Product details

Number of series cells 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 Charge current (max) (A) 20 Vin (max) (V) 70 Cell chemistry Li-Ion/Li-Polymer, Lithium Phosphate/LiFePO4, NiMH, SuperCap Battery charge voltage (min) (V) 0 Battery charge voltage (max) (V) 70 Absolute max Vin (max) (V) 85 Control topology Switch-Mode Buck-boost Control interface I2C 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) 4.2 Rating Automotive Operating temperature range (°C) -40 to 150
Number of series cells 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 Charge current (max) (A) 20 Vin (max) (V) 70 Cell chemistry Li-Ion/Li-Polymer, Lithium Phosphate/LiFePO4, NiMH, SuperCap Battery charge voltage (min) (V) 0 Battery charge voltage (max) (V) 70 Absolute max Vin (max) (V) 85 Control topology Switch-Mode Buck-boost Control interface I2C 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) 4.2 Rating Automotive 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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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 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
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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
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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