STMicroelectronics B-G474E-DPOW1, Manual

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10.2.2 CHGR
Figure 13 shows 5 V DC power from CHGR on JP5, with a power source connected to USB ST-LINK (CN3) and
without any current protection. Thus, if the B-G474E-DPOW1 Discovery kit is powered by a USB PC port, debug
features are available, but with the risk to damage the PC. If a dumb USB wall charger powers the B-G474E-
DPOW1 Discovery kit, the debug features are not available. CHGR pin can draw a 1.5 A maximum recommended
current.
Figure 13. JP5 (CHGR) from CN3 (USB STLK)
10.2.3 USBC
Figure 14 shows the selection of 5 V DC power from USBC on JP5, with a power source connected to USB Type-
C
®
CN2 connector. The LTC3114-1 converter (U6) provides the 5 V regulated voltage, from the USB Type-C
®
CN2 connector.
By default, the USB Type-C
®
V
BUS
nominal voltage must be in the 5 V to 15 V range. Nevertheless, some
exceptions may apply, so refer to the dedicated application note.
The default input current protection set on USB Type-C
®
CN2 implies the following constraints on USB Host types
to be used:
•
Low-power USB Hosts are not supported, and permanent damage can occur.
• USB 2.0 or USB 3.x legacy high-power Hosts are not recommended in this configuration, because of the
100 mA current limit before enumeration, which is not sufficient to start the product.
• Any other USB Host can supply and startup the B-G474E-DPOW1 board, like a dumb USB wall charger or a
USB battery charging 1.2 Host or a USB Type-C
®
Host.
Figure 14. JP5 (USBC) from CN2 (USB Type-C
®
)
10.2.4 E5V
Figure 15 shows the selection of 5 V DC power from E5V on JP5, with a power source connected to external
5V_VIN on CN9 pin 1 (5V_I on the silkscreen) and connected to GND on CN9 pin 2. Note that GND is also
available on other pins of extension connectors CN8 and CN9. Refer to
Section 13.5 for details.
In this case, the B-G474E-DPOW1 product must be powered by a power supply unit or by auxiliary equipment
complying with the standard EN-60950-1: 2006+A11/2009 and must be safety extra-low voltage (SELV) with
limited power capability.
Note there is no input current protection in this configuration. The recommended maximum current to be drawn
from this E5V pin is 1.5 A.
UM2577
Power source selection
UM2577 - Rev 2
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