Product details


Number of series cells 1, 2, 3, 4, 5 Charge current (Max) (A) 16.2 Operating Vin (Max) (V) 26 Cell chemistry Lead Acid, Li-Ion/Li-Polymer, Lithium Phosphate/LiFePO4, NiCd, NiMH, SuperCap Battery charge voltage (Min) (V) 23 Absolute Vin (safety rating) (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) Operating Vin (Min) (V) 3.5 Rating Catalog open-in-new Find other Battery charger ICs

Package | Pins | Size

WQFN (RSN) 32 16 mm² 4 x 4 open-in-new Find other Battery charger ICs


  • Charge 1s to 5s Battery From Wide Range Of Input Source
    • 3.5-V to 26-V Input Operating Voltage
    • Supports USB2.0, USB 3.0, USB 3.1 (Type C), and USB Power Delivery (USB-PD) Input Current Settings
    • Seamless transition among buck, buck-boost and boost operations
    • Input current and voltage regulation (IIN_DPM and VINDPM) against source overload
    • Input Current Optimizer (ICO) to extract max input power
  • No additional battery MOSFET is needed to save BOM
  • Power up USB port from battery (USB OTG)
    • 3-V to 24-V VOTG with 8-mV resolution
  • Switching frequency dithering feature for EMI improvement
  • Two level discharge current limit protection to avoid battery wire-out
  • Host control interface for flexible system configuration
    • I2C (BQ25731) port optimal system performance and status reporting
    • Hardware pin to set input current limit without EC control
  • Integrated ADC to monitor voltage, current and power
  • High accuracy for the regulation and monitor
    • ±0.5% Charge voltage regulation
    • ±3% Input/charge current regulation
    • ±2% Input/charge current monitor
    • ±4% Power monitor
  • Safety
    • Thermal shutdown
    • Input, system, battery overvoltage protection
    • Input, MOSFET, inductor overcurrent protection
  • Low battery quiescent current
  • Package: 32-Pin 4 × 4 WQFN

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This device is a synchronous buck-boost battery charge controller, offering a low component count, high efficiency solution for space constrained, 1s-5s battery charging applications.

The BQ25731 charges a battery from a wide range of input sources including USB adapter, high voltage USB PD sources, and traditional adapters.

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 automatically transits among the buck, boost, and buck-boost configuration without host control.

In the absence of an input source, the BQ25731 supports a USB On-the-Go (OTG) function from a 1- to 5-cell battery to generate an adjustable 3 V to 24 V on VBUS with 8-mV resolution. The OTG output voltage transition slew rate can be configurable, which complies with the USB PD 3.0 PPS specifications.

The BQ25731 monitors adapter current, battery current, and system power. No additional BATFET is needed, when a depleted battery is inserted charge is enabled by default for 256 mA.

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Request samples & more information

  • The full data sheet and other information are available. Request now
  • Preproduction samples are available (PQ25731RSNT). Request now
  • 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

Technical documentation

= Top documentation for this product selected by TI
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Type Title Date
* Datasheet BQ25731 I2C 1- to 5-Cell Narrow VDC Buck-Boost Battery Charge Controller datasheet Jun. 25, 2020
User guide BQ2573x Evaluation Module (Rev. A) Jan. 19, 2021
Technical articles Adding USB Type-C® with USB Power Delivery to battery-powered applications Nov. 11, 2020
More literature BQ25731EVM EU Declaration of Conformity (DoC) Jun. 19, 2020
Technical articles When to use rechargeable batteries in small battery applications Oct. 01, 2019
Technical articles Should I use a linear charger or a switching charger? Oct. 30, 2015
Technical articles Summertime and the livin' is easy Jun. 20, 2014

Design & development

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

Hardware development

The BQ25731 evaluation module (EVM) is an I2C controlled NVDC (narrow voltage DC) buck boost charge controller with N-CH MOSFET Selector and Current Monitoring. The input voltage range, for the buck converter, is between 3.5V and 24 V, with a programmable output of 1–5 cells and a charge (...)
  • Host-controlled NVDC 1S-5S battery buck boost charger with 3.5-V to approximately 24-V input; 1-V to approximately 19.2-V charging output and 3-V to approximately 20.8-V OTG output
  • Ultra low quiescent current of 600 μA and high PFM light load efficiency >80% at 200-mW load and PTM operation to (...)

Software development

Battery Management Studio (bqStudio) Software
BQSTUDIO 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 (...)
  • Real-time Gauge Dashboard for monitoring basic registers
  • Full register access and logging
  • Full data memory access and logging
  • Product configuration and monitoring tools
  • Import and export of product configurations
  • Calibration and test automation
  • Export of FS files for the target production environment 

CAD/CAE symbols

Package Pins Download
QFN (RSN) 32 View options

Ordering & quality

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  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
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  • Qualification summary
  • Ongoing reliability monitoring

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