ICS1722 datasheet(9/24 Pages) GALAXY

9 / 24 page

ICS1722

Pin Descriptions

The ICS1722 requires some external components to control the

clock rate 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 Pins

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 mode

as shown in Table 2.

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.

The maintenance mode (MMN) indicator is on when the

ICS1722 is either in the topping charge, maintenance charge, direct

maintenance mode, or the condition mode. 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 ICS1722 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.

Charge Rate Selection: SEL0, SEL1 Pins

The SEL0 and SEL1 inputs must be programmed by the user to

inform the ICS1722 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 VDD. The voltage

ranges for low (L), open (Z) and high (H) are listed in Table 6, DC

Characteristics. To program the SEL0 and SEL1 inputs, refer to

the Charge Rate List in Table 3.

The ICS1722 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.

Table 2: Indicator Description List

PFN

MMN

CMN

Description

Polling mode or battery fault

Maintenance or topping charge, direct maintenance or condition mode

Fast charge

Flash

Discharge portion of the discharge-to-charge or discharge-only mode

Flash

See Applications Information

Flash

See Applications Information

Fast Charge (See Applications Information)

ICS1722 Scheda tecnica(PDF) 9 Page - Galaxy Power, Inc.

ICS1722 Scheda tecnica(HTML) 9 Page - Galaxy Power, Inc.

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Scheda tecnica Scarica

Link URL