AIC1782
Dual-Battery Charge Controller
Analog Integrations Corporation 4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC www.analog.com.tw
DS-1782-00 TEL: 886-3-5772500 FAX: 886-3-5772510 1
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FEATURES
tensans Quick and Easy Testing for Production.
tensans Sequential Charging Control of Two
NiMH/NiCd Battery Packs.
tensans Reliable Sequential Fast Charge Control of
Dual NiMH and/or NiCd Battery Packs, even
with a Fluctuating Charging Current.
tensans Fast Charge Termination by: ∆∆T / t, −∆V,
0V∆ , Safety Timer, Maximum Temperature,
Maximum Voltage.
tensans Safety Timer and ∆∆T / t Detection Slope
Linearly Adjustable.
tensans Battery Voltage Protection Range Selectable.
tensans Mode of Battery Temperature Protection Se-
lectable.
tensans Protection against Battery Voltage and Battery
Temperature Faults.
tensans Selectable LED Display Mode for Battery
Status.
tensans Five Pulsed Trickle Charge Modes.
tensans Discharge-before-Charge Function Available to
Eliminate Memory Effect.
tensans 20-pin DIP or SO Packages.
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APPLICATIONS
Dual-Battery Fast Chargers for:
tensans Mobile Phones.
tensans Notebook and Laptop Personal Computers.
tensans Portable Power Tools and Toys.
tensans Portable Communication Equipments.
tensans Portable Video & Stereo Equipments.
0 10 20 30 40 50 60
1.15
1.25
1.35
1.45
1.55 100
80
60
40
20
T
e
m
p
er
atur
e (
°
C)
Charge Current = 600mA
Cell Capacity = 550mA
NiMH Battery
Cell Voltage
C
e
l
l
V
o
l
t
age (
V
)
Charge Time (min.)
Temperature
Fig. 1 Battery Charging Characteristics Resulted from
an AIC1782-Controlled Charger with a Fluc-
tuating Charging Current
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DESCRIPTION
The AIC1782 fast charge controller is designed
for intelligent sequential charging of dual NiMH
and NiCd batteries without the risk of malfunction.
After powered on, the AIC1782 charging se-
quence gives priority to battery pack A, repre-
sented by input signals of ATS and ABV pins,
over battery pack B, represented by BTS and
BBV pin signals. The AIC1782 automatically
switches charging current to charge the standby
battery pack after the battery pack being charged
finishes its charging or encounters a fault condi-
tion. −∆V (-0.25%) detection, 0V∆ (peak voltage
timer) detection, and ∆∆T / t detection are the
primary methods employed by the AIC1782 to
terminate fast charge. The fast charge can also
be cut off by maximum battery voltage and
maximum battery temperature detection along
with the safety timer to prevent charging under
fault conditions of the charging system or the
battery itself.
Both ∆∆T / t and −∆V detection methods have
been proved powerful in terminating fast charging
for NiMH and NiCd batteries. The AIC1782 utilizes
the combination of these two methods to achieve
reliable decision of ending fast charge and prevent
misaction caused by using −∆V detection alone
under certain conditions. Fig. 1 shows an example
of charging curve of a battery charged by a fluc-
tuating current from a NiMH battery charger which
uses the AIC1782 controller IC to achieve optimal
charging. The ∆∆T / t or −∆V detection circuitry
may be disabled independently for different appli-
cations, such as system-integrated chargers,
chargers with varying charge current, or battery
packs lack of temperature sensing thermistor.