ZHCSJV0G June   2018  – July 2021 TPS25830-Q1 , TPS25831-Q1

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 说明（续）
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Timing Requirements
    7. 8.7 Switching Characteristics
    8. 8.8 Typical Characteristics
  9. 9 Parameter Measurement Information
  10. 10Detailed Description
    1. 10.1 Overview
    2. 10.2 Functional Block Diagram
    3. 10.3 Feature Description
      1. 10.3.1  Buck Regulator
      2. 10.3.2  Enable/UVLO and Start-up
      3. 10.3.3  Switching Frequency and Synchronization (RT/SYNC)
      4. 10.3.4  Spread-Spectrum Operation
      5. 10.3.5  VCC, VCC_UVLO
      6. 10.3.6  Minimum ON-time, Minimum OFF-time
      7. 10.3.7  Internal Compensation
      8. 10.3.8  Bootstrap Voltage (BOOT)
      9. 10.3.9  RSNS, RSET, RILIMIT and RIMON
      10. 10.3.10 Overcurrent and Short Circuit Protection
        1. 10.3.10.1 Current Limit Setting using RILIMIT
        2. 10.3.10.2 Buck Average Current Limit Design Example
        3. 10.3.10.3 External MOSFET Gate Drivers
        4. 10.3.10.4 Cycle-by-Cycle Buck Current Limit
      11. 10.3.11 Overvoltage, IEC and Short to Battery Protection
        1. 10.3.11.1 VBUS and VCSN/OUT Overvoltage Protection
        2. 10.3.11.2 DP_IN and DM_IN Protection
        3. 10.3.11.3 CC IEC and OVP Protection
      12. 10.3.12 Cable Compensation
        1. 10.3.12.1 Cable Compensation Design Example
      13. 10.3.13 USB Port Control
      14. 10.3.14 FAULT Response
      15. 10.3.15 USB Specification Overview
      16. 10.3.16 USB Type-C® Basics
        1. 10.3.16.1 Configuration Channel
        2. 10.3.16.2 Detecting a Connection
        3. 10.3.16.3 Configuration Channel Pins CC1 and CC2
        4. 10.3.16.4 Current Capability Advertisement and VCONN Overload Protection
        5. 10.3.16.5 Plug Polarity Detection
      17. 10.3.17 Device Power Pins (IN, CSN/OUT, and PGND)
      18. 10.3.18 Thermal Shutdown
      19. 10.3.19 Power Wake
      20. 10.3.20 Thermal Sensing with NTC (TPS25831-Q1)
    4. 10.4 Device Functional Modes
      1. 10.4.1 Shutdown Mode
      2. 10.4.2 Standby Mode
      3. 10.4.3 Active Mode
      4. 10.4.4 Device Truth Table (TT)
      5. 10.4.5 USB Port Operating Modes
        1. 10.4.5.1 USB Type-C Mode
        2. 10.4.5.2 Standard Downstream Port (SDP) Mode — USB 2.0, USB 3.0, and USB 3.1
        3. 10.4.5.3 Charging Downstream Port (CDP) Mode
        4. 10.4.5.4 Dedicated Charging Port (DCP) Mode (TPS25831-Q1 Only)
          1. 10.4.5.4.1 DCP BC1.2 and YD/T 1591-2009
          2. 10.4.5.4.2 DCP Divider-Charging Scheme
          3. 10.4.5.4.3 DCP 1.2-V Charging Scheme
        5. 10.4.5.5 DCP Auto Mode (TPS25831-Q1 Only)
      6. 10.4.6 High-Bandwidth Data-Line Switches (TPS25830-Q1 only)
  11. 11Application and Implementation
    1. 11.1 Application Information
    2. 11.2 Typical Application
      1. 11.2.1 Design Requirements
      2. 11.2.2 Detailed Design Procedure
        1. 11.2.2.1  Output Voltage
        2. 11.2.2.2  Switching Frequency
        3. 11.2.2.3  Inductor Selection
        4. 11.2.2.4  Output Capacitor Selection
        5. 11.2.2.5  Input Capacitor Selection
        6. 11.2.2.6  Bootstrap Capacitor Selection
        7. 11.2.2.7  VCC Capacitor Selection
        8. 11.2.2.8  Enable and Undervoltage Lockout Set-Point
        9. 11.2.2.9  Current Limit Set-Point
        10. 11.2.2.10 Cable Compensation Set-Point
        11. 11.2.2.11 LD_DET, POL, and FAULT Resistor Selection
      3. 11.2.3 Application Curves
  12. 12Power Supply Recommendations
  13. 13Layout
    1. 13.1 Layout Guidelines
    2. 13.2 Ground Plane and Thermal Considerations
    3. 13.3 Layout Example
  14. 14Device and Documentation Support
    1. 14.1 Related Links
    2. 14.2 接收文档更新通知
    3. 14.3 支持资源
    4. 14.4 Trademarks
    5. 14.5 Electrostatic Discharge Caution
    6. 14.6 术语表
  15. 15Mechanical, Packaging, and Orderable Information

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11.2.2.3 Inductor Selection

The most critical parameters for the inductor are the inductance, saturation current and the rated current. The inductance is based on the desired peak-to-peak ripple current ΔiL. Since the ripple current increases with the input voltage, the maximum input voltage is always used to calculate the minimum inductance LMIN. Use Equation 10 to calculate the minimum value of the output inductor. KIND is a coefficient that represents the amount of inductor ripple current relative to the maximum output current of the device. A reasonable value of KIND should be 20% to 40%. During an instantaneous short or overcurrent operation event, the RMS and peak inductor current can be high. The inductor current rating should be higher than the current limit of the device.

Equation 9. GUID-51A33FF0-5020-4DE3-8DE9-0ED01F43D095-low.gif
Equation 10. GUID-4F1EB62A-7FF3-484A-BE44-046CF481D822-low.gif

In general, it is preferable to choose lower inductance in switching power supplies, because it usually corresponds to faster transient response, smaller DCR, and reduced size for more compact designs. But too low of an inductance can generate too large of an inductor current ripple such that overcurrent protection at the full load could be falsely triggered. Larger inductor current ripple also implies larger output voltage ripple with same output capacitors. With peak current mode control, it is not recommended to have too small of an inductor current ripple. A larger peak current ripple improves the comparator signal to noise ratio.

For this design example, choose KIND = 0.3, the minimum inductor value is calculated to be 8.7 µH. Choose the nearest standard 10-μH ferrite inductor with a capability of 4-A RMS current and 6-A saturation current.