M20 Hardware Design
DDLO charging terminates when the battery voltage reaches 2.4V. UVLO charging terminates
when the battery voltage is up to 3.2V. Both DDLO and UVLO charging are controlled by the
module hardware only.
CC charging:
When an external charger supply and battery have been inserted and the battery voltage is higher
than 3.2V, the module enters CC charging stage. CC charging controlled by the software. In this
charging stage, the module provides a constant current (about 550mA) through VBAT pins to the
battery until battery voltage reaches to 4.18
±
0.02V.
CV charging:
After CC charging ending, the module automatically enters constant voltage charging. When
charging current steadily decreases to 50mA, the module begins to carry out 30 minutes charging
delay. The CV charging will terminate after this delay.
Charging hold (only for Li-Ion battery):
The charging hold state is exclusively for Li-Ion battery. When the charger is applied, a voice call
is connected and the battery voltage is above 4.05V, the module would enter Charge Hold state.
The charging will pause until the battery voltage falls below 3.8V or the module goes into idle
mode.
Note: The module has a maximum charging time threshold, 6 hours. If the battery is not fully
charged after 6 hours’ constant charging, the module would terminate the charging operation
immediately.
M20_HD_V1.01
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