AIC1761-CN08 AD [Analog Devices], AIC1761-CN08 Datasheet - Page 10

• Manufacturer Part Number: AIC1761-CN08
• Description: BATTERY CHARGE CONTROLLER
• Manufacturer: AD [Analog Devices]

ANALOG INTEGRATIONS CORPORATION
4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C.
The LED indicators work as the following table:
LED pin is used in conjunction with VOUT pin
while FLASH pin works alone.
Referring to the APPLICATION EXAMPLES (Fig.
10), the temperature limits beyond where the fast
charge is prohibited can be set by choosing values
for resistors and the thermistor of the thermistor
divider according to the following formula:
R18 = 3.57 R
R19 = 10 R
R
R
BATTERY VOLTAGE DIVIDER
To ensure proper operation of the AIC1761/1766,
selection of resistor values for battery voltage di-
vider must meet the following two crucial require-
ments:
1. When the battery pack is disconnected from
2. When the battery pack is connected in normal
Take charging a 8-cell battery pack as an example.
The highest voltage would be 16V when fully
charged if the highest voltage of a fully charged
battery cell is assumed to be 2V. Since the VBT
pin voltage is restricted to be no higher than 3.5V,
the battery voltage divider ratio must be higher
than 3.57 (16V/3.5V -1). In other words, resistor
Abnormal
Fast Charge
Trickle
Charge
V
T1
T2
BT
the charge circuitry, the voltage of VBT pin
must be higher than 4.0V or lower than 0.5 V to
put the AIC1761/1766 in reset status, where
VOUT and LED pins become high impedance
and FLASH pin (only for 14 pin version) goes to
high level.
operation, the VBT pin voltage must remain in
the range of 0.8V to 3.5V even when the bat-
tery pack voltage reaches to its peak when
near full charge.
: Thermistor resistance at low temperature
: Thermistor resistance at high temperature
limit.
limit.
T1
T1
R
T2
R
T2
OFF
OFF
/ (1.218 R
LED
PIN
ON
/ (R
T1
-
R
T1
T2
VOUT
-
OFF
OFF
)
PIN
ON
11.2 R
T2
)
FLASH
FLASH
OFF
PIN
ON
VBT
GND
+V
V
BAT
TEL: [phone] FAX:[phone]
IN
0.1 F
Fig. 4 Battery Voltage can be Raised to V
www.analog.com.tw
R14+R13 must be greater than 535K
150K
disconnected from the charging circuitry the VBT
pin voltage must be higher than 4.0V, dictating
V
higher than 18.3V (4V x 4.57). Practically, however,
the charging circuit supply voltage +V
higher than 18.5V in order to ensure proper op-
eration. In the case that supply voltage +V
not meet this requirement, application circuit of Fig.
4 can be adopted to get around this problem.
CHARGER CIRCUIT DESIGN TIPS
1.
2.
BAT
A stable constant charge current is crucial for
reliable precision
AIC1761/1766 since fluctuation of the charge
current can cause fluctuation of the battery
terminal voltage due to battery internal series
resistance, which will likely result in errors
AIC1761/1766.
To prevent the AIC1761/1766 from over-
voltage damage, make sure that none of
AIC1761/1766 pins sees any voltage beyond
the supply voltage, which needs to be be-
tween +9V and +18V.
BATTERY CHARGE CONTROLLER
node voltage of the charging circuitry to be
when being Charged.
(refer to Fig. 4). When the battery pack is
C3
V detection by a properly functioning
150K
R7
150K
150K
R14
R13
R15
390K
9012
Q1
AIC1761/1766
+
4.7 F
C2
V detection by the
SPEC NO: DS-1761-02
27K
R2
0.1 F
C1
IN
270K
R3
should be
if R15 is
R5
IN
IN
9012
Q2
10
- 0.9V
can
270K