ZHCSHS4 March   2018 TPS62243-Q1 , TPS62244-Q1

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      典型应用原理图
      2.      效率与输出电流间的关系
  4. 4 修订历史记录
  5. 5 Device Comparison Table
  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 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 Undervoltage Lockout
      2. 8.3.2 Enable
      3. 8.3.3 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Soft Start
      2. 8.4.2 Power Save Mode
        1. 8.4.2.1 100% Duty Cycle Low Dropout Operation
      3. 8.4.3 Short-Circuit Protection
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Output Filter Design (Inductor and Output Capacitor)
          1. 9.2.2.1.1 Inductor Selection
          2. 9.2.2.1.2 Output Capacitor Selection
          3. 9.2.2.1.3 Input Capacitor Selection
      3. 9.2.3 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 第三方产品免责声明
    2. 12.2 接收文档更新通知
    3. 12.3 社区资源
    4. 12.4 商标
    5. 12.5 静电放电警告
    6. 12.6 Glossary
  13. 13机械、封装和可订购信息
    1. 13.1 Package Option Addendum
      1. 13.1.1 Packaging Information
      2. 13.1.2 Tape and Reel 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

8.4.2.1 100% Duty Cycle Low Dropout Operation

The device starts to enter 100% duty-cycle mode once the input voltage comes close to the nominal output voltage. To maintain the output voltage, the high-side MOSFET switch is turned on 100% for one or more cycles.

With further decreasing VIN the high-side MOSFET switch is turned on completely. In this case, the converter offers a low input-to-output voltage difference. This is particularly useful in battery-powered applications to achieve longest operation time by taking full advantage of the entire battery voltage range.

The minimum input voltage to maintain regulation depends on the load current and output voltage, and can be calculated as:

Equation 1. VINmin = VOmax + IOmax (RDS(on)max + RL)

where

  • IOmax = maximum output current plus inductor ripple current
  • RDS(on)max = maximum P-channel switch RDS(on)
  • RL = DC resistance of the inductor
  • VOmax = nominal output voltage plus maximum output voltage tolerance