SLASEE9C September   2017  – May 2025 TPA3221

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Audio Characteristics (BTL)
    7. 6.7 Audio Characteristics (PBTL)
    8.     Typical Characteristics, BTL Configuration, AD-mode
    9.     Typical Characteristics, PBTL Configuration, AD-mode
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagrams
    3. 8.3 Feature Description
      1. 8.3.1 Internal LDO
        1. 8.3.1.1 Input Configuration, Gain Setting And Controller/Peripheral Operation
      2. 8.3.2 Gain Setting And Controller / Peripheral Operation
      3. 8.3.3 AD-Mode and HEAD-Mode PWM Modulation
      4. 8.3.4 Oscillator
      5. 8.3.5 Input Impedance
      6. 8.3.6 Error Reporting
    4. 8.4 Device Functional Modes
      1. 8.4.1 Powering Up
        1. 8.4.1.1 Startup Ramp Time
      2. 8.4.2 Powering Down
        1. 8.4.2.1 Power Down Ramp Time
      3. 8.4.3 Device Reset
      4. 8.4.4 Device Soft Mute
      5. 8.4.5 Device Protection System
        1. 8.4.5.1 Overload and Short Circuit Current Protection
        2. 8.4.5.2 Signal Clipping and Pulse Injector
        3. 8.4.5.3 DC Speaker Protection
        4. 8.4.5.4 Pin-to-Pin Short Circuit Protection (PPSC)
        5. 8.4.5.5 Overtemperature Protection OTW and OTE
        6. 8.4.5.6 Undervoltage Protection (UVP) and Power-on Reset (POR)
        7. 8.4.5.7 Fault Handling
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Stereo BTL Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedures
          1. 9.2.1.2.1 Decoupling Capacitor Recommendations
          2. 9.2.1.2.2 PVDD Capacitor Recommendation
          3. 9.2.1.2.3 BST capacitors
          4. 9.2.1.2.4 PCB Material Recommendation
      2. 9.2.2 Typical Application, Differential (2N), AD-Mode PBTL (Outputs Paralleled before LC filter)
        1. 9.2.2.1 Design Requirements
      3. 9.2.3 Typical Application, Differential (2N), AD-Mode PBTL (Outputs Paralleled after LC filter)
        1. 9.2.3.1 Design Requirements
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 Power Supplies
        1. 9.3.1.1 VDD Supply
        2. 9.3.1.2 AVDD and GVDD Supplies
        3. 9.3.1.3 PVDD Supply
        4. 9.3.1.4 BST Supply
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Examples
        1. 9.4.2.1 BTL Application Printed Circuit Board Layout Example
        2. 9.4.2.2 PBTL (Outputs Paralleled before LC filter) Application Printed Circuit Board Layout Example
        3. 9.4.2.3 PBTL (Outputs Paralleled after LC filter) Application Printed Circuit Board Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Community Resources
    4. 10.4 Trademarks
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

8.4.5.2 Signal Clipping and Pulse Injector

A built in activity detector monitors the PWM activity of the OUT_X pins. TPA3221 is designed to drive unclipped output signals all the way to PVDD and GND rails. In case of audio signal clipping when applying excessive input signal voltage, or in case of CB3C current protection being active, the amplifier feedback loop of the audio channel will respond to this condition with a saturated state, and the output PWM signals stops unless special circuitry is implemented to handle this situation. To prevent the output PWM signals from stopping in a clipping or CB3C situation, narrow pulses are injected to the gate drive to maintain output activity. The injected narrow pulses are injected at every 4th PWM frame, and thus the effective switching frequency during this state is reduced to 1/4 of the normal switching frequency.

Signal clipping is signalled on the OTW_CLIP pin and is self clearing when signal level reduces and the device reverts to normal operation. The OTW_CLIP pulses starts at the onset to output clipping, typically at a THD level around 0.01%, resulting in narrow OTW_CLIP pulses starting with a pulse width of ~500ns.

TPA3221 Signal Clipping PWM and Speaker Output SignalsFigure 8-23 Signal Clipping PWM and Speaker Output Signals