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KMew
KMew
Senior III
February 6, 2023
Solved

SMPS: Necessary or Not?

  • February 6, 2023
  • 1 reply
  • 3213 views

Hello,

I am working on a custom board design and we are looking into using the STM32H7B3IIT6 or the STM32H7B3IIT6Q. The main difference I've seen between the two is the Q-version removes some of the IOs to add an SMPS.

I am trying to determine if that is necessary for my project and the documentation I'm finding doesn't really explain its necessity. It simply mentions how to use it.

My application is not ultra-low power by any means. We have a large battery bank that powers the MCU and the MCU's power consumption is VERY negligible for our application, so MCU efficiency is not mandatory.

Based on that, would that mean that we do not require SMPS? Or is there other benefits or things to consider?

This topic has been closed for replies.
Best answer by Peter BENSCH

The SMPS reduces the power loss that otherwise occurs when VDD is regulated down to the core voltage with an internal LDO. The SMPS therefore increases energy efficiency.

If you don't need to save every milliwatt, you are better off with the LDO version, also because you have more GPIOs and also one less coil and capacitor on the BOM.

Does it answer your question?

Regards

/Peter

1 reply

Peter BENSCH
Peter BENSCHBest answer
ST Technical Moderator
February 6, 2023

The SMPS reduces the power loss that otherwise occurs when VDD is regulated down to the core voltage with an internal LDO. The SMPS therefore increases energy efficiency.

If you don't need to save every milliwatt, you are better off with the LDO version, also because you have more GPIOs and also one less coil and capacitor on the BOM.

Does it answer your question?

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
    KMew
    KMewAuthor
    Senior III
    February 6, 2023

    Hello Peter,

    ​

    Thank you for the reply! Yes, that does answer my question.

    So now, I just feed the LDO and all other voltage inputs (Vref, VDDA, Vcap, Vusb, etc.) from the 3.3V power supply on my board? ​

    Peter BENSCH
    Peter BENSCH
    ST Technical Moderator
    February 7, 2023

    Correct, that's exactly how it is.

    <edit>except VCAP, as mentioned later</edit>

    Regards

    /Peter

    In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
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