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TPS65987EVM: can LM3489 controller be replaced?

MK
Intellectual 1650 points

Part Number: TPS65987EVM

Hi,

In the reference design file of TPS6587EVM, a hysteresis control mode buck controller, LM3489 is utilized.

Based on this design I have a few questions -

  • Can LM3489 buck controller be replaced by any other buck circuitry?
  • What are the key characteristics of the buck converter connected to TPS6587EVM?
  • Is hysteresis control mode used for stability? or any particular reason?
  • Can I replace it with a internal compensated buck converter in current control mode?

Looking forward to a discussion!

Best Regards,

Madhurya

  • +1
    TI__Mastermind 30000 points

    Hi Madhurya,

    The main reason why the LM3489 was used is its ability to operate in a bypass mode allowing for essentially a 100% duty cycle. This was so that you could pass through the 20V EVM power supply directly to VBUS during a 20V contract. You do not need to use the LM3489 though for your design. If the DCDC device you choose has a similar feedback pin implementation to the LM3489, then that is sufficient. 

  • 0 in reply to Adam Mc Gaffin
    TI__Intellectual 1650 points

    Hi Adam!

    Thank you for the clarifications :)  I understood its working better now!

    Best Regards,

    Madhurya