JAJSJH4D december   2010  – september 2020 BQ24133

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Revision History
  6. 5 Description (continued)
  7. 6 Device Comparison Table
  8. 7 Pin Configuration and Functions
    1.     Pin Functions
  9. 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
  10. 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  Battery Precharge Current Regulation
      4. 9.3.4  Input Current Regulation
      5. 9.3.5  Charge Termination, Recharge, And Safety Timers
      6. 9.3.6  Power Up
      7. 9.3.7  Input Undervoltage Lockout (UVLO)
      8. 9.3.8  Input Overvoltage/Undervoltage Protection
      9. 9.3.9  Enable and Disable Charging
      10. 9.3.10 System Power Selector
      11. 9.3.11 Converter Operation
      12. 9.3.12 Automatic Internal Soft-Start Charger Current
      13. 9.3.13 Charge Overcurrent Protection
      14. 9.3.14 Charge Undercurrent Protection
      15. 9.3.15 Battery Detection
        1. 9.3.15.1 Example
      16. 9.3.16 Battery Short Protection
      17. 9.3.17 Battery Overvoltage Protection
      18. 9.3.18 Temperature Qualification
      19. 9.3.19 MOSFET Short Circuit and Inductor Short Circuit Protection
      20. 9.3.20 Thermal Regulation and Shutdown Protection
      21. 9.3.21 Timer Fault Recovery
      22. 9.3.22 Charge Status Outputs
    4. 9.4 Device Functional Modes
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Inductor Selection
        2. 10.2.2.2 Input Capacitor
        3. 10.2.2.3 Output Capacitor
        4. 10.2.2.4 Input Filter Design
        5. 10.2.2.5 Input ACFET and RBFET Selection
        6. 10.2.2.6 Inductor, Capacitor, and Sense Resistor Selection Guidelines
      3. 10.2.3 Application Curve
    3. 10.3 System Examples
  12. 11Power Supply Recommendations
  13. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Examples
  14. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 サード・パーティ製品に関する免責事項
    2. 13.2 ドキュメントの更新通知を受け取る方法
    3. 13.3 サポート・リソース
    4. 13.4 Trademarks
    5. 13.5 静電気放電に関する注意事項
    6. 13.6 用語集
  15. 14Mechanical, Packaging, and Orderable Information

9.3.5 Charge Termination, Recharge, And Safety Timers

The charger monitors the charging current during the voltage regulation phase. Termination is detected when the SRN voltage is higher than recharge threshold and the charge current is less than the termination current threshold, as calculated below:

Equation 4. GUID-C78F4956-6522-45C4-A947-2FD5E9410EC6-low.gif

where

  • VISET is the voltage on the ISET pin.
  • RSR is the sense resistor.

There is a 25-ms deglitch time during transition between fast charge and precharge.

As a safety backup, the charger also provides an internal fixed 30 minutes precharge safety timer and a programmable fast charge timer. The fast charge time is programmed by the capacitor connected between the TTC pin and AGND, and is given by the formula:

Equation 5. GUID-D7C9CB33-ED38-4333-BEF7-78F6AD87262D-low.gif

where

  • CTTC is the capacitor connected to TTC.
  • KTTC is the constant multiplier.

A new charge cycle is initiated when one of the following conditions occurs:

  • The battery voltage falls below the recharge threshold
  • A power-on-reset (POR) event occurs
  • ISET pin toggled below 40 mV (disable charge) and above 120 mV (enable charge)

Pull the TTC pin to AGND to disable both termination and fast charge safety timer (reset timer). Pull the TTC pin to VREF to disable the safety timer, but allow charge termination.