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UCC28250: UCC28250, Thermal Problem,

kwangwoon Lee
Prodigy 230 points
Part Number: UCC28250

Hello,

I am developing an ac/dc converter using UCC28250.

It is used as secondary side control, and the topology applies full bridge.

I am developing 3kW, and even if I load only 0.1A,

the heat rises close to 70 degrees in the UCC28250.

Even if you apply a little more load, the temperature continues to rise.

Other peripheral devices are fine, but only UCC28250 generates heat.

In case of no load, no heat is produced.

Which part should be reviewed? 

Best Regards

Kwangwoon

  • 0
    TI__Expert 7080 points

    Hello , Kwangwoon,

    Could you please attach the schematic and PCB layout for reviewing ?

    How to you drive the primary and secondary switches , and if any external load on VREF and VDD? and what is switching frequency when you found the controller temp. is high.

    If there is thermal dissipation copper under controller thermal pad ? Please check above items.

    Thanks.

  • 0 in reply to Jaden Ning
    Prodigy 230 points

    Hello,

    The attached picture is the schematic diagram and PCB data.

    The gate drive transformer is applied to the primary driver, and VDD is used by connecting an external 

    power source, and an external circuit is not connected to Vref.

    The secondary rectifier is diode.

    The switching frequency is 100kHz.

    Please review.

    Best Regards

    Kwangwoon.

  • 0 in reply to kwangwoon Lee
    TI__Expert 7080 points

    Hi Kwangwon,

    What the resistors value of R13,R15 on your board ? can you check if this driver resistors contribute to much power loss on the controller . then enlarge it.

    On the other hand , could you please use a heat sink attach on the chip for thermal dissipation to see if the temp. can be dramatically decrease.

    Thanks.