Standalone single cell 2.0-A buck battery charger

The BQ25302 is a

highly-integrated standalone switch-mode battery charger for single cell Li-Ion

and Li-polymer

batteries. The BQ25302 supports 4.1-V to 6.2-V input voltage and 2-A fast charge.

The integrated current sensing topology of the device enables

high charge efficiency and low BOM cost. The best-in-class 200-nA low quiescent

current of the device conserves battery energy and maximizes the shelf time for portable

devices. The BQ25302 is available in a 3x3 WQFN package for easy 2-layer

layout and space limited applications.

The BQ25302supports 4.1-V to 6.2-V

input to charge single cell batteries. The BQ25302 provides up to 2-A

continuous fast charge current to a single cell battery.

The device features fast charging for portable devices. Its

input voltage regulation delivers maximum charging power to the battery from input

source. The solution is highly integrated with an input reverse-blocking FET (RBFET,

Q1), high-side switching FET (HSFET, Q2), and low-side switching FET (LSFET,

Q3).

The BQ25302 features

lossless integrated current sensing to reduce power loss and BOM cost with minimized

component count. It also integrates a bootstrap diode for the high-side gate drive

and battery temperature monitor to simplify system design. The device initiates and

completes a charging cycle without host control. The BQ25302 charge

voltage and charge current are set by external resistors. The BQ25302detects the charge voltage setting at startup and charges the battery in four

phases: battery short, pre-conditioning, constant current, and constant

voltage.

At the end of the

charging cycle, the charger automatically terminates if the charge current is below

the termination current threshold and the battery voltage is above the recharge

threshold. When the battery voltage falls below the recharge threshold, the charger

will automatically start another charging cycle. The charger provides various safety

features for battery charging and system operations, including battery temperature

monitoring based on negative temperature coefficient (NTC) thermistor, charge safety

timer, input over-voltage and over-current protections, as well as battery

over-voltage protection. Pin open and short protection is also built in to protect

against the charge current setting pin ICHG accidently open or short to GND.

The thermal

regulation regulates charge current to limit die temperature during high power

operation or high ambient temperature conditions.

The STAT pin output reports charging

status and fault conditions. When the input voltage is removed, the device

automatically enters HiZ mode with very low leakage current from battery to the

charger device. The BQ25302 is available in a 3 mm x 3 mm thin WQFN

package.