SLASEM8A January   2019  – March 2019 TPA3255-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Total Harmonic Distortion
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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 (SE)
    8. 6.8  Audio Characteristics (PBTL)
    9. 6.9  Typical Characteristics, BTL Configuration
    10. 6.10 Typical Characteristics, SE Configuration
    11. 6.11 Typical Characteristics, PBTL Configuration
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagrams
    3. 8.3 Feature Description
      1. 8.3.1 Error Reporting
    4. 8.4 Device Functional Modes
      1. 8.4.1 Device Protection System
        1. 8.4.1.1 Overload and Short Circuit Current Protection
        2. 8.4.1.2 Signal Clipping and Pulse Injector
        3. 8.4.1.3 DC Speaker Protection
        4. 8.4.1.4 Pin-to-Pin Short Circuit Protection (PPSC)
        5. 8.4.1.5 Overtemperature Protection OTW and OTE
        6. 8.4.1.6 Undervoltage Protection (UVP) and Power-on Reset (POR)
        7. 8.4.1.7 Fault Handling
        8. 8.4.1.8 Device Reset
  9. 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 PCB Material Recommendation
          4. 9.2.1.2.4 Oscillator
      2. 9.2.2 Application Curves
      3. 9.2.3 Typical Application, Single Ended (1N) SE
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedures
        3. 9.2.3.3 Application Curves
      4. 9.2.4 Typical Application, Differential (2N) PBTL
        1. 9.2.4.1 Design Requirements
        2. 9.2.4.2 Detailed Design Procedures
        3. 9.2.4.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 Power Supplies
      1. 10.1.1 VDD Supply
      2. 10.1.2 GVDD_X Supply
      3. 10.1.3 PVDD Supply
    2. 10.2 Powering Up
    3. 10.3 Powering Down
    4. 10.4 Thermal Design
      1. 10.4.1 Thermal Performance
      2. 10.4.2 Thermal Performance with Continuous Output Power
      3. 10.4.3 Thermal Performance with Non-Continuous Output Power
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
      1. 11.2.1 BTL Application Printed Circuit Board Layout Example
      2. 11.2.2 SE Application Printed Circuit Board Layout Example
      3. 11.2.3 PBTL Application Printed Circuit Board Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.4.1.2 Signal Clipping and Pulse Injector

A built in activity detector monitors the PWM activity of the OUT_X pins. TPA3255-Q1 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 would stop if the device did not have special circuitry 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 CLIP_OTW pin and is self clearing when signal level reduces and the device reverts to normal operation. The CLIP_OTW pulses start at the onset to output clipping, typically at a THD level around 0.01%, resulting in narrow CLIP_OTW pulses starting with a pulse width of ~500 ns.

TPA3255-Q1 OutputClipping.gifFigure 28. Signal Clipping PWM and Speaker Output Signals