ISL9221IRZ-T Datasheet ISL9221IRZ, ISL9221IRZ-T | P4-P6

FN6541.1

April 3, 2008

Functional Pin Descriptions

VDC

Adapter input pin. This pin is usually connected to adapter

power. The maximum input voltage is 28V. The charge

current from this pin is programmable up to 1.2A by selection

of the resistor on the IVDC pin. When this pin is connected to

a power source, no charge current is drawn from the USB

pin. A 1µF or larger value ceramic capacitor is

recommended for decoupling.

VDC_LDO

Linear regulator output. A 0.1µF to 1µF ceramic capacitor

from this pin to ground is required.

USB_BYP

USB input bypass pin. This is an output from the low current

bypass FET connected to the USB input pin. The USB_BYP

can be connected to the system to provide safe,

voltage-limited power from the USB input pin.

VUSB

VUSB Input pin. This pin is usually connected to a USB port

power connector. The maximum input voltage is 28V.

However, the internal OVP circuitry will trip at 5.4V.

The maximum current drawn from the VUSB pin is the

combination of the load at USB_BYP and the programmed

USB charging current.

A 1µF bypass capacitor is recommended on the VUSB pin.

Higher values of bypass capacitance can be utilized but the

designer should refer to the maximum allowed bus capacitance

per USB application standard. When using ceramic capacitors,

a small resistance value, such as 1 in series with the

capacitor, is recommended to reduce voltage overshoot.

IVDC

Adapter charging current setting pin. A resistor on this pin

sets the maximum charging current to be delivered to the

BAT pin. The maximum current, however, may be reduced

by the adapter’s current limit or by the power dissipation

within the charging IC.

IUSB

USB charge current pin. This pin is connected internally to a

current source for setting the programmed charging current

delivered to the BAT pin.

BAT

Charger IC output pin. This pin is to be connected to the

positive (+) terminal of the battery. The charging IC monitors

this pin to determine the charge state of the battery.

A 1µF bypass capacitor from the BAT pin to ground is

recommended. The charging IC relies on the battery to help

stabilize the circuitry and it is not recommended to operate

the charger IC without a battery connected to this pin.

Enable charging pin. This pin is a logic level input to control

charging by the system processor. An external pull-up

resistor should be connected to processor’s I/O power

supply.

Pin Assignments

NAME PIN TYPE DESCRIPTION

VDC 1 AI Input pin from car adapter or AC/DC adapter

VUSB 2 AI Input pin from USB host device

VDC_LDO 12 AO Output pin of Linear Regulator

USB_BYP 10 AO Output pin from USB bypass circuitry

IVDC 9 AI Battery current setting pin for adapter power

IUSB 7 AI Current setting pin for USB power

IMIN 6 AI End-of-charge current setting pin

BAT 11 AO Output pin to battery

5 DI Active low charge enable pin

PPR

3 OD Active low power present indicator pin

CHG

4 OD Active low charging indication pin

GND 8 G Ground pad

TABLE 1. TYPE CHART

SYMBOL DESCRIPTION

A Analog Pin

D Digital Pin

I Input Pin

O Output Pin

OD Open-Drain

GGround

ISL9221

FN6541.1

April 3, 2008

The USB_BYP and VDC_LDO stay on regardless of the

state of this pin. This ensures that the processor can be

powered up when an external source is connected to the

VDC or VUSB input pin.

PPR

Power presence indication pin. This pin is used to notify the

system processor or enable the power circuitry when a

source is connected. The pin is an open drain output pin,

which pulls low when a valid voltage (above POR) is present

at either the VDC or VUSB pin. The PPR

pin is held low

regardless of the state of the EN

pin. If connected to the

processor, a pull-up resistor should be connected to the

processors I/O supply. If connected to power circuitry, a

pull-up should be tied to the appropriate bypass supply.

CHG

Charge indication pin. This open-drain pin is pulled low to

indicate when the battery is being charged. If connected to

the processor, a pull-up resistor should be connected to the

processors I/O supply.

The CHG

pin can also be used to drive an LED to indicate to

the user the battery is being charged.

GND

Ground pin. This provides the ground path for all internal

circuits.

Typical Application

FIGURE 1. APPLICATIONS CIRCUIT

ISL9221

USB_BYP

IMIN

IUSB

IVDC

VUSB

VDC

VDC_LDO

BAT

GND

I/O_VDD

RIVDC

RIUSB

VDC INPUT

USB INPUT

LDO OUTPUT

TO BATTERY

OFF

USB_BYP

TO MCU

RIMIN

PPR

CHG

ISL9221

FN6541.1

April 3, 2008

Block Diagram

USB Charge Current

When the EN pin is pulled low and a valid USB voltage is

present at the USB pin, the IC will charge the battery at a

rate dependent on the IUSB setting. The charge current

maybe reduced by the USB source if it is set to a value

higher than the current limit of the USB source.

Equation 1 for setting the IUSB current is as follows:

Where R

IUSB

is in k.

The current set by the IUSB pin for charging the battery is in

addition to current drawn by the load on the USB_BYP. The

system designer should consider the maximum expected

USB_BYP load current when selecting the USB charging

current so as not to exceed the current limits set by the USB

standards.

Typically at room temperature, the r

DS(ON)

across the charge

path, VUSB to BAT is 600m. If the entire USB current limit

of 465mA is being supplied to the battery, the drop across

the charging FET could be more than 300mV. Thus, the

voltage at the USB pin needs to be maintained above ~4.5V.

Otherwise, the period to charge the battery may be

prolonged.

Adapter Charge Current

When the EN pin is pulled low and a valid adapter voltage is

present at the VDC pin, the IC will charge the battery at a

rate dependent on the IVDC setting; the charge on the

battery and the source connected to the VDC pin. An

example of this is while the IVDC is set for 1000mA, the

adapter supply may only provide 800mA and the battery is

limited to the 800mA.

Typically the r

DS(ON)

across the charge path, VDC to BAT is

600m. At a 1.0A charging rate, 600mV is dropped across

the charge path. Thus, the voltage at the VDC pin needs to

be maintained above ~4.80V. Otherwise the period to charge

the battery may be prolonged.

Where R

IVDC

is in k.

It is recommended that the maximum charging current be

programmed to between 100mA and 1200mA.

5.4VOVP

VOLTAGE/CURRENT CONTROLLER

THERM

USB_BYP

IMIN

IUSB

IDC

VUSB

VDC

LDO

BAT

PPR

CHG

GND

I/O CNTL

4.35V TO 6.5V

4.35V TO 5.25V

6.8VOVP

1.22V

VDC

VUSB

150/80mV

VOS

2.6V

3.9V

VMIN

VRCH

4.2V

CC/CV

LDO

BYPASS

FIGURE 1. SIMPLIFIED BLOCK DIAGRAM

IUSB

6820

IUSB

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

mA=

(EQ. 1)

IVDC

6820

IVDC

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

mA=

(EQ. 2)

ISL9221

P1-P3 P4-P6 P7-P9 P10-P11

ISL9221IRZ-T

Mfr. #:

Buy ISL9221IRZ-T

Manufacturer:

Renesas / Intersil

Description:

Battery Management DL INPUT LITHIUM ION BATRY CHRGR W/OVP

Lifecycle:

New from this manufacturer.

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ISL9221IRZ-T

ISL9221IRZ-T

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