7.8.2
5V_STLK power source
5V_STLK is a DC power with limitation from STLINK-V3E USB connector (USB type Micro-B connector of
STLINK-V3E). In this case, the JP25 jumper must be on pin [1-2] to select the 5V_STLK power source. This is the
default setting. If the USB enumeration succeeds, the 5V_STLK power is enabled, by asserting the T_PWR_EN
signal (from U26 STLINK-V3E MCU). This pin is connected to the U20 USB power switch, which powers the
board. This power switch features also a 500 mA current limitation to protect the PC in case of an onboard
short-circuit.
The STM32U575I-EV board, with its shield on it, can be powered from the CN26 STLINK-V3E USB connector,
but only the STLINK-V3E circuit has the power before USB enumeration, as the host PC only provides 100 mA to
the board at that time. During the USB enumeration, the STM32U575I-EV board asks for the 500 mA power to the
host PC.
If the host can provide the required power, the enumeration finishes by a
SetConfiguration
command, and then,
the power switch is switched ON, the LD2 green LED turns ON, thus the STM32U575I-EV board and its shield on
it can consume 500 mA current, but no more.
If the host cannot provide the requested current, the enumeration fails. Therefore the power switch remains OFF
and the MCU part, including the extension board, is not powered. As a consequence, the 5V LD2 green LED
remains turned OFF. In this case, it is mandatory to use an external power supply.
5V_STLK power source configuration for the JP25 jumper is described in
Figure 14.
JP25 [1-2]: 5V_STLK power source
STM32U575I-EV
Power supply
UM2854
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Rev 1
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