Figure 3-2. WFI32-IoT Board Power Supply Block Diagram
Battery Charger
MCP73871
Li-Ion/Li-Po
LDO
MCP1727
LDO
MCP1727
3V3_PKoB
3V3_Mod
USB
WFI32E01PC
Module
USB HUB
USB2514B
PKoB4
ATSAME70N
Peripherals
5V0
VBAT_OUT
Battery
Connector
VBAT
VBUS
PKOB4 Micro-B USB (Debug USB) (J200)
The Debug USB (
) supplies power to the WFI32-IoT board from the host PC using Type-A male to Micro-B USB
cable.
Note:
The maximum available current from the Debug USB (
) is limited to 500 mA. The current is shared
between charging the external battery (if connected) and the target application section.
Battery Header (J101)
Connect a 4.2V Li-ion/Li-Po battery to the battery header (
).
Notes:
1.
The 4.2V Li-ion/Li-Po battery is not a part of the EV36W50A kit.
2.
The minimum recommended battery capacity is 400 mAh with a battery charge voltage of 4.2V.
3.
Uses a standard battery connector, which is a 2 pin, 2 mm pitch and right angle male battery header.
3.1.1
Li-ion/Li-Po Battery Charger (U101)
The WFI32-IoT board features an on-board MCP73871 Li-ion/Li-Po battery charger. The battery management circuit
automatically handles the selection between the USB power supply and battery supply. The current is shared
between charging the battery (if connected) and the target application section. For more details on the MCP73871
Li-ion/Li-Po battery charger, refer to the
Stand-Alone System Load Sharing and Li-Ion/Li-Polymer Battery Charge
Management Controller Data Sheet
(
).
Note:
The charger is configured to limit the charge current to 100 mA to prevent the overcharging of small capacity
batteries.
WARNING
The MCP73871 has a battery charge voltage of 4.2V and ensures that the battery has the same charge
voltage.
3.1.2
Voltage Regulators (U102 and U104)
The following are the two on-board MCP1727 voltage regulators on the WFI32-IoT board that ge3.3V power
supply:
•
– Gen3.3V that powers the WFI32E01PC module along with the associated circuits
EV36W50A
Hardware
©
2022 Microchip Technology Inc.
and its subsidiaries
User Guide
DS50003262A-page 9
