ICS1702 Galaxy Power, Inc., ICS1702 Datasheet - Page 11

• Manufacturer Part Number: ICS1702
• Description: 20 Pin Quicksaver Full-featured Charge Controller For Ni-cd & Ni-mh Batteries.
• Manufacturer: Galaxy Power, Inc.

Pin Descriptions
The ICS1702 requires some external components to control the
clock rate, sense temperature and provide an indicator display. The
controller must be interfaced to an external power source that will
provide the current required to charge a battery pack and, if
desired, a circuit that will sink discharge current.
Output Logic Signals: CHG, DCHG Pins
The CHG and DCHG pins are active high, TTL compatible
outputs. In addition to being TTL compatible, the CMOS outputs
are capable of sourcing current which adds flexibility when
interfacing to other circuitry. A logic high on the CHG pin
indicates that the charging current supply should be activated. If
applicable, a logic high on the DCHG pin indicates that the
discharge circuit should be activated.
Care must be taken to control wiring resistance and inductance.
The load resistor must be capable of handling this short duration
high-amplitude pulse. If the auxiliary discharge-to-charge mode is
selected, the power dissipation of the load resistor must be properly
selected to accept the extended length of the discharge pulse.
Indicators: CMN, MMN, PFN, OTN Pins
The controller has four outputs for driving external indicators.
These pins are active low. The four indicator outputs have open
drains and are designed to be used with LEDs. Each output can
sink over 20mA which requires the use of an external current
limiting resistor. The four indicator signals denote fast charge
stage, topping and maintenance stages, and the polling detect and
out-of-temperature range modes as shown in Table 3.
The charge mode (CMN) indicator is activated continuously during
the soft start and fast charge stages. When the controller enters the
topping charge stage, the output goes high and the indicator turns
off.
PFN
on
MMN
flash
flash
flash
on
on
CMN
flash
flash
on
on
Table 3: Indicator Description List
OTN
on
on
on
on
Polling detect mode
Maintenance or topping charge, direct maintenance or condition mode
Fast Charge
Hot battery shutdown
Cold Battery Charge
Discharge portion of the discharge-to-charge or discharge-only mode
see Applications Information
see Applications Information
see Applications Information
see Applications Information
11
The maintenance mode (MMN) indicator is on when the ICS1702
is either in the topping charge, maintenance charge, direct
maintenance mode, or the condition mode. The MMN indicator is
also lit in conjunction with the OTN indicator when cold battery
charging is in progress. The maintenance mode indicator flashes at
a one second rate when the ICS1702 is controlling the discharge
portion of the discharge-to-charge or the discharge-only mode.
The polling detect (PFN) indicator is on when the ICS1702 polls
for a battery. The controller applies periodic charge pulses to detect
the presence of a battery. The indicator is a warning that these
charge pulses are appearing at the charging system terminals at
regular intervals. When a battery is detected, the indicator is turned
off.
The out-of-temperature range (OTN) indicator is active whenever
the voltage at the temperature sense (THERM) input enters a range
that indicates that the attached battery is too hot to charge. The
OTN indicator is also activated with the MMN indicator if the
controller is initialized with the battery in the cold battery charge
region.
Charge Rate Selection: SEL0, SEL1 Pins
The SEL0 and SEL1 inputs must be programmed by the user to
inform the ICS1702 of the desired charge rate. When left
unconnected (open), these tri-level pins will float to about 2.3V.
When a low level is required, the pin must be grounded. When a
high level is required, the pin must be tied to V
ranges for low (L), open (Z) and high (H) are listed in Table 10,
DC Characteristics. To program the SEL0 and SEL1 inputs, refer
to the Charge Rate List in Table 4.
The ICS1702 does not control the current flowing into the battery
in any way other than turning it on and off. The required current
for the selected charge rate must be provided by the user’s power
source. The external charging circuitry should provide current at
the selected charge rate. For example, to charge a 1.2 ampere hour
battery in 30 minutes (2C), approximately 2.4 amperes of current is
required.
Description
ICS1702
DD
. The voltage