SLVAE57B February   2021  – October 2021 LM5050-1 , LM5050-2 , LM5051 , LM66100 , LM74202-Q1 , LM74500-Q1 , LM74610-Q1 , LM74700-Q1 , LM74720-Q1 , LM74721-Q1 , LM74722-Q1 , LM7480-Q1 , LM7481-Q1 , LM76202-Q1 , SM74611 , TPS2410 , TPS2411 , TPS2412 , TPS2413 , TPS2419

 

  1.   Trademarks
  2. 1 Introduction
  3. 2 Reverse Battery Protection
    1. 2.1 Reverse Battery Protection with Schottky Diode
  4. 3 ORing Power Supplies
  5. 4 Reverse Battery Protection using MOSFETs
    1. 4.1 Reverse Battery Protection using P-Channel MOSFET
    2. 4.2 Input Short or supply interruption
    3. 4.3 Diode Rectification During Line Disturbance
    4. 4.4 Reverse Battery Protection using N-Channel MOSFET
  6. 5 Reverse Polarity Protection vs Reverse Current Blocking
    1. 5.1 Reverse Polarity Protection Controller vs. Ideal Diode Controller
    2. 5.2 Performance Comparison of P-Channel and Reverse Polarity Protection Controller Based Solution
  7. 6 What is an Ideal Diode Controller?
    1. 6.1 Linear Regulation Control Vs Hysteretic ON/OFF Control
    2. 6.2 Low Forward Conduction Loss
    3. 6.3 Fast Reverse Recovery
    4. 6.4 Very Low Shutdown Current
    5. 6.5 Fast Load Transient Response
    6. 6.6 Additional Features in Ideal Diode Controllers
      1. 6.6.1 Back-to-Back FET Driving Ideal Diode Controllers
      2. 6.6.2 Very Low Quiescent Current
      3. 6.6.3 TVSless Operation
  8. 7 Automotive Transient protection with Ideal Diode Controllers
    1. 7.1 LM74700-Q1 with N-Channel MOSFET
    2. 7.2 Static Reverse Polarity
    3. 7.3 Dynamic Reverse Polarity
    4. 7.4 Input Micro-Short
    5. 7.5 Diode Rectification of Supply Line disturbance
  9. 8 ORing Power Supplies with Ideal Diode Controllers
  10. 9 Integrated Ideal Diode Solution
  11. 10Summary
  12. 11References
  13. 12Revision History

7.4 Input Micro-Short

Many power systems are required to withstand short interruption in supply line or input micro-short and continue to function uninterrupted. In Figure 7-4, when the input micro-short is applied at the input, the LM74700-Q1 reacts quickly to turn off the MOSFET to block reverse current from flowing back into the shorted supply. Output remains ON during the input short as the output hold-up capacitors are isolated from input short and supply load current until the input recovers from micro-short. Note that after the MOSFET is turned off, input current rings due to the parasitic inductance in the supply path and does not contribute to reverse current.

GUID-2A08D751-09F6-4C3F-98B7-6FE4ABAC1BE3-low.gifFigure 7-4 LM74700-Q1 Response to Input Micro-short