AIC1761 Datasheet, PDF (7/15 Pages) Analog Devices – BATTERY CHARGE CONTROLLER

The AIC1761/1766 constantly monitors the voltage
at VBT pin, which rises as battery cells are being
fast-charged till battery full condition is nearly ap-
proached. The battery temperature is also con-
stantly being sensed to guard against abnormal
temperature situations. VOUT pin will be pulled high
by an external pull-up device and the fast charge
process be switched to trickle charge when one of
the following situations is encountered:
A negative delta voltage (-∆V) at VBT pin is de-
tected when compared to its peak value. The
sampling rate of -∆V detection is 2seconds/
sample. The detection level of -∆V is -1% for the
AIC1761 and -0.25% for the AIC1766.
The battery voltage stays at its peak value for
the duration determined by the peak voltage
timer setting (0∆V).
The VBT pin voltage exceeds the “high” battery
voltage protection limit (VCO).
The battery temperature, sensed by the ther-
mistor divider, exceeds the fault temperature
range (TCO).
The selected safety timer period has finished.
TIMER PIN
The TIMER pin can be used as follows to select
one of the preset safety timer period and its cor-
responding periods of initial timer and peak volt-
age timer:
TIMER
Pin
V_DD
GND
Floating
Safety
Timer
40 min.
80 min.
160 min.
Peak Volt- Initial Timer
age Timer
2 min. 1.5 min.
4 min. 3.0 min.
8 min. 3.0 min.
AIC1761/1766
BATTERY CHARGE CONTROLLER
SPEC NO: DS-1761-02
Power ON
If
0.65V<V_BT<3.7V
V_OUT goes high for
trickle charge,
safety timer and
NO ^{-∆V detector reset.}
V_OUT goes low for
fast charge,
safety timer starts
counting.
YES
YES
If
αNTCL>αNTC
& αNTC>αNTCH
NO
V_OUT goes high for
trickle charge ,
-∆V detector reset,
safety timer stops.
-∆V detector &
peak voltage timer
start working after
initial period ends.
-∆V detector &
peak voltage timer
working.
If
αNTCL>αNTC
& αNTC>αNTCH
NO
YES
V_OUT goes high
for trickle
charge, -∆V
detector reset,
safety timer
stops.
If
0.65V<V_BT<3.7V
YES
V_OUT goes high
for trickle charge,
NO ^{Safety Timer and}
-∆V Detector
reset
If
safetytimer period
has finished.
YES
NO
If
If
-∆V decline of VBT
NO
is detected.
NO
peak voltage timer
period has finished.
YES
YES
V_OUT goes to high, fast charge finished, and trickle charge start.
Fig. 2 Operation Chart of the AIC1761/1766
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