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BQ25856-Q1

ACTIVE

Automotive I2C controlled 70-V bidirectional buck-boost charge controller

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Data sheet

BQ25856-Q1

ACTIVE
Data sheet Order now

Product details

Rating Automotive Number of series cells 16 Cell chemistry Li-Ion/Li-Polymer, LiFePO4, Lithium Phosphate/LiFePO4, NiMH, SuperCap Charge current (max) (A) 20 Features AEC-Q100 Automotive Qual, Adjustable switching frequency, BAT temp thermistor monitoring (JEITA profile), Bidirectional, IC thermal regulation, ICO (Input Current Optimization), IINDPM (Input current limit), Input OVP, Integrated ADC, Integrated LDO, SYNC Pin, USB C/PD compatible, VINDPM (Input voltage threshold to maximize adaptor power) Vin (min) (V) 4.4 Vin (max) (V) 70 Absolute max Vin (max) (V) 85 Control topology Switch-Mode Buck-boost Battery charge voltage (min) (V) 0 Battery charge voltage (max) (V) 70 Control interface I2C Operating temperature range (°C) -40 to 150
Rating Automotive Number of series cells 16 Cell chemistry Li-Ion/Li-Polymer, LiFePO4, Lithium Phosphate/LiFePO4, NiMH, SuperCap Charge current (max) (A) 20 Features AEC-Q100 Automotive Qual, Adjustable switching frequency, BAT temp thermistor monitoring (JEITA profile), Bidirectional, IC thermal regulation, ICO (Input Current Optimization), IINDPM (Input current limit), Input OVP, Integrated ADC, Integrated LDO, SYNC Pin, USB C/PD compatible, VINDPM (Input voltage threshold to maximize adaptor power) Vin (min) (V) 4.4 Vin (max) (V) 70 Absolute max Vin (max) (V) 85 Control topology Switch-Mode Buck-boost Battery charge voltage (min) (V) 0 Battery charge voltage (max) (V) 70 Control interface I2C Operating temperature range (°C) -40 to 150
VQFN (RRV) 36 30 mm² 6 x 5
  • 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
  • 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

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.

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.
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BQ25756 ACTIVE Stand-alone or I²C-controlled 70-V bidirectional buck-boost charge controller with MPPT BQ25756 is a non-automotive version that is pin-to-pin with BQ25856-Q1

Technical documentation

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Type Title Date
* Data sheet BQ25856-Q1: Automotive, Standalone/I2C Controlled, 1- to 14-Cell Bidirectional Buck-Boost Battery Charge Controller datasheet (Rev. A) PDF | HTML 31 Oct 2024
Application note Capacitor Backup Circuits with the BQ25856-Q1 PDF | HTML 30 Apr 2025
Application brief Designing a fast charging and discharging supercapacitor backup system for automotive applications PDF | HTML 21 Nov 2024

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

BQ25856EVM — BQ25856 evaluation module

The BQ25856 evaluation module (EVM) is a complete evaluation system for the BQ25856 IC, a buck-boost battery charge controller with a wide input range of 4.2V to 70V, a wide output voltage range of up to 70V, bidirectional capabilities and AEC-Q100 qualification. The device offers high-efficiency (...)
User guide: PDF | HTML
Not available on TI.com
Calculation tool

BQ25756-DESIGN-CALC — BQ25756 design calculator

BQ25756 design calculator is a calculation tool for BQ25756 which is a wide input voltage, switched mode buck-boost Li-Ion, Li-polymer, or LiFePO4 battery charge controller with bidirectional power flow support.
Supported products & hardware

Supported products & hardware

Products
Battery charger ICs
  • BQ25756 — Stand-alone or I²C-controlled 70-V bidirectional buck-boost charge controller with MPPT
  • BQ25758 — I²C controlled 60-V bi-directional buck-boost controller with USB PD EPR and PPS support
  • BQ25756E — Stand-alone or I²C-controlled bidirectional buck-boost charge controller for up to 7S batteries
  • BQ25856-Q1 — Automotive I2C controlled 70-V bidirectional buck-boost charge controller
  • BQ25758A — I²C controlled 60V bi-directional buck-boost controller with USB PD EPR and PPS support
  • BQ25750 — Stand-alone or I²C-controlled 70-V bidirectional buck-boost charge controller with power path
  • BQ25858-Q1 — Automotive stand-alone or I²C controlled 70V bidirectional buck-boost controller
  • BQ25858B-Q1 — Automotive stand-alone or I²C controlled 70V bidirectional buck-boost controller
  • BQ25751 — Stand-alone or I²C controlled, 70V, buck-boost, lead acid battery charge controller with power path
  • BQ25820 — Stand-alone or I²C controlled 70V bidirectional buck charge controller with power path
  • BQ25758S — I²C controlled 32V bidirectional buck-boost controller with USB PD EPR and PPS support
  • BQ25822 — 70V bidirectional buck charge controller with power path and automatic backup mode
Hardware development
Evaluation board
  • BQ25756EVM — BQ25756 evaluation module for 1- to 14-cell bidirectional buck-boost battery charge controller
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VQFN (RRV) 36 Ultra Librarian
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