude and phase) over the audio frequency. A
portion of speaker load current can flow back into the boost converter output via the Class-D output H-bridge
high-side device. This is dependent on the speaker's phase change over frequency, and the audio signal
amplitude and frequency content.
Most portable speakers have limited phase change at the resonant frequency, typically no more than 40 or 50
degrees. To avoid excess flow-back current, use speakers with limited phase change. Otherwise, flow-back
current could exceed the 10 mA rating of the boost converter voltage clamp and drive the PVOUT voltage above
the absolute maximum recommended operational voltage.
Confirm proper operation by connecting the speaker to the TPA2015D1 and driving it at maximum output swing.
Observe the PVOUT voltage with an oscilloscope. In the unlikely event the PVOUT voltage exceeds 6.5 V, add a
6.8 V Zener diode between PVOUT and ground to ensure the TPA2015D1 operates properly.
The amplifier has thermal overload protection and decatives if the die temperature exceeds 150°C. It
automatically reactivates once die temperature returns below 150°C. Built-in output over-current protection
deactivates the amplifier if the speaker load becomes short-circuited. The amplifier automatically restarts within
200 ms after the over-current event. Although the TPA2015D1 Class-D output can withstand a short between
OUT+ and OUT-, do not connect either output directly to GND, PVDD, or VBAT as this could damage the device.
WARNING
Do not connect OUT+ or OUT- directly to GND, PVDD, or VBAT as this could
damage the Class-D output stage.
Copyright © 2011, Texas Instruments Incorporated
Product Folder Link(s): TPA2015D1
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