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

2.2.2 Half-Bridge LLC Stage

A half-bridge LLC stage follows the PFC stage to step down the high voltage DC bus voltage to lower levels as per the system requirement. The controller is now locally referenced and generates the PWM control for switching the power FETs on the isolated side.

As illustrated in Figure 2-5, the half-bridge stage can also effectively make use of ISO65xx family of devices for high-side level shifting and blocking high-voltage switching transients of 100kV/us and beyond.

Half Bridge LLC Stage