Technical data

Hardware and Firmware
Designer Reference Manual DRM043/D — Rev 0
14 Hardware and Firmware MOTOROLA
mode. If the voltage does not raise up to 2.5V after 10 mins trickle
charge, the charger will signify that the battery is a bad battery and stop
the charging process.
2.3.3 Fast charge
The fast charging is divided into two states. They are constant current
charging and constant voltage charging. A max charging time is also set
for the fast charging mode.
2.3.3.1 Constant current charging
Constant current charging mode is a close loop control. The firmware
continuously checks the charging current by sensing the voltage at the
current sense resistors (R13, R14) and adjusts the duty of PWM output
from MCU. The battery's voltage is checked frequently. Whenever found
the battery's voltage reaches or above 4.1V, the charger will switch to
constant voltage charging mode.
************************************************************************
* Constant Current Charging Control
* R sense = 0.5 ohm, VrefH = 4.40V
*------------------------------------------------------------------------------------
* I (mA) 380 310 200 100 75 50
* Isense(mV) 190 155 100 50 37 25
* CURRENT $0B $09 $06 $03 $02 $01
*************************************************************************
2.3.3.2 Constant voltage charging
In constant voltage charging state, the battery voltage is checked and
maintained at 4.1V by controlling the duty of PWM output. The charging
current will gradually decrease when the battery is close to battery full.
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
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