ZHCSL64D april   2019  – may 2023 TPS7H4001-SP

PRODMIX  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Revision History
  6. 5 Device Options Table
  7. 6 Pin Configuration and Functions
  8. 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 - All Devices
    6. 7.6  Electrical Characteristics: CDFP and KGD Options
    7. 7.7  Electrical Characteristics: HTSSOP (SHP) Option
    8. 7.8  Electrical Characteristics: HTSSOP (QMLP) Option
    9. 7.9  Quality Conformance Inspection
    10. 7.10 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  VIN and Power VIN Pins (VIN and PVIN)
      2. 8.3.2  Voltage Reference
      3. 8.3.3  Adjusting the Output Voltage
      4. 8.3.4  Safe Start-Up Into Prebiased Outputs
      5. 8.3.5  Error Amplifier
      6. 8.3.6  Enable and Adjust UVLO
      7. 8.3.7  Adjustable Switching Frequency and Synchronization (SYNC)
        1. 8.3.7.1 Internal Oscillator Mode
        2. 8.3.7.2 External Synchronization Mode
        3. 8.3.7.3 Primary-Secondary Operation Mode
      8. 8.3.8  Soft-Start (SS/TR)
      9. 8.3.9  Power Good (PWRGD)
      10. 8.3.10 Sequencing
      11. 8.3.11 Output Overvoltage Protection (OVP)
      12. 8.3.12 Overcurrent Protection
        1. 8.3.12.1 High-Side MOSFET Overcurrent Protection
        2. 8.3.12.2 Low-Side MOSFET Overcurrent Protection
      13. 8.3.13 Thermal Shutdown
      14. 8.3.14 Turn-On Behavior
      15. 8.3.15 Slope Compensation
        1. 8.3.15.1 Slope Compensation Requirements
      16. 8.3.16 Small Signal Model for Frequency Compensation
    4. 8.4 Device Functional Modes
      1. 8.4.1 Fixed-Frequency PWM Control
  10. 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 Operating Frequency
        2. 9.2.2.2 Output Inductor Selection
        3. 9.2.2.3 Output Capacitor Selection
        4. 9.2.2.4 Input Capacitor Selection
        5. 9.2.2.5 Soft-Start Capacitor Selection
        6. 9.2.2.6 Undervoltage Lockout (UVLO) Set Point
        7. 9.2.2.7 Output Voltage Feedback Resistor Selection
          1. 9.2.2.7.1 Minimum Output Voltage
        8. 9.2.2.8 Compensation Component Selection
      3. 9.2.3 Parallel Operation
      4. 9.2.4 Application Curve
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 接收文档更新通知
    3. 10.3 支持资源
    4. 10.4 Trademarks
    5. 10.5 静电放电警告
    6. 10.6 术语表
  12. 11Mechanical, Packaging, and Orderable Information

封装选项

请参考 PDF 数据表获取器件具体的封装图。

机械数据 (封装 | 引脚)
  • DDW|44
  • KGD|0
  • HKY|34
散热焊盘机械数据 (封装 | 引脚)
订购信息

8.3.8 Soft-Start (SS/TR)

The device uses the lower voltage of the internal voltage reference or the SS/TR pin voltage as the reference voltage and regulates the output accordingly. A CSS capacitor on the SS/TR pin to GND implements a soft-start time. Equation 5 shows the equation for the nominal soft-start time, tSS. This is the time it will take VOUT to go from 10% to 90% of the programmed voltage. The voltage reference (VREF) is 0.604 V and the soft-start charge current (ISS) is 2.5 μA. When calculating the soft-start time tSS, it is important to take into account the variation of the parameters CSS, VREF and ISS as these may cause tSS to deviate from the nominal value in the actual implementation.

Equation 5. GUID-F291CA83-D380-4D6A-81ED-E472DE0A4A5F-low.gif

When any of the following four scenarios occur the SS/TR pin is discharged:

  • the input UVLO is triggered,
  • the EN pin is pulled below 1.05 V,
  • the high-side switch current limit threshold is exceeded, or
  • a thermal shutdown event occurs

With the exception of the scenario where the high-side current limit threshold is exceeded, the device will then stop switching and enter into low current operation. At the subsequent power-up, when the shutdown condition is removed, the device does not start switching until it has discharged its SS/TR pin to ground ensuring proper soft-start behavior.

The device will enter into a pulse-skipping mode during startup in the event that VSENSE is greater than the voltage at the SS/TR pin. During this period, the high-side switch will remain off and the low-side switch will remain on until VSENSE again falls below the voltage at SS/TR.