SLAAEU7 February   2025 TAS5805M

 

  1.   1
  2.   Abstract
  3. 1Power Architecture of a Class-D Digital Audio Amplifier and Its Loss Breakdown
  4. 2Improving Audio Amplifier Efficiency with Class-H Mode
    1. 2.1 How Class-H Mode Improves Efficiency
    2. 2.2 TI's Digital Class-H Innovation
  5. 3Improving Efficiency With External GVDD and AVDD and Considerations
    1. 3.1 Testing Power Saving from External GVDD and AVDD and Testing the Impact on Audio Metrics
    2. 3.2 Considerations for External GVDD and AVDD:
      1. 3.2.1 Voltage Range of External GVDD and AVDD:
      2. 3.2.2 Sequence Requirements for External GVDD and AVDD:
  6. 4Summary
  7. 5References

3.1 Testing Power Saving from External GVDD and AVDD and Testing the Impact on Audio Metrics

Figure 3-2 below presents the data of static power saving from external GVDD and AVDD. As the PVDD voltage rises, the power saving becomes more significant. At PVDD = 26V, external GVDD and AVDD can save approximately 431mW of power.

image11_TAS5825P External GVDD/AVDD Idle Power Saving vs PVDDFigure 3-2 image11_TAS5825P External GVDD/AVDD Idle Power Saving vs PVDD

Test Condition: Idle status, 384kHz, Hybrid mode, 10uH+0.68uF filter, external GVDD/AVDD 5.1V.

Table 3-1 compares the efficiency with load. It shows efficiency improvements under both light and heavy loads, with more significant improvements under light loads. In portable speakers, which operate at low power for most of the time, this approach provides a significant efficiency improvement.

Table 3-1 External GVDD/AVDD Efficiency vs Internal AVDD/GVDD Efficiency
Efficiency Internal GVDD/AVDD External 5.1 V to AVDD/GVDD
2 * 0.5W 59.400% 63.873%
2 * 1W 68.876% 71.690%
2 * 5W 83.333% 84.817%
2 * 10W 85.910% 86.421%
2 * 20W 86.955% 87.856%

The following Figure 3-3 and Figure 3-4 show that testing the audio amplifier's THD metrics reveals that the external GVDD and AVDD have no impact on audio amplifier performance.

image12_THD vs FrequencyFigure 3-3 image12_THD vs Frequency
image13_THD vs Output PowerFigure 3-4 image13_THD vs Output Power