SLVSEZ7A March   2019  – October 2019 TPS22948

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Switching Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Timing Waveform Diagram
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 On and Off Control
      2. 8.3.2 Fault Indication (FLT)
      3. 8.3.3 Current Limiting (VSC)
      4. 8.3.4 Reverse Current Blocking (RCB)
    4. 8.4 Device Functional Modes
  9. 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 Limiting Inrush Current
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Support Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.3 Current Limiting (VSC)

The TPS22948 responds to overcurrent conditions by limiting its output current to the ILIM level shown in Figure 6.

TPS22948 ILIM3.gifFigure 6. TPS22948 Current Limiting Behavior

When an overcurrent condition is detected, the device maintains a constant output current and reduces the output voltage accordingly. Two possible overload conditions can occur.

The first condition is when a short circuit or partial short circuit is present on the output and the ON pin is toggled high, turning the device on. The output voltage is held near zero potential with respect to ground and the TPS22948 ramps the output current to ILIM. The TPS22948 device will limit the current to ILIM until the overload condition is removed or the internal junction temperature of the device reaches thermal shutdown and the device turns itself off. The device remains off until the junction temperature has lowered by TSDHYS, and the device will turn itself back on. This will cycle until the overload condition is removed.

The second condition is when a short circuit, partial short circuit, or transient overload occurs after the device has been fully powered on. The device responds to the overcurrent condition within time tLIM (see Figure 7), and before this time, the current is able to exceed ILIM. In the case of a fast transient, the current-sense amplifier is overdriven and momentarily disables the internal power FET. The current-sense amplifier recovers and limits the output current to ILIM. Similar to the previous case, the TPS22948 limits the current to ILIM until the overload condition is removed or the internal junction temperature of the device reaches thermal shutdown and begins thermally cycling on and off.

TPS22948 ILIM1.pngFigure 7. Transient Current Limit Waveform