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BQ25798

ACTIVE

I²C controlled, 1-4-cell, 5-A buck-boost solar battery charger with dual-input selector and MPPT

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Data sheet

BQ25798

ACTIVE
Data sheet Order now

Product details

Rating Catalog Number of series cells 1, 2, 3, 4 Cell chemistry Li-Ion/Li-Polymer, Lithium Phosphate/LiFePO4 Charge current (max) (A) 5 Features BAT temp thermistor monitoring (JEITA profile), BAT temp thermistor monitoring (hot/cold profile), IC thermal regulation, ICO (Input Current Optimization), IINDPM (Input current limit), Input OVP, Integrated ADC, Integrated LDO, Power Path, Solar input/MPPT, USB C/PD compatible, USB D+/D-/BC1.2 integrated, USB OTG integrated, VINDPM (Input voltage threshold to maximize adaptor power) Vin (min) (V) 3.6 Vin (max) (V) 24 Absolute max Vin (max) (V) 30 Control topology Switch-Mode Buck-boost Battery charge voltage (min) (V) 3 Battery charge voltage (max) (V) 18.8 Control interface I2C Operating temperature range (°C) -40 to 85
Rating Catalog Number of series cells 1, 2, 3, 4 Cell chemistry Li-Ion/Li-Polymer, Lithium Phosphate/LiFePO4 Charge current (max) (A) 5 Features BAT temp thermistor monitoring (JEITA profile), BAT temp thermistor monitoring (hot/cold profile), IC thermal regulation, ICO (Input Current Optimization), IINDPM (Input current limit), Input OVP, Integrated ADC, Integrated LDO, Power Path, Solar input/MPPT, USB C/PD compatible, USB D+/D-/BC1.2 integrated, USB OTG integrated, VINDPM (Input voltage threshold to maximize adaptor power) Vin (min) (V) 3.6 Vin (max) (V) 24 Absolute max Vin (max) (V) 30 Control topology Switch-Mode Buck-boost Battery charge voltage (min) (V) 3 Battery charge voltage (max) (V) 18.8 Control interface I2C Operating temperature range (°C) -40 to 85
VQFN-HR (RQM) 29 16 mm² 4 x 4
  • High power density, high integration buck -boost charger for 1-4 cell batteries supporting USB PD 3.0 profile
    • Integrates four switching MOSFETs, BATFET
    • Integrates input and charging current sensing
  • Highly efficient
    • 750-kHz or 1.5-MHz switching frequencies
    • 5-A charging current with 10-mA resolution
      • 96.5% efficient: 16-V battery at 3A from 20V
  • Supports a wide range of input sources
    • Autonomously sampled open circuit voltage (VOC) maximum power point tracking (MPPT) for charging from a photovoltaic panel
    • 3.6-V to 24-V wide input operating voltage range with 30-V absolute maximum rating
    • Detects USB BC1.2, HVDCP and non-standard adapters
  • Dual-input power mux controller (optional)
  • Narrow voltage DC (NVDC) power path
  • Backup Mode with Ultra-fast switchover to adjustable voltage
  • Powers USB port from battery (USB OTG)
    • 2.8-V to 22-V OTG output voltage with 10-mV resolution to support USB-PD PPS
    • OTG output current regulation up to 3.32 A with 40-mA resolution
  • Flexible autonomous and I2C mode for optimal system performance
  • Integrated 16-bit ADC for voltage, current, and temperature monitoring
  • Low battery quiescent current
    • 17 µA for battery only operation
    • 500 nA in Charger Shutdown Mode
  • High accuracy
    • -0.25% to +0.65% charge voltage regulation for 2S batteries
    • ±5% charge current regulation
    • ±5% input current regulation
  • Safety
    • Thermal regulation and thermal shutdown
    • Input/battery OVP and OCP
    • Converter MOSFETs OCP
    • Charging safety timer
  • Package
    • 29-Pin 4 mm × 4 mm QFN
  • High power density, high integration buck -boost charger for 1-4 cell batteries supporting USB PD 3.0 profile
    • Integrates four switching MOSFETs, BATFET
    • Integrates input and charging current sensing
  • Highly efficient
    • 750-kHz or 1.5-MHz switching frequencies
    • 5-A charging current with 10-mA resolution
      • 96.5% efficient: 16-V battery at 3A from 20V
  • Supports a wide range of input sources
    • Autonomously sampled open circuit voltage (VOC) maximum power point tracking (MPPT) for charging from a photovoltaic panel
    • 3.6-V to 24-V wide input operating voltage range with 30-V absolute maximum rating
    • Detects USB BC1.2, HVDCP and non-standard adapters
  • Dual-input power mux controller (optional)
  • Narrow voltage DC (NVDC) power path
  • Backup Mode with Ultra-fast switchover to adjustable voltage
  • Powers USB port from battery (USB OTG)
    • 2.8-V to 22-V OTG output voltage with 10-mV resolution to support USB-PD PPS
    • OTG output current regulation up to 3.32 A with 40-mA resolution
  • Flexible autonomous and I2C mode for optimal system performance
  • Integrated 16-bit ADC for voltage, current, and temperature monitoring
  • Low battery quiescent current
    • 17 µA for battery only operation
    • 500 nA in Charger Shutdown Mode
  • High accuracy
    • -0.25% to +0.65% charge voltage regulation for 2S batteries
    • ±5% charge current regulation
    • ±5% input current regulation
  • Safety
    • Thermal regulation and thermal shutdown
    • Input/battery OVP and OCP
    • Converter MOSFETs OCP
    • Charging safety timer
  • Package
    • 29-Pin 4 mm × 4 mm QFN

The BQ25798 is a fully integrated switch-mode buck -boost charger for 1-4 cell Li-ion batteries and Li-polymer batteries. The integration includes 4 switching MOSFETs, input and charging current sensing circuits, the battery FET and all the loop compensation of the buck-boost converter. It uses NVDC power path management, regulating the system not dropping below a configurable minimum system voltage. When system power exceeds the input source rating, battery supplement mode supports the system without overloading the input source. BQ25798 also maximizes power from photovoltaic panels using its built-in VOC scaling MPPT algorithm. BQ25798 supports ultra-fast switchover from the adapter to a converted battery voltage in Backup Mode.

