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

4.2 Input Short or supply interruption

Figure 4-4 and Figure 4-5 show the performance comparison of P-Channel MOSFET with a schottky diode during an input short or interruption. During an input short, the schottky diode is quickly reverse biased and blocks reverse current from flowing back into the shorted input. Output is isolated from the input short and hold capacitors at the output provide back-up power to the load, leading to droop in the output voltage. When the input short is removed, load is powered through the schottky diode.

In Figure 4-5, P-Channel MOSFET turns off when the gate-source voltage crosses VTH of MOSFET, close to 0 V. Output voltage sees a huge drop due to lack of reverse current blocking functionality.

GUID-C1F73C2C-37DF-4FCE-96E4-18F9772E2297-low.gifFigure 4-4 Input Short - Schottky Diode
GUID-B850683A-7A99-4415-AA05-E1B7F6BFF066-low.gifFigure 4-5 Input Short - P-Channel MOSFET