Product details

Number of series cells 1, 2, 3, 4, 5 Charge current (max) (A) 16.2 Vin (max) (V) 26 Cell chemistry Lead Acid, Li-Ion/Li-Polymer, Lithium Phosphate/LiFePO4, NiCd, NiMH, SuperCap Battery charge voltage (min) (V) 1.024 Battery charge voltage (max) (V) 23 Absolute max Vin (max) (V) 32 Control topology Switch-Mode Buck-boost Control interface I2C Features IC thermal regulation, ICO (Input Current Optimization), IINDPM (Input current limit), Input OVP, Integrated ADC, USB C/PD compatible, USB OTG integrated, VINDPM (Input voltage threshold to maximize adaptor power) Vin (min) (V) 3.5 Rating Catalog Operating temperature range (°C) -40 to 85
Number of series cells 1, 2, 3, 4, 5 Charge current (max) (A) 16.2 Vin (max) (V) 26 Cell chemistry Lead Acid, Li-Ion/Li-Polymer, Lithium Phosphate/LiFePO4, NiCd, NiMH, SuperCap Battery charge voltage (min) (V) 1.024 Battery charge voltage (max) (V) 23 Absolute max Vin (max) (V) 32 Control topology Switch-Mode Buck-boost Control interface I2C Features IC thermal regulation, ICO (Input Current Optimization), IINDPM (Input current limit), Input OVP, Integrated ADC, USB C/PD compatible, USB OTG integrated, VINDPM (Input voltage threshold to maximize adaptor power) Vin (min) (V) 3.5 Rating Catalog Operating temperature range (°C) -40 to 85
WQFN (RSN) 32 16 mm² 4 x 4
  • No battery MOSFET for saving cost and high efficiency
  • 400-kHz/800-kHz programmable switching frequency for high efficiency/high power density
  • Buck-boost charger for USB-C Power Delivery (PD) interface platform
    • 3.5-V to 26-V input range to charge 1- to 5-cell battery
    • Charge current up to 16.2 A/8.1 A with 128-mA/64-mA resolution based on 5-mΩ/10-mΩ sensing resistor
    • Input current limit up to 10 A/6.35 A with 100-mA/50-mA resolution based on 5-mΩ/10-mΩ sensing resistor
    • Support USB 2.0, USB 3.0, USB 3.1 and USB Power Delivery (PD)
    • Input Current Optimizer (ICO) to extract max input power without overloading the adapter
    • Seamless transition between buck, buck-boost, and boost operations
    • Input current and voltage regulation (IINDPM and VINDPM) against source overload
  • TI patented switching frequency dithering pattern for EMI noise reduction
  • TI patented Pass Through Mode (PTM) for system power efficiency improvement and battery fast charging achieving 99% efficiency.
  • Input and battery current monitor through dedicated pins
  • Integrated 8-bit ADC to monitor voltage, current and power
  • Support independent comparator logic with dedicated pins
  • Power up USB port from battery (USB OTG)
    • 3-V to 24-V OTG with 8-mV resolution
    • Output current limit up to 12.7 A/6.35 A with 100-mA/50-mA resolution based on 5-mΩ/10-mΩ sensing resistor
  • I2C host control interface for flexible system configuration
  • High accuracy for the regulation and monitor
    • ±0.5% Charge voltage regulation
    • ±3% Charge current regulation
    • ±2.5% Input current regulation
    • ±2% Input/charge current monitor
  • Safety
    • Thermal shutdown
    • Input, system, battery overvoltage protection
    • Input, MOSFET, inductor overcurrent protection
  • Package: 32-Pin 4.0 mm × 4.0 mm WQFN
  • No battery MOSFET for saving cost and high efficiency
  • 400-kHz/800-kHz programmable switching frequency for high efficiency/high power density
  • Buck-boost charger for USB-C Power Delivery (PD) interface platform
    • 3.5-V to 26-V input range to charge 1- to 5-cell battery
    • Charge current up to 16.2 A/8.1 A with 128-mA/64-mA resolution based on 5-mΩ/10-mΩ sensing resistor
    • Input current limit up to 10 A/6.35 A with 100-mA/50-mA resolution based on 5-mΩ/10-mΩ sensing resistor
    • Support USB 2.0, USB 3.0, USB 3.1 and USB Power Delivery (PD)
    • Input Current Optimizer (ICO) to extract max input power without overloading the adapter
    • Seamless transition between buck, buck-boost, and boost operations
    • Input current and voltage regulation (IINDPM and VINDPM) against source overload
  • TI patented switching frequency dithering pattern for EMI noise reduction
  • TI patented Pass Through Mode (PTM) for system power efficiency improvement and battery fast charging achieving 99% efficiency.
  • Input and battery current monitor through dedicated pins
  • Integrated 8-bit ADC to monitor voltage, current and power
  • Support independent comparator logic with dedicated pins
  • Power up USB port from battery (USB OTG)
    • 3-V to 24-V OTG with 8-mV resolution
    • Output current limit up to 12.7 A/6.35 A with 100-mA/50-mA resolution based on 5-mΩ/10-mΩ sensing resistor
  • I2C host control interface for flexible system configuration
  • High accuracy for the regulation and monitor
    • ±0.5% Charge voltage regulation
    • ±3% Charge current regulation
    • ±2.5% Input current regulation
    • ±2% Input/charge current monitor
  • Safety
    • Thermal shutdown
    • Input, system, battery overvoltage protection
    • Input, MOSFET, inductor overcurrent protection
  • Package: 32-Pin 4.0 mm × 4.0 mm WQFN

