9 Detailed Description

9.1 Overview

The TPA2015D1 is a high efficiency Class-D audio power amplifier with battery-tracking SpeakerGuard™ AGC

technology. It drives up to 2 W into an 8 Ω speaker.

The built-in boost converter generates a 5.5 V supply voltage for the Class-D amplifier. The SpeakerGuard™

AGC adjusts the Class-D gain to limit battery current and prevent heavy clipping. The TPA2015D1 has an

integrated low-pass filter to improve the RF rejection and reduce DAC out-of-band noise, increasing the signal to

noise ratio (SNR).

See Section 13.1.1.1 for a list of terms and definitions used throughout the following sections.

9.2 Functional Block Diagram

IN-

VBAT

IN+

PVDD

AGND

OUT-

OUT+

GAIN

Oscillator

Boost

Converter

Battery

Monitor

+

–

PWM

H-

Bridge

GND

PVDD

PVOUT

GND

Bias &

Control

END

ENB

SW

Gain

Select:

+20 dB

+15.5 dB

+6 dB

AGC

AGC

9.3 Feature Description

9.3.1 SpeakerGuard™ Theory of Operation

SpeakerGuard™ protects speakers, improves loudness, and limits peak supply current. If the output audio

signal exceeds the limiter level, then SpeakerGuard™ decreases amplifier gain. The rate of gain decrease, the

attack time, is fixed at 0.026 ms/dB. SpeakerGuard™ increases the gain once the output audio signal is below

the limiter level. The rate of gain increase, the release time, is fixed at 1600 ms/dB. Figure 9-1 shows this

relationship.

www.ti.com

TPA2015D1

SLOS638C – NOVEMBER 2011 – REVISED JUNE 2022

Copyright © 2022 Texas Instruments Incorporated

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Product Folder Links: TPA2015D1