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UCC28880: How to enable CCM or DCM mode in power supply design?

Part Number: UCC28880

I am designing a non-isolated power supply design. I have a doubt (may be a dumb question) How can I Choose between CCM and DCM mode? 

or Controller automatically chooses the mode based on Load current?

  • CCM can provide higher power than DCM, please refer to the datasheet page 10 table 1.

    You can use the typical buck converter design procedures to design the inductance for CCM or DCM.

  • Thank you for the reply,

    CCM and DCM mode are understood but my question is How can I make my controller to work in CCM or DCM mode?

    Do I have to change any components in circuit to make controller work in CCM/DCM mode?

  • You may refer to the datasheet page 10, section 8.3. If your load level Iout is close to 225mA, then there will be CCM operation.

    The peak current threshold plays an important role, or Ilimit, as shown in page 6, range from 330mA to 570mA. If Iout > 0.5 x Ilimit, then it will be in CCM, otherwise it will be in DCM.

    But maximum load is recommended up to 225mA, in which most likely in CCM but still possible in DCM depending the individual device current limit.

    You can use the excel spreadsheet calculation tool to check where it is likely your design in operation, CCM or DCM.

    http://www.ti.com/lit/zip/sluc625

    As the device control has a wide frequency adjustable, DCM and CCM is mainly based on the load level, and not able purposely design in a mode on a load level.