The BQ25731 is a synchronous buck-boost battery charge controller to charge a 1- to 5-cell battery from a wide range of input sources including USB adapter, high voltage USB-C Power Delivery (PD) sources, and traditional adapters. It offers a low component count, high efficiency solution for space constrained, 1- to 5-cell battery charging applications.

During power up, the charger sets the converter to a buck, boost, or buck-boost configuration based on the input source and battery conditions. The charger seamlessly transits between the buck, boost, and buck-boost operation modes without host control.

The BQ25731 is a synchronous buck-boost battery charge controller to charge a 1- to 5-cell battery from a wide range of input sources including USB adapter, high voltage USB-C Power Delivery (PD) sources, and traditional adapters. It offers a low component count, high efficiency solution for space constrained, 1- to 5-cell battery charging applications.

During power up, the charger sets the converter to a buck, boost, or buck-boost configuration based on the input source and battery conditions. The charger seamlessly transits between the buck, boost, and buck-boost operation modes without host control.

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More information

  • If you would like to consider a universal standards compliant, up to 20V USB Type-C PD Port to power the charger, please consider TPS25750

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Technical documentation

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Type Title Date
* Data sheet BQ25731 I2C 1- to 5-Cell Buck-Boost Battery Charge Controller with USB-C PD 3.0 OTG Output datasheet (Rev. A) PDF | HTML 28 Jan 2021
Application note Finding the Correct Battery Charging Design to Power Vacuum Robot System PDF | HTML 04 Mar 2024
Application note Layout Guide for Buck-Boost Charger BQ257XX Series PDF | HTML 30 Jan 2024
Product overview Scalable Battery Backup Subsystem With Adjustable Output (Rev. A) PDF | HTML 16 Oct 2023
EVM User's guide BQ2573x Evaluation Module (Rev. A) PDF | HTML 19 Jan 2021
Technical article Adding USB Type-C® with USB Power Delivery to battery-powered applications PDF | HTML 11 Nov 2020
Certificate BQ25731EVM EU Declaration of Conformity (DoC) 19 Jun 2020

Design & development

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

Evaluation board

BQ25731EVM — I2C NVDC 1 to 5 cell, 16-A, buck-boost charger controller evaluation module

The BQ25731EVM evaluation module (EVM) is an I2C controlled NVDC (narrow voltage DC) buck-boost charge controller with N-channel MOSFET selector and current monitoring. The input voltage range for the buck converter is between 3.5 V and 26 V, with a programmable output of 1 to 5 cells and a charge (...)
User guide: PDF | HTML
Not available on TI.com
Application software & framework

BQSTUDIO-STABLE Battery Management Studio (bqStudio) Software – stable version downloads for bq series of TI battery fuel gauges

Battery Management Studio (bqStudio) offers a full suite of robust tools to assist with the process of evaluating, designing with, configuring, testing, or otherwise utilizing TI Battery management products. This includes features that provide full access to registers and data memory including (...)

