7.8.7
Programing/debugging when the power supply is not from STLINK-V3E (5V_STLK)
5V_EXT, 5V_DC, or 5V_UCPD can be used as an external power supply in case the current consumption of
the STM32U575I-EV with expansion boards exceeds the allowed current on USB. In such a condition, it is still
possible to use USB for communication for programming or debugging only.
In this case, it is mandatory to power the board first using 5V_EXT, 5V_DC or 5V_UCPD then connect the
STLINK-V3E USB cable to the PC. Proceeding this way, the enumeration succeeds thanks to the external power
source.
The following power sequence procedure must be respected:
1.
Connect JP25 jumper according to the external 5 V power source selected.
2.
Connect the external power source selected.
3.
Power ON the external power source.
4.
Check LD2 5 V green LED is turned ON.
5.
Connect the PC to the CN26 STLINK-V3E USB connector.
If this sequence is not respected, the board may be powered by V
BUS
first from STLINK-V3E, and the following
risks may be encountered:
•
If more than 500 mA current is needed by the board, the PC may be damaged or current can be limited by
PC, As a consequence the board is not powered correctly.
•
500 mA is requested at enumeration so there is a risk that the request is rejected and enumeration does not
succeed if PC does not provide such current. Consequently, the board is not powered (LD2 LED remains
OFF).
7.8.8
Power supply output
5V
: When the STM32U575I-EV board is powered by STLINK-V3E USB, 5V_EXT, or 5V_DC, the 5 V (CN10 pin
50) can be used as an output power supply for an extension board plugged on CN10. In this case, the maximum
current of the power source specified in
must be respected.
3V3
: CN9 pin 50, CN14 pin 34, or CN15 pin 34 can also be used as power supply output. The current is limited
by the 1.3 A maximum current capability of the regulator U19 (ST1L05BPUR from STMicroelectronics) provided
to the STM32U575I-EV board and its shield.
7.8.9
Internal power supply
For all general information concerning design recommendations for STM32U5 with INTERNAL SMPS, and design
guide for ultra-low-power applications with performance, refer to
Getting started with STM32U575/585 MCU
hardware development
) at the
3V3
Regardless of the 5V power source, the U19 LDO is used to deliver a fixed 3.3 V power supply, with a current
capability of 1.3 A. This power source of 3.3 V is shared between the STM32U575I-EV and its expansion boards.
VDD_ADJ
Regardless of the 5 V power source, the U18 LDO is used to deliver an adjusted power voltage, with a range
of 1.7 to 3.6 V, and a current capability of 1.3 A. This voltage is tuned, thanks to the RV3 potentiometer. This
adjustable voltage must be reserved for MCU debugging capability. Be careful to set and select the feature
compatible with this adjustable voltage range before updating the board accordingly.
Caution:
The power
‑
on sequence is not respected when using VDD_ADJ below 3.3 V, refer to the application note
Getting started with STM32U575/585 MCU hardware development
(
datasheets for low voltage power sequencing.
2V8
Regardless of the 5 V power source, the U10 LDO is used to deliver a fixed 2.8 V voltage, with a current
capability of 800 mA. This voltage source is mainly reserved for the camera daughterboard. This one is not
targeted to supply the MCU. To drive the MCU in low voltage, use the VDD_ADJ supply voltage.
STM32U575I-EV
Power supply
UM2854
-
Rev 1
page 31/105