SLVSCM2D October   2014  – December 2019 TPS1H100-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application 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 Timing Requirements – Current Sense Characteristics
    7. 6.7 Switching Characteristics
    8. 6.8 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 Accurate Current Sense
      2. 7.3.2 Programmable Current Limit
      3. 7.3.3 Inductive-Load Switching-Off Clamp
      4. 7.3.4 Full Protections and Diagnostics
        1. 7.3.4.1  Short-to-GND and Overload Detection
        2. 7.3.4.2  Open-Load Detection
        3. 7.3.4.3  Short-to-Battery Detection
        4. 7.3.4.4  Reverse-Polarity Detection
        5. 7.3.4.5  Thermal Protection Behavior
        6. 7.3.4.6  UVLO Protection
        7. 7.3.4.7  Loss of GND Protection
        8. 7.3.4.8  Loss of Power Supply Protection
        9. 7.3.4.9  Reverse Current Protection
        10. 7.3.4.10 Protection for MCU I/Os
      5. 7.3.5 Diagnostic Enable Function
    4. 7.4 Device Functional Modes
      1. 7.4.1 Working Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Distinguishing of Different Fault Modes
        2. 8.2.2.2 AEC Q100-012 Test Grade A Certification
        3. 8.2.2.3 EMC Transient Disturbances Test
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
      1. 10.2.1 Without a GND Network
      2. 10.2.2 With a GND Network
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

7.3.4.9 Reverse Current Protection

Method 1: Block diode connected with VS. Both the device and load are protected when in reverse polarity.

TPS1H100-Q1 rev_current_prot_lvscm2.gifFigure 41. Reverse Protection With Block Diode

Method 2 (GND network protection): Only the high-side device is protected under this connection. The load reverse loop is limited by the load itself. Note when reverse polarity happens, the continuous reverse current through the power FET should be less than Irev. Of the three types of ground pin networks, TI strongly recommends type 3 (the resistor and diode in parallel). No matter what types of connection are between the device GND and the board GND, if a GND voltage shift happens, ensure the following proper connections for the normal operation:

  • Leave the NC pin floating or connect to the device GND. TI recommends to leave floating.
  • Connect the current limit programmable resistor to the device GND.
TPS1H100-Q1 GND_net_prot_lvscm2.gifFigure 42. Reverse Protection With GND Network
  • Type 1 (resistor): The higher resistor value contributes to a better current limit effect when the reverse battery or negative ISO pulses. However, it leads to higher GND shift during normal operation mode. Also, consider the resistor’s power dissipation.
    • Equation 9. TPS1H100-Q1 eq_09_lvscm2.gif
    Equation 10. TPS1H100-Q1 eq_10_lvscm2.gif

    where

    • VGNDshift is the maximum value for the GND shift, determined by the HSD and microcontroller. TI suggests a value ≤ 0.6 V.
    • Inom is the nominal operating current.
    • –VCC is the maximum reverse voltage seen on the battery line.
    • –IGND is the maximum reverse current the ground pin can withstand, which is available in the Absolute Maximum Ratings.

    If multiple high-side power switches are used, the resistor can be shared among devices.

  • Type 2 (diode): A diode is needed to block the reverse voltage, which also brings a ground shift (≈ 600 mV). However, an inductive load is not acceptable to avoid an abnormal status when switching off.
  • Type 3 (resistor and diode in parallel (recommended)): A peak negative spike may occur when the inductive load is switching off, which may damage the HSD or the diode. So, TI recommends a resistor in parallel with the diode when driving an inductive load. The recommended selection are 1-kΩ resistor in parallel with an IF > 100-mA diode. If multiple high-side switches are used, the resistor and diode can be shared among devices.