JAJSQU2A August   2023  – October 2023 TPS25983

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Revision History
  6. 5 Device Comparison 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
    6. 7.6 Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 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 Undervoltage Protection (UVLO and UVP)
      2. 8.3.2 Overvoltage Protection (OVP)
      3. 8.3.3 Inrush Current, Overcurrent, and Short-Circuit Protection
        1. 8.3.3.1 Slew Rate and Inrush Current Control (dVdt)
        2. 8.3.3.2 Circuit Breaker
        3. 8.3.3.3 Active Current Limiting
        4. 8.3.3.4 Short-Circuit Protection
      4. 8.3.4 Overtemperature Protection (OTP)
      5. 8.3.5 Analog Load Current Monitor (IMON)
      6. 8.3.6 Power Good (PG)
      7. 8.3.7 Reverse Current Blocking FET Driver
      8. 8.3.8 Fault Response
    4. 8.4 Device Functional Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application: Standby Power Rail Protection in Datacenter Servers
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Device Selection
        2. 9.2.2.2 Setting the Current Limit Threshold: RILIM Selection
        3. 9.2.2.3 Setting the Undervoltage and Overvoltage Lockout Set Point
        4. 9.2.2.4 Choosing the Current Monitoring Resistor: RIMON
        5. 9.2.2.5 Setting the Output Voltage Ramp Time (TdVdt)
          1. 9.2.2.5.1 Case 1: Start-Up Without Load: Only Output Capacitance COUT Draws Current
          2. 9.2.2.5.2 Case 2: Start-Up With Load: Output Capacitance COUT and Load Draw Current
        6. 9.2.2.6 Setting the Transient Overcurrent Blanking Interval (tITIMER)
        7. 9.2.2.7 Setting the Auto-Retry Delay and Number of Retries
      3. 9.2.3 Application Curves
    3. 9.3 System Examples
      1. 9.3.1 Optical Module Power Rail Path Protection
        1. 9.3.1.1 Design Requirements
        2. 9.3.1.2 Device Selection
        3. 9.3.1.3 External Component Settings
        4. 9.3.1.4 Voltage Drop
        5. 9.3.1.5 Application Curves
      2. 9.3.2 Input Protection for 12-V Rail Applications: PCIe Cards, Storage Interfaces, and DC Fans
      3. 9.3.3 Priority Power MUXing
    4. 9.4 Power Supply Recommendations
      1. 9.4.1 Transient Protection
      2. 9.4.2 Output Short-Circuit Measurements
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 ドキュメントの更新通知を受け取る方法
    3. 10.3 サポート・リソース
    4. 10.4 Trademarks
    5. 10.5 静電気放電に関する注意事項
    6. 10.6 用語集
  12. 11Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

9.2.2.3 Setting the Undervoltage and Overvoltage Lockout Set Point

The supply undervoltage and overvoltage thresholds are set using the resistors R1, R2, and R3, whose values can be calculated using Equation 13 and Equation 14.

Equation 13. VIN(UV)=VUVLO(R) x (R1 + R2 + R3)R2+R3
Equation 14. VIN(OV)=VOV(R) x (R1 + R2 + R3)R3

Where VUVLO(R) is the UVLO rising threshold and VOV(R) is the OVLO rising threshold. Because R1, R2, and R3 leak the current from input supply VIN, these resistors must be selected based on the acceptable leakage current from input power supply VIN. The current drawn by R1, R2, and R3 from the power supply is IR123 = VIN / (R1 + R2 + R3). However, leakage currents due to external active components connected to the resistor string can add error to these calculations. So, the resistor string current, IR123 must be chosen to be 20 times greater than the leakage current expected on the EN/UVLO and OVLO pins.

From the device electrical specifications, both the EN/UVLO and OVLO leakage currents are 0.1 μA (maximum), VOV(R) = 1.2 V and VUVLO(R) = 1.2 V. From design requirements, VIN(OV) = 16 V and VIN(UV) = 10.8 V. To solve the equation, first choose the value of R1 = 1 MΩ and use the above equations to solve for R2 = 40.6 kΩ and R3 = 84.4 kΩ.

Using the closest standard 1% resistor values, we get R1 = 1 MΩ, R2 = 41.2 kΩ, and R3 = 84.5 kΩ.