Smart Module Series
SA800U-WF Hardware Design
SA800U-WF_Hardware_Design 45 / 106
3.8. Battery Charging and Management
SA800U-WF supports a fully programmable switch-mode Li-ion battery charging function. It can charge
single-cell Li-ion and Li-polymer batteries. It supports QC 3.0 and QC 4.0 and the maximum charging
current is up to 4.5 A. The battery charger of SA800U-WF supports trickle charging, pre-charge, constant
current charging and constant voltage charging modes, which optimize the charging procedure for Li-ion
and Li-polymer batteries.
Trickle charging:
When the battery voltage is below 2.1 V, a 45 mA trickle charging current is
applied to the battery.
Pre-charge:
When the battery voltage is charged up and is between 2.1 V and 3.0 V (the maximum
pre-charge voltage is 2.1
–3.0 V programmable, 3.0 V by default), the system will enter the
pre-charge mode. The charging current is 500 mA (0
–1575 mA programmable).
Constant current mode (CC mode):
When the battery voltage is between the maximum pre-charge
voltage and 4.35 V (3.0
–4.35 V programmable, 4.35 V by default), the system will switch to CC mode.
The charging current is programmable from 300
–4500 mA. The default charging current is 500 mA
for USB charging and 4000 mA for adapter.
Constant voltage mode (CV mode):
When the battery voltage reaches the final value 4.35 V, the
system will switch to CV mode and the charging current will decrease gradually. When the charging
current reduces to about 100 mA, the charging is completed.
Table 6: Pin Definition of Charging Interface
Pin Name
Pin No.
I/O Description
Comment
USB_VBUS
J2-160, J2-162,
J2-164, J2-166,
J2-168, J4-13,
J4-14, J4-15,
J4-16, J4-17,
J4-18
PI/PO
Charging power input.
Power output for OTG
device.
USB/adaptor insertion
detect.
Vmax = 14 V
Vmin = 4.0 V
Vnom = 5.0 V
VBAT
J1-159, J1-160,
J1-161, J1-162,
J1-163, J1-164,
J1-165, J1-166,
J1-167, J1-168
PI/PO
Power supply for the
module
Vmax = 4.4 V
Vmin = 3.55 V
Vnom = 3.8 V
BAT_THERM
J2-143
AI
Battery temperature detect
Internally pulled up.
Supports 47 k
Ω NTC by
default - externally
connect BAT_THERM to
47 k
Ω NTC to GND.
If you need to connect
10 k
Ω NTC, pull up
