AIC1781A
Battery Charge Controller
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FEATURES
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DESCRIPTION
The AIC1781A fast charge controller IC is
designed for intelligent charging of NiMH or NiCd
batteries without the risk of overcharge.
−∆V
Detection
(-0.25%), 0
∆
V detection (peak
voltage timer) and
∆
T /
∆
t detection are the
primary methods employed by the AIC1781A 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 AIC1781A
utilizes the combination of these two methods to
achieve reliable decision of ending fast charge and
prevent misacting caused by using
−∆V
detection
alone under certain conditions. Fig. 1 shows an
example of charging curve of a battery charged by
a fluctuating current from a NiMH battery charger,
which uses the AIC1781A controller IC to achieve
optimal charging. This technique, in cooperating
with the 0
∆
V detection (peak voltage timer), is
particularly suitable for NiMH batteries, whose
voltage drop is hardly significant yet temperature
rises rapidly. The
∆
T /
∆
t or
−∆V
detection
Temperature (°C)
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Fast Charge Control of NiMH/NiCd Batteries,
even with a Fluctuating Charging Current.
Fast Charge Termination by:
∆
T /
∆
t ,
−∆V
,
0
∆
V , Safety Timer, Maximum Temperature,
Maximum Voltage.
Linearly Adjustable
∆
T /
∆
t Detection Slope and
Safety Timer.
Adjustable Peak Voltage Timer for 0
∆
V .
Battery Voltage Protection Range Selectable.
Selectable Battery Temperature Protection
Mode.
Protection against Battery Voltage and Battery
Temperature Faults.
Selectable LED Display Mode for Battery Status.
Five Pulsed Trickle Charge Modes.
Discharge-before-Charge Function Available for
Eliminating Memory Effect.
Quick and Easy Testing for Production.
16-pin DIP or SO Packages.
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APPLICATIONS
Battery Fast Chargers for:
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Mobile Phones.
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Notebook and Laptop Personal Computers.
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Portable Power Tools and Toys.
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Portable Communication Equipments.
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Portable Video & Stereo Equipments.
1.55
100
Charge Current = 600 mA
Cell Capacity = 550 mA
NiMH Battery
Cell Voltage (V)
1.45
80
circuitry
may
be
disabled
independently
for
Cell Voltage
1.35
60
different applications, such as system-integrated
chargers, chargers with varying charge current, or
battery
packs
lack
of
temperature
sensing
thermistor.
1.25
40
Temperature
1.15
20
0
10
20
30
40
50
60
Charge Time (min.)
The
safety
timer
period,
mode
of
battery
temperature protection, battery voltage protection
Fig. 1
Battery Charging Characteristics Resulting from
an
AIC1781A-Controlled
Charger
with
a
Fluctuating Charging Current
Analog Integrations Corporation
range, pulsed trickle charge duty, and LED display
mode
are
all
adjustable
or
selectable.
011604
4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan
TEL: 886-3-5772500
FAX: 886-3-5772510
www.analog.com.tw
DS-1781AP-01
1
AIC [ ANALOG INTERGRATIONS CORPORATION ]
