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XC6805 Series
■OPERATIONAL EXPLANATION (Continued)
●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 elapses during trickle
charging, if 5 hours elapses during main charging, or if thermal shutdown, 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. If an abnormal condition is detected, the charge status output pin repeats ON-OFF at 1kHz on the XC6805A, and turns off on the
XC6805B.
●Charge current
The set charge current of the IC, I
CHG
, can be set within the range 5mA to 40mA by an external resistance (R
ISET
).
The R
ISET
and I
CHG
are approximated by the following equation.
R
ISET
(kΩ)=351 x I
CHG
-1.11
(mA)
●IC temperature monitoring function
In order to prevent destruction due to IC heat generation as well as abnormal charging due to thermal runaway, a thermal shutdown
circuit is incorporated into the IC. If the chip temperature rises to 140°C or higher and after 50ms elapses, the output driver is turned off and
charging is stopped. At this time, the charge status output pin repeats ON-OFF at 1kHz on the XC6805A, and turns off on the XC6805B.
When voltage is reapplied to the power input pin or the Li-ion battery is reconnected to the BAT pin, the IC starts and charging begins.
●Dropout voltage monitoring function
To prevent reverse current from the Li-ion battery to the battery charger, this function monitors the dropout voltage between the BAT pin
voltage (V
BAT
) and power input pin voltage (V
IN
). When the V
IN
falls to VBAT +40mV, the function turns off the output driver and switches the
backgating connection of the driver from the power pin to the BAT pin. When V
IN
rises higher than V
BAT
+0.1V, this function is released, the
output driver turns ON, and the driver backgate connects to the power pin and charging resumes. In addition, this function continues the
t
CHG
count even when charging is stopped, and the charge status output pin maintains the ON state. After charging is completed, the charge
status output pin remains off even if the function activates due to the input power being removed or otherwise.
●UVLO function
A UVLO function is incorporated. If the power input pin falls to 3.8V or lower during charging, this function turns off the output driver and
stops charging.
In addition, charge status output pin changes to OFF. When the power input pin rises to 4V or higher, the IC starts up
and charging begins. This function also detects voltage application to the power input pin.
●Charge over-voltage monitoring function
This function stops charging to prevent charging the over-voltage battery if the BAT pin voltage is 4.45V or higher and after 50ms elapses. At
this time, the charge status output pin repeats ON-OFF at 1kHz on the XC6805A, and turns off on the XC6805B. When voltage is reapplied to
the power input pin or the Li ion battery is reconnected to the BAT pin, the IC starts and charging begins.
(*1)
●Charge over-current monitoring function
To prevent charging of a battery by excessive current, this function stops charging if the charge current rises to 110mA or higher and after
50ms elapses. At this time, the charge status output pin repeats ON-OFF at 1kHz on the XC6805A, and turns off on the XC6805B.
When voltage is reapplied to the power input pin or the Li ion battery is reconnected to the BAT pin, the IC starts up and charging begins.
(*1)
●Recharge function
With the completion of charging, when the NTC thermistor temperature is 0°C or higher and less than 45°C, and the BAT pin voltage (V
BAT
)
falls to 3.9V or less, charging resumes. (charging is resumed 150ms after the charge start state is entered).
On the XC6805xx4, if the NTC thermistor temperature is 0°C or higher, less than 45°C and BAT pin voltage(V
BAT) drops less than 3.9V,
charging automatically resumes. If the NTC thermistor temperature is 45°C or higher and less than 60°C, charging automatically resumes
when the voltage falls to 3.75V or less.
(*1)
Insertion and removal of the battery is detected by thermistor connection (THIN pin voltage). For this reason, restarting of the IC is not
possible by battery reinsertion on the XC6805xN, as the THIN voltage is fixed to the internal IC. When voltage is reapplied to the power input
pin, the IC starts up and charging begins.
