
ICS1708
QuickSaver Charge Control IC for Nickel-Cadmium
and Nickel-Metal Hydride Batteries
General Description
The
ICS1708
is a low cost 8 pin CMOS control IC for the intelligent charging of either nickel-cadmium (NiCd) or nickel-metal hydride
(NiMH) batteries. The
ICS1708
uses a pulsed-current charging technique together with multiple voltage slope termination methods. The
ICS1708
employs a four stage charge sequence that provides a complete recharge without overcharging. The controller has three (3) user
selectable charge rates, user accessible clock, and two (2) charge status output pins. On power-up, the
ICS1708
monitors for the presence of
a battery and begins charging. The
ICS1708
is for applications where battery temperature protection is not required of the charge controller.
Applications
Embedded and charger stands for: Portable consumer products, Power tools, Audio/video products, Communications products, RC toys,
and Wireless products
Features
Charge termination methods include: Voltage slope (+
V
/dt and +/- peak detect), and Fast charge time out to maintenance mode
Four stage charge sequence:
SoftStart
conditioning, Fast charge, Topping charge, and Maintenance charge
Three (3) user selectable charge rates: 15 minutes (4C), 60 minutes (1C), 150 minutes (C/2.5)
Continuous polling mode for battery detection
Adjustable open circuit (no battery) voltage reference
Benefits
-compared to other methods
Peak battery performance and extended cycle life
Improved battery efficiency and reliability
Lower internal resistance build-up
Lower capacity fade
Block Diagram
CURRENT
SOURCE
BATTERY
VOLTAGE
SENSE
OPEN CIRCUIT
REFERENCE
VOLTAGE
PROCESSOR
MICROCODE CONTROL
ADC
RAM
ROM
OUTPUT
CONTROL
0.5V
FAST
CHARGE
CHARGE
COMPLETE
RC (CLOCK)
OSCILLATOR