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BQ24735

ACTIVE

SMBus 1-4 cell Buck battery charge controller to support turbo boost mode

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Data sheet

BQ24735

ACTIVE
Data sheet Order now

Product details

Number of series cells 1, 2, 3, 4 Charge current (max) (A) 8 Vin (max) (V) 24 Cell chemistry Li-Ion/Li-Polymer Battery charge voltage (min) (V) 1.024 Battery charge voltage (max) (V) 19.2 Absolute max Vin (max) (V) 30 Control topology Switch-Mode Buck Control interface SMBus Features Input OVP Vin (min) (V) 4.5 Rating Catalog Operating temperature range (°C) -40 to 85
Number of series cells 1, 2, 3, 4 Charge current (max) (A) 8 Vin (max) (V) 24 Cell chemistry Li-Ion/Li-Polymer Battery charge voltage (min) (V) 1.024 Battery charge voltage (max) (V) 19.2 Absolute max Vin (max) (V) 30 Control topology Switch-Mode Buck Control interface SMBus Features Input OVP Vin (min) (V) 4.5 Rating Catalog Operating temperature range (°C) -40 to 85
VQFN (RGR) 20 12.25 mm² 3.5 x 3.5
  • Adapter and Battery Provide Power to System
    Together to Support Intel® CPU Turbo Boost
    Mode
  • SMBus Host-Controlled NMOS-NMOS
    Synchronous Buck Converter With Programmable
    615-, 750-, and 885-kHz Switching Frequencies
  • Automatic N-Channel MOSFET Selection of
    System Power Source From Adapter or Battery
    Driven by Internal Charge Pumps
  • Enhanced Safety Features for Overvoltage
    Protection, Overcurrent Protection, Battery,
    Inductor and MOSFET Short-Circuit Protection
  • Programmable Input Current, Charge Voltage,
    Charge Current Limits
    • ±0.5% Charge Voltage Accuracy up to 19.2 V
    • ±3% Charge Current Accuracy up to 8.128 A
    • ±3% Input Current Accuracy up to 8.064 A
    • ±2% 20× Adapter Current or Charge Current
      Amplifier Output Accuracy
  • Programmable Battery Depletion Threshold, and
    Battery LEARN Function
  • Programmable Adapter Detection and Indicator
  • Integrated Loop Compensation and Soft Start
  • Real-Time System Control on ILIM Pin to Limit
    Charge Current
  • AC Adapter Operating Range: 4.5 V to 24 V
  • 5-µA Off-State Battery Discharge Current
  • 0.65 mA (0.8 mA Max) Adapter Standby
    Quiescent Current
  • Adapter and Battery Provide Power to System
    Together to Support Intel® CPU Turbo Boost
    Mode
  • SMBus Host-Controlled NMOS-NMOS
    Synchronous Buck Converter With Programmable
    615-, 750-, and 885-kHz Switching Frequencies
  • Automatic N-Channel MOSFET Selection of
    System Power Source From Adapter or Battery
    Driven by Internal Charge Pumps
  • Enhanced Safety Features for Overvoltage
    Protection, Overcurrent Protection, Battery,
    Inductor and MOSFET Short-Circuit Protection
  • Programmable Input Current, Charge Voltage,
    Charge Current Limits
    • ±0.5% Charge Voltage Accuracy up to 19.2 V
    • ±3% Charge Current Accuracy up to 8.128 A
    • ±3% Input Current Accuracy up to 8.064 A
    • ±2% 20× Adapter Current or Charge Current
      Amplifier Output Accuracy
  • Programmable Battery Depletion Threshold, and
    Battery LEARN Function
  • Programmable Adapter Detection and Indicator
  • Integrated Loop Compensation and Soft Start
  • Real-Time System Control on ILIM Pin to Limit
    Charge Current
  • AC Adapter Operating Range: 4.5 V to 24 V
  • 5-µA Off-State Battery Discharge Current
  • 0.65 mA (0.8 mA Max) Adapter Standby
    Quiescent Current

The bq24735 device is a high-efficiency, synchronous battery charger, offering low component count for space-constrained, multichemistry battery charging applications. The bq24735 device supports turbo boost by allowing battery discharge energy to the system when system power demand is temporarily higher than the adapter maximum power level so the adapter will not crash.

