4

FN6435.0

February 25, 2008

Block Diagram

Pin Descriptions

VIN - Power input. The absolute maximum input voltage is

28V. A 10µF or larger value capacitor is recommended to be

placed very close to the input pin for decoupling purposes.

Additional capacitance may be required to provide a stable

input voltage.

VBAT - Charger output pin. Connect this pin to the battery. A

1µF or larger X5R ceramic capacitor is recommended for

decoupling and stability purposes. When the BATON pin is

pulled to logic LOW or left floating, the VBAT pin is

disconnected from the IC.

TIME - Timing resistor pin. The TIME pin determines the

oscillation period by connecting a timing resistor between

this pin and GND. The oscillator also provides a time

reference for the charger calculated in Equation 1.

by Equation 2:

timeout interval is approximately 5.6 hours.

PPR - Open-drain power presence indication. The

open-drain MOSFET turns on when the input voltage is

above the POR threshold but below the OVP threshold and

off otherwise. This pin is capable to sink 10mA (minimum)

current to drive a LED. The maximum voltage rating for this

pin is 7V.

CHG - Open-drain charge indication pin. This pin outputs a

logic LOW when a charge cycle starts and turns to HIGH

when the end-of-charge (EOC) condition is qualified. This

pin is capable to sink 10mA min. current to drive an LED.

When the charger is disabled, the CHG outputs high

impedance.

IMIN - End-of-charge (EOC) current program pin. Connect a

resistor between this pin and the GND pin to set the EOC

current. The EOC current IMIN can be programmed by

Equation 3:

(or 10mA, whichever is higher) to 50% of IREF when

programmed to less than 5% or 10mA.

Cell1

CHG

IBAT_REF

VBAT_REF

VOUT_REF

VBAT

IREF

VOUT

1V

Die Temp

142 oC

Die Temp

VBAT

VIN

1

1000

1

1000

PPR

IBAT

POR

Timer

EOC

Re-charge

OVP

DispIay

Logic

To system load

CLK

SHUTDOWN

TIME

0.2V

VIN

VBAT

115 oC

VBAT

IBAT

ILIM_REF

VCC

COMP

COMP

Q

S

R

VOUT

IMIN

GND

SHUTDOWN

PPM CTRL

IOUT

IOUT

To uP

RILIM

t

OSC

75

R

TIME

×μs

()

=

(EQ. 1)

t

TIMEOUT

2

28

t

OSC

×

3600

-----------------------------

Hour

()

=

(EQ. 2)

I

MIN

3151

R

IMIN

----------------

mA

()

=

(EQ. 3)

ISL9301