SLVSCV8D December   2015  – December 2019 TPS4H160-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Schematic
      2.      Driving a Capacitive Load With Adjustable Current Limit
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin 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 Switching Characteristics
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Pin Current and Voltage Conventions
      2. 8.3.2 Accurate Current Sense
      3. 8.3.3 Adjustable Current Limit
      4. 8.3.4 Inductive-Load Switching-Off Clamp
      5. 8.3.5 Fault Detection and Reporting
        1. 8.3.5.1 Diagnostic Enable Function
        2. 8.3.5.2 Multiplexing of Current Sense
        3. 8.3.5.3 Fault Table
        4. 8.3.5.4 STx and FAULT Reporting
      6. 8.3.6 Full Diagnostics
        1. 8.3.6.1 Short-to-GND and Overload Detection
        2. 8.3.6.2 Open-Load Detection
          1. 8.3.6.2.1 Channel On
          2. 8.3.6.2.2 Channel Off
        3. 8.3.6.3 Short-to-Battery Detection
        4. 8.3.6.4 Reverse Polarity Detection
        5. 8.3.6.5 Thermal Fault Detection
          1. 8.3.6.5.1 Thermal Shutdown
      7. 8.3.7 Full Protections
        1. 8.3.7.1 UVLO Protection
        2. 8.3.7.2 Loss-of-GND Protection
        3. 8.3.7.3 Protection for Loss of Power Supply
        4. 8.3.7.4 Reverse-Current Protection
        5. 8.3.7.5 MCU I/O Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Working 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
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
      1. 11.2.1 Without a GND Network
      2. 11.2.2 With a GND Network
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community 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 Adjustable Current Limit

A high-accuracy current limit allows high reliability of the design. It protects the load and the power supply from overstressing during short-circuit-to-GND or power-up conditions. The current limit can also save system cost by reducing the size of PCB traces and connectors, and the capacity of the preceding power stage.

When a current-limit threshold is hit, a closed loop activates immediately. The output current is clamped at the set value, and a fault is reported out. The device heats up due to the high power dissipation on the power FET. If thermal shutdown occurs, the current limit is set to ICL(TSD) to reduce the power dissipation on the power FET. See Figure 23 for more details.

The device has two current-limit thresholds.

  • Internal current limit – The internal current limit is fixed at ICL(int). Tie the CL pin directly to the device GND for large-transient-current applications.
  • External adjustable current limit – An external resistor is used to set the current-limit threashold. Use the Equation 4 to calculate the R(CL). VCL(th) is the internal band-gap voltage. K(CL) is the ratio of the output current and the current-limit set value. It is constant across the temperature and supply voltage. The external adjustable current limit allows the flexibility to set the current limit value by applications.
Equation 4. TPS4H160-Q1 eq04-Rcl_SLVSCV8.gif
TPS4H160-Q1 CurrLimBD_SLVSCV8.gifFigure 23. Current-Limit Block Diargam

Note that if using a GND network which causes a level shift between the device GND and board GND, the CL pin must be connected with device GND.

For better protection from a hard short-to-GND condition (when the INx pins are enabled, a short to GND occurs suddenly), the device implements a fast-trip protection to turn off the related channel before the current-limit closed loop is set up. The fast-trip response time is less than 1 μs, typically. With this fast response, the device can achieve better inrush current-suppression performance.