• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 64 subscribers
  • Views 606 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS54541 is realy hot !

PA M
Prodigy 150 points
Other Parts Discussed in Thread: TPS54541

Hello guys,

I'm working on two DC/DC based on TPS54541 ( 24V to 9.6V and 24V to 5V ).

TPS54541 series is quite good about efficiency, ripple, soft start, Load/line responce, and so on... but it is a nightmare about thermal.

At Vin=24V - Vout=5V - Iout=2.5A and Tamb=25°C, my efficiency is egual to 87% and Tc is close to 65°C ( Tc: Case temperature )

So at Tamb=65°C Tc gonna be close to 105°C so Tj gonna be realy realy hot !

Moreover at Vin=24V - Vout=9.6V - Iout=3A, Tamb=25°C, Tc is close to 75°C

So at Tamb=65°C Tc gonna be close to 115°C !

And It is even worst if both DC/DC are enable at the same time.

Did i have made a mistake ?  How can i improve that ?

Thank you,

  • 0
    TI__Guru**** 191445 points

    For a well designed pcb, the junction temperatures should be closer to 35 and 43 deg. C respectively at Ta = 25 C. As you may know thermal performance is greatly dependent on pcb layout. If the loads are close to the respective converters, they may be contributing heat to the TPS54541 ICs as well.  Can we see your layout?

  • 0 in reply to JohnTucker
    Prodigy 150 points

    Hello John,


    Loads are not in the PCB, there is only a µC ( Iuc=80mA MAX ).
    I think our layout is realy poor. There is only a tiny winy little GND power plate on top. An heat is dissipated by the bottom power plate due to 5 vias in the thermal Pad.
    I know this is a realy realy bad layout,... Do you think I'll get a significant advance with a better one ?

    I saw SLVA412 and SLVA464 Application-Note. Do you have thermal captures of those desing ( or other example )?

    Thanks,
    Munck PA

  • 0 in reply to PA M
    TI__Guru**** 191445 points
    Unfortunately, we did not capture any thermal images for either of those designs. PCB layout and copper area are the primary determining factors for thermal performance. If I happen to have an EVM, I can take a thermal image. I'll let you know.
  • 0 in reply to JohnTucker
    Prodigy 150 points

    Hello John,

    Do you think, Tc will realy decereas to  40°C with a better layout ? ( that means it will earn 35°C ).
    I hope, you'll can take a thermal image of SLVA412 and/or SLVA464 .


    Thanks
    Munck P.A.

  • 0 in reply to PA M
    TI__Guru**** 191445 points
    The webench simulations indicate that the temperatures will be much less than you observe. I'll see if I can take a thermal image for you after the holidays.