OUTP

OUTN

OUTP

Speaker

Current

OUTP

OUTN

Speaker

Current

OUTP

OUTN

OUTP

Speaker

Current

0 V

0 V

PVCC

No Output

Positive Output

Negative Output

0 A

0 A

0 V

TPA3116D2

TPA3118D2

TPA3130D2

SLOS708B – APRIL 2012 – REVISED MAY 2012

www.ti.com

TPA3116/18/30D2 MODULATION SCHEME

The TPA31xxD2 family has the option of running in either BD modulation or 1SPW modulation; this is set by the

MODSEL pin.

MODSEL = GND: BD-modulation

This is a modulation scheme that allows operation without the classic LC reconstruction filter when the amp is

driving an inductive load with short speaker wires. Each output is switching from 0 volts to the supply voltage.

The OUTPx and OUTNx are in phase with each other with no input so that there is little or no current in the

speaker. The duty cycle of OUTPx is greater than 50% and OUTNx is less than 50% for positive output voltages.

The duty cycle of OUTPx is less than 50% and OUTNx is greater than 50% for negative output voltages. The

voltage across the load sits at 0V throughout most of the switching period, reducing the switching current, which

Figure 31. BD Mode Modulation

20

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