The bq24735 device uses two charge pumps to separately drive N-channel MOSFETs (ACFET, RBFET, and BATFET) for automatic system power source selection.

SMBus controlled input current, charge current, and charge voltage digital-to-analog converters (DACs) allow for very high-regulation accuracies that can be easily programmed by the system power management microcontroller.

The bq24735 device uses an internal input current register or an external ILIM pin to throttle down PWM modulation to reduce the charge current. The bq24735 device charges 1-, 2-, 3-, or 4-series Li+ cells.

The bq24735 device is a high-efficiency, synchronous battery charger, offering low component count for space-constrained, multichemistry battery charging applications. The bq24735 device supports turbo boost by allowing battery discharge energy to the system when system power demand is temporarily higher than the adapter maximum power level so the adapter will not crash.

The bq24735 device uses two charge pumps to separately drive N-channel MOSFETs (ACFET, RBFET, and BATFET) for automatic system power source selection.

SMBus controlled input current, charge current, and charge voltage digital-to-analog converters (DACs) allow for very high-regulation accuracies that can be easily programmed by the system power management microcontroller.

The bq24735 device uses an internal input current register or an external ILIM pin to throttle down PWM modulation to reduce the charge current. The bq24735 device charges 1-, 2-, 3-, or 4-series Li+ cells.
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Technical documentation

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Type Title Date
* Data sheet bq24735 1- to 4-Cell Li+ Battery SMBus Charge Controller for Supporting Turbo Boost Mode With N-Channel Power MOSFET Selector datasheet (Rev. B) PDF | HTML 29 Apr 2015
Application note Autonomous Smart Battery Guide PDF | HTML 15 Oct 2021
Technical article When to use rechargeable batteries in small battery applications 01 Oct 2019
Technical article Understanding battery charger features and charging topologies 19 Sep 2016
Technical article Should I use a linear charger or a switching charger? 31 Oct 2015
Technical article Summertime and the livin' is easy 20 Jun 2014
Analog Design Journal 1Q 2012 Issue Analog Applications Journal 31 Jan 2012
Analog Design Journal Turbo boost charger supports CPU turbo mode 31 Jan 2012
User guide bq24735/725A Battery Charger Evaluation Module (Rev. A) 16 Aug 2011

Design & development

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

Evaluation board

BQ24735EVM-710 — Evaluation Module for BQ24735, 1-4 Cell Li+ Battery SMBus Charge Controller

The BQ24735EVM-710 evaluation module (EVM) is a complete charger module for evaluating a multicell synchronous notebook turbo boost charge using the bq24735 devices. It is designed to deliver up to 4 A of charge current to Li-ion or Li-polymer applications. The charge current is programmable by (...)

User guide: PDF
Not available on TI.com
Driver or library

BQ24735SW-LINUX — Linux Driver for BQ24735

The Linux driver supports the BQ24735 1-4 cell Li+ battery charge controller. The Linux driver supports communication through the I2C bus and interfaces with the power supply sub-system.

 

Linux mainline status

Available in Linux Main line: Yes
Available through git.ti.com: N/A 

Linux source files

The (...)

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GUI for evaluation module (EVM)

bq24725A/735/728/738 SMBus Gui (Rev. A)

SLUC258A.ZIP (2259 KB)
Download
Calculation tool

bq24725_725A_726_707_73x Calculation Tool (Rev. A)

SLUC203A.ZIP (394 KB)
Download
Reference designs

TIDA-00039 — 1-4 Cell Li+ Battery SMBus Charge Controller Reference Design

This reference design is a complete charger module for evaluating a multi-cell synchronous notebook turbo boost charge using the bq24735 devices. It is designed to deliver up to 4 A of charge current to Li-ion or Li-polymer applications. The charge current is programmable by SMBus interface through (...)
Test report: PDF
Schematic: PDF
Package Pins Download
VQFN (RGR) 20 View options

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