SLVSF24C december   2020  – may 2023 TPS272C45

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
    1. 6.1 Recommended Connections for Unused Pins
  8. 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 SNS Timing Characteristics
    7. 7.7 Switching Characteristics
    8. 7.8 Typical Characteristics
  9. 8 Parameter Measurement Information
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Programmable Current Limit
        1. 9.3.1.1 Inrush Current Handling
        2. 9.3.1.2 Calculating RILIMx
        3. 9.3.1.3 Configuring ILIMx From an MCU
      2. 9.3.2 Low Power Dissipation
      3. 9.3.3 Protection Mechanisms
        1. 9.3.3.1 Short-Circuit Protection
          1. 9.3.3.1.1 VS During Short-to-Ground
        2. 9.3.3.2 Inductive Load Demagnetization
        3. 9.3.3.3 Thermal Shutdown
        4. 9.3.3.4 Undervoltage Lockout on VS (UVLO)
        5. 9.3.3.5 Undervoltage Lockout on Low Voltage Supply (VDD_UVLO)
        6. 9.3.3.6 Power-Up and Power-Down Behavior
        7. 9.3.3.7 Overvoltage Protection (OVPR)
      4. 9.3.4 Diagnostic Mechanisms
        1. 9.3.4.1 Current Sense
          1. 9.3.4.1.1 RSNS Value
            1. 9.3.4.1.1.1 Current Sense Output Filter
        2. 9.3.4.2 Fault Indication
          1. 9.3.4.2.1 Fault Event Diagrams
        3. 9.3.4.3 Short-to-Supply or Open-Load Detection
          1. 9.3.4.3.1 Detection With Switch Enabled
          2. 9.3.4.3.2 Detection With Switch Disabled
        4. 9.3.4.4 Current Sense Resistor Sharing
    4. 9.4 Device Functional Modes
      1. 9.4.1 Off
      2. 9.4.2 Diagnostic
      3. 9.4.3 Active
      4. 9.4.4 Fault
  11. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 IEC 61000-4-5 Surge
      2. 10.1.2 Inverse Current
      3. 10.1.3 Loss of GND
      4. 10.1.4 Paralleling Channels
      5. 10.1.5 Thermal Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 RILIM Calculation
        2. 10.2.2.2 Diagnostics
          1. 10.2.2.2.1 Selecting the RISNS Value
      3. 10.2.3 Application Curves
    3. 10.3 Power Supply Recommendations
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
      2. 10.4.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

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

9.3.3.1 Short-Circuit Protection

TPS272C45 provides output short-circuit protection to ensure that the device prevents current flow in the event of a low impedance path to GND, removing the risk of damage or significant supply droop. The device is specified to protect against short-circuit events regardless of the state of the ILIM pins and or supply voltages up to 36V and across the entire opeprating temperature range -40 °C 125°C.

Figure 9-7 shows the behavior of the TPS272C45 when the device is enabled into an overload condition and then recovers to a normal load.

GUID-20211123-SS0I-BGRW-DBNG-KTDWSXDJR3LV-low.svgFigure 9-7 Enable into Short-Circuit Behavior

Due to the low impedance path, the output current rapidly increases until it hits the current limit threshold. Due to the response time of the current limiting circuit, the measured maximum current can temporarily exceed the ICL value defined as ICL_ENPS, before it settles to the current limit regulation value (ICL).

In this state high power is dissipated in the FET, so eventually the internal thermal protection temperature for the FET is reached and the device safely shuts down. Then if LATCH pin is low the part waits tRETRY amount of time and turns back on.

Figure 9-8 shows the behavior of the TPS272C45 when a short-circuit occurs when the device is in the on-state and already outputting current. When the internal pass FET is fully enabled, the current clamping settling time is slower so to ensure overshoot is limit, the device implements a fast trip turn-off at a high current threshold (approximately 40% higher than ICL). When this fast trip threshold is hit, the device shuts off after a delay for a short period of time before quickly re-enabling and clamping the current to the regulation current limit level (ICL) after a brief transient overshoot to the higher peak current level. The device then keeps the current clamped at the regulation current limit until the thermal shutdown temperature is hit and the device safely shuts off.

GUID-20211118-SS0I-XMTG-ZLCG-THRTZZ4TTMSH-low.svgFigure 9-8 On-State Short-Circuit Behavior

Overload Behavior shows the behavior of the TPS272C45 when there is a small change in impedance that sends the load current above the ICL threshold. The current rises to ICL_LIN above the regulation level. Then the current limit regulation loop kicks in and the current drops to the ICL value.

GUID-20211123-SS0I-J2JT-XQPN-CDXNP76W5PGF-low.svgFigure 9-9 Overload Behavior

In all of these cases, the internal thermal shutdown is safe to hit repetitively. There is no device risk or lifetime reliability concerns from repeatedly hitting this thermal shutdown level.