Reference Design For Power Supply - Quectel SG560D Series Hardware Design

A reference design for the battery charging circuit is shown below.
VBAT
BAT_ID
NTC
R3
100 K
GND
1%
NTC
Battery
Mobile devices such as mobile phones and handheld POS systems are powered by batteries. For
different batteries, the charging and discharging curves must be modified correspondingly to achieve the
best performance.
If the thermistor is not available in the battery, or the adapter is utilized for powering the module, then you
must connect BAT_THERM to GND via a 100 kΩ resistor. Otherwise, the system may mistakenly judge
that the battery temperature is abnormal, which will cause battery charging failure. BAT_P and BAT_M
pins must be connected. Otherwise, the module will have abnormalities in voltage detection, as well as
related turn-on/off and battery charging or discharging issues.

3.1.3. Reference Design for Power Supply

The performance of the module largely depends on the power source. The power supply of the module
should be able to provide sufficient current of 5 A at least. If the voltage difference between input and
output is not too large, it is suggested that an LDO should be used for the module. If there is a large
voltage difference between the input source and the desired output (VBAT), a buck converter is preferred
to be used as the power supply.
SG560D_Series_Hardware_Design
1
2
3
D1 D2
4
100 μF
TVS
TVS
Figure 2: Reference Circuit for Battery Charging Circuit
Adapter or USB
R1
R2
C1 C3 C4
C2
+
4.7 μF
33 pF 10 pF
100 nF
Smart Module Series
USB_VBUS
0 R
BAT_P
0 R
BAT_M
VBAT
BAT_ID
BAT_THERM
C5
GND
SG560D
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