Battery Charge And Management - Quectel Smart LTE Module Series Hardware Design

3.8. Battery Charge and Management

SC650T module supports a fully programmable switch-mode Li-ion battery charge function. It can
charge single-cell Li-ion and Li-polymer battery. The battery charger of SC650T module supports trickle
charging, pre-charge, constant current charging and constant voltage charging modes, which optimize
the charging procedure for Li-ion batteries.

Trickle charging: When the battery voltage is below 2.1V, a 45mA trickle charging current is applied
to the battery.

Pre-charge: When the battery voltage is charged up and is between 2.1V and 3.0V (the maximum
pre-charge voltage is 2.4V~3.0V programmable, 3.0V by default), the system will enter into
pre-charge mode. The charging current is 250mA (100mA~250mA programmable, 250mA by
default).

Constant current mode (CC mode): When the battery voltage is increased to between the
maximum pre-charge voltage and 4.2V (3.6V~4.5V programmable, 4.2V by default), the system will
switch to CC mode. The charging current is programmable from 300mA~3000mA. The default
charging current is 500mA for USB charging and 2A for adapter.

Constant voltage mode (CV mode): When the battery voltage reaches the final value 4.2V, the
system will switch to CV mode and the charging current will decrease gradually. When the charging
current reduces to about 100mA, the charging is completed.
Table 7: Pin Definition of Charging Interface
Pin Name Pin No.
USB_VBUS 41, 42
36,37,
VBAT
38
BAT_ID 17
BAT_PLUS 27
BAT_MINUS 28
BAT_THERM 29
SC650T module supports battery temperature detection in the condition that the battery integrates a
SC650T_Hardware_Design
I/O Description
Charging power input.
PI/PO Power supply output for OTG device.
USB/charger insertion detection.
PI/PO Power supply for the module
AI Battery type detection
Differential input signal of battery voltage
AI
detection (plus)
Differential input signal of battery voltage
AI
detection (minus)
AI Battery temperature detection
Smart LTE Module Series
SC650T Hardware Design
Comment
Vmax=10V
Vmin=4.0V
Vnorm=5.0V
Vmax=4.4V
Vmin=3.55V
Vnorm=3.8V
If unused, keep this
pin open.
Must be connected.
Must be connected.
Internally pulled up.
Externally connected
to GND via a 47K
NTC resistor.
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