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TAS5760MD Current Sensing

Adam Garrison1
Intellectual 580 points
Other Parts Discussed in Thread: TAS5760MD, TAS5760M

A question from a local customer:

I'm interested in implementing my TAS5760MD amplifier system so that I can monitor the power delivered to the output loads by each individual amplifier. Assuming that the PVDD voltage is a known value, one method of doing this would be to measure the PVDD current into the amplifier chip at PVDD. However, this may only provide the overall PVDD current into the chip for both output stages, not the current drawn by each output stage individually. That brings me to my first question:

  1. Is there any difference between the PVDD input pins? Does each pair of PVDD pins (p44/p45 vs. p32/p33) power a different output stage?
  2. Do you have any suggestions for alternate methods of measuring the output current on the TAS5760 output stages?

Line/Headphone Driver Stages:
My current project is not using the Line/Headphone driver section of the TAS5760MD, but I would prefer to stock that part so we can use that functionality in future designs.

  1. Is it ok to leave the Line/Headphone driver pins unconnected? I had planned on connecting the DRGND pins to system ground and leaving all other DR_ pins floating.

Thanks for your help,

Adam

  • 0
    TI__Guru**** 189399 points

    Hi, Adam,

    Sorry for the delay.

    We do not recommend splitting the PVDD terminals apart like that.

    As for the HP, I would recommend using the TAS5760M which is essentially pin to pin with the TAS5760MD except for the HP/line terminals.

    -d2

  • 0
    TI__Mastermind 34675 points

    Hello Adam,

    Let me review your questions and provide feedback on the best way to approach this based on your use case.

  • 0
    TI__Mastermind 34675 points

    Hello Adam,

    The PVDDs are all shorted internally in the TAS5760 device. Therefore, separating them will not provide the desired data and isn't recommended. A possible solution is to put a small precision resistor in series with the speaker load and monitor the voltage across the resistor to determine the output current for each channel.

    Headphone/Linedriver:

    If pin 26 can be grounded or pulled down then all other DR pins can be left floating, but it needs to be verified. 

    pin 18: Pull down to ground

    pin 19: Pull down to ground

    pin 20: Pull down to ground

    pin 22: Pull down to ground

    pin 23: Floating

    pin 24: Floating

    pin 25: Floating

    pin 26: Pull down to ground (need to check that no other needed circuitry is power from this supply)

    pin 28: Floating

    pin 29: Pull down to ground

    pin 30 : Pull down to ground

    pin 31: Pull down to ground