ZHCS517E April   2000  – June 2019 LM2587

PRODUCTION DATA.  

  1. 特性
  2. 典型 应用
  3. 说明
    1.     Device Images
      1.      反激式稳压器
  4. 修订历史记录
  5. Pin Configurations
  6. Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESDRatings
    3. 6.3  Recommended Operating Ratings
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics: 3.3 V
    6. 6.6  Electrical Characteristics: 5 V
    7. 6.7  Electrical Characteristics: 12 V
    8. 6.8  Electrical Characteristics: Adjustable
    9. 6.9  Electrical Characteristics: All Output Voltage Versions
    10. 6.10 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Step-Up (Boost) Regulator Operation
  8. Application And Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Typical Boost Regulator Applications
      2. 8.2.2 Typical Flyback Regulator Applications
        1. 8.2.2.1 Transformer Selection (T)
        2. 8.2.2.2 Transformer Footprints
          1. 8.2.2.2.0.1 T4
      3. 8.2.3 Design Requirements
      4. 8.2.4 Detailed Design Procedure
        1. 8.2.4.1 Custom Design With Webench® Tools
        2. 8.2.4.2 Programming Output Voltage (Selecting R1 And R2)
        3. 8.2.4.3 Short Circuit Condition
        4. 8.2.4.4 Flyback Regulator Input Capacitors
        5. 8.2.4.5 Switch Voltage Limits
        6. 8.2.4.6 Output Voltage Limitations
        7. 8.2.4.7 Noisy Input Line Condition)
        8. 8.2.4.8 Stability
    3. 8.3 Additional Application Examples
      1. 8.3.1 Test Circuits
  9. Layout
    1. 9.1 Layout Guidelines
    2. 9.2 Layout Example
    3. 9.3 Heat Sink/Thermal Considerations
      1. 9.3.1 European Magnetic Vendor Contacts
      2. 9.3.2 Coilcraft
      3. 9.3.3 Pulse Engineering
  10. 10器件和文档支持
    1. 10.1 器件支持
      1. 10.1.1 第三方米6体育平台手机版_好二三四免责声明
      2. 10.1.2 开发支持
        1. 10.1.2.1 使用 Webench® 工具创建定制设计方案
    2. 10.2 接收文档更新通知
    3. 10.3 社区资源
    4. 10.4 商标
    5. 10.5 静电放电警告
    6. 10.6 Glossary
  11. 11机械、封装和可订购信息

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 Voltage Limitations

The maximum output voltage of a boost regulator is the maximum switch voltage minus a diode drop. In a flyback regulator, the maximum output voltage is determined by the turns ratio, N, and the duty cycle, D, by the equation:

Equation 4. VOUT ≈ N × VIN × D/(1 − D)

The duty cycle of a flyback regulator is determined by the following equation:

Equation 5. LM2587 1231660.png

Theoretically, the maximum output voltage can be as large as desired—just keep increasing the turns ratio of the transformer. However, there exists some physical limitations that prevent the turns ratio, and thus the output voltage, from increasing to infinity. The physical limitations are capacitances and inductances in the LM2587 switch, the output diode(s), and the transformer—such as reverse recovery time of the output diode (mentioned above).