M20 Hardware Design
characteristics listed below. To use the module’s charging algorithm properly, it is recommended
that the battery pack is compliant with these specifications, as it is important for the AT command
“AT+CBC” to monitor the voltage of battery properly, or the “AT+CBC” may return incorrect
battery capacity value.
z
The maximum charging voltage of the Li-Ion battery pack is 4.2V and the capacity is greater
than 500mAh.
z
The battery pack should have a protection circuit to avoid overcharging, over-discharging and
over-current. This circuit should be insensitive to pulsed current.
z
On the GSM part of the module, the build-in power management chipset monitors the supply
voltage constantly. Once the Under-voltage is detected, the module will power down
automatically. Under-voltage thresholds are specific to the battery pack.
z
The internal resistance of the battery and the protection circuit should be as low as possible.
It is recommended that the battery internal resistance should not exceed 70m
Ω
and the
internal resistance include battery and protection circuit of battery pack should not exceed
130m
Ω
.
z
The battery pack must be protected from reverse pole connection.
z
The Li-Ion/Polymer battery charging protection parameter is required as the following table
Table 9: Recommended battery protect circuit parameter
Item
Min.
Typ.
Max.
Over-charge protect threshold.(V)
4.25
4.3
4.35
Released Voltage from Over-charge(V)
4.1
4.2
Over-discharge protect threshold(V)
2.2
2.35
Released Voltage from Over-discharge(V)
2.35
2.4
2.45
3.5.2 Recommended battery pack
The following is the specification of the recommended battery pack:
Table 10: Specification of the recommended battery pack
Item
Remark
Product name & type
SCUD Li-Ion, 3.7V, 800mAh
To obtain more information,
Please contact :
SCUD (FU JIAN) Electronic CO., LTD.
Normal voltage
3.7V
Capacity
Minimum 800mAh
M20_HD_V1.01
- 35 -
Quectel
