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  • BQ24725A SMBus 1- to 4-Cell Li+ Buck Battery Charge Controller with N-Channel Power MOSFET Selector

    • SLUSAL0C September   2011  – January 2020 BQ24725A

      PRODUCTION DATA.  

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  • BQ24725A SMBus 1- to 4-Cell Li+ Buck Battery Charge Controller with N-Channel Power MOSFET Selector
  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 SMBus Interface
    4. 8.4 Device Functional Modes
      1. 8.4.1  Adapter Detect and ACOK Output
      2. 8.4.2  Adapter Over Voltage (ACOVP)
      3. 8.4.3  System Power Selection
      4. 8.4.4  Battery LEARN Cycle
      5. 8.4.5  Enable and Disable Charging
      6. 8.4.6  Automatic Internal Soft-Start Charger Current
      7. 8.4.7  High Accuracy Current Sense Amplifier
      8. 8.4.8  Charge Timeout
      9. 8.4.9  Converter Operation
      10. 8.4.10 Continuous Conduction Mode (CCM)
      11. 8.4.11 Discontinuous Conduction Mode (DCM)
      12. 8.4.12 Input Over Current Protection (ACOC)
      13. 8.4.13 Charge Over Current Protection (CHGOCP)
      14. 8.4.14 Battery Over Voltage Protection (BATOVP)
      15. 8.4.15 Battery Shorted to Ground (BATLOWV)
      16. 8.4.16 Thermal Shutdown Protection (TSHUT)
      17. 8.4.17 EMI Switching Frequency Adjust
      18. 8.4.18 Inductor Short, MOSFET Short Protection
    5. 8.5 Register Maps
      1. 8.5.1 Battery-Charger Commands
      2. 8.5.2 Setting Charger Options
        1. Table 3. Charge Options Register (0x12H)
      3. 8.5.3 Setting the Charge Current
        1. Table 4. Charge Current Register (0x14H), Using 10mΩ Sense Resistor
      4. 8.5.4 Setting the Charge Voltage
        1. Table 5. Charge Voltage Register (0x15H)
      5. 8.5.5 Setting Input Current
        1. Table 6. Input Current Register (0x3FH), Using 10mΩ Sense Resistor
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Typical System with Two NMOS Selector
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Negative Output Voltage Protection
          2. 9.2.1.2.2 Reverse Input Voltage Protection
          3. 9.2.1.2.3 Reduce Battery Quiescent Current
          4. 9.2.1.2.4 Inductor Selection
          5. 9.2.1.2.5 Input Capacitor
          6. 9.2.1.2.6 Output Capacitor
          7. 9.2.1.2.7 Power MOSFETs Selection
          8. 9.2.1.2.8 Input Filter Design
          9. 9.2.1.2.9 BQ24725A Design Guideline
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Simplified System without Power Path
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
    3. 9.3 System Examples
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Third-Party Products Disclaimer
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information
  14. IMPORTANT NOTICE

Package Options

Mechanical Data (Package|Pins)
  • RGR|20
    • MPQF239A
Thermal pad, mechanical data (Package|Pins)
  • RGR|20
    • QFND242E
Orderable Information
  • slusal0c_oa
  • slusal0c_pm
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DATA SHEET

BQ24725A SMBus 1- to 4-Cell Li+ Buck Battery Charge Controller with N-Channel Power MOSFET Selector

1 Features

  • SMBus Host-controlled NMOS-NMOS synchronous buck converter with programmable 615kHz, 750kHz, and 885kHz switching frequencies
  • Automatic N-channel MOSFET selection of system power source from adapter or battery driven by internal charge pumps
  • Enhanced safety features for over voltage protection, over current protection, battery, inductor and MOSFET short circuit protection
  • Programmable input current, charge voltage, charge current limits
    • ±0.5% Charge voltage accuracy up to 19.2V
    • ±3% Charge current accuracy up to 8.128A
    • ±3% Input current accuracy up to 8.064A
    • ±2% 20x Adapter current or charge current amplifier output accuracy
  • Programmable battery depletion threshold, and battery LEARN function
  • Programmable adapter detection and indicator
  • Integrated soft start
  • Integrated loop compensation
  • Real time system control on ILIM pin to limit charge current
  • AC Adapter operating range 4.5V-24V
  • 5µA Off-state battery discharge current
  • 0.65mA (0.8mA max) Adapter standby quiescent current
  • 20-pin 3.5 x 3.5 mm2 VQFN Package

2 Applications

  • Portable notebook computers, UMPC, Ultra-thin notebook, and Netbook
  • Handheld terminal
  • Industrial and medical equipment
  • Portable equipment

3 Description

The BQ24725A is a high-efficiency, synchronous battery charger, offering low component count for space-constraint, multi-chemistry battery charging applications.

The BQ24725A utilizes 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 DACs allow for very high regulation accuracies that can be easily programmed by the system power management micro-controller.

The BQ24725A uses internal input current register or external ILIM pin to throttle down PWM modulation to reduce the charge current.

The BQ24725A charges one, two, three or four series Li+ cells.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
BQ24725A VQFN (20) 3.50mm x 3.50mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.
BQ24725A fp_schem_lusal0.gif

4 Revision History

Changes from B Revision (November 2018) to C Revision

  • Changed Title Go
  • Added Description for Figure 18Go
  • Added Simplified System without Power Path sectionGo

Changes from A Revision (August 2014) to B Revision

  • Changed Handling Ratings To: ESD RatingsGo
  • Moved Tstg From: Handling Ratings table To: Absolute Maximum RatingsGo
  • Added the Application NOTE Go
  • Changed the Notes to Figure 27 for additional resistor requirement to the application circuit when using low VGS input FETs Go

Changes from * Revision (September 2011) to A Revision

  • Changed the format to the new TI standard Go
  • Added the Device Information table Go
  • Added LODRV, HIDRV, and PHASE (2% duty cycle) to the Abs Max TableGo
  • Added the Handling Ratings tableGo

 
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