ZHCSGY5A October   2017  – December 2017


  1. 特性
  2. 应用范围
  3. 说明
    1.     典型应用电路
  4. 修订历史记录
  5. 说明 (续)
  6. Device Comparison Table
  7. Pin Configuration and Functions
    1.     Pin Functions
    2. 7.1 EN1/EN2 Settings
  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 Dissipation Ratings
    6. 8.6 Electrical Characteristics
    7. 8.7 Typical Characteristics
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Undervoltage Lockout (UVLO)
      2. 9.3.2 Power On
      3. 9.3.3 Overvoltage Protection (OVP)
      4. 9.3.4 Dynamic Power-Path Management
        1. Input Source Connected (ADAPTER or USB)
          1. Input DPM Mode (VIN-DPM)
          2. DPPM Mode
          3. Battery Supplement Mode
        2. Input Source Not Connected
      5. 9.3.5 Battery Charging
        1. Charge Current Translator
        2. Battery Detection and Recharge
        3. Battery Disconnect (SYSOFF Input, bq24076, bq24078)
        4. Dynamic Charge Timers (TMR Input)
        5. Status Indicators (PGOOD, CHG)
        6. Thermal Regulation and Thermal Shutdown
      6. 9.3.6 Battery Pack Temperature Monitoring
    4. 9.4 Device Functional Modes
      1. 9.4.1 Sleep Mode
      2. 9.4.2 Explanation of Deglitch Times and Comparator Hysteresis
  10. 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. bq2407x Charger Design Example
          1. System ON/OFF (SYSOFF) (bq24076 or bq24078 only)
        2. Calculations
          1. Program the Fast Charge Current (ISET):
          2. Program the Input Current Limit (ILIM)
          3. Program 6.25-hour Fast-Charge Safety Timer (TMR)
        3. TS Function
        4. CHG and PGOOD
        5. Selecting IN, OUT, and BAT Pin Capacitors
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Considerations
  13. 13器件和文档支持
    1. 13.1 器件支持
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 相关链接
    3. 13.3 接收文档更新通知
    4. 13.4 社区资源
    5. 13.5 商标
    6. 13.6 静电放电警告
    7. 13.7 Glossary
  14. 14机械、封装和可订购信息


机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)

Power On

When VIN exceeds the UVLO threshold, the bq2407x powers up. While VIN is below VBAT + VIN(DT), the host commands at the control inputs (CE, EN1 and EN2) are ignored. The Q1 FET connected between IN and OUT pins is off, and the status outputs CHG and PGOOD are high impedance. The Q2 FET that connects BAT to OUT is ON. (If SYSOFF is high, Q2 is off). During this mode, the VOUT(SC2) circuitry is active and monitors for overload conditions on OUT.

Once VIN rises above VBAT + VIN(DT), PGOOD is driven low to indicate the valid power status and the CE, EN1, and EN2 inputs are read. The device enters standby mode if (EN1 = EN2 = HI) or if an input overvoltage condition occurs. In standby mode, Q1 is OFF and Q2 is ON so OUT is connected to the battery input. (If SYSOFF is high, FET Q2 is off). During this mode, the VOUT(SC2) circuitry is active and monitors for overload conditions on OUT.

When the input voltage at IN is within the valid range: VIN > UVLO AND VIN > VBAT + VIN(DT)AND VIN < VOVP, and the EN1 and EN2 pins indicate that the USB suspend mode is not enabled [(EN1, EN2) ≠ (HI, HI)] all internal timers and other circuit blocks are activated. The device then checks for short-circuits at the ISET and ILIM pins. If no short conditions exists, the device switches on the input FET Q1 with a 100mA current limit to checks for a short circuit at OUT. When VOUT is above VO(SC1), the FET Q1 switches to the current limit threshold set by EN1, EN2 and RILIM and the device enters into the normal operation. During normal operation, the system is powered by the input source (Q1 is regulating), and the device continuously monitors the status of CE, EN1 and EN2 as well as the input voltage conditions.

bq24076 bq24078 start_flow_lus810.gifFigure 13. Startup Flow Diagram