TPA3116D2
TPA3118D2
TPA3130D2
SLOS708B –APRIL 2012–REVISED MAY 2012
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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
reduces any I2R losses in the load.
OUTP
OUTN
No Output
0V
OUTP-OUTN
Speaker
Current
OUTP
OUTN
Positive Output
PVCC
-
OUTP OUTN
0V
Speaker
Current
0A
OUTP
Negative Output
OUTN
0V
OUTP-OUTN
-
PVCC
0A
Speaker
Current
Figure 31. BD Mode Modulation
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