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BQ25798
  • BQ25798
  • BQ25798

BQ25798

ACTIVE

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

Texas Instruments BQ25798 Product Info

1 April 2026 1

Parameters

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

Package

VQFN-HR (RQM)-29-16 mm² 4 x 4

Features

  • 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

Description

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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