SLUSEK7 September   2024 BQ25773

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Typical Characteristics BQ2577X
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Power-Up Sequence
      2. 7.3.2  MODE Pin Detection
      3. 7.3.3  REGN Regulator (REGN LDO)
      4. 7.3.4  Independent Comparator Function
      5. 7.3.5  Battery Charging Management
        1. 7.3.5.1 Autonomous Charging Cycle
        2. 7.3.5.2 Battery Charging Profile
        3. 7.3.5.3 Charging Termination
        4. 7.3.5.4 Charging Safety Timer
      6. 7.3.6  Temperature Regulation (TREG)
      7. 7.3.7  Vmin Active Protection (VAP) When Battery Only Mode
      8. 7.3.8  Two Level Battery Discharge Current Limit
      9. 7.3.9  Fast Role Swap Feature
      10. 7.3.10 CHRG_OK Indicator
      11. 7.3.11 Input and Charge Current Sensing
      12. 7.3.12 Input Current and Voltage Limit Setup
      13. 7.3.13 Battery Cell Configuration
      14. 7.3.14 Device HIZ State
      15. 7.3.15 USB On-The-Go (OTG)
      16. 7.3.16 Quasi Dual Phase Converter Operation
      17. 7.3.17 Continuous Conduction Mode (CCM)
      18. 7.3.18 Pulse Frequency Modulation (PFM)
      19. 7.3.19 Switching Frequency and Dithering Feature
      20. 7.3.20 Current and Power Monitor
        1. 7.3.20.1 High-Accuracy Current Sense Amplifier (IADPT and IBAT)
        2. 7.3.20.2 High-Accuracy Power Sense Amplifier (PSYS)
      21. 7.3.21 Input Source Dynamic Power Management
      22. 7.3.22 Integrated 16-Bit ADC for Monitoring
      23. 7.3.23 Input Current Optimizer (ICO)
      24. 7.3.24 Two-Level Adapter Current Limit (Peak Power Mode)
      25. 7.3.25 Processor Hot Indication
        1. 7.3.25.1 PROCHOT During Low Power Mode
        2. 7.3.25.2 PROCHOT Status
      26. 7.3.26 Device Protection
        1. 7.3.26.1  Watchdog Timer (WD)
        2. 7.3.26.2  Input Overvoltage Protection (ACOV)
        3. 7.3.26.3  Input Overcurrent Protection (ACOC)
        4. 7.3.26.4  System Overvoltage Protection (SYSOVP)
        5. 7.3.26.5  Battery Overvoltage Protection (BATOVP)
        6. 7.3.26.6  Battery Charge Overcurrent Protection (BATCOC)
        7. 7.3.26.7  Battery Discharge Overcurrent Protection (BATDOC)
        8. 7.3.26.8  BATFET Charge Current Clamp Protection under LDO Regulation Mode
        9. 7.3.26.9  Sleep Comparator Protection Between VBUS and ACP_A (SC_VBUSACP)
        10. 7.3.26.10 High Duty Buck Exit Comparator Protection (HDBCP)
        11. 7.3.26.11 REGN Power Good Protection (REGN_PG)
        12. 7.3.26.12 System Under Voltage Lockout (VSYS_UVP) and Hiccup Mode
        13. 7.3.26.13 OTG Mode Over Voltage Protection (OTG_OVP)
        14. 7.3.26.14 OTG Mode Under Voltage Protection (OTG_UVP)
        15. 7.3.26.15 Thermal Shutdown (TSHUT)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Forward Mode
        1. 7.4.1.1 System Voltage Regulation with Narrow VDC Architecture
        2. 7.4.1.2 Battery Charging
      2. 7.4.2 USB On-The-Go Mode
      3. 7.4.3 Pass Through Mode (PTM)-Patented Technology
      4. 7.4.4 Learn Mode
    5. 7.5 Programming
      1. 7.5.1 I2C Serial Interface
        1. 7.5.1.1 Timing Diagrams
        2. 7.5.1.2 Data Validity
        3. 7.5.1.3 START and STOP Conditions
        4. 7.5.1.4 Byte Format
        5. 7.5.1.5 Acknowledge (ACK) and Not Acknowledge (NACK)
        6. 7.5.1.6 Target Address and Data Direction Bit
        7. 7.5.1.7 Single Read and Write
        8. 7.5.1.8 Multi-Read and Multi-Write
        9. 7.5.1.9 Write 2-Byte I2C Commands
    6. 7.6 BQ25773 Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input Snubber and Filter for Voltage Spike Damping
        2. 8.2.2.2 ACP-ACN Input Filter
        3. 8.2.2.3 Inductor Selection
        4. 8.2.2.4 Input Capacitor
        5. 8.2.2.5 Output Capacitor
        6. 8.2.2.6 Power MOSFETs Selection
  10. 9 Power Supply Recommendations
  11. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
      1. 10.2.1 Layout Example Reference Top View
  12. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information

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発注情報

8.2.2.3 Inductor Selection

The BQ25773 has two selectable fixed switching frequency 600 kHz/800 kHz. Higher switching frequency allows the use of smaller inductance. Inductor saturation current should be higher than the charging current (ICHG) plus half the ripple current (IRIPPLE):

Equation 3. BQ25773

The inductor ripple current in buck operation depends on input voltage (VIN), duty cycle (DBUCK = VOUT/VIN), switching frequency (fS) and inductance (L):

Equation 4. IRIPPLE_BUCK = VIN × DBUCK× (1-DBUCK) / (fS × L)

During boost operation, the duty cycle is:

DBOOST = 1 – (VIN/VBAT)

and the ripple current is:

IRIPPLE_BOOST = (VIN × DBOOST) / (fS × L)

The maximum inductor ripple current happens with D = 0.5 or close to 0.5. For example, the battery charging voltage range is from 12 V to 16.8 V for 4-cell battery pack. For 28-V adapter voltage, 14-V battery voltage gives the maximum inductor ripple current.

The recommended inductor DCR range is 5 mΩ ~ 25 mΩ for each phase. Inductor DCR beyond this range may hold system stability risk which is not recommended. Upon different switching frequency and VBUS input voltage recommended inductance are summarized in Table 8-6. Inductance lower than the recommendation could result in large inductor ripple and high inductor core loss which is not preferred.

Table 8-1 Inductance Selection Recommendation
VBUS = 20 V VBUS = 28 V VBUS = 36 V
Fsw=600 kHz 2.2 μH 2.2 μH 3.3 μH
Fsw=800 kHz 1.5 μH 1.5 μH 2.2 μH