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XC6803 Series
■OPERATIONAL EXPLANATION
●Charge Function
Ｉ
ＢＡＴ
≦C x 0.1ｍＡ under 5 hrs
Charging start
When a thermistor is connected to the THIN pin after a voltage is applied to the power input pin (①), or when a voltage is applied to the
power input pin after a thermistor is connected to the THIN pin (②), the power on reset function activates and initializes the internal counter.
After 200 ms elapse in the case of ①, or 150 ms in the case of ②, charging starts.
Trickle charging: Less than 0.5 hour
Trickle charging determines if main charging of the Li-ion battery is possible. The Li-ion battery is charged at a trickle charge current that
is one-tenth the charge current set with the external resistor RISET. If the BAT pin voltage VBAT is above 2.9 V in the charging start state,
trickle charging takes place for 1ms and then main charging begins. If VBAT is less than 2.9 V, trickle charging takes place, and main
charging begins 50ms after 2.9 V is reached. If the BAT pin voltage is less than 2.9 V after 0.5 hours, the IC changes to the error state and
stops charging the Li ion battery. In addition, the error in the trickle charge current increases if V
BAT
drops below about 1V.
Main charging: Less than 5 hours
When the condition for transition from trickle charging is satisfied, it is determined that rapid charging of the Li-ion battery is possible and
the IC changes to the main charging state. In main charging, the IC charges an Li-ion battery at a CC charge current that is set with the
external resistor R
ISET
. If the BAT pin voltage V
BAT
rises to the CV charge voltage V
BAC
within 5 hours, the charge current drops to the charge
completed current, and after 50 ms elapse, the state changes to charge completed and charging stops. If the charge current is higher than
the charging completed current after 5 hours, the IC changes to the error state and stops charging.
Charging completed
When 50 ms elapse after the charge current drops from the main charging state to the charge completed current, which is one-tenth the
charge current set with the external resistance R
ISET
, the state changes to charge completed and charging of the Li ion battery stops. At this
time, the charge status output pin changes from ON to OFF. On the XC6803xxE, when the BAT pin voltage (V
BAT
) falls from the charge
completion state to the recharge voltage (V
RCHG
) or less, charging automatically restarts. When a voltage is reapplied to the power input pin
or a Li-ion battery is reconnected to the BAT pin, the IC starts up and charging begins.
Error state
If it is determined that charging is abnormal in any state, the IC treats this as an error state and stops charging. When the power is turned
off and then on, or the battery is reinserted, the IC starts up again and chaging starts. An error state occurs if 0.5 hours elapse during trickle
charging, if 5 hours elapse during main charging, or if thermal shutdown, charging over-voltage, or charging over-current is detected.
●Charging status output pin CSO
The charge status output pin is ON during trickle charging and main charging with Nch open drain output, and turns OFF when charging
is completed. A LED can be connected to allow confirmation of charging by illumination of the LED. When an error state is detected, the
charge status output pin repeats ON-OFF at 1kHz on the XC6803A and turns OFF on the XC6803B.
An error state indicates a state in
which 0.5 hours have elapsed during trickle charging, 5 hours have elapsed during main charging, the thermal shutdown or charging
over-voltage or charging over-current is detected.
●Charge current
The charge current I
BAT
of this IC can be set within the range 40mA to 280mA with the external resistance R
ISET
. The relation between
R
ISET
and I
BAT
is approximated by the equation below.
R
ISET
(kΩ) = 6620 x I
BAT
-1.136
(mA)
(*1)
The XC6803xxD does not have a recharge function.
