SLUSDY3 December   2023 BQ25750

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Description (continued)
  6. 5 Device Comparison
  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 (BQ25750)
  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 Thermistor Qualification
          1. 8.3.4.6.1 JEITA Guideline Compliance in Charge Mode
          2. 8.3.4.6.2 Cold/Hot Temperature Window in Reverse Mode
      5. 8.3.5 Power Path 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
        1. 8.3.6.1 Auto Reverse Mode
      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 Serial Interface
        1. 8.3.9.1 Data Validity
        2. 8.3.9.2 START and STOP Conditions
        3. 8.3.9.3 Byte Format
        4. 8.3.9.4 Acknowledge (ACK) and Not Acknowledge (NACK)
        5. 8.3.9.5 Target Address and Data Direction Bit
        6. 8.3.9.6 Single Write and Read
        7. 8.3.9.7 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 BQ25750 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 / SYS) 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  ACFETs and BATFETs Selection
          10. 9.2.1.2.10 Converter Fast Transient Response
        3. 9.2.1.3 Application Curves
  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 Third-Party Products Disclaimer
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  14. 13Revision History
  15. 14Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information
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 (58.8 V in this example)
  • RFBG is the internal FBG pull-down resistor (33 Ω)

RFB_BOT = 6.712 kΩ.

Choosing the nearest 0.1% resistor value, gives RFB_BOT = 6.65 kΩ, for a nominal charge voltage of 58.75 V. Further fine-tuning of the regulation voltage can be achieved by changing the internal feedback reference.

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