AIC1784
Battery Charge Controller
FEATURES
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.
Protection against Battery Voltage and Battery
Temperature Faults.
Pulsed Trickle Charge Modes.
Quick and Easy Testing for Production.
8-pin DIP or SO Packages.
DESCRIPTION
The AIC1784 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 AIC1784 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 AIC1784 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 AIC1784 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 safety timer period is adjustable. Test mode is
provided for charger manufactures to dramatically
reduce production test time.
APPLICATIONS
Battery Fast Chargers for:
Mobile Phones.
Notebook and Laptop Personal Computers.
Portable Power Tools and Toys.
Portable Communication Equipments.
Portable Video & Stereo Equipments.
1.55
100
Charge Current = 600 mA
Cell Capacity = 550 mA
NiMH Battery
Cell Voltage
1.35
60
1.25
40
Temperature
1.15
0
10
20
30
40
50
60
20
Charge Time (min.)
Fig. 1 Battery Charging Characteristics Resulting from
an
AIC1784-Controlled
Charger
with
a
Fluctuating Charging Current
Analog Integrations Corporation
Si-Soft Research Center
3A1, No.1, Li-Hsin Rd. I , Science Park , Hsinchu 300, Taiwan , R.O.C.
TEL: 886-3-5772500
FAX: 886-3-5772510
www.analog.com.tw
Temperature (°C)
Cell Voltage (V)
1.45
80
DS-1784G-01
121708
1
AIC [ ANALOG INTERGRATIONS CORPORATION ]
