AAT3689(2007) データシートの表示（PDF） - Advanced Analogic Technologies

部品番号

コンポーネント説明

メーカー

AAT3689
(Rev.:2007)

0.5A/1.0A USB Port/Adapter Lithium-Ion/Polymer Battery Charger

Advanced Analogic Technologies 

BatteryManagerTM

PRODUCT DATASHEET

AAT3689

0.5A/1.0A USB Port/Adapter Lithium-Ion/Polymer Battery Charger

Charge Complete Voltage

Regulated Current

Preconditioning

Trickle Charge

Phase

Constant Current

Charge Phase

I = Max CC

Constant Voltage

Charge Phase

Constant Current Mode

Voltage Threshold

Figure 1: Current vs. Voltage Profile During Charging Phases.

Battery Preconditioning

Before the start of charging, the AAT3689 checks sev-

eral conditions in order to assure a safe charging envi-

ronment. The input supply must be above the minimum

operating voltage, or under-voltage lockout threshold

(VUVLO), for the charging sequence to begin. Also, the cell

temperature, as reported by a thermistor connected to

the TS pin from the battery, must be within the proper

window for safe charging. When these conditions have

been met and a battery is connected to the BAT pin, the

AAT3689 checks the state of the battery. If the cell volt-

age is below the Preconditioning Voltage Threshold

(VMIN), the AAT3689 begins preconditioning the cell.

The battery preconditioning trickle charge current is equal

to the fast charge constant current divided by 10. For

example, if the programmed fast charge current is

500mA, then the preconditioning mode (trickle charge)

current will be 50mA. Cell preconditioning is a safety pre-

caution for a deeply discharged battery and also aids in

limiting power dissipation in the pass transistor when the

voltage across the device is at the greatest potential.

Fast Charge / Constant Current Charging

The cell preconditioning continues until the voltage on

the BAT pin exceeds the Preconditioning Voltage

Threshold (VMIN). At this point, the AAT3689 begins the

constant-current fast charging phase. The fast charge

Constant Current (ICC) amplitude is determined by the

charge mode, ADP or USB, and is programmed by the

user via the RSETADP and RSETUSB resistors. The AAT3689

remains in constant current charge mode until the bat-

tery reaches the voltage regulation point, VBAT_EOC.

Constant Voltage Charging

The system transitions to a constant voltage charging

mode when the battery voltage reaches output charge

regulation threshold (VBAT_EOC) during the constant cur-

rent fast charge phase. The regulation voltage level is

factory programmed to 4.2V (±1%). The charge current

in the constant voltage mode drops as the battery cell

under charge reaches its maximum capacity.

End of Charge Cycle Termination

and Recharge Sequence

When the charge current drops to 7.5% of the pro-

grammed fast charge current level in the constant volt-

age mode, the device terminates charging and goes into

a standby state. The charger will remain in a standby

state until the battery voltage decreases to a level below

the battery recharge voltage threshold (VRCH).

When the input supply is disconnected or drops below

UVLO or EN = 0, the charger will automatically enter

power-saving sleep mode. Consuming an ultra-low

0.3μA in sleep mode, the AAT3689 minimizes battery

drain when it is not charging. This feature is particularly

useful in applications where the input supply level may

fall below the battery charge or under-voltage lockout

level. In such cases where the AAT3689 input voltage

drops, the device will enter the sleep mode and auto-

matically resume charging once the input supply has

recovered from its fault condition.

3689.2007.12.1.1

www.analogictech.com

11

Share Link: