System
architecture
UM2191
30/55
DocID030479 Rev 2
2.3.4
P-NUCLEO-USB002 expansion board: VBUS management
Figure 24: P-NUCLEO-USB002 expansion board Port 0 schematic view of the VBUS
management mechanism
Figure 25: P-NUCLEO-USB002 expansion board Port 1 schematic view of the VBUS
management mechanism
This circuit description uses port 0 for reference, but the same applies to port 1.
The V
BUS
management block can manage different V
BUS
, as described by USB PD
specification. It provides energy if the STUSB1602 is set as a provider and supplies energy
when it is a consumer.
Transistors Q401 and Q402 are set in back-to-back configuration to protect and isolate the
V
BUS
supplying path in both directions.
When the port acts as a provider, the V
BUS
power can be supplied via power connector
CN4 (jumper JP400 must be left open). V
BUS
is put on the supply path via the discrete load
switch (Q401-Q402), driven by the STUSB1602 VBUS_EN_SRC pin.
If no external power supply is available, closing jumper JP400 allows using the 5 V from the
NUCLEO-F072RB board as V
BUS
in the provider role only. This is mainly used for
demonstration purposes.
When the port is a consumer, the same V
BUS
path is managed by the VBUS_EN_SNK pin
of the STUSB1602 device that enables the discrete load switch Q416.