SLVAF01 October   2020 TPS55340

 

  1.   Trademarks
  2. 1Switching Node Voltage Stress from Flyback
    1. 1.1 Reflected Voltage, VOR
    2. 1.2 Leakage Inductance Factor
  3. 2Mitigating Voltage Spike on Switch Node
    1. 2.1 Zener or TVS Clamping
    2. 2.2 Forward Recovery Characteristic of Blocking Diode
  4. 3Design Example with TPS55340
    1. 3.1 Initial Key Designs and Test Results
    2. 3.2 Redesign Procedure to Mitigate Vsw
    3. 3.3 Using Blocking Diode that has a good Tfr
  5. 4Summary
  6. 5References

4 Summary

If there is a strict requirement regarding to switching node waveform in the flyback converter, the user needs to check whether the reflected voltage is optimized at first and then consider proper snubbing methods. There also should not be a pcb design error that usually generates parasitic inductance in the critical path. Lastly, keeping correct measurements is also important to receive exact voltage waveform on SW node as well.