SLAA899 December   2019 TAS2110 , TAS2555 , TAS2557 , TAS2559 , TAS2560 , TAS2562 , TAS2563 , TAS2564 , TAS2770

 

  1.   Battery Voltage Tracking Limiter and Brown-Out Protection
    1.     Trademarks
    2. 1 Introduction
    3. 2 Benefits
    4. 3 Brown Out Protection and Limiter Design
    5. 4 VBAT tracking limiter
      1. 4.1 Threshold
      2. 4.2 Inflection Point and Slope
      3. 4.3 Attack
      4. 4.4 Hold Time
      5. 4.5 Release
    6. 5 Brown Out Protection (BOP)
    7. 6 System Testing
      1. 6.1 BOP (1)
      2. 6.2 BOP Release (2)
      3. 6.3 Limiter Release (3)
      4. 6.4 Maximum Output (4)
      5. 6.5 Limiter Attack (5)
      6. 6.6 BOP Attack (6)
    8. 7 Design Consideration
    9. 8 References

1 Introduction

In battery powered audio applications the user may experience a change in audible performance as the device begins to deplete battery charge. When the battery voltage (VBAT) begins to droop, the supply headroom required to prevent audio clipping will be reduced. This may result in distortion of the output audio if severe enough. Additionally, as the battery voltage continues to decrease, the ability to supply current tends to diminish. If an audio amplifier continues to drive significant current into the speaker it can cause the system battery voltage to dip below normal system operating levels which will result with the system shutting down or possibly causing electrical damage to other devices sharing the same supply. This type of event is commonly known as Brown Out.

As a solution to this problem, many Texas Instruments audio amplifiers include programmable VBAT tracking limiter and brown-out protection functions that help the designer to vary peak power consumption over the life of the battery, protect the system from brown out events, and extend usable battery life.