SLLA646 August   2024 ISO6520 , ISO6521

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Where are Digital Isolators Commonly Used?
    2. 1.2 What is Functional Isolation?
    3. 1.3 Key Benefits of Functional Isolation
  5. 2Application Use Cases
    1. 2.1 Telecom Power Supplies
      1. 2.1.1 48V Isolated DC-DC
      2. 2.1.2 48V Non-Isolated DC-DC
    2. 2.2 Server Power Supply
      1. 2.2.1 Totem-Pole Power Factor Correction Stage
      2. 2.2.2 Half-Bridge LLC Stage
    3. 2.3 AC - DC Power Supply in Pluggable Wall-Chargers
      1. 2.3.1 Introduction
      2. 2.3.2 Topology Details
      3. 2.3.3 Using ISO65xx for Reliable PWM Signaling
    4. 2.4 Semiconductor Test and Measurement
  6. 3Conclusion
  7. 4References

2.2.1 Totem-Pole Power Factor Correction Stage

A Power Factor Correction (PFC) stage is implemented to improve overall efficiency while rectifying incoming AC power to the DC bus voltage. Figure 2-4 depicts a typical PFC stage with a fast switching leg using power FETs (like GaN) and a slow switching leg.

Totem Pole PFC Stage Using ISO6521 Figure 2-4 Totem Pole PFC Stage Using ISO6521

The switching control input comes from a controller that generates appropriate PWM signals. An isolator is generally used to block high voltage common mode and also withstand fast switching transients.

The ISO65xx family of devices are an area-optimized solution that can be used to block the high voltage common mode >400V and switching-noise of >100kV/us on across the isolation barrier.