SLOS810A October 2019 – August 2020 TPA3139D2
PRODUCTION DATA
If selected, the PLIMIT operation limits the output voltage to a level below the supply rail. If the amplifier operates like it is powered by a lower supply voltage, then it limits the output power by voltage clipping. Add a resistor divider from GVDD to ground to set the threshold voltage at the PLIMIT pin.
The PLIMIT circuit sets a limit on the output peak-to-peak voltage. The limiting is done by limiting the duty cycle to a fixed maximum value. The limit can be thought of as a "virtual" voltage rail which is lower than the supply connected to PVCC. The "virtual" rail is approximately 5.7 times (with BD mode) and 11.4 times (with 1SPW mode) the voltage at the PLIMIT pin. The output voltage can be used to calculate the maximum output power for a given maximum input voltage and speaker impedance.
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