6

FN9180.1

January 4, 2006

CHG (Pin 4)

Charge indication pin. When the charge current from the

cradle input during the constant current mode falls to below

8% of the programmed reference current by the ICDL pin or

the charge current from the USB input is below 10% of the

programmed charge current, the open-drain MOSFET is

turned off. The pin will be pulled to logic HIGH by an external

resistor to indicate the End Of Charge.

EN (Pin 5)

Enable logic input. Connect to LOW or leave floating to

enable the charger.

IUSB (Pin 6)

The IUSB pin programs the USB charge current. This pin is

regulated to 0.8V. The current flowing out of this pin is

mirrored to the USB charge current control reference. When

the USBP pin is connected to logic HIGH, the typical USB

charge current can be found as:

thus the USB current has a nominal value ranging from

350mA to 450mA.

When the USBP pin is driven to logic LOW, the charge

current is approximately 1/5 of the above value.

USBP (Pin 7)

USB port selection logic input. When this pin is left floating or

driven to logic LOW, the USB port is regarded as a

low-power port, in such case the charge current is 100mA

maximum. When this pin is driven to logic HIGH, the USB

port is considered a high-power port, and the charge current

is 500mA maximum. The ratio of the charge current when

this pin is HIGH or LOW is fixed at approximately 5:1.

GND (Pin 8)

System ground.

ICDL (Pin 9)

The ICDL pin has two functions. The first function is to

program the cradle charge current during the constant-

current phase. The voltage of this pin is 1.20V during the

constant-current phase of the cradle input charger. The

constant-current is programmed by the following equation:

Typical Application). The ratio is given by the following table

and curve.

It is recommended that the charge current be programmed

in the range of 300mA to 1A.

The second function of the ICDL pin is to monitor the actual

cradle charger. When the cradle charger or the USB charger

is working with USBP connected to logic HIGH, the ICDL pin

voltage is given by the following equation:

where the ratio has the same value given in Table 1.

The cradle charge current should be programmed equal or

higher than the USB current; otherwise, the ICDL pin voltage

will be higher than 1.20V during the constant current phase

when the USB charger is working. The charger still works

properly but the accuracy of the current monitoring voltage

degrades and saturates at approximately 2.1V.

When the USB charger is working with the USBP pin

connected to logic LOW, the ICDL pin voltage is

approximately five times of the above equation.

BAT (Pin 10)

Charger output pin. Connect this pin to the battery pack or

the battery cell. A 1µF or larger value ceramic capacitor is

recommended for decoupling. The charger relies on the

battery for stability so a battery should always be connected

to the BAT pin.

45000

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

45000

0.8V

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

×

A

()

=

⋅

=

1.20V

----------------- ratio

⋅

=

A

()

1.5

2.2

3.0

3.9

4.6

Ratio

1291

1216

1155

1122

1088

FIGURE 1. THE RATIO USED IN THE CHARGE CURRENT

1280

1250

1220

1190

1160

1130

1100

1070

1

2345

1.20V

⋅

ratio

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

=

⋅

=

ISL6293