SLUSFF4 November   2023 BQ25756E

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 (BQ25756E)
  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 BQ25756E 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 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
8.3.5.1.1.1 ILIM_HIZ Pin

To set the maximum input current using the ILIM_HIZ pin, a pull-down resistor to PGND is used. When using a 2-mΩ RAC_SNS resistor, the input current limit is controlled by: IAC_MAX = KILIM / RILIM_HIZ.

The actual input current limit is the lower value between ILIM_HIZ pin setting and register setting (IAC_DPM). For example, if the register setting is 20 A, and ILIM_HIZ pin has a 5-kΩ resistor (KILIM = 50 A-kΩ) to ground for 10 A, the actual input current limit is 10 A. ILIM_HIZ pin can be used to set the input current limit when EN_ILIM_HIZ_PIN bit is set to 1. The device regulates the pin at VREF_ILIM_HIZ. If pin voltage exceeds VREF_ILIM_HIZ, the device enters input current regulation. Entering input current regulation through the pin sets the IAC_DPM_STAT and FLAG bits, and produces an interrupt to host. The interrupt can be masked via the IAC_DPM_MASK bit.

The ILIM_HIZ pin can also be used to monitor input current. When not in input current regulation, the voltage on ILIM_HIZ pin (VILIM_HIZ) is proportional to the input current. Pin voltage can be used to monitor input current with the following relationship: IAC = KILIM x VILIM_HIZ / (RILIM_HIZ x VREF_ILIM_HIZ).

For example, if the pin is set with 5-kΩ resistor, and the pin voltage is 1.0 V, the actual input current is between 4.8 A to 5.2 A (based on KILIM specified).

If ILIM_HIZ pin is shorted, the input current limit is set by the IAC_DPM register. If hardware input current limit function is not needed, it is recommended to short this pin to GND. If ILIM_HIZ pin is pulled above VIH_ILIM_HIZ, the device enters HIZ mode (refer to Section 8.3.3.5). The ILIM_HIZ pin function can be disabled by setting the EN_ILIM_HIZ_PIN bit to 0. When the pin is disabled, input current limit and monitoring functions as well as HIZ mode control via the pin are not available.

KILIM is defined as 50 A×kΩ referenced to a 2-mΩ sense resistor. A larger sense resistor provides a larger sense voltage and higher regulation accuracy, but changes the gain from the ILIM_HIZ pin. For example, using a 5-mΩ resistor yields KILIM = 50 (A×kΩ) × 2 (mΩ) / 5 (mΩ) = 20 (A×kΩ).