SDAA430 June   2026 TAS2118 , TAS2120 , TAS2572 , TAS2574 , TAS2764 , TAS2780 , TAS2781

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Detailed Description
    1. 2.1 Boost over voltage fault considerations for highly inductive speakers
    2. 2.2 Class-D Y-Bridge hysteresis minimum requirement to prevent over current shutdown
    3. 2.3 Class-D Y-Bridge over current shutdown when using EMI filters on the class-D output
  6. 3Summary
  7. 4References

Abstract

Class-D audio amplifiers are high-efficiency switching converters widely used in audio applications across consumer electronics. Texas Instruments offers a comprehensive portfolio of Class-D devices — including those with integrated boost converters like TAS2120, TAS2572 and TAS2563 and those driven by an external PVDD supply like TAS2320, TAS2780 and TAS2781. These amplifiers support a diverse range of actuators including micro speakers, woofers, sub-woofers, tweeters, bone conduction actuators, LRAs, ERMs, haptic coils, and piezo/MEMS speakers, each with distinct electrical characteristics. When driving highly inductive loads, amplifiers may run into boost over-voltage (OV) faults caused by reverse inductive kickback current, and Over-Current shutdowns due to insufficient Y-Bridge switching hysteresis. The over current scenario can also occur when using a Y-Bridge with a large LC (EMI) filter on the Class-D output. This application note identifies the root causes of these modes and provides practical, quantitative design solutions to mitigate them.