SLUSDV2A May   2020  ā€“ May 2021 BQ25798

PRODUCTION DATA  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Description (continued)
  6. Pin Configuration and Functions
  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
  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  PROG Pin Configuration
      3. 8.3.3  Device Power Up from Battery without Input Source
      4. 8.3.4  Device Power Up from Input Source
        1. 8.3.4.1 Power Up REGN LDO
        2. 8.3.4.2 Poor Source Qualification
        3. 8.3.4.3 ILIM_HIZ Pin
        4. 8.3.4.4 Default VINDPM Setting
        5. 8.3.4.5 Input Source Type Detection
          1. 8.3.4.5.1 D+/Dā€“ Detection Sets Input Current Limit
          2. 8.3.4.5.2 HVDCP Detection Procedure
          3. 8.3.4.5.3 Connector Fault Detection
      5. 8.3.5  Dual-Input Power Mux
        1. 8.3.5.1 ACDRV Turn On Condition
        2. 8.3.5.2 VBUS Input Only
        3. 8.3.5.3 One ACFET-RBFET
        4. 8.3.5.4 Two ACFETs-RBFETs
      6. 8.3.6  Buck-Boost Converter Operation
        1. 8.3.6.1 Force Input Current Limit Detection
        2. 8.3.6.2 Input Current Optimizer (ICO)
        3. 8.3.6.3 Maximum Power Point Tracking for Small PV Panel
        4. 8.3.6.4 Pulse Frequency Modulation (PFM)
        5. 8.3.6.5 Device HIZ State
      7. 8.3.7  USB On-The-Go (OTG)
        1. 8.3.7.1 OTG Mode to Power External Devices
        2. 8.3.7.2 Backup Power Supply Mode
        3. 8.3.7.3 Backup Mode with Dual Input Mux
      8. 8.3.8  Power Path Management
        1. 8.3.8.1 Narrow VDC Architecture
        2. 8.3.8.2 Dynamic Power Management
      9. 8.3.9  Battery Charging Management
        1. 8.3.9.1 Autonomous Charging Cycle
        2. 8.3.9.2 Battery Charging Profile
        3. 8.3.9.3 Charging Termination
        4. 8.3.9.4 Charging Safety Timer
        5. 8.3.9.5 Thermistor Qualification
          1. 8.3.9.5.1 JEITA Guideline Compliance in Charge Mode
          2. 8.3.9.5.2 Cold/Hot Temperature Window in OTG Mode
      10. 8.3.10 Integrated 16-Bit ADC for Monitoring
      11. 8.3.11 Status Outputs ( STAT, and INT)
        1. 8.3.11.1 Charging Status Indicator (STAT Pin)
        2. 8.3.11.2 Interrupt to Host ( INT)
      12. 8.3.12 Ship FET Control
        1. 8.3.12.1 Shutdown Mode
        2. 8.3.12.2 Ship Mode
        3. 8.3.12.3 System Power Reset
      13. 8.3.13 Protections
        1. 8.3.13.1 Voltage and Current Monitoring
          1. 8.3.13.1.1  VAC Over-voltage Protection (VAC_OVP)
          2. 8.3.13.1.2  VBUS Over-voltage Protection (VBUS_OVP)
          3. 8.3.13.1.3  VBUS Under-voltage Protection (POORSRC)
          4. 8.3.13.1.4  System Over-voltage Protection (VSYS_OVP)
          5. 8.3.13.1.5  System Short Protection (VSYS_SHORT)
          6. 8.3.13.1.6  Battery Over-voltage Protection (VBAT_OVP)
          7. 8.3.13.1.7  Battery Over-current Protection (IBAT_OCP)
          8. 8.3.13.1.8  Input Over-current Protection (IBUS_OCP)
          9. 8.3.13.1.9  OTG Over-voltage Protection (OTG_OVP)
          10. 8.3.13.1.10 OTG Under-voltage Protection (OTG_UVP)
        2. 8.3.13.2 Thermal Regulation and Thermal Shutdown
      14. 8.3.14 Serial Interface
        1. 8.3.14.1 Data Validity
        2. 8.3.14.2 START and STOP Conditions
        3. 8.3.14.3 Byte Format
        4. 8.3.14.4 Acknowledge (ACK) and Not Acknowledge (NACK)
        5. 8.3.14.5 Slave Address and Data Direction Bit
        6. 8.3.14.6 Single Write and Read
        7. 8.3.14.7 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 Register Map
      1. 8.5.1 I2C Registers
  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 PV Panel Selection
        2. 9.2.2.2 Inductor Selection
        3. 9.2.2.3 Input (VBUS / PMID) Capacitor
        4. 9.2.2.4 Output (VSYS) Capacitor
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

Buck-Boost Converter Operation

The charger employs a synchronous buck-boost converter that allows charging the 1s to 4s battery from a legacy 5V USB input source, HVDCP and USB-PD power sources. The charger operates in buck, buck-boost or boost mode based on different input voltage and output voltage combinations. The converter can operate uninterruptedly and continuously across the Buck, Buck-boost and Boost operating states.

With a battery attached at BAT and input power at VBUS, the charger can provide at least the MINSYS voltage at SYS and charge current for the battery at BAT. Once the battery voltage reaches the MINSYS voltage, the SYS voltage follows the BAT voltage up. With no battery attached to BAT and input power at VBUS, the voltages at SYS and BAT vary depending on the whether or not charge is enabled.

  1. No battery or battery removed and charge disabled (by CE pin or EN_CHG register or thermistor removed from TS pin) - The charger keeps the BAT pin voltage at low-level, steady-state voltage and regulates SYS pin to MINSYS. The host can monitor the ADC BAT pin voltage and TS fault register to determine when a valid battery is attached.
  2. No battery or battery removed while charge enabled and TS pin funtion is disabled - The charger continuously tries to charge the BAT capacitance, typically resulting in the BAT voltage alternating between a low level and BATOVP fault. The SYS voltage follows the battery voltage up, potentially reaching SYSOVP fault but the converter never allows SYS to fall below the MINSYS threshold even if the BAT voltage falls below MINSYS. In order to determine if a battery is attached, the host must perididcally disable charge, force IBAT discharge current and then read the ADC BAT pin voltage. Alternatively, the host can monitor the INT pin for rapid interrupts and then read the charge status bits for fast (<1 s) toggling between charging, taper and termination.