aic1761 Analog Devices, Inc., aic1761 Datasheet - Page 7

• Manufacturer Part Number: aic1761
• Description: Battery Charge Controller
• Manufacturer: Analog Devices, Inc.

ANALOG INTEGRATIONS CORPORATION
4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C.
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:
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:
V
GND
Floating
TIMER
DD
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.
Pin
160 min.
40 min.
80 min.
Safety
Timer
Peak Volt-
age Timer
2 min.
4 min.
8 min.
Initial Timer
1.5 min.
3.0 min.
3.0 min.
Fig. 2 Operation Chart of the AIC1761/1766
NO
TEL: [phone] FAX:[phone]
www.analog.com.tw
- V detector &
peak voltage timer
working.
- V decline of VBT
- V detector &
peak voltage timer
start working after
initial period ends.
V
fast charge,
safety timer starts
counting.
V
OUT
OUT
is detected.
BATTERY CHARGE CONTROLLER
goes low for
goes to high, fast charge finished, and trickle charge start.
If
YES
YES
NO
& NTC> NTCH
0.65V<V
& NTC> NTCH
Power ON
NTCL> NTC
0.65V<V
safety timer period
period has finished.
peak voltage timer
NTCL> NTC
has finished.
AIC1761/1766
If
If
BT
If
YES
If
If
BT
<3.7V
If
YES
YES
NO
<3.7V
SPEC NO: DS-1761-02
NO
NO
NO
NO
V
trickle charge,
safety timer and
- V detector reset.
V
trickle charge ,
- V detector reset,
safety timer stops.
YES
V
for trickle charge,
Safety Timer and
- V Detector
reset
V
for trickle
charge, - V
detector reset,
safety timer
stops.
YES
OUT
OUT
OUT
OUT
goes high for
goes high for
goes high
goes high
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