Supported products & hardware

Supported products & hardware

Products
Battery monitors & balancers
BQ76942 3-series to 10-series multicell battery monitor and protector BQ76952 3-s to 16-s high-accuracy battery monitor and protector for Li-ion, Li-polymer and LiFePO4
Battery charger ICs
BQ24800 SMBus 1-4 cell Buck battery charge controller to support hybrid power boost and battery boost mode BQ25720 SMBus 1- to 4-cell NVDC buck-boost battery charge controller with power path and USB-C® PD OTG BQ25723 I²C 1-4 cell NVDC buck-boost battery charge controller with power path and USB-C® PD OTG BQ25731 I2C 1-5 cell NVDC buck-boost battery charge controller with USB type-C PD support BQ25790 Integrated, NVDC, 5-A 1-cell to 4-cell switch-mode buck-boost battery charger BQ25792 I2C controlled, 5-A, 1-4 cell buck-boost charger with dual-input selector and USB PD 3.0 OTG output
Battery fuel gauges
BQ27220 Single cell pack/system-side CEDV battery fuel (gas) gauge w/pre-programmed chemistry profiles BQ27320 Single cell pack/System-side CEDV battery fuel (gas) gauge BQ27425-G1 System-side Impedance Track™; fuel gauge with direct battery connection | gas gauge battery BQ27425-G2A System-side Impedance Track™; fuel gauge for LiCoO2 battery BQ27425-G2B System-side Impedance Track™; fuel gauge LiMn2O4 battery BQ27520-G4 System side Impedance Track™ fuel gauge with integrated LDO. BQ27530-G1 System-side Impedance-Track fuel (gas) gauge with direct battery connection BQ27531-G1 Battery management unit Impedance Track™ fuel (gas) gauge for bq2419x charger controller BQ27532-G1 Battery management unit Impedance Track™ fuel gauge for bq2425x charger BQ27545-G1 Single cell, pack side, Impedance Track™ fuel gauge BQ27546-G1 Single cell Impedance Track™ pack side fuel gauge with DSBGA package BQ27621-G1 System-side fuel gauge with Dynamic Voltage Correlation, battery gas gauge BQ27741-G1 Pack-side Impedance Track™(tm) fuel (gas) gauge with integrated protector BQ27742-G1 Single cell Li-ion battery fuel gauge with integrated protection | battery gas gauge BQ27Z561 Impedance Track™ integrated circuit gas gauge solution for 1-series BQ28Z610 Battery fuel gauge with integrated protector for 1-2 series packs BQ34110 Multi-chemistry high-cell Count battery fuel gauge with integrated rarely discharged module BQ34210-Q1 Automotive Qualified Single cell system-side CEDV fuel gauge BQ34Z100-G1 Multi-chemistry Impedance Track™ standalone fuel gauge | battery gas gauge BQ35100 Battery fuel gauge for non-rechargeable batteries (lithium primary) and end-of-service monitor BQ4050 1-4 series CEDV battery fuel (gas) gauge BQ40Z50 1-4 series Li-ion battery pack manager | battery fuel (gas) gauge BQ40Z50-R1 1-4 series Li-ion battery pack manager supporting Turbo Mode 1.0 BQ40Z50-R2 1-4 series Li-ion battery pack manager supporting Turbo Mode 2.0 BQ40Z60 Complete multi-cell battery manager | battery fuel (gas) gauge BQ40Z80 2-s to 6-s battery pack manager with Impedance Track™ gas gauging BQ78350 Companion CEDV Fuel Gauge Battery Management Controller for bq76940 Monitor Family BQ78350-R1 CEDV li-ion gas gauge and battery management controller BQ78Z100 Impedance Track™ battery fuel (gas) gauge for 1-series to 2-series
Download options
Application software & framework

BQSTUDIO-TEST Battery Management Studio (bqStudio) Software – Beta version downloads

Battery Management Studio (bqStudio) offers a full suite of robust tools to assist with the process of evaluating, designing with, configuring, testing, or otherwise utilizing TI Battery management products. This includes features that provide full access to registers and data memory including (...)

