SLOS638C November   2011  – June 2022 TPA2015D1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Operating Characteristics
    7. 7.7 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 SpeakerGuard™ Theory of Operation
        1. 9.3.1.1 SpeakerGuard™ With Varying Input Levels
        2. 9.3.1.2 Battery Tracking SpeakerGuard™
      2. 9.3.2 Fully Differential Class-D Amplifier
        1. 9.3.2.1 Advantages of Fully Differential Amplifiers
        2. 9.3.2.2 Improved Class-D Efficiency
      3. 9.3.3 Adaptive Boost Converter
        1. 9.3.3.1 Boost Converter Overvoltage Protection
      4. 9.3.4 Operation With DACs and CODECs
      5. 9.3.5 Filter Free Operation and Ferrite Bead Filters
      6. 9.3.6 Speaker Load Limitation
      7. 9.3.7 Fixed Gain Setting
    4. 9.4 Device Functional Modes
      1. 9.4.1 Shutdown Mode
      2. 9.4.2 Battery Tracking SpeakerGuard™ Operation
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 TPA2015D1 With Differential Input Signals
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
          1. 10.2.1.2.1 Boost Converter Inductor Selection
            1. 10.2.1.2.1.1 Inductor Equations
          2. 10.2.1.2.2 Boost Converter Capacitor Selection
          3. 10.2.1.2.3 Components Location and Selection
            1. 10.2.1.2.3.1 Decoupling Capacitors
            2. 10.2.1.2.3.2 Input Capacitors
        3. 10.2.1.3 Application Curves
      2. 10.2.2 TPA2015D1 with Single-Ended Input Signals
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
        3. 10.2.2.3 Application Curves
  11. 11Power Supply Recommendations
    1. 11.1 Power Supply Decoupling Capacitors
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 Component Placement
      2. 12.1.2 Trace Width
      3. 12.1.3 Pad Size
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Device Nomenclature
        1. 13.1.1.1 TPA2015D1 Glossary
        2. 13.1.1.2 Boost Terms
    2. 13.2 Community Resources
    3. 13.3 Trademarks
  14. 14Mechanical, Packaging, and Orderable Information
    1. 14.1 Package Option Addendum
      1. 14.1.1 Packaging Information
      2. 14.1.2 Tape and Reel Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.3.1.2 Battery Tracking SpeakerGuard™

The TPA2015D1 monitors the battery voltage and the audio signal, automatically decreasing gain when battery voltage is low and audio output power is high. It finds the optimal gain to maximize loudness and minimize battery current, providing louder audio and preventing early shutdown at end-of-charge battery voltages. SpeakerGuard™ decreases amplifier gain when the audio signal exceeds the limiter level. The limiter level automatically decreases when the supply voltage (VBAT) is below the inflection point. Figure 9-3 shows a plot of the limiter level as a function of the supply voltage.

GUID-D2CBB95E-C8D5-4FCF-8BA7-D13E31989615-low.gifFigure 9-3 Limiter Level vs Supply Voltage

The limiter level decreases within 60 µs of the supply voltage dropping below the inflection point. Although this is slightly slower than the 26 µs/dB SpeakerGuard™ attack time, the difference is audibly imperceptible.

Connect a resistor between the AGC pin and ground to set the inflection point, as shown in Table 9-1. Leave the AGC pin floating to disable the inflection point, keeping the limiter level constant over all supply voltages.

The maximum limiter level is fixed, as is the slope of the limiter level versus supply voltage. If different values for maximum limiter level and slope are required, contact your local Texas Instruments representative.

Table 9-1 AGC Function Table
FUNCTIONRESISTOR ON AGC PININFLECTION POINT
Constant limiter level; battery track OFFFloating or connected to VBATdisabled
AGC battery track option 139 kΩ3.55 V
AGC battery track option 227 kΩ3.78 V
AGC battery track option 318 kΩ3.96 V

The audio signal is not affected by the SpeakerGuard™ function unless the peak audio output voltage exceeds the limiter level. Figure 9-7 shows the relationship between the audio signal, the limiter level, the supply voltage, and the supply current.

When VBAT is greater than the inflection point, the limiter level allows the output signal to slightly clip to roughly 6% THD at 2 W into 8 Ω. This is an acceptable peak distortion level for most small-sized portable speakers, while ensuring maximum loudness from the speaker.