7.4.2 MODE_SEL = HIGH: Low-Idle-Current 1SPW Modulation

The 1SPW mode alters the normal modulation scheme in order to achieve higher efficiency with a slight penalty

in THD degradation and more attention required in the output filter selection. In 1SPW mode, the outputs

operate at ~15% modulation during idle conditions. When an audio signal is applied, one output decreases and

the other output increases. The decreasing output signal rails to GND. At which point, all the audio modulation

takes place through the rising output. The result is that only one output is switching during a majority of the audio

cycle. Efficiency is improved in this mode due to the reduction of switching losses.

OUTP

OUTN

OUTP

-OUTN

Speaker

Current

OUTP

OUTN

OUTP

-OUTN

Speaker

Current

OUTP

OUTN

OUTP

-OUTN

Speaker

Current

0 V

0 V

PVCC

No Output

Positive Output

Negative Output

0 A

0 A

0 V

-PVCC

Figure 7-3. Low-Idle-Current 1SPW Modulation

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TPA3139D2

SLOS810A – OCTOBER 2019 – REVISED AUGUST 2020

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