Supported products & hardware

Supported products & hardware

Products
Battery monitors & balancers
BQ76905 Low-power monitor and protector for 2S to 5S with high accuracy cell voltage measurement BQ76907 Low-power monitor and protector for 2S to 7S with high accuracy cell voltage measurement BQ769142 3-s to 14-s high-accuracy battery monitor and protector for Li-ion, Li-polymer and LiFePO4 battery BQ76942 3-series to 10-series multicell battery monitor and protector BQ76952 3-s to 16-s high-accuracy battery monitor and protector for Li-ion, Li-polymer and LiFePO4 BQ76972 3s-to-16s high-accuracy battery monitor and protector for Li-ion, Li-poly and LiFePO4
Battery charger ICs
BQ24800 SMBus 1-4 cell Buck battery charge controller to support hybrid power boost and battery boost mode BQ25720 SMBus 1- to 4-cell NVDC buck-boost battery charge controller with power path and USB-C® PD OTG BQ25723 I²C 1-4 cell NVDC buck-boost battery charge controller with power path and USB-C® PD OTG BQ25731 I2C 1-5 cell NVDC buck-boost battery charge controller with USB type-C PD support BQ25756 Stand-alone or I²C-controlled 70-V bidirectional buck-boost charge controller with MPPT BQ25790 Integrated, NVDC, 5-A 1-cell to 4-cell switch-mode buck-boost battery charger BQ25792 I2C controlled, 5-A, 1-4 cell buck-boost charger with dual-input selector and USB PD 3.0 OTG output
Battery fuel gauges
BQ27220 Single cell pack/system-side CEDV battery fuel (gas) gauge w/pre-programmed chemistry profiles BQ27320 Single cell pack/System-side CEDV battery fuel (gas) gauge BQ27425-G1 System-side Impedance Track™; fuel gauge with direct battery connection | gas gauge battery BQ27425-G2A System-side Impedance Track™; fuel gauge for LiCoO2 battery BQ27425-G2B System-side Impedance Track™; fuel gauge LiMn2O4 battery BQ27427 Single-cell battery fuel gauge with pre-programmed chemistry and integrated sense resistor BQ27520-G4 System side Impedance Track™ fuel gauge with integrated LDO. BQ27530-G1 System-side Impedance-Track fuel (gas) gauge with direct battery connection BQ27531-G1 Battery management unit Impedance Track™ fuel (gas) gauge for bq2419x charger controller BQ27532-G1 Battery management unit Impedance Track™ fuel gauge for bq2425x charger BQ27545-G1 Single cell, pack side, Impedance Track™ fuel gauge BQ27546-G1 Single cell Impedance Track™ pack side fuel gauge with DSBGA package BQ27621-G1 System-side fuel gauge with Dynamic Voltage Correlation, battery gas gauge BQ27741-G1 Pack-side Impedance Track™(tm) fuel (gas) gauge with integrated protector BQ27742-G1 Single cell Li-ion battery fuel gauge with integrated protection | battery gas gauge BQ27Z561 Impedance Track™ integrated circuit gas gauge solution for 1-series BQ27Z746 Pack-side, single-cell Impedance Track™ technology fuel gauge with integrated protector BQ28Z610 Battery fuel gauge with integrated protector for 1-2 series packs BQ34110 Multi-chemistry high-cell Count battery fuel gauge with integrated rarely discharged module BQ34210-Q1 Automotive Qualified Single cell system-side CEDV fuel gauge BQ34Z100-G1 Multi-chemistry Impedance Track™ standalone fuel gauge | battery gas gauge BQ35100 Battery fuel gauge for non-rechargeable batteries (lithium primary) and end-of-service monitor BQ4050 1-4 series CEDV battery fuel (gas) gauge BQ40Z50 1-4 series Li-ion battery pack manager | battery fuel (gas) gauge BQ40Z50-R1 1-4 series Li-ion battery pack manager supporting Turbo Mode 1.0 BQ40Z50-R2 1-4 series Li-ion battery pack manager supporting Turbo Mode 2.0 BQ40Z60 Complete multi-cell battery manager | battery fuel (gas) gauge BQ40Z80 2-s to 6-s battery pack manager with Impedance Track™ gas gauging BQ78350 Companion CEDV Fuel Gauge Battery Management Controller for bq76940 Monitor Family BQ78350-R1 CEDV li-ion gas gauge and battery management controller BQ78Z100 Impedance Track™ battery fuel (gas) gauge for 1-series to 2-series
Battery protectors
BQ77307 Low-power protector for 2S to 7S with high accuracy cell voltage measurement
Hardware development
Evaluation board
MKST-3P-ALT-EV2300 MKS Technology alternative for EV2300 communications transceiver
Download options
Application software & framework

TI-CHARGER-GUI — GUI software for use with USB2ANY & battery charging evaluation modules

The TI-CHARGER-GUI offers a web-based or standalone graphical user interface to assist in the process of evaluating, designing with, configuring or testing battery charger products. The software provides full access to registers and an easy interface to send and sequence commands.
Reference designs

PMP41013 — Integrated USB Type-C® and USB PD bidirectional charging reference design for 1- to 5-cell batter

This reference design is an integrated USB Type-C® power delivery (PD) and charging reference design for one- to five-cell batteries for applications such as power tool charger with USB Type-C port, vacuum cleaner, portable power station and more.
Test report: PDF
Reference designs

TIDA-010240 — Scalable multi-pack smart battery charger reference design

Lithium batteries with more than 100 watt-hours (Wh) are generally not permitted in carry-on luggage, and any exceptions to this rule lie at the discretion of airlines and require prior approval. This reference design is a smart high-efficiency charger design for dual smart battery packs of up to (...)
Design guide: PDF
Reference designs

PMP22805 — 24-VIN, 240-W, 98% efficient, compact 5S battery charger with USB On-The-Go (OTG) reference design

This battery charger reference design is designed for a 5 to 24-VIN, 240-W power tool that features BQ25731 one- to five-cell NVDC buck-boost battery charge controller. This is a high power, high efficiency and high density design. PMP22805 delivers 240 W with 98% efficiency and fits in a compact (...)
Test report: PDF
Package Pins CAD symbols, footprints & 3D models
WQFN (RSN) 32 Ultra Librarian

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  • Ongoing reliability monitoring
Information included:
  • Fab location
  • Assembly location

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