JAJSBJ1B July   2010  – January 2020 BQ24650

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      代表的なアプリケーション
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Battery Voltage Regulation
      2. 8.3.2  Input Voltage Regulation
      3. 8.3.3  Battery Current Regulation
      4. 8.3.4  Battery Precharge
      5. 8.3.5  Charge Termination and Recharge
      6. 8.3.6  Power Up
      7. 8.3.7  Enable and Disable Charging
      8. 8.3.8  Automatic Internal Soft-Start Charger Current
      9. 8.3.9  Converter Operation
      10. 8.3.10 Synchronous and Non-Synchronous Operation
      11. 8.3.11 Cycle-by-Cycle Charge Undercurrent
      12. 8.3.12 Input Overvoltage Protection (ACOV)
      13. 8.3.13 Input Undervoltage Lockout (UVLO)
      14. 8.3.14 Battery Overvoltage Protection
      15. 8.3.15 Cycle-by-Cycle Charge Overcurrent Protection
      16. 8.3.16 Thermal Shutdown Protection
      17. 8.3.17 Temperature Qualification
      18. 8.3.18 Charge Enable
      19. 8.3.19 Inductor, Capacitor, and Sense Resistor Selection Guidelines
      20. 8.3.20 Charge Status Outputs
      21. 8.3.21 Battery Detection
        1. 8.3.21.1 Example
    4. 8.4 Device Functional Modes
      1. 8.4.1 Converter Operation
      2. 8.4.2 Synchronous and Non-Synchronous Operation
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Inductor Selection
        2. 9.2.2.2 Input Capacitor
        3. 9.2.2.3 Output Capacitor
        4. 9.2.2.4 Power MOSFETs Selection
        5. 9.2.2.5 Input Filter Design
        6. 9.2.2.6 MPPT Temperature Compensation
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 デバイス・サポート
      1. 12.1.1 デベロッパー・ネットワークの製品に関する免責事項
    2. 12.2 ドキュメントの更新通知を受け取る方法
    3. 12.3 サポート・リソース
    4. 12.4 商標
    5. 12.5 静電気放電に関する注意事項
    6. 12.6 Glossary
  13. 13メカニカル、パッケージ、および注文情報

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

8.3.1 Battery Voltage Regulation

The BQ24650 uses a high accuracy voltage regulator for the charging voltage. The charge voltage is programmed through a resistor divider from the battery to ground, with the midpoint tied to the VFB pin. The voltage at the VFB pin is regulated to 2.1 V, giving Equation 1 for the regulation voltage:

Equation 1. BQ24650 EQ1_vbat_lusa75.gif

where

  • R2 is connected from VFB to the battery
  • and R1 is connected from VFB to GND.

Li-Ion, LiFePO4, and sealed lead acid are widely used battery chemistries. Most commercial Li-ion cells can now be charged to 4.2 V/cell. A LiFePO4 battery allows a much higher charge and discharge rate, but the energy density is lower. The typical cell voltage is 3.6 V. The charge profile of both Li-Ion and LiFePO4 is preconditioning, constant current, and constant voltage. For maximum cycle life, the end-of-charge voltage threshold could be lowered to 4.1 V/cell.

Although the energy density is much lower than Li-based chemistry, lead acid is still popular due to its low manufacturing cost and high discharge rates. The typical voltage limit is from 2.3 V to 2.45 V. After the battery has been fully charged, a float charge is required to compensate for the self-discharge. The float charge limit is 100 mV to 200 mV below the constant voltage limit.

BQ24650 chg_profile_lusa75.gifFigure 9. Typical Charging Profile