N1_Hardware_User_Guide
Copyright © Neoway Technology Co., Ltd
23
3.6 Battery Management
Neoway N1module supports battery charging. For information about how to select a proper battery, refer
to
GB /T18287-2000 Chinese National Standard for Lithium Ion batteries for mobile phones
. Available
voltages range between 3.5V to 4.2V. It is recommended to connect ESD and capacitors to VBAT and
VBAT_THERM in parallel in case that abnormal electrical signal might damage the module.
The charging process consists of three stages:
Pre-charging stage:
−
A: using current of 90 mA when the battery voltage is lower than 2.8 V.
−
B: using current of 450 mA when the battery voltage ranges from 2.8 V to 3.2 V.
Constant current charging
When the cell voltage is between 3.2 V and 4.2 V,
−
A max current of 1.44 A if using an adapter
−
A current of 450 mA if using USB
Constant voltage charging
The battery voltage remains at 4.2v while the charge current drops gradually. When the charge
current is 100 mA, the battery is considered fully charged.
PDA, mobile POS and other mobile devices all use battery as power supply. For different batteries,
modify the charging/discharging curve in the software. N1 has two pins forbattery connection.
Pin
Signal
I/O
Function
Remarks
2, 3
VBAT
Power supply input
3.5V~4.2V
130
VBAT_THERM
Battery temperature check
Ensure that the VBAT_THERM pin is connected. Otherwise, the battery might fail to charge or the
remaining power is displayed incorrectly. Figure 3-13 shows the connection of the battery pins, wherein
C1 is 47μF, C2 is 100pF, R1 is 13 kΩ,R2 is 2.1 kΩ, recommended model for R_THis
SDNT1005X103F3380FTF (10 kΩ, precision of 1%), and the constant B is 3380.
