1 Features

• AEC-Q100 qualified for automotive applications

– Temperature grade 1: −40ºC ≤ TA≤ 150ºC

• Wide input voltage operating range: 4.4V to 70V

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

with multi-chemistry support:

– 1- to 14-cell Li-ion charge profile

– 1- to 16-cell LiFePO4 charge profile

– Up-to 70V supercapacitor charging

• Synchronous buck-boost charge controller with

NFET drivers

– Adjustable fSW from 200kHz to 600kHz

– Switching frequency dithering for EMI noise

reduction (DRSS)

– Optional synchronization to external clock

– Integrated loop compensation with soft start

– Optional gate driver supply input for optimized

efficiency

• Bidirectional converter operation (Reverse Mode)

supporting USB-PD Extended Power Range (EPR)

– Adjustable input voltage (VAC) regulation from

3.3V to 65V with 20mV/step

– Adjustable input current regulation (RAC_SNS)

from 0.4A to 20A with 50mA/step using 5mΩ

resistor

• High accuracy

– ±0.5% charge voltage regulation

– ±3% charge/input current regulation

– ±2% input voltage 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

– Thermal shutdown

• Status outputs

– Input power present status (PG)

– Charger operation status (STAT1, STAT2)

• Package

– 36-pin 5mm × 6mm QFN with wettable flanks

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

2 Applications

• Low voltage battery system

• Battery management unit

• Domain Gateway

• ADAS Domain Controller

• Front Door Module

3 Description

The BQ25856-Q1 is an automotive grade, wide

input voltage, switched-mode 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 buck-boost 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.

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.