6.4 Power supply and power selection
6.4.1 External power supply input
Several DC power sources can power the STM32U083C-DK Discovery kit. It is possible to supply the
STM32U083C-DK Discovery kit with any of the following sources:
• 5V_STLK: 5 V from the STLINK-V2EC USB Type-C
®
connector
• 5V_VIN: 7 to 12 V from the ARDUINO
®
or extension connectors, with 5 V adaptation from LDO
• E5V: External 5 V power from extension connectors
• VBUS_STLK: 5 V from the user USB Type-C
®
connector without enumeration
• 5V_USB: 5 V from the USB Type-C
®
connector
Note: If the 5V_VIN or E5V DC power source is used to power a board, this power must comply with the EN-62368-1:
2014/A11:2017 standard and must be safety extralow voltage (SELV) with limited power capability.
The power supply capabilities are shown in Table 7.
Table 7. Power source capabilities
Input power
Connector
pins
Voltage range
Maximum
current
Limitation
5V_STLK CN1 JP3[1-2] 4.75 to 5.5 V 500 mA
The maximum current depends on the USB
enumeration:
• 100 mA without enumeration
• 500 mA with good enumeration
VIN
CN6 pin 8
JP3[7-8]
7 to 12 V 800 mA
From 7 to 12 V only and the input current capability
is linked to the input voltage:
• 800 mA input current when VIN = 7 V
• 450 mA input current when 7 V < VIN < 9 V
• 250 mA input current when 9 V < VIN < 12 V
E5V
CN7 pin 6
JP3[3-4]
4.75 to 5.5 V 1 A
The maximum current depends on the power source.
1 A maximum is recommended for this board.
VBUS_STLK
CN1
JP3[9-10]
4.75 to 5.5 V 500 mA
The maximum current depends on the USB Host
used to power the board. No USB enumeration.
5V_USB
CN14
JP3[5-6]
4.75 to 5.5 V 500 mA
The maximum current depends on the presence or
absence of the USB enumeration.
5V_STLK is a 5 V DC power with limitations from the STLINK-V2EC USB connector (CN1). In this case, the 5V
jumper selection (JP3) must be on [1-2] to select the STLK power source on the JP3 connector. This is the default
setting. If the USB enumeration succeeds, the STLK power is enabled, by asserting the T_PWR_EN signal
coming from
STLINK-V2EC. This pin is connected to a power switch, which powers the board. This power switch
also features a current limitation to protect the PC in case of a short circuit on board, detected with a current
higher than 750 mA.
The STM32U083C-DK Discovery kit and its shield can be powered from the STLINK-V2EC USB connector
(CN1), but only the STLINK-V2EC circuit is powered before USB enumeration because the host PC only provides
100 mA to the board at that time. During the USB enumeration, the STM32U083C-DK Discovery kit and its shield
request no more than 500 mA current.
• If the host can provide the required power, the enumeration ends with a SetConfiguration command. Then,
the power transistor is switched ON and the green
LED (LD3) is turned ON. Thus, the STM32U083C-DK
Discovery kit and its shield request no more than 500 mA current.
• If the host is not able to provide the required current, the enumeration fails. Therefore, the power switch
stays OFF and the MCU part including the expansion board is not powered. As a consequence, the green
LED (LD3) stays turned OFF. In this case, it is mandatory to use an external power supply.
UM3292
Hardware layout and configuration
UM3292 - Rev 1
page 12/33
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