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Circuit Description
CHARGE MAIN PATH
MPU turns on Q8 or Q9 with high level output
from pin 2 for front port and pin 1 for rear port.
Q8 and Q9 pull down the base voltage level of
PNP TRQ3 and Q4. It turns on main path, then
charging is started.
DETECTION OF CHARGE VOLTAGE
The battery voltage of front port is divided by R28,
R30 and R32, measured as A/D value by MPU pin
12 through OP-amp. And the battery voltage of
rear port is divided by R29, R31 and R33, and
measured as A/D value by MPU pin 13.
4-10
BATTERY TEMPERATURE DETECTION
The temperature of the battery pack in the front
port and rear port is detected by R36/R37 and
R34/R35, respectively, and measured as A/D
value at MPU pin 15.
Analog switch U5 selects 2 channels (CH1 : pin 6,
CH2 : pin 7) sequentially by the Enable Pulse of
MPU pin 19 and assigns the NTC voltage of the
front and rear batteries to pin 1 of U5.
MONITORING AMBIENT TEMPERATURE
Ambient temperature is detected by R43 and
R44/R61+TH1 and measured by MPU pin 14.
As the temperature is very important, it is
constantly checked once program is started.
Samsung Electronics
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