SLUS892D December   2009  – December 2019 BQ24610 , BQ24617

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
    1.     Pin Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Battery Voltage Regulation
      2. 9.3.2  Battery Current Regulation
      3. 9.3.3  Input Adapter Current Regulation
      4. 9.3.4  Precharge
      5. 9.3.5  Charge Termination, Recharge, and Safety Timer
      6. 9.3.6  Power Up
      7. 9.3.7  Enable and Disable Charging
      8. 9.3.8  System Power Selector
      9. 9.3.9  Automatic Internal Soft-Start Charger Current
      10. 9.3.10 Converter Operation
      11. 9.3.11 Synchronous and Nonsynchronous Operation
      12. 9.3.12 Cycle-by-Cycle Charge Undercurrent Protection
      13. 9.3.13 Input Overvoltage Protection (ACOV)
      14. 9.3.14 Input Undervoltage Lockout (UVLO)
      15. 9.3.15 Battery Overvoltage Protection
      16. 9.3.16 Cycle-by-Cycle Charge Overcurrent Protection
      17. 9.3.17 Thermal Shutdown Protection
      18. 9.3.18 Temperature Qualification
      19. 9.3.19 Timer Fault Recovery
      20. 9.3.20 PG Output
      21. 9.3.21 CE (Charge Enable)
      22. 9.3.22 Charge Status Outputs
      23. 9.3.23 Battery Detection
    4. 9.4 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 System with Power Path
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
          1. 10.2.1.2.1 Inductor Selection
          2. 10.2.1.2.2 Input Capacitor
          3. 10.2.1.2.3 Output Capacitor
          4. 10.2.1.2.4 Power MOSFETs Selection
          5. 10.2.1.2.5 Input Filter Design
          6. 10.2.1.2.6 Inductor, Capacitor, and Sense Resistor Selection Guidelines
        3. 10.2.1.3 Application Curves
      2. 10.2.2 Simplified System without Power Path or DPM
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
        3. 10.2.2.3 Application Curves
      3. 10.2.3 Lead-Acid Charging System
        1. 10.2.3.1 Design Requirements
        2. 10.2.3.2 Detailed Design Procedure
        3. 10.2.3.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Related Links
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Support Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

10.2.3 Lead-Acid Charging System

Compared to Li-ion batteries, Lead-acid batteries have a wider recharge threshold. The charger begins in CC mode and then switches to CV mode. From Figure 25 charge regulation voltage, and float voltage can be calculated according to Equation 1 where R1 = R15 when Q3 is off, and R1 = R15||R16 when Q3 is on. The circuit uses the STAT2 pin, which is pulled high while the battery is charging, to turn on Q3 and increase the charger’s CV regulation point, to the battery’s bulk voltage until the charger senses that the current has tapered off. Once the charging current falls below the termination current threshold, STAT2 goes to low impedance. This causes Q3 to turn off, thus lowering the recharge threshold voltage, VRECHG, to the battery’s float voltage. When VBAT drops to VRECHG, the charger returns to CC charging and sends a pulse of current to recharge the battery to the bulk voltage and the cycle repeats.

BQ24610 BQ24617 FBD_611D.gifFigure 25. Lead-Acid Charging System Schematic