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XC6804
Series
■ OPERATIONAL EXPLANATION
<Charging function>
● 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 200ms elapses in the case of ①, or 150ms in the case of ②, charging starts.
● Trickle charging: Less than 2 hours
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 R
ISET
. If the BAT pin voltage V
BAT
is above 2.9V in the charging start state,
trickle charging takes place for 1ms and then main charging begins. If V
BAT
is less than 2.9V, trickle charging takes place, and main charging
begins 50ms after 2.9V is detected. If the BAT pin voltage is less than 2.9V after 2 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 10 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 a Li-ion battery at a CC charge current that is set with the
external resistor R
ISET
. When the BAT pin voltage rises to the CV charge voltage in less than 10 hours and the charge current drops to the
charging completed current, and after 50ms elapses,the IC changes to the charging completed state and charging stops. If the charge
current is higher than the charging completed current after 10 hours, the IC changes to the error state and stops charging.
● Charging completed
When the charge current reaches the charge completion current, which is one-tenth the charge current set with the external resistor R
ISET
,
and after 50 ms elapses, the IC changes to charging completed and stops charging the Li-ion battery.
At this time, the charge status output
pin changes from ON to OFF.
On the XC6804xxE, 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 in the charging completed state, the IC starts 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 gain and starts charging. An error state occurs if 2 hours elapses during trickle
charging, if 10 hours elapses during main charging, or if charging overvoltage or charging overcurrent is detected.
● Charging status output pin, CSO
The charge status output pin turns ON by Nch open drain output during trickle charging and main charging, and turns OFF after charging
is completed. An LED can be connected to enable confirmation of charging by illumination of the LED. If an abnormal condition is detected,
the charge status output pin repeats ON-OFF at 1kHz on the XC6804A, and turns off on the XC6804B. An error state indicates a state in
which 2 hours have elapsed during trickle charging, 10 hours have elapsed during main charging,or charging over-voltage or charging
over-current is detected.
● Charge current
The charge current I
CHG
of this IC can be set in the range 200mA to 800mA by means of the external resistance R
ISET
. The relation
between R
ISET
and I
CHG
is approximated by the equation below.
R
ISET
(kΩ) = 15950 x I
CHG
-1.122
(mA)
(*1)
The XC6804xxD does not have the recharge function.
V
BAT
≧2.9V under 2 hrs
Charge Start
Trickle Charge：
2 hrs
Main Charge：
10 hrs
Completed Charge
Ｉ
ＢＡＴ
≦C x 0.1ｍＡ under 10 hrs
Re-attached Battery or Re-input Power Supply
or
Ｖ
ＢＡＴ
≦3.9Ｖ
Abnormal Mode
Re-attached Battery or Re-input Power Supply
V
BAT
＜ 2.9V under 10 hrs
