Smart LTE Module Series
SC600Y&SC600T Hardware Design
SC600Y&SC600T_Hardware_Design 50 / 128
pre-charge mode. The charging current is 450mA (100mA~450mA programmable, 450mA 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 9: Pin Definition of Charging Interface
Pin Name
Pin No. I/O Description
Comment
USB_VBUS
41, 42
PI/PO
Charging power input.
Power supply output for OTG device.
USB/charger insertion detection.
Vmax=10V
Vmin=4.0V
Vnorm=5.0V
VBAT
36, 37,
38
PI/PO Power supply for the module
Vmax=4.4V
Vmin=3.55V
Vnorm=3.8V
BAT_ID
17
AI
Battery type detection
If unused, keep this
pin open.
BAT_PLUS
27
AI
Differential input signal of battery voltage
detection (plus)
Must be connected.
BAT_MINUS
28
AI
Differential input signal of battery voltage
detection (minus)
Must be connected.
BAT_THERM 29
AI
Battery temperature detection
Internally pulled up.
Externally connected
to GND via a 47K
NTC resistor.
SC600Y&SC600T modules support battery temperature detection in the condition that the battery
integrates a thermistor (47K 1% NTC thermistor with B-constant of 4050K by default;
SDNT1608X473F4050FTF of SUNLORD is recommended) and the thermistor is connected to
BAT_THERM pin. If BAT_THERM pin is not connected, there will be malfunctions such as boot error,
battery charging failure, battery level display error, etc.
A reference design for battery charging circuit is shown as below.