ICS1712
Indicators: CMN, PFN, OTN Pins
Pin Descriptions
The controller has three outputs for driving external indicators.
These pins are active low. The three 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 three indicator signals denote fast charge
stage, topping and maintenance stages, and the polling detect or
battery fault and out-of-temperature range modes as shown in
Table 2.
The ICS1712 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.
The charge mode (CMN) indicator is activated continuously during
the soft start and fast charge stages. The CMN indicator flashes at a
one-second rate when the ICS1712 is applying a topping or
maintenance charge.
The polling fault (PFN) indicator is on when the ICS1712 polls for
a battery for the first 10 seconds. 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 indicator is also active if the battery
is removed from the system, warning that a fault has occurred.
Care must be taken to control wiring resistance and inductance.
The load resistor must be capable of handling this short duration
high-amplitude pulse.
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 CMN indicator if the
controller is initialized with the battery in the cold battery charge
region.
Table 2: Indicator Description List
PFN
On
CMN
OTN
Description
Polling mode or battery fault
Flash
On
Maintenance and topping charge
Fast charge
On
On
on
Hot battery shutdown
Cold battery charge
See Applications Information
See Applications Information
Flash
On
One flash
On
10
GALAXY [ GALAXY POWER, INC. ]
