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TPA3255EVM: Power supply current

Jack Frederick
Prodigy 50 points
Part Number: TPA3255EVM

Tool/software:

Hi,

I'm designing a linear power supply for the TPA3255EVM and will be providing close to the maximum Vdc, around 50V. My current design will provide 6 amps @ 50Vdc. The board requires 5-14 amps. Will providing more current allow the amplifier board to make more power, or is the maximum output based more on providing the maximum allowable Vdc?

Thanks

  • 0
    TI__Genius 9175 points

    Hi Jack,

    There are a few considerations for getting the highest power out of the TAS3255. The device is a closed loop amplifier which means that it will try and amplify the signal the same amount regardless of PVDD. Just because the power supply can provide more power to the device does not mean that it will draw more current. It will only draw more current if the input signal is larger or the output load is reduced. If the power to the device can provide 300W of power, then you can expect less than that as the total output power since the device is not 100% efficient and the filter on the output will also dissipate some power.

    Regards,

    Ramsey

  • 0 in reply to Ramsey Foote
    Prodigy 50 points

    Hi Ramsey,

    Makes sense. At 50V and 6 Amps I'm already at 300W, so that should give me the max, understanding that there are some losses. I noticed that some of the  manufacturers that are implementing the TAS3255 chip are using an SMPS that is providing 48 volts but only 5 amps, so depending on the load they may not be using the full potential of the amplifier. Also they are using a pad down design which may not have the heat dissipation for the full 300 watts, or may not actually be using 3255 chip.

    Thanks!

    Best Regards

    Jack

  • +1 in reply to Jack Frederick
    TI__Genius 9175 points

    Hi Jack,

    If you are interested in a pad down device, the analog input class-D part we have that can do the most power is the TPA3250. However, since it is pad down, thermals will be harder to manage since a heatsink can't be directly on the thermal pad.

    Regards,

    Ramsey

  • 0 in reply to Ramsey Foote
    Prodigy 50 points

    Great help, Thanks!