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LM5148: LM5148 became hot while no load...

Peter Tseng
Mastermind 6550 points

Part Number: LM5148

Tool/software:

Hi Team,

The LM5148 and ext. MOS will become hot around 45 degreeC wihle no load is attached.

After checked, when Vin=25V, the 12V output of LM5148 will be hot.

And the current is about 55 mA, as read from the power supply.

Is that normal or not?

If not, what can I check for this issue?

Thanks.

 LM5148 PCB.pdf  sch.pdf

  • 0
    TI__Guru* 86617 points

    Hi Peter,

    Is the ripple current amplitude high, leading to high core loss? This is typically the main cause of high NL input current. Also, consider using lower capacitance (Qg, Qrr, Qoss) FETs. 40V FETs have better figure-of merit than 60V.

    --

    Tim