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PTH12050W no load current

Ross Parlour
Intellectual 1550 points
Other Parts Discussed in Thread: PTH12050W

Hi All,

I am unfamiliar with our Power Modules and wanted to ask a question with relation to the no load current.

If the PTH12050W is supplied with 5V and there are no caps input or output, would the 'Input standby current' go from drawing 10mA, to approx. 100mA?

I am keen to help my customer get to the bottom of the overheating of part (approx. 80 degrees C) when under a no load condition.  My customer has so far connected a PSU voltage of 5V to the module.

Many thanks,
Ross

  • 0
    TI__Intellectual 1550 points

    Additionally to above, I can now add that the customer is using two input caps, a 150uF elec and a 10uF ceramic.

    No load conditions are - 12Vin, 5Vout, no load = temperature 80C,

    Load conditions are - 12Vin, 5Vout, 5A load = temperature 106C, efficiency 93% & 83% - Iq measured at 120mA.

    I have asked the customer to perform the following in the lab;

    • Where are you seeing the temperature’s to on the module? Is it specifically on the inductor for example?

    • Could you set the inhibit pin (pin 4) to GND and check there isn’t any heat coming from the module?

    • For a 12V input, and Vout of 5V, you definitely have a 280R resisitor. Is it possible to try a 2A load and check both the efficiency and temperature? Are they as expected?

    • Instead of a no-load output, try a 1KR load. I know the efficiency will be poor, but this should only draw 5mA. Even with 10% efficiency, the worst scenario would 250mW.

    If you can help advise me any further on this, I would be extremely grateful.

    Thanks, Ross