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TPS40077: Component selection

Denny Huang
Expert 7170 points
Part Number: TPS40077

Dear team

There is a good news that we design in TPS40077 in customer's new project.

The spec of customer's application is Vin=24V,Vo=12V,Io=12.5A

I refer the schematic from user's guide of  TPS40077EVM-001. 

Because of the different spec, which component is need to modify, ex output capacitor、inductor、mosfet? 

Could you help to recommend?

Many thanks 

Denny

  • 0
    TI__Guru 51745 points

     

    A lot of the components will need to be updated:

    Input Capacitors will need to be updated for both RMS ripple current and voltage rating

    Inductor will need to be updated to account for the increase in inductor voltage and duty cycle increasing volt-seconds

    MOSFETS will likely want to be updated to optimize loss balances

    Output capacitors will need to be updated for voltage rating and capacitance to meet ripple and transient requirements

    The KFF resistor from VIN to KFF will need to be update to adjust the UVLO voltage, which should be above the output voltage level.

    Soft-start capacitor may need to be resized to increase the soft-start time and control the start-up charge current.

    The feed back divider (R7, R3, R13) will need to be updated to adjust the output voltage

    Compensation (C4, C5, C6, R5, and R8) will need to be updated to compensate the changes in UVLO, which changes the feedforward gain, L and C.

    There is a design example in the TPS40077 datasheet that you can follow, but I would recommend using TI's WeBench to create a TPS40077 design with your specifications as a better place to start.