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TPS54560: Power management - temperature issue in TPS54560

Part Number: TPS54560

We are facing temperature raise issue while output current is 3.2A , input & output ratings are given below.

Input voltage - 32 V ,Output voltage - 5V, Load current - 3.2A continuous load

The entire PCB temperature is raised to greater than 90 deg C when the ambient temperature is 30 Deg.C.

I am really worried about component degradation due to temperature stress.

We were using thermal pad and same was connected with ground.Refer below image.

  • Max recommended operating junction temperature for this device is 150degC. 

    We guarantee device operation at this specification.

    You are stepping the input voltage down a good amount from high VIn so efficiency is degraded causing power loss in IC.

    To what ambient temperature do you require you design to operate to?

    What is case temperature of IC?

    What do layers of board look like underneath component layer?

    What is p/n of catch diode and p/n of inductor? If you can reduce DCR of these components you can reduce heat sharing between IC and these components.

  • Hi Thanks for your reply..

    Our design requirement is 30V ( max input ) to 5V  and operating frequency is 700 KHz , is it affect the performance & efficiency ? ,we are getting maximum efficiency of 80%

    Max operating ambient temperature is 60 Deg.

    Case temperature is ? 80 deg

    Inductor part number - SRP1038C-220M ( 220 UH , 5.2A) , Diode part number - V8PA10-M3 ,entire boards including bulk capacitor used in input filter getting heats because power pad is connected with ground layer.

    Heat generated due to power loss is spread into all the component , our worry is component degradation due to high temperature stress..

    Please let us know the solution to reduce the heat .

    Thanks

    Regards,

    Rajasekaran

  • If you want lower loss in converter, you can try switching at different frequency (ie: 400kHz), as switching losses become smaller.

    You are burning 3W of power, so you will need to manage your thermals and components are correctly rated for temperature rise.

    Besides component changes, switching frequency is the only thing I can think of to improve efficiency.

  • Can you please give some suggestion on thermal handling in PCB board

    Regards,

    Rajasekaran

  • Please send me all the layer plots to my personal email: m-beck1@ti.com

    I'll get back to you with feedback.