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

10.2.3 Application Curves

Upon enabling our device into a capacitive load, TPS272C45 defaults the current limit to 2 times ICL for a period of time programmed set by ILIMD. In Figure 10-4, TPS272C45 charges a 1-mF capacitor using the inrush current handling feature. During the first 4 mS after enabling the device, IOUT1 is 2 times the ICL programmed (4 A). After the 4-mS period, the current folds back to the programmed ICL (2 A).

GUID-20211116-SS0I-1WXR-H3T1-TMPZFW50NGXK-low.png Figure 10-4 TPS272C45 Capacitor Charging

If the device has a no-load case due to an open load or wire-break, the device registers the fault even in an off-state if the DIA_EN pin is high. Figure 10-5 shows the device behavior when an open load event is registered with EN low and DIAG_EN is raised. Systems can PWM DIA_EN to lower system power losses while still watching for open load events and the same timing applies.

GUID-20211116-SS0I-KFT8-XPVS-NKTMQRQSVG09-low.pngFigure 10-5 Open-Load (tOL) Detection Time

If the output of the TPS272C45 is short-circuited, the device protects the system from failure. Depending on RILIM, the current limit set-point varies. The waveforms below show examples of the current limit behavior when the device is enabled into a short circuit.

In Figure 10-6, the output is permanently shorted. Upon enabling the device, the current reaches the 2 times current limit is enabled for 6 mS set by ILIMD resistor. After the inrush current period, the current is reduced to the programmed current limit set by RILIM. In this case, because the power dissipation is low enough, the device is able to constantly act as a current source.

GUID-20211118-SS0I-4DH1-CXHJ-HGKM9SHSVVXD-low.png Figure 10-6 Enabling Into Short (RILIM = 10 k, VS = 6 V, Delay = 6 mS)

In Figure 10-6, the output is also permanently shorted. Upon enabling the device, the current reaches the 2 times current limit, however because the power dissipation is greater due to the higher input voltage at VS the device reaches its thermal shutdown threshold and disables itself before reaching the programmed delay time.

GUID-20211116-SS0I-FTK5-DHZG-XNLMGK24TLM1-low.png Figure 10-7 Enabling Into Short (RILIM = 10 k, VS = 24 V, Delay = 6 mS)

Figure 10-8 shows that after the device has been enabled into a short and due to the high power dissipation, the device reaches its thermal shutdown threshold. The device then shuts down the FET for a period of tRETRY and re-enables the FET into the short. The capture shows the continuous retry cycle and protection because the short is permanently applied.

GUID-20211118-SS0I-2CJH-LNTS-JTH5TMPCK8LX-low.png Figure 10-8 Permanent Short Behavior (RILIM = 10 k, VS = 24 V, Delay = 6 mS)

In the event a short is applied to the output while a load is being driven, the device activates its fast trip comparator and shutdown the output to limit the inrush current. The device then immediately re-enables into the short and limit the current to the programmed current limit value. Figure 10-9 describes the behavior.

GUID-20211118-SS0I-FJS2-9HRG-KZ2PGDJ8HZDT-low.png Figure 10-9 On-State Short Circuit (RILIM = 10 k, VS = 24 V )