ZHCSIQ7A august   2018  – december 2021 UCC28951

PRODUCTION DATA  

  1. 特性
  2. 应用
  3. 说明
  4. Revision History
  5. Pin Configuration and Functions
  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 Dissipation Ratings
    8. 6.8 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Start-Up Protection Logic
      2. 7.3.2  Voltage Reference (VREF)
      3. 7.3.3  Error Amplifier (EA+, EA–, COMP)
      4. 7.3.4  Soft-Start and Enable (SS/EN)
      5. 7.3.5  Light-Load Power Saving Features
      6. 7.3.6  Adaptive Delay, (Delay Between OUTA and OUTB, OUTC and OUTD (DELAB, DELCD, ADEL))
      7. 7.3.7  Adaptive Delay (Delay Between OUTA and OUTF, OUTB and OUTE (DELEF, ADELEF)
      8. 7.3.8  Minimum Pulse (TMIN)
      9. 7.3.9  Burst Mode
      10. 7.3.10 Switching Frequency Setting
      11. 7.3.11 Slope Compensation (RSUM)
      12. 7.3.12 Dynamic SR ON/OFF Control (DCM Mode)
      13. 7.3.13 Current Sensing (CS)
      14. 7.3.14 Cycle-by-Cycle Current Limit Current Protection and Hiccup Mode
      15. 7.3.15 Synchronization (SYNC)
      16. 7.3.16 Outputs (OUTA, OUTB, OUTC, OUTD, OUTE, OUTF)
      17. 7.3.17 Supply Voltage (VDD)
      18. 7.3.18 Ground (GND)
    4. 7.4 Device Functional Modes
  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  Power Loss Budget
        2. 8.2.2.2  Preliminary Transformer Calculations (T1)
        3. 8.2.2.3  QA, QB, QC, QD FET Selection
        4. 8.2.2.4  Selecting LS
        5. 8.2.2.5  Selecting Diodes DB and DC
        6. 8.2.2.6  Output Inductor Selection (LOUT)
        7. 8.2.2.7  Output Capacitance (COUT)
        8. 8.2.2.8  Select FETs QE and QF
        9. 8.2.2.9  Input Capacitance (CIN)
        10. 8.2.2.10 Current Sense Network (CT, RCS, R7, DA)
          1. 8.2.2.10.1 Voltage Loop Compensation Recommendation
      3. 8.2.3 Application Curves
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
      1.      Mechanical, Packaging, and Orderable Information

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

Output Inductor Selection (LOUT)

Inductor LOUT is designed for 20% inductor ripple current (∆ILOUT) calculated in Equation 60 and Equation 61:

Equation 60. GUID-C8A5006C-89BB-4419-8193-A7407030EDCB-low.gif
Equation 61. GUID-A1AA1412-0224-4C54-A77B-32E7C5598C48-low.gif

Calculate output inductor RMS current (ILOUT_RMS) using Equation 62:

Equation 62. GUID-9B3B97B3-FCF2-4282-81F2-76B69BC7878C-low.gif

A 2-µH inductor from Vitec Electronics Corporation, part number 75PR8108, is suitable for this design. The inductor has the following specifications:

Equation 63. GUID-979FDEC3-01C9-4C6D-A692-288CD5E8A936-low.gif

The output inductor DC resistance is:

Equation 64. GUID-926A410A-A142-42B2-B27D-2527BF867884-low.gif

Estimate output inductor losses (PLOUT) using Equation 65 and recalculate the power budget using Equation 66. Note PLOUT is an estimate of inductor losses that is twice the copper loss. Note this may vary based on magnetic manufactures. It is advisable to double check the magnetic loss with the magnetic manufacture.

Equation 65. GUID-3F0A24A9-6DD2-4F7B-8F72-15B5E4D3F585-low.gif
Equation 66. GUID-37BBAB48-F5C5-40AB-A022-85A6F7ADD1CC-low.gif