Battery Charging And Management - Quectel Smart Module Series Hardware Design

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.
J2-160, J2-162,
J2-164, J2-166,
J2-168, J4-13,
USB_VBUS
J4-14, J4-15,
J4-16, J4-17,
J4-18
J1-159, J1-160,
J1-161, J1-162,
VBAT J1-163, J1-164,
J1-165, J1-166,
J1-167, J1-168
BAT_THERM J2-143
SA800U-WF_Hardware_Design
I/O Description
Charging power input.
Power output for OTG
PI/PO device.
USB/adaptor insertion
detect.
Power supply for the
PI/PO
module
AI Battery temperature detect
Smart Module Series
SA800U-WF Hardware Design
Comment
Vmax = 14 V
Vmin = 4.0 V
Vnom = 5.0 V
Vmax = 4.4 V
Vmin = 3.55 V
Vnom = 3.8 V
Internally pulled up.
Supports 47 kΩ NTC by
default - externally
connect BAT_THERM to
47 kΩ NTC to GND.
If you need to connect
10 kΩ NTC, pull up
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