SLVSFZ2C April   2023  – February 2024 TPS274C65

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
    1.     7
  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 SPI Timing Requirements
    8. 6.8 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Pin Diagrams
      2. 8.3.2 SPI Mode Operation
        1. 8.3.2.1 Diagnostic Bit Behavior
      3. 8.3.3 Programmable Current Limit
        1. 8.3.3.1 Inrush Current Handling
      4. 8.3.4 DO_EN Feature
      5. 8.3.5 Protection Mechanisms
        1. 8.3.5.1 Overcurrent Protection
        2. 8.3.5.2 Short Circuit Protection
          1. 8.3.5.2.1 VS During Short-to-Ground
        3. 8.3.5.3 Inductive-Load Switching-Off Clamp
        4. 8.3.5.4 Inductive Load Demagnetization
        5. 8.3.5.5 Thermal Shutdown
        6. 8.3.5.6 Undervoltage protection on VS
        7. 8.3.5.7 Undervoltage Lockout on Low Voltage Supply (VDD_UVLO)
        8. 8.3.5.8 Power-Up and Power-Down Behavior
        9. 8.3.5.9 Reverse Current Blocking
      6. 8.3.6 Diagnostic Mechanisms
        1. 8.3.6.1 Current Sense
          1. 8.3.6.1.1 RSNS Value
            1. 8.3.6.1.1.1 SNS Output Filter
        2. 8.3.6.2 Fault Indication
          1. 8.3.6.2.1 Current Limit Behavior
        3. 8.3.6.3 Short-to-Battery and Open-Load Detection
        4. 8.3.6.4 On-State Wire-Break Detection
        5. 8.3.6.5 Off State Wire-Break Detection
        6. 8.3.6.6 ADC
      7. 8.3.7 LED Driver
    4. 8.4 Device Functional Modes
      1. 8.4.1 OFF/POR
      2. 8.4.2 INIT
      3. 8.4.3 Active
    5. 8.5 TPS274C65BS Available Registers List
    6. 8.6 TPS274C65 Registers
  10. 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 IEC 61000-4-5 Surge
        2. 9.2.2.2 Loss of GND
        3. 9.2.2.3 Paralleling Channels
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.5.3 Inductive-Load Switching-Off Clamp

When an inductive load is switching off, the output voltage is pulled down to negative, due to the inductance characteristics. The power FET may break down if the voltage is not clamped during the current-decay period. To protect the power FET in this situation, internally clamp the drain-to-source voltage, namely VDS,clamp, the clamp diode between the drain and gate.

Equation 1. VDS,Clamp = VS – VOUT

During the current-decay period (TDECAY), the power FET is turned on for inductance-energy dissipation. Both the energy of the power supply (ES) and the load (ELOAD) are dissipated on the high-side power switch itself, which is called EHSD. If resistance is in series with inductance, some of the load energy is dissipated in the resistance.

Equation 2. EHSD = ES + ELOAD = ES + EL – ER

From the high-side power switch’s view, EHSD equals the integration value during the current-decay period.

Equation 3. GUID-87664A16-486A-4B92-99DD-CC043FE7984D-low.gif
Equation 4. GUID-A298B928-F6B0-41C1-A51F-2AF954E741F2-low.gif
Equation 5. GUID-21066C26-F031-4A4B-B756-4800F6B75597-low.gif

When R approximately equals 0, EHSD can be given simply as:

Equation 6. GUID-C7E46332-DD3C-4B51-8522-0FBC69EF27B3-low.gif
GUID-4D1C0551-26BA-4CAF-92DB-3DBC632B84A3-low.svgFigure 8-24 Driving Inductive Load
GUID-08163EAD-4487-4AAA-966E-9E9347C6937B-low.svgFigure 8-25 Inductive-Load Switching-Off Diagram

As discussed previously, when switching off, supply energy and load energy are dissipated on the high-side power switch, which leads to the large thermal variation. For each high-side power switch, the upper limit of the maximum safe power dissipation depends on the device intrinsic capacity, ambient temperature, and board dissipation condition.