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Circuit Description
4-5-3 Master and Slave Mode
Status
Fastcharging on front port
Fastcharging on rear port
Front port master charging
Rear port slave charging
Rear port master charging
Front port slave charging
Fast charging on front port
Trickle charging on rear port
Fast charging on rear port
Trickle charging on front port
Trickle charging on both front and rear ports
4-5-4 Watch Dog and Reset Circuit
MPU U1 Reset pin is active in low state. U4 is used
as A/D reference voltage for MPU and whole
charging system, so the circuitry composed of
Q30-Q32 and D30 detects the voltage. In normal
state, Q31 turns on so U4 pin 3 becomes low. It
causes MPU Reset to be high. If an excessive
impulsive voltage is supplied to U4, Q30 turns on,
and U4 pin 3 becomes high. It causes MPU to be
reset.
4-5-5 Timer
Timer is used to protect the battery from being
overcharged. The timer is set at initial routine. If
fast charge is not completed until maximum time
value, fast charge is stopped by the timer and it
moves to automatic trickle charge routing. This is
the final step to protect battery from excessive
charging and damage. There are four timers
available, and the default timer is 140 minutes.
Time (minute)
Time-1 (RX1)
140
210
280
350
4-8
MPU(11)
Signal
CUR_CTRL
Time-2 (RX2)
VCC
VCC
GND
VCC
VCC
GND
GND
GND
MPU(4)
CHG_A
HIGH
LOW
LOW
HIGH
HIGH
LOW
LOW
LOW
HIGH
LOW
LOW
LOW
HIGH
LOW
4-5-6 Temperature Detection
The battery temperature and ambient temperature
can seriously damage Ni-MH battery, so the
temperature is constantly detected by MPU. The
ambient temperature is detected by MPU pin 19
through R54, TH1, and R56. The battery
temperature is detected by R45, R46, and NTC,
and measured as A/D value by MPU pin 20.
4-5-7 Charging Voltage Detection
The charging voltage of the battery is detected by
R47 and R48, and measured as A/D value by MPU
pin 18. The parameters, -ßEV, 0 ßEV, and Vmax,
used for checking charge level are also measured
by MPU.
4-5-8 Discharging Circuit
Discharging is available on the rear port only.
When MPU pin 14 acknowledges that the
discharging button is pressed, MPU pin 2 starts
discharging. Discharging is initiated immediately
when the button is pressed for over than 0.7
seconds within 30 seconds after battery installed. If
the voltage reaches 1 V/cell by discharge,
discharging stops, then fast charging starts
automatically.
MPU(3)
MPU(13)
CHG_B
FRNT_GRN
HIGH
LOW
LOW
LOW
LOW
LOW
LOW
HIGH
LOW
LOW
LOW
HIGH
LOW
HIGH
Samsung Electronics
MPU(9)
REAR_GRN
LOW
LOW
HIGH
LOW
HIGH
LOW
HIGH
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