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UCC28750: /UCC28881 design for 9.6W (24V 0.4A) output (AC/DC).

WF KWOK
Prodigy 70 points
Part Number: UCC28750
Other Parts Discussed in Thread: UCC28911, UCC28910, UCC28881, PMP11236, , PMP31338

Tool/software:

We are going to design a buck converter for 24V 0.4A output. 
The first choice is UCC28910 / UCC28911, but it seems both cannot support the current output over 150mA.
So we are suggested to use UCC28881 for our application. (or any other better choice?)
UCC28881 can meet our voltage and output requirements, right?

Actually we prefer non-isolated buck converter for 24V 0.4A output, any more IC options available?


A reference design for UCC28881 is found which is PMP11236. (24V 0.1A output)
https://www.ti.com/tool/PMP11236

And here is the schematic:
https://www.ti.com/lit/df/tidris2/tidris2.pdf?ts=1756949997632

What components and values do we need to change effectively from the design in the application note for 24V 0.4A output?

---------------------------------------------

Furthermore, if UCC28881 cannot meet our buck converter for 24V 0.4A output requirement, how about UCC28750??

A reference design for UCC28750 is found which is PMP31338. (13V 0.6A output)
www.ti.com/.../PMP31338

And here is the schematic:
www.ti.com/.../tidmdp7.pdf

What components and values do we need to change the design in the application note for 24V 0.4A output?
Thank you very much.

Thank you very much.

  • 0
    TI__Guru* 86266 points

    Hello,

     

    The UCC28881 can only support an average output current of 225 mA in a buck converter.  So, I would not recommend this in your buck converter that requires 400 mA.

     

    The UCC287502 will work in your application.  The PMP31338 is a buck reference design using the UCC287502 with an external buck.  It was designed for a 13 V output with 0.6A of load current and uses an external FET.  This design can modify to meet your specification needs. 

     

    Since your output is 24 V you will need to resize the output capacitor and diode.  The inductor should work for this application.

    You will need to change your output diode and output capacitor based on the output voltage requirements of your design.   Make sure the capacitors peak current and RMS currents are higher or exceed the existing capacitors ratings.

    To set the output voltage to 24 V you will need to adjust resistor R16.

    Vout/(R16+R9) = 2.5 V/R16

     

    This design is cable of delivering 600 mA of output current and will meet your 400 mA output current requirements so no other adjustment is needed.

     

    Regards,