ZHCSI22F October   2017  – December 2021 TPS2662

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and 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 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Undervoltage Lockout (UVLO)
      2. 9.3.2 Overvoltage Protection (OVP)
      3. 9.3.3 Hot Plug-In and Inrush Current Control
      4. 9.3.4 Reverse Polarity Protection
        1. 9.3.4.1 Input Side Reverse Polarity Protection
        2. 9.3.4.2 Output Side Reverse Polarity Protection
      5. 9.3.5 Overload and Short-Circuit Protection
        1. 9.3.5.1 Overload Protection
        2.       28
        3. 9.3.5.2 Short-Circuit Protection
          1. 9.3.5.2.1 Start-Up With Short-Circuit On Output
      6. 9.3.6 Reverse Current Protection
      7. 9.3.7 FAULT Response
      8. 9.3.8 IN, OUT, RTN, and GND Pins
      9. 9.3.9 Thermal Shutdown
    4. 9.4 Device Functional Modes
      1. 9.4.1 Low Current Shutdown Control (SHDN)
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Step-by-Step Design Procedure
        2. 10.2.2.2 Programming the Current Limit Threshold R(ILIM) Selection
        3. 10.2.2.3 Undervoltage Lockout and Overvoltage Set Point
        4. 10.2.2.4 Setting Output Voltage Ramp Time—(tdVdT)
          1. 10.2.2.4.1 Case 1: Start-Up Without Load—Only Output Capacitance C(OUT) Draws Current During Start-Up
          2. 10.2.2.4.2 Case 2: Start-Up With Load —Output Capacitance C(OUT) and Load Draws Current During Start-Up
          3. 10.2.2.4.3 Support Component Selections – R FLT and C(IN)
      3. 10.2.3 Application Curves
    3. 10.3 System Examples
      1. 10.3.1 Field Supply Protection in PLC, DCS I/O Modules
      2. 10.3.2 Simple 24-V Power Supply Path Protection
      3. 10.3.3 Power Stealing in Smart Thermostat
    4. 10.4 Do's and Don'ts
  11. 11Power Supply Recommendations
    1. 11.1 Transient Protection
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 接收文档更新通知
    3. 13.3 支持资源
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 术语表
  14. 14Mechanical, Packaging, and Orderable Information

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11.1 Transient Protection

In case of short circuit and over load current limit, when the device interrupts current flow, input inductance generates a positive voltage spike on the input and output inductance generates a negative voltage spike on the output. The peak amplitude of voltage spikes (transients) depends on the value of inductance in series to the input or output of the device. These transients can exceed the Absolute Maximum Ratings of the device if steps are not taken to address the issue.

Typical methods for addressing transients include:

  • Minimizing lead length and inductance into and out of the device
  • Using large PCB GND plane
  • Use of a Schottky diode across the output and GND to absorb negative spikes in the designs with TPS26620, TPS26621, TPS26622, TPS26623 devices and a TVS clamp in the designs withTPS26624 and TPS26625 devices
  • A low value ceramic capacitor (C(IN) to approximately 0.1 μF) to absorb the energy and dampen the transients.

The approximate value of input capacitance can be estimated with Equation 13.

Equation 13. GUID-69E8BDAD-05FE-4765-9A22-158EFC2178B0-low.gif

where

  • V(IN) is the nominal supply voltage
  • I(LOAD) is the load current
  • L(IN) equals the effective inductance seen looking into the source
  • C(IN) is the capacitance present at the input

Some applications can require additional Transient Voltage Suppressor (TVS) to prevent transients from exceeding the Absolute Maximum Ratings of the device. These transients can occur during positive and negative surge tests on the supply lines. In such applications TI recommends to place at least 1 µF of input capacitor to limit the falling slew rate of the input voltage within a maximum of 20 V/µs.

The circuit implementation with optional protection components (a ceramic capacitor, TVS and Schottky diode) is shown in Figure 11-1 and Figure 11-2.

GUID-35D4F0D4-CF84-48E2-A53F-B6370E30B677-low.gif
* Optional components needed for suppression of transients
Figure 11-1 Circuit Implementation With Optional Protection Components for TPS26620, TPS26621, TPS26622, and TPS26623
GUID-2919694B-4488-4161-A307-466FD4440BFF-low.gif
* Optional components needed for suppression of transients
Figure 11-2 Circuit Implementation With Optional Protection Components for TPS26624 and TPS26625