ZHCSK97B September   2019  – August 2020 TPS61023

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Undervoltage Lockout
      2. 7.3.2 Enable and Soft Start
      3. 7.3.3 Switching Frequency
      4. 7.3.4 Current Limit Operation
      5. 7.3.5 Pass-Through Operation
      6. 7.3.6 Overvoltage Protection
      7. 7.3.7 Output Short-to-Ground Protection
      8. 7.3.8 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Mode
      2. 7.4.2 Power-Save Mode
  8. 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 Setting the Output Voltage
        2. 8.2.2.2 Inductor Selection
        3. 8.2.2.3 Output Capacitor Selection
        4. 8.2.2.4 Loop Stability, Feedforward Capacitor Selection
        5. 8.2.2.5 Input Capacitor Selection
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 第三方产品免责声明
    2. 11.2 接收文档更新通知
    3. 11.3 支持资源
    4. 11.4 Trademarks
    5. 11.5 静电放电警告
    6. 11.6 术语表
  12. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Package Option Addendum
    2. 12.2 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)

8.2.2.4 Loop Stability, Feedforward Capacitor Selection

When the switching waveform shows large duty cycle jitter or the output voltage or inductor current shows oscillations, the regulation loop can be unstable.

The load transient response is another approach to check the loop stability. During the load transient recovery time, VOUT can be monitored for settling time, overshoot or ringing that helps judge the stability of the converters. Without any ringing, the loop has usually more than 45° of phase margin.

A feedforward capacitor (C3 in the Figure 8-2) in parallel with R1 induces a pair of zero and pole in the loop transfer function. By setting the proper zero frequency, the feedforward capacitor can increase the phase margin to improve the loop stability. For large output capacitance more than 40 μF application, TI recommends a feedforward capacitor to set the zero frequency (fFFZ) to 1 kHz. As for the input voltage lower than 1-V application, TI recommends to use the effective output capacitance is about 100 µF and set the zero frequency (fFFZ) to 1 kHz. The value of the feedforward capacitor can be calculated by Equation 10.

Equation 10. GUID-CF5A4A8E-69FC-4911-8F9C-F133B3B233EC-low.gif

where

  • R1 is the resistor between the VOUT pin and FB pin
  • fFFZ is the zero frequency created by the feedforward capacitor
GUID-10C7FECE-E92A-4725-89BC-0F251AF45B3A-low.gifFigure 8-2 TPS61023 Circuit With Feedforward Capacitor