BQ24297 Datasheet, PDF (2/48 Pages) Texas Instruments – I2C Controlled 3A Single Cell USB Charger

bq24296
bq24297
SLUSBP6A – SEPTEMBER 2013 – REVISED OCTOBER 2013
www.ti.com
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
DESCRIPTION
The bq24296 and bq24297 are highly-integrated switch-mode battery charge management and system power
path management device for 1 cell Li-Ion and Li-polymer battery in a wide range of smartphone and tablet
applications. Its low impedance power path optimizes switch-mode operation efficiency, reduces battery charging
time and extends battery life during discharging phase. The I2C serial interface with charging and system
settings makes the device a truly flexible solution.
The device supports a 3.9V-6.2V USB input sources, including standard USB host port and USB charging port
with 6.4V over-voltage protection. The device is compliant with USB 2.0 and USB 3.0 power specifications with
input current and voltage regulation. To set the default input current limit, the bq24296 takes the result from the
detection circuit in the system, such as USB PHY device and the bq24297 detects the input source through
D+/D- detection following the USB battery charging spec 1.2. In addition, the bq24297 detects non-standard
2A/1A adapters. The device also supports USB On-the-Go operation by providing fast startup and supplying
adjustable voltage 4.55-5.5V (default 5V) on the VBUS with a accurate current limit up to 1.5A.
The power path management regulates the system slightly above battery voltage but does not drop below 3.5V
minimum system voltage (programmable). With this feature, the system keeps operating even when the battery
is completely depleted or removed. When the input source current or voltage limit is reached, the power path
management automatically reduces the charge current to zero and then starts discharges the battery until the
system power requirement is met. This supplement mode operation keeps the input source from getting
overloaded.
The device initiates and completes a charging cycle when host control is not available. It automatically charges
the battery in three phases: pre-conditioning, constant current and constant voltage. In the end, the charger
automatically terminates when the charge current is below a preset limit in the constant voltage phase. Later on,
when the battery voltage falls below the recharge threshold, the charger will automatically start another charging
cycle.
The charge device provides various safety features for battery charging and system operation, including negative
thermistor monitoring, charging safety timer and over-voltage/over-current protections. The thermal regulation
reduces charge current when the junction temperature exceeds 120°C (programmable).
The STAT output reports the charging status and any fault conditions. The INT immediately notifies host when
fault occurs.
The bq24296 and bq24297 are available in 24-pin, 4x4 mm2 thin QFN package.
I²C Address
USB OTG
USB Detection
Default Battery Voltage
Default Charge Current
Default Adapter Current Limit
Default Pre-charge Current / Max Pre-charge
Current
Default Termination Current
Charging Temperature Profile
Status Output
STAT During Fault
Default Safety Timer
Default VINDPM
Default Pre-charge Timer
bq24296/bq24297 Family Table
bq24296
6BH
Yes
Adjustable 4.5V-5.5V@1.5A (max)
PSEL
4.208V
2.048A
3A
256mA / 2.048A
256mA
Cold/Hot
STAT, PG
Blinking @ 1Hz
12hr
4.36V
4hr
bq24297
6BH
Yes
Adjustable 4.5V-5.5V@1.5A (max)
D+/D–
4.208V
2.048A
3A
256mA / 2.048A
256mA
Cold/Hot
STAT
Blinking @ 1Hz
12hr
4.36V
4hr
2
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