1 Features

? Wide input voltage operating range: 4.2 V to 70 V

? Wide battery voltage operating range: up-to 70 V

with multi-chemistry support:

– 1- to 14-cell Li-ion charge profile

– 1- to 16-cell LiFePO4 charge profile

? Synchronous buck-boost charge controller with

NFET drivers

– Adjustable switching frequency from 200 kHz to

600 kHz

– Optional synchronization to external clock

– Integrated loop compensation with soft start

– Optional gate driver supply input for optimized

efficiency

? Automatic maximum power point tracking (MPPT)

for solar charging

? Buck-only mode

? Bidirectional converter operation (Reverse Mode)

supporting USB-PD Extended Power Range (EPR)

– Adjustable input voltage (VAC) regulation from

3.3 V to 65 V with 20-mV/step

– Adjustable input current regulation (RAC_SNS)

from 400 mA to 20 A with 50-mA/step using

5-mΩ resistor

? High accuracy

– ±0.5 charge voltage regulation

– ±3 charge current regulation

– ±3 input current regulation

? I2C controlled for optimal system performance with

resistor-programmable option

– Hardware adjustable input and output current

limits

? Integrated 16-bit ADC for voltage, current, and

temperature monitoring

? High safety integration

– Adjustable input overvoltage and undervoltage

protection

– Battery overvoltage and overcurrent protection

– Charging safety timer

– Battery short protection

– Thermal shutdown

? Status outputs

– Adapter present status (PG)

– Charger operation status (STAT1, STAT2)

? Package

– 36-pin 5 mm × 6 mm QFN

2 Applications

? Kick eScooter, eBike

? Cordless power tool, Garden tool

? Robotic lawn mower

? Portable power station

? Cordless vacuum cleaner, Vacuum robot

? Solar charger

? USB-PD EPR (Extended Power Range)

3 Description

The BQ25756 is a wide input voltage, switchedmode

buck-boost Li-Ion, Li-polymer, or LiFePO4

battery charge controller with bidirectional power flow

support. The device offers high-efficiency battery

charging over a wide voltage range with accurate

charge current and charge voltage regulation,

in addition to automatic charge preconditioning,

termination, and charge status indication. The device

integrates all the loop compensation for the buckboost

converter, thereby providing a high density

solution with ease of use. In reverse mode, the device

draws power from the battery and regulates the input

terminal voltage with an added constant current loop

for protection, supporting USB-PD EPR power profile.

Besides the I2C host-controlled charging mode, the device also supports standalone charging mode via resistor

programmable limits. Input current, charge current and charge voltage regulation targets can be set via the

ILIM_HIZ, ICHG and FB pins, respectively.