Differences between with and without SMPS

Freedom_Neo · ‎2022-02-09

There are two variants, STM32H7B3IIT6 without SMPS and STM32H7B3IIT6Q with SMPS. What are the differences between using or not using SMPS? Why is it preferred with SMPS?

Peter BENSCH · ‎2022-02-09

You will find the answer in the datasheet, section 3.5.4: The built-in SMPS step-down converter is a highly power-efficient DC/DC non-linear switching regulator that provides lower power consumption than a conventional voltage regulator (LDO).

Without SMPS, the STM32H7B3 is supplied via a built-in LDO, i.e. a linear regulator, which "burns" the differential voltage between VDD and VCORE. If, on the other hand, an SMPS (switched mode power supply) is included (requires a few pins), the differential voltage can be regulated by a step-down regulator, which is considerably more energy-efficient.

Regards

/Peter

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Peter BENSCH · ‎2022-02-09

You will find the answer in the datasheet, section 3.5.4: The built-in SMPS step-down converter is a highly power-efficient DC/DC non-linear switching regulator that provides lower power consumption than a conventional voltage regulator (LDO).

Without SMPS, the STM32H7B3 is supplied via a built-in LDO, i.e. a linear regulator, which "burns" the differential voltage between VDD and VCORE. If, on the other hand, an SMPS (switched mode power supply) is included (requires a few pins), the differential voltage can be regulated by a step-down regulator, which is considerably more energy-efficient.

Regards

/Peter

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Freedom_Neo · ‎2022-02-09

Seems better to use Without SMPS.

Peter BENSCH · ‎2022-02-09

This may be true for your current setup, but it is not a valid general statement. There is a reason why the version with SMPS is available as an alternative. :smiling_face_with_smiling_eyes:

Regards

/Peter

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Peter BENSCH · ‎2022-02-09

If the problem is resolved, please mark this topic as answered by selecting Select as best. This will help other users find that answer faster.

/Peter

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Freedom_Neo · ‎2022-02-09

What is the best reason fou you?

Piranha · ‎2022-02-09

Generally SMPS has a higher power efficiency and component count, while LDO has lower noise.

Freedom_Neo · ‎2022-02-09

Are you talking about the SMPS inside the MCU? Externally, we agree on the difference between LDO and SMPS. But I could not fully understand the SMPS in the MCU.

Piranha · ‎2022-02-10

Internal or external doesn't matter. The whole point of having SMPS is to increase the efficiency. And even for the internal one, a capacitors and inductors are still external. Read the AN5307 and start with taking a look on Figure 2. :)