ZHCSPA4 march   2023 TPS548C26

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 绝对最大额定值
    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  Internal VCC LDO and Using an External Bias on VCC and VDRV Pin
      2. 7.3.2  Input Undervoltage Lockout (UVLO)
        1. 7.3.2.1 Fixed VCC_OK UVLO
        2. 7.3.2.2 Fixed VDRV UVLO
        3. 7.3.2.3 Fixed PVIN UVLO
        4. 7.3.2.4 Enable
      3. 7.3.3  Set the Output Voltage
      4. 7.3.4  Differential Remote Sense and Feedback Divider
      5. 7.3.5  Start-up and Shutdown
      6. 7.3.6  Loop Compensation
      7. 7.3.7  Set Switching Frequency and Operation Mode
      8. 7.3.8  Switching Node (SW)
      9. 7.3.9  Overcurrent Limit and Low-side Current Sense
      10. 7.3.10 Negative Overcurrent Limit
      11. 7.3.11 Zero-Crossing Detection
      12. 7.3.12 Input Overvoltage Protection
      13. 7.3.13 Output Undervoltage and Overvoltage Protection
      14. 7.3.14 Overtemperature Protection
      15. 7.3.15 Power Good
    4. 7.4 Device Functional Modes
      1. 7.4.1 Forced Continuous-Conduction Mode
      2. 7.4.2 Auto-Skip Eco-mode Light Load Operation
      3. 7.4.3 Powering the Device from a 12-V Bus
      4. 7.4.4 Powering the Device From a Split-rail Configuration
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Application
      2. 8.2.2 Design Requirements
      3. 8.2.3 Detailed Design Procedure
        1. 8.2.3.1 Inductor Selection
        2. 8.2.3.2 Input Capacitor Selection
        3. 8.2.3.3 Output Capacitor Selection
        4. 8.2.3.4 VCC and VRDV Bypass Capacitor
        5. 8.2.3.5 BOOT Capacitor Selection
        6. 8.2.3.6 PG Pullup Resistor Selection
      4. 8.2.4 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
        1. 8.4.2.1 Thermal Performance on TPS548C26 Evaluation Board
  9. 9 Device and Documentation Support
    1. 9.1 接收文档更新通知
    2. 9.2 支持资源
    3. 9.3 Trademarks
    4. 9.4 静电放电警告
    5. 9.5 术语表
  10. 10Mechanical, Packaging, and Orderable Information

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7.3.10 Negative Overcurrent Limit

The TPS548C26 device is a synchronous buck converter, thus the current can flow from the device to the load or from the load into the device through SW node. When the current is flowing from the device SW node to the load the device is said to be sourcing current and the output current declared to be positive. When the current is flowing into the device SW node from the load, the device is said to be sinking current and the current is declared to be negative.

The device offers a fixed, cycle-by-cycle negative overcurrent (NOC) limit which is set to −16 A. Similar with the positive overcurrent limit, the inductor current is monitored during the low-side FET on period. To prevent too large negative current and a damage of low-side FET, the device turns off the low-side FET after the detected negative current through the low-side FET exceeds the NOC limit. And then the high-side FET is turned on for an on-time determined by PVIN, VOUT, and fSW setting. After the high-side FET on-time expires, the low-side FET turns on again.

The device is unlikely to trigger the −16-A negative current limit during the nominal operation unless too small inductor value is chosen or the inductor becomes saturated. This NOC operation feature is used to discharge output capacitors during an overvoltage event.