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TPA3255-Q1: No signal/load current excessive

Tony Stoor
Prodigy 10 points
Part Number: TPA3255-Q1
Other Parts Discussed in Thread: TPA3255,

Hi, we have used 5pcs TPA3255 in a design, and new design version uses TPA3255-Q1. GVDD and VDD have been lowered to the suggested 10,6V.
Otherwise the same design as the old one, just the output inductors have been changed to have a larger saturation current.

The old board consumes ~50mA from 52V supply, when reset is active, then with no reset ~600mA

The new board starts at ~500mA and quickly ramps up to over 800mA and th chips get very hot. I activated reset at this point.

Question is: Is this normal behavior for the Q1? At <47V the current stays at ~600mA and doesn´t ramp up.

There was no heatsink in use in either of the tests. This test is meant to be a production test that shows that nothing is seriously wrong.

  • 0
    TI__Mastermind 46340 points

    Hi Tony

    Tony Stoor said:
    Question is: Is this normal behavior for the Q1? At <47V the current stays at ~600mA and doesn´t ramp up.

    Without heatsink, it could be a normal behavior. When using smaller power supply, there still possibly balance between loss and dissapation.

    But higher voltage, the loss is too much. The temperature keep going up, MOS Rdson will increase, then higher loss generated.