The BQ25798 is a fully integrated switch-mode buck -boost charger for 1-4 cell Li-ion batteries and Li-polymer batteries. The integration includes 4 switching MOSFETs, input and charging current sensing circuits, the battery FET and all the loop compensation of the buck-boost converter. It uses NVDC power path management, regulating the system not dropping below a configurable minimum system voltage. When system power exceeds the input source rating, battery supplement mode supports the system without overloading the input source. BQ25798 also maximizes power from photovoltaic panels using its built-in VOC scaling MPPT algorithm. BQ25798 supports ultra-fast switchover from the adapter to a converted battery voltage in Backup Mode.
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Technical documentation

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* Data sheet BQ25798 I2C Controlled, 1- to 4-Cell, 5-A Buck-Boost Battery Charger with Dual-Input Selector, MPPT for Solar Panels and Fast Backup Mode datasheet (Rev. B) PDF | HTML 13 Jan 2023
Application note Single Cell Battery Charger Applications with Dual Sources PDF | HTML 11 Aug 2025
Design guide Integrated USB Type-C®, USB Power Delivery and Charging Reference Design for 2–4 Cell Batteries (Rev. C) PDF | HTML 13 Jun 2025
Application note How to Prevent Solar-Powered Chargers From Shutting Down in Low Light Conditions PDF | HTML 11 Mar 2025
Technical article USB Type-C® 與 USB 電力輸送：專為延伸功率範圍和電池供電系統進行設計 (Rev. A) PDF | HTML 28 Oct 2024
Technical article USB Type-C® 및 USB Power Delivery: 확장 전력 범위 및 배터리 구동 시스템 모두를 위한 설계 (Rev. A) PDF | HTML 28 Oct 2024
Technical article USB Type-C® and USB Power Delivery: Designing for both Extended Power Range and battery-powered systems (Rev. A) PDF | HTML 14 Oct 2024
Application note Finding the Correct Battery Charging Design to Power Vacuum Robot System PDF | HTML 04 Mar 2024
Application note Increasing NVCD Battery Chargers' Discharge Current PDF | HTML 10 Jan 2024
Application note LiFePO4 Design Considerations PDF | HTML 26 Jul 2023
Application note Choosing the Correct Solar Battery Charger for Your Solar Application PDF | HTML 22 Jun 2023
Application note How to Quickly and Safely Charge Supercapacitors PDF | HTML 27 Mar 2023
White paper Combining Buck-Boost Battery Chargers and USB Type-C Power Delivery for Maximum (Rev. A) PDF | HTML 19 May 2022
Application note Implementing a Simple Maximum Power Point Tracking (MPPT) Algorithm PDF | HTML 16 Dec 2021
Application note State of Charge Estimation Using Smart Battery Charger PDF | HTML 11 Oct 2021
Technical article How to choose the right battery-charger IC for ultrasound point-of-care products PDF | HTML 24 Mar 2021
Technical article Maximize power density with buck-boost charging and USB Type C™ Power Delivery PDF | HTML 29 Jun 2020

Design & development

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

Evaluation board

BQ25798BKUPEVM — BQ25798 evaluation module I²C controlled 5-A, 1- to 4-cell buck-boost charger in QFN package

The BQ25798BKUPEVM evaluation module (EVM) is used to evaluate the BQ25798 device in back-up mode applications. The BQ25798 is an integrated switched-mode buck-boost battery charge management device in HOTROD (QFN) package, intended for 1- to 4-series cell Li-ion and Li-polymer batteries from 3.6-V (...)
User guide: PDF | HTML
Not available on TI.com
Evaluation board

BQ25798EVM — BQ25798 evaluation module I²C controlled, 1- to 4-cell, 5-A buck-boost charger, dual input and MPPT

The BQ25798EVM evaluation module (EVM) is used to evaluate the BQ25798 device. The BQ25798 is an integrated switched-mode buck-boost battery charge management device in HOTROD (QFN) package, intended for 1-series to 4-series cell Li-ion and Li-polymer batteries from 3.6-V to 24-V input with (...)
User guide: PDF | HTML
Not available on TI.com
Evaluation board

USB-PD-CHG-EVM-01 — Integrated USB Type-C® Power Delivery (PD) and charging reference design for 2-4 cell batteries EVM

The USB-PD-CHG-EVM-01 evaluation module (EVM) is used to evaluate the BQ25798 device and TPS25751 device together. The BQ25798 is an integrated switched-mode buck-boost battery charge management device in HOTROD (QFN) package, intended for 1- to 4-series cell Li-ion and Li-polymer batteries from (...)

Not available on TI.com
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.
Evaluate in the cloud
Reference designs

TIDA-050047 — Integrated USB Type-C®, USB Power Delivery and charging reference design for 2–4 cell batteries

This reference design features charging up to 20V at 5A without the need for any external FETs, enabling a much smaller solution size and reducing total BOM cost. A microprocessor is also not necessary as the TPS25750 Power Delivery (PD) controller will handle the I2C communication to the BQ25798 (...)
Design guide: PDF
Schematic: PDF
Package Pins CAD symbols, footprints & 3D models
VQFN-HR (RQM) 29 Ultra Librarian
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