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

8.3.3.2 Circuit Breaker

The TPS25983xO (circuit breaker) variants respond to output overcurrent conditions by turning off the output after a user adjustable transient fault blanking interval. During steady-state operation, if the load current exceeds a user-adjustable overcurrent threshold (ILIM) set by the ILIM pin resistor (RILIM), but lower than the fast-trip threshold (IFT), the device starts discharging the ITIMER pin capacitor using an internal pull-down current (IITIMER). If the load current drops below the overcurrent before the ITIMER capacitor drops by ΔVITIMER, the circuit-breaker action is not engaged and the ITIMER is reset by pulling up to VINT internally. This behavior allows short transient overcurrent pulses to pass through the device without tripping the circuit. If the overcurrent condition persists, the ITIMER capacitor continues to discharge and once the capacitor falls by ΔVITIMER, the circuit-breaker action turns off the FET immediately. The following equation can be used to calculate the RILIM value for a desired overcurrent threshold.

Equation 5. GUID-2DE0C858-548C-42BE-8C6D-6F1EE1854526-low.gif
Note:

Leaving the ILIM pin Open sets the overcurrent threshold to zero and causes the FET to shut off as soon as any load current is detected. Shorting the ILIM pin to ground at any point during normal operation is detected as a fault and the part shuts down. The ILIM pin Short to GND fault detection circuit does not allow any load current higher than ICB to flow through the device. This design provides robust eFuse behavior even under single point failure conditions. Refer to the Fault Response section for details on the device behavior after a fault.

GUID-20231011-SS0I-VHCJ-MPDQ-WMBDWX204DSS-low.svg Figure 8-4 Circuit Breaker Response

The duration for which load transients are allowed can be adjusted using an appropriate capacitor value from ITIMER pin to ground. The transient overcurrent blanking interval can be calculated using Equation 6.

Equation 8. GUID-C2966E94-7F93-4DD2-865D-112A62177882-low.gif

Leave the ITIMER pin open to allow the part to break the circuit with the minimum possible delay.

Table 8-1 Device ITIMER Functional Mode Summary
ITIMER Pin ConnectionTimer Delay Before Overcurrent Response
OPEN0 s
Capacitor to groundAs per Equation 6
Short to GNDITIMER pin fault; part shuts off
Note:

1. Shorting the ITIMER pin to ground is detected as a fault and the part shuts down. This provides robust eFuse behavior even in case of single point failure conditions. Refer to the Fault Response section for details on the device behavior after a fault.

2. Larger ITIMER capacitors take longer to charge during start-up and can lead to incorrect fault assertion if the ITIMER voltage is still below the pin short detection threshold after the device has reached steady state. To avoid this behavior, limit the maximum ITIMER capacitor to the value suggested by the following equation.

GUID-C3AD1CF8-9EEB-4EE7-9E6C-974617EBD36C-low.gif
GUID-52A2EFA2-7545-42CC-9770-DAE8FF39F7FA-low.gif
Where

  • tGHI is the time taken by the device to reach steady state
  • tD,ON is the device turn-on delay
  • Cdvdt is the dVdt capacitance
  • Idvdt is the dVdt charging current

It is possible to avoid incorrect ITIMER pin fault assertion and achieve higher ITIMER intervals if needed by increasing the dVdt capacitor value accordingly, but at the expense of higher start-up time.

Once the part shuts down due to a circuit-breaker fault, the part can be configured to either stay latched off or restart automatically. Refer to the Fault Response section for details.