I made a prototype board using STM32H7A3LIH6Q. Before the firmware was written, a current of 500mA flowed(@+3.3V).

[DE.1]

I made a prototype board using STM32H7A3LIH6Q.

Before the firmware was written, a current of 500mA flowed(@+3.3V).

VDD and VSS were not shorted.

Q1)Have there been such cases in the past?

Q2)Are there any mistakes in the wiring of the circuit?

Q3)VFBSMPS is plane on the inner layer of the board, is there any problem?

[Tesla DeLorean]

Does seem excessive, is that the point the supply limits out?

Not sure what the expectations are when it thinks its in LDO mode, or what the ROM software does.

Perhaps find a local FAE you can discuss with.

In the mean time walk the schematic and check the pin/ball assignments again.

[Tesla DeLorean]

VDD_LDO shouldn't connect to 3V3, its the same node a VCAP / VFBSMPS

Perhaps look at H7B3I-DK schematic

[DE.1]

Thank you for your reply.

I looked at the H7B3I-DK schematic.

I understand there is a difference with the H7B3I-DK schematic.

When I set SMPS and LDO to [SMPS_2V5_SUPPLY_LDO], I observed 3.3V, 0.05A.

When I set SMPS and LDO to [POWER_LDO_SUPPLY], I observed 3.3V, 0.05A.

There was a 10x difference.

I'm thinking the problem is because when I have the LDO set it consumes less power than when I have the SMPS set.

I think I'm doing something serious wrong, but I don't know why.

[DE.1]

Sorry, ​I made a mistake.

Below are the measurement results.

When I set SMPS and LDO to [SMPS_2V5_SUPPLY_LDO], I observed 3.3V, 0.5A.

When I set SMPS and LDO to [POWER_LDO_SUPPLY], I observed 3.3V, 0.05A.

[AScha.3 · Accepted solution]

is C48 correct there ? 100nF ? :*

[DE.1]

Thank you for your reply.

The value was wrong.

After fixing the capacitor, the current value decreased.

Thank you for your pointing out.

[LCE]

Wow, 100 nF at the switching output!

Amazing, and a good sign for the SMPS's robustness that it survived that!

[Piranha]

Tesla pointed out another flaw...

And just in case you don't know, there is AN5307.