JAJSMK1 August   2023 BQ25756

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 概要 (続き)
  7. 6 Pin Configuration and Functions
  8. 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 Timing Requirements
    7. 7.7 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Device Power-On-Reset
      2. 8.3.2  Device Power-Up From Battery Without Input Source
      3. 8.3.3  Device Power Up from Input Source
        1. 8.3.3.1 VAC Operating Window Programming (ACUV and ACOV)
        2. 8.3.3.2 REGN Regulator (REGN LDO)
        3. 8.3.3.3 Compensation-Free Buck-Boost Converter Operation
          1. 8.3.3.3.1 Light-Load Operation
        4. 8.3.3.4 Switching Frequency and Synchronization (FSW_SYNC)
        5. 8.3.3.5 Device HIZ Mode
      4. 8.3.4  Battery Charging Management
        1. 8.3.4.1 Autonomous Charging Cycle
          1. 8.3.4.1.1 Charge Current Programming (ICHG pin and ICHG_REG)
        2. 8.3.4.2 Li-Ion Battery Charging Profile
        3. 8.3.4.3 LiFePO4 Battery Charging Profile
        4. 8.3.4.4 Charging Termination for Li-ion and LiFePO4
        5. 8.3.4.5 Charging Safety Timer
        6. 8.3.4.6 CV Timer
        7. 8.3.4.7 Thermistor Qualification
          1. 8.3.4.7.1 JEITA Guideline Compliance in Charge Mode
          2. 8.3.4.7.2 Cold/Hot Temperature Window in Reverse Mode
      5. 8.3.5  Power Management
        1. 8.3.5.1 Dynamic Power Management: Input Voltage and Input Current Regulation
          1. 8.3.5.1.1 Input Current Regulation
            1. 8.3.5.1.1.1 ILIM_HIZ Pin
          2. 8.3.5.1.2 Input Voltage Regulation
            1. 8.3.5.1.2.1 Max Power Point Tracking (MPPT) for Solar PV Panel
      6. 8.3.6  Reverse Mode Power Direction
      7. 8.3.7  Integrated 16-Bit ADC for Monitoring
      8. 8.3.8  Status Outputs (PG, STAT1, STAT2, and INT)
        1. 8.3.8.1 Power Good Indicator (PG)
        2. 8.3.8.2 Charging Status Indicator (STAT1, STAT2 Pins)
        3. 8.3.8.3 Interrupt to Host (INT)
      9. 8.3.9  Protections
        1. 8.3.9.1 Voltage and Current Monitoring
          1. 8.3.9.1.1 VAC Over-voltage Protection (VAC_OVP)
          2. 8.3.9.1.2 VAC Under-voltage Protection (VAC_UVP)
          3. 8.3.9.1.3 Battery Over-voltage Protection (BAT_OVP)
          4. 8.3.9.1.4 Battery Over-current Protection (BAT_OCP)
          5. 8.3.9.1.5 Reverse Mode Over-voltage Protection (REV_OVP)
          6. 8.3.9.1.6 Reverse Mode Under-voltage Protection (REV_UVP)
          7. 8.3.9.1.7 DRV_SUP Under-voltage and Over-voltage Protection (DRV_OKZ)
          8. 8.3.9.1.8 REGN Under-voltage Protection (REGN_OKZ)
        2. 8.3.9.2 Thermal Shutdown (TSHUT)
      10. 8.3.10 Serial Interface
        1. 8.3.10.1 Data Validity
        2. 8.3.10.2 START and STOP Conditions
        3. 8.3.10.3 Byte Format
        4. 8.3.10.4 Acknowledge (ACK) and Not Acknowledge (NACK)
        5. 8.3.10.5 Target Address and Data Direction Bit
        6. 8.3.10.6 Single Write and Read
        7. 8.3.10.7 Multi-Write and Multi-Read
    4. 8.4 Device Functional Modes
      1. 8.4.1 Host Mode and Default Mode
      2. 8.4.2 Register Bit Reset
    5. 8.5 BQ25756 Registers
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Typical Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 ACUV / ACOV Input Voltage Operating Window Programming
          2. 9.2.1.2.2 Charge Voltage Selection
          3. 9.2.1.2.3 Switching Frequency Selection
          4. 9.2.1.2.4 Inductor Selection
          5. 9.2.1.2.5 Input (VAC) Capacitor
          6. 9.2.1.2.6 Output (VBAT) Capacitor
          7. 9.2.1.2.7 Sense Resistor (RAC_SNS and RBAT_SNS) and Current Programming
          8. 9.2.1.2.8 Power MOSFETs Selection
          9. 9.2.1.2.9 Converter Fast Transient Response
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Typical Application (USB-PD EPR Configuration)
        1. 9.2.2.1 Design Requirements
  11. 10Power Supply Recommendations
  12. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  13. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 サード・パーティ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 Trademarks
    5. 12.5 静電気放電に関する注意事項
    6. 12.6 用語集
  14. 13Mechanical, Packaging, and Orderable Information

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
9.2.1.2.2 Charge Voltage Selection

The battery regulation voltage is programmed using a resistor divider to the FB pin. The default internal voltage reference is 1.536 V, and can be changed via the VFB_REG register bits. The top of the resistor divider is selected to be 249 kΩ.

RTOP = 249 kΩ

The bottom resistor can be calculated as:

Equation 10. R B O T = R T O P × V F B V B A T R E G - V F B + R F B G  

where

  • VFB is the target feedback voltage programmed through I2C (default 1.536 V),
  • VBATREG is the desired battery regulation target (16.8 V in this example)
  • RFBG is the internal FBG pull-down resistor (33 Ω)

RFB_BOT = 25.09 kΩ.

Choosing the nearest 0.1% resistor value, gives RFB_BOT = 24.88 kΩ, for a nominal charge voltage of 16.89 V. Further fine-tuning of the regulation voltage can be achieved by changing the internal feedback reference. For example, to get the regulation voltage to exactly 16.8 V with the selected resistor divider, the internal voltage reference could be changed to 1.528 V via VFB_REG.

It is recommended to use 0.1% accurate resistors to maximize the charge voltage accuracy.