Quectel SC200R Series Hardware Design page 48

CHG_SEL 127
SC200R series module supports battery temperature detection in the condition that the battery integrates
a thermistor (47 kΩ 1 % NTC thermistor with a B-constant of 4050 K by default) and the thermistor is
connected to BAT_THERM pin. If the BAT_THERM pin is not connected, there will be malfunctions such
as battery charging failure, battery level display error, etc. The default battery temperature range is
-3.0 ° C to 48.5 ° C.
A reference design for the battery charging circuit is shown below.
VBAT
NTC
GND
Battery
Figure 10: Reference Design for Battery Charging Circuit
Mobile devices such as mobile phones or handheld POS systems are powered by batteries. For different
batteries, you should modify the charging and discharging curve correspondingly to achieve the best
performance.
If the thermistor is not available in the battery, or an adapter is utilized to power the module, you must
connect BAT_THERM to GND via a 47 kΩ resistor. Otherwise, the system may mistakenly judge that the
battery temperature is abnormal, and therefore cause battery charging failure.
BAT_SNS must be connected. Otherwise, the module will have abnormalities in voltage detection, as well
as associated problems with power-on/off and battery charging/discharging.
SC200R&SC262R_Series_Hardware_Design
DI Charging select
1
2
3
D2
D1
C4
NM_1 nF
ESD
ESD
If you use an internal charging chip,
keep this pin open.
If you use an external charging chip,
connect it to GND.
Adapter or USB
R1
0R
C1 C2 C2 C3
100 μF 1 μF 1 μF
33 pF
Smart Module Series
USB_VBUS
VBAT
BAT_SNS
BAT_THERM
GND
Module
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