10

FN6435.0

February 25, 2008

VOUT is regulated at 4.5V, the charger is ON, delivering a

trickle charge current.

The IC moves to a fast charge constant current mode when

VBAT reaches the VMIN threshold. There are 3 possible

states in this mode depending on the output current. When

the sum of the output current and the fast charge current is

smaller than the input current limit, the IC enters the Fast

output current and the fast charge current are greater than

the input current limit, the IC will enter the PPM mode, where

the charging current is reduced to a point such that the sum

of output current and the charging current equals to the input

current limit. If the output current by itself is greater than the

input current limit, the IC enters the Battery Discharge state,

where the battery is discharged to the system to supply a

part of the output demand.

When the battery voltage reaches 4.2V, the IC enters the CV

Charge state, where PPR is LO, CHG is LO and VOUT is

regulated at 4.5V. The battery is being charged at a constant

voltage while the charging current decreases.

When the charging current is reduced to the IMIN threshold,

the IC enters a Charge Complete state, where PPR is LO,

CHG is HI, VOUT is regulated at 4.5V and the charger

continues to charge the battery.

When the timeout interval has elapsed after the Charge

Complete state, the IC will enter the Disabled state, where

the PPR is LO, CHG is HI, VOUT is regulated at 4.5V and

the charger is OFF. After the Charge Complete state, if VBAT

is below the re-charge threshold, the IC will re-initialize and

start a new cycle.

If the timeout limit is reached before the Charge Complete

state, the IC enters the Charger Fault state, where PPR is

LO, CHG is blinking, VOUT is regulated at 4.5V and the

charger is OFF. This state is latched until the input power is

removed and re-applied to start a new cycle.

Any time during the operation, if the die temperature reaches

the OTP threshold, the IC will enter the OTP state, where

PPR is LO, CHG is HI, and the charger is OFF. VOUT is

disconnected from VIN and connected to VBAT internally to

maintain system power need.

Summary of Output States

The output states under various fault conditions are

summarized in Table 1.

TABLE 1. OUTPUT STATES UNDER FAULT CONDITIONS

OTP

OVP

BATON

M1

M2

Y

Y

H

OFF

ON

Y

N

H

OFF

ON

N

Y

H

OFF

ON

Y

Y

L

OFF

OFF

Y

N

L

OFF

OFF

N

Y

L

OFF

OFF

N

N

X

Regulating

Charging

NOTES:

BATON: BATON Pin

OVP: Input Over Voltage Protection

OTP: Over Temperature Protection

M1: Output Path MOSFET

M2: Battery Path MOSFET

ISL9301