ZHCSFQ9B November   2016  – June 2018 TPS54200 , TPS54201

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      简化电路原理图
      2.      ADIM 中的深度调光性能出色
  4. 4 修订历史记录
  5. 5 说明 （续）
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 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 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Fixed-Frequency PWM Control
      2. 8.3.2  Error Amplifier
      3. 8.3.3  Slope Compensation and Output Current
      4. 8.3.4  Input Undervoltage Lockout
      5. 8.3.5  Voltage Reference
      6. 8.3.6  Setting LED Current
      7. 8.3.7  Internal Soft Start
      8. 8.3.8  Bootstrap Voltage (BOOT)
      9. 8.3.9  Overcurrent Protection
        1. 8.3.9.1 High-Side MOSFET Overcurrent Protection
        2. 8.3.9.2 Low-Side MOSFET Overcurrent Protection
        3. 8.3.9.3 Low-Side MOSFET Reverse Overcurrent Protection
      10. 8.3.10 Fault Protection
        1. 8.3.10.1 LED-Open Protection
        2. 8.3.10.2 LED Short Protection
        3. 8.3.10.3 Sense-Resistor Short Protection
        4. 8.3.10.4 Sense-Resistor Open Protection
        5. 8.3.10.5 Overvoltage Protection
        6. 8.3.10.6 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Enable and Disable Device
      2. 8.4.2 Mode Detection
      3. 8.4.3 Analog Dimming Mode Operation
      4. 8.4.4 PWM Dimming-Mode Operation
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 TPS5420x 12-V Input, 1.5-A, 3-Piece IR LED Driver With Analog Dimming
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Inductor Selection
          2. 9.2.1.2.2 Input Capacitor Selection
          3. 9.2.1.2.3 Output Capacitor Selection
          4. 9.2.1.2.4 FB Pin RC Filter Selection
          5. 9.2.1.2.5 Sense Resistor Selection
        3. 9.2.1.3 Application Curves
      2. 9.2.2 TPS5420x 24-V Input, 1-A, 4-Piece WLED Driver With PWM Dimming
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Inductor Selection
          2. 9.2.2.2.2 Input Capacitor Selection
          3. 9.2.2.2.3 Output Capacitor Selection
          4. 9.2.2.2.4 FB Pin RC Filter Selection
          5. 9.2.2.2.5 Sense Resistor Selection
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 器件支持
      1. 12.1.1 第三方产品免责声明
    2. 12.2 文档支持
      1. 12.2.1 相关链接
    3. 12.3 接收文档更新通知
    4. 12.4 社区资源
    5. 12.5 商标
    6. 12.6 静电放电警告
    7. 12.7 术语表
  13. 13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

9.2.1.2.2 Input Capacitor Selection

The device requires an input capacitor to reduce the surge current drawn from the input supply and the switching noise from the device. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. For most applications, a 10-μF capacitor is enough. An additional 0.1-μF capacitor from VIN to GND is optional to provide additional high-frequency filtering. The input capacitor must have a voltage rating greater than the maximum input voltage and have a ripple-current rating greater than the maximum input-current ripple of the converter. The rms input-ripple current is calculated in Equation 7, where D is the duty cycle (output voltage divided by input voltage).

Equation 7. TPS54200 TPS54201 qu7_lusco8.gif

Use Equation 8 to calculate the input ripple voltage, where ESRCIN is the ESR of input capacitor. Ceramic capacitance tends to decrease as the applied dc voltage increases. This depreciation must be accounted for when calculating input ripple voltage.

Equation 8. TPS54200 TPS54201 qu8_lusco8.gif

In this design, a 10-µF, 35-V X7R ceramic capacitor, part number GRM32ER7YA106KA12L from muRata, is chosen. This yields around 70-mV input ripple voltage. The calculated rms input ripple current is 0.75 A, well below the ripple-current rating of the capacitor.