SLVSCV8E December   2015  – June 2025 TPS4H160-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Pin Current and Voltage Conventions
      2. 7.3.2 Accurate Current Sense
      3. 7.3.3 Adjustable Current Limit
      4. 7.3.4 Inductive-Load Switching-Off Clamp
      5. 7.3.5 Fault Detection and Reporting
        1. 7.3.5.1 Diagnostic Enable Function
        2. 7.3.5.2 Multiplexing of Current Sense
        3. 7.3.5.3 Fault Table
        4. 7.3.5.4 STx and FAULT Reporting
      6. 7.3.6 Full Diagnostics
        1. 7.3.6.1 Short-to-GND and Overload Detection
        2. 7.3.6.2 Open-Load Detection
          1. 7.3.6.2.1 Channel On
          2. 7.3.6.2.2 Channel Off
        3. 7.3.6.3 Short-to-Battery Detection
        4. 7.3.6.4 Reverse Polarity Detection
        5. 7.3.6.5 Thermal Fault Detection
          1. 7.3.6.5.1 Thermal Shutdown
      7. 7.3.7 Full Protections
        1. 7.3.7.1 UVLO Protection
        2. 7.3.7.2 Loss-of-GND Protection
        3. 7.3.7.3 Protection for Loss of Power Supply
        4. 7.3.7.4 Reverse-Current Protection
        5. 7.3.7.5 MCU I/O Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Working Modes
  9. 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
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Examples
        1. 8.4.2.1 Without a GND Network
        2. 8.4.2.2 With a GND Network
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.3.4 Inductive-Load Switching-Off Clamp

When switching an inductive load off, the inductive reactance tends to pull the output voltage negative. Excessive negative voltage could cause the power FET to break down. To protect the power FET, an internal clamp between drain and source is implemented, namely VDS(clamp).

Equation 5. TPS4H160-Q1

During the period of demagnetization (tdecay), the power FET is turned on for inductance-energy dissipation. The total energy is dissipated in the high-side switch. Total energy includes the energy of the power supply (E(VS)) and the energy of the load (E(load)). If resistance is in series with inductance, some of the load energy is dissipated on the resistance.

Equation 6. TPS4H160-Q1

When an inductive load switches off, E(HSS) causes high thermal stressing on the device.. The upper limit of the power dissipation depends on the device intrinsic capacity, ambient temperature, and board dissipation condition.

TPS4H160-Q1 Drain-to-Source Clamping StructureFigure 7-5 Drain-to-Source Clamping Structure
TPS4H160-Q1 Inductive Load Switching-Off DiagramFigure 7-6 Inductive Load Switching-Off Diagram

From the perspective of the high-side switch, E(HSS) equals the integration value during the demagnetization period.

Equation 7. TPS4H160-Q1

When R approximately equals 0, E(HSD) can be given simply as:

Equation 8. TPS4H160-Q1

Figure 7-7 is a waveform of the device driving an inductive load, and Figure 7-8 is waveform with an expanded time scale. Channel 1 is the IN signal, channel 2 is the supply voltage VVS, channel 3 is the output voltage VOUT, channel 4 is the output current IOUT, and channel M is the measured power dissipation E(HSS).

On the waveform, the duration of VOUT from VVS to (VVS – VDS(clamp)) is around 120 µs. The device also optimizes the switching-off slew rate when the clamp is active. This optimization can help the system design by keeping the effects of transient power and EMI to a minimum. As shown in Figure 7-7 and Figure 7-8, the controlled slew rate is around 0.5 V/µs.

TPS4H160-Q1 Inductive Load Switching-Off WaveformFigure 7-7 Inductive Load Switching-Off Waveform
TPS4H160-Q1 Inductive Load Switching-Off Expanded WaveformFigure 7-8 Inductive Load Switching-Off Expanded Waveform

Note that for PWM-controlled inductive loads, it is recommended to add the external freewheeling circuitry shown in Figure 7-9 to protect the device from repetitive power stressing. TVS is used to achieve the fast decay. See Figure 7-9 for more details.

TPS4H160-Q1 Protection With External CircuitryFigure 7-9 Protection With External Circuitry