BQ24296_15 Datasheet, PDF (3/55 Pages) Texas Instruments – bq2429x I2C Controlled 3-A Single Cell USB Charger With Narrow VDC Power Path Management and Adjustable Voltage USB OTG

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bq24296, bq24297
SLUSBP6B – SEPTEMBER 2013 – REVISED NOVEMBER 2014
5 Description (Continued)
Its low impedance power path optimizes switch-mode operation efficiency, reduces battery charge 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 3.9-V to 6.2-V USB input sources, including standard USB host port and USB charging port
with 6.4-V 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 2-
A/1-A adapters. The device also supports USB On-the-Go operation by providing fast startup and supplying
adjustable voltage 4.55-V to 5.5-V (default 5 V) on the VBUS with an accurate current limit up to 1.5 A.
The power path management regulates the system slightly above battery voltage but does not drop below 3.5-V
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 automatically starts 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 the host
when a fault occurs.
The bq24296 and bq24297 are available in a 24-pin, 4.00 x 4.00 mm² thin VQFN package.
6 Device Comparison Table
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
6BH
Yes
Adjustable 4.5 V to 5.5 V at 1.5 A (max)
PSEL
4.208 V
2.048 A
3A
256 mA / 2.048 A
256 mA
Cold/Hot
STAT, PG
Blinking at 1 Hz
12 hr
4.36 V
4 hr
bq24297
6BH
Yes
Adjustable 4.5 V to 5.5 V at 1.5 A (max)
D+/D–
4.208 V
2.048 A
3A
256 mA / 2.048 A
256 mA
Cold/Hot
STAT
Blinking at 1 Hz
12 hr
4.36 V
4 hr
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