Overcurrent Issue on STM32H753ZIT6 Nucleo

[aditya3]

Hi,

I am using an STM32H753ZIT6 NUCLEO board. While powering the board with an external supply, we faced an overvoltage issue on the board.

As the user manual reccomends that the board be supplied between 7 to 12 V, we provided it a constant supply of 9.5 V. After a while, the overvoltage warning LED turned on on the board hence the source was disconnected and we found that the voltage regulator on the board was heating excessively. However, even after replacing the regulator with a new one we are facing the same issue. Any help regarding how this can be fixed would be appreciated.

Thank you.

[Peter BENSCH]

What else is connected to the NUCLEO-H753ZI apart from the supply voltage of 9.5V?

Is it U12 (LD1117S50TR) that is overheating?

Regards
/Peter

[Andrew Neil]

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@aditya3 wrote:

the overvoltage (sic?) warning LED turned on on the board

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I don't see an over-voltage LED. Do you mean the over-current LED - LD6 ?

https://www.st.com/resource/en/user_manual/um2407-stm32h7-nucleo144-boards-mb1364-stmicroelectronics.pdf#page=12

The User Manual says this indicates over-current on the USB connection to the ST-Link:

As @Peter BENSCH said, you need to show a schematic of your full setup.

Some good, clear photos would also help.

[aditya3]

Thanks for the reply.
Our setup consisted of a few sensors connected on a breadboard, which are interfaced with the NUCLEO board.
This included 3.3V digital inputs as well as analog inputs from two potentiometers (a 5V input to PC0 (A1) and a 3.3V input to PA3 (A0)).
After troubleshooting we found that the U12 (LD1117S50TR) was overheating, but even after replacing the U12 there is no change to the issue. As soon as we power on the NUCLEO board with even a laptop connection the LD6 LED turns on.

[Peter BENSCH]

@aditya3 

@Andrew Neil and I have already asked you to provide precise details of the external connections, ‘a few sensors’ is too imprecise for this.

LD6 shows overcurrent on the track ‘5V_USB_CHGR’, i.e. the supply voltage of 5V coming from the USB micro socket. This means that more than the permitted 500mA is definitely flowing there.

Regards
/Peter

[Andrew Neil]

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@Peter BENSCH wrote:

‘a few sensors’ is too imprecise for this.

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Indeed!

@aditya3 - you need to show a schematic of your full setup - showing sensors, power supply, PC connection, etc.

Hand-drawn is sufficient.

Some good, clear photos would also help.

Also, full details of this 9.5V power supply.

Please see: How to write your question to maximize your chances to find a solution.

[aditya3]

Thank you for the prompt reply. I just wanted to mention that we are a team of college students using the NUCLEO board for a project, hence our resources are a little limited and we are learning as we go.

Our setup consisted of:

• 2 potentiometers which would be our ADC inputs
  
  • Potentiometer 1 was connected to the 3.3V line of the NUCLEO board and the input of this was connected to PA3 / A0
  • Potentiometer 2 was connected to the 5V line of the nucleo board and the input of this was connected to PC0 / A1
• Digital inputs (all 3.3V supplied from the board itself)
  
  • PG14
  • PG12
  • PE14
  • PE8
  • PE7
  • PE5
  • PE4
• Digital outputs (sent to LEDs such as those on the breadboard in the attached image)
  
  • PE13
  • PE11
  • PE10
  • PE9
• 1 DAC output (only configured but not connected)
  
  • PA4

When we first had this issue the board was given 9.5V from a regulated DC dual power supply and the procedure given in the datasheets and user manual was followed regarding uploading code and powering up the board (jumper position and supply connection marked in yellow in schematic).
The first few times this worked great, we came back to it and were faced with the overcurrent LED lighting up, we even saw the current on our power source jump quite a bit exceeding the 800mA maximum current restriction, so we immediately shut off our power source and disconnected our board.
Upon further troubleshooting we found out that U12 (LD1117S50TR) was heating up, so we ordered a replacement for the U12 and tried to power our NUCLEO board simply via the laptop (marked PC connection on the schematic)
Upon doing so the overcurrent led would still show up and we would immediately have to disconnect our laptop from the board.

I've attached a hand-drawn schematic as well as the only photo we have from our testing, apologies for the image quality.

 

 

[aditya3]

Hi,

During testing with our other NUCLEO-H753 board (exact same model), we probed Vin and GND with the voltage setting on our multimeter (Sonel CMP-2000), below are the exact pins:

GND on CN10

Vin on CN8

The board was being supplied wtih 12V via an external supply (PS-303S Single Channel DC Power Supply).

Immediately following this, the overcurrent LED turned on on this board as well. Having looked again at the datasheet, at the end of section 6.4.1 (Power supply input from STLINK-V3E USB connector), the when the overcurrent LED turns on, the board should still be able to operate when powered externally as specified, when we tried this again only LD5 turned on on the board. It was flickering and very dim. Futher U12 is only overheating when powered via PC, not when powered using Vin.

USB PWR used for PC connection

What can we do to fix the overcurrent issue? Thank you again for your help and advice.