ZHCSHZ1 April   2018 TPA3126D2

PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1.      TPA3126 和 TPA3116 空闲电流
      2.      简化应用电路
  4. 修订历史记录
  5. Device Comparison Table
  6. Pin Configuration and Functions
    1.     Pin Functions
  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 DC Electrical Characteristics
    6. 7.6 AC Electrical Characteristics
    7. 7.7 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Gain Setting and Master and Slave
      2. 8.3.2  Input Impedance
      3. 8.3.3  Startup and Shutdown Operation
      4. 8.3.4  PLIMIT Operation
      5. 8.3.5  GVDD Supply
      6. 8.3.6  BSPx and BSNx Capacitors
      7. 8.3.7  Differential Inputs
      8. 8.3.8  Device Protection System
      9. 8.3.9  DC Detect Protection
      10. 8.3.10 Short-Circuit Protection and Automatic Recovery Feature
      11. 8.3.11 Thermal Protection
      12. 8.3.12 Device Modulation Scheme
        1. 8.3.12.1 BD Modulation
      13. 8.3.13 Efficiency: LC Filter Required with the Traditional Class-D Modulation Scheme
      14. 8.3.14 Ferrite Bead Filter Considerations
      15. 8.3.15 When to Use an Output Filter for EMI Suppression
      16. 8.3.16 AM Avoidance EMI Reduction
    4. 8.4 Device Functional Modes
      1. 8.4.1 Mono PBTL Mode
      2. 8.4.2 Mono BTL Mode (Single Channel Mode)
  9. Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Typical Application
        1. 9.1.1.1 Design Requirements
        2. 9.1.1.2 Detailed Design Procedure
          1. 9.1.1.2.1 Select the PWM Frequency
          2. 9.1.1.2.2 Select the Amplifier Gain and Master/Slave Mode
          3. 9.1.1.2.3 Select Input Capacitance
          4. 9.1.1.2.4 Select Decoupling Capacitors
          5. 9.1.1.2.5 Select Bootstrap Capacitors
        3. 9.1.1.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 Power Supply Mode
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Heat Sink Used on the EVM
  12. 12器件和文档支持
    1. 12.1 器件支持
      1. 12.1.1 开发支持
    2. 12.2 接收文档更新通知
    3. 12.3 相关文档
    4. 12.4 社区资源
    5. 12.5 商标
    6. 12.6 静电放电警告
    7. 12.7 Glossary
  13. 13机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

Efficiency: LC Filter Required with the Traditional Class-D Modulation Scheme

Many traditional Class-D amplifiers are based on the AD modulation. Due to the out-of-phase nature of a BTL or PBTL amplifier operating in the AD modulation, if no LC filter was present, the load sees the full PWM signal across its terminals. This causes a high-frequency ripple current to pass through the load, which leads to high power dissipation, poor efficiency, and potential speaker damage. The ripple current is large in the AD modulation scheme, because it is proportional to voltage multiplied by the time at that voltage. The differential voltage swing is 2 × VCC, and the time at each voltage is half the period for the AD modulation scheme. An ideal LC filter is required to store the ripple current from each half cycle for the next half cycle, while any resistance causes power dissipation. The speaker is both resistive and reactive, whereas an LC filter is almost purely reactive.

The modulation schemes implemented in the TPA3126D2 have little loss in the load even without a filter because the pulses are short and the change in voltage is VCC instead of 2 × VCC. As the output power increases and the pulses widen, the ripple current can go up. In this case, the ripple current can be filtered with an LC filter for increased efficiency. However, in most applications the filter is not required.

With an LC filter, specifically as the cut-off frequency of the LC filter is smaller than the PWM switching frequency of the amplifier, the ripple current is reduced such that only a small residual ripple voltage is present after the LC filter. The filter has less resistance but higher impedance at the switching frequency than the speaker, which results in less power dissipation, hence increasing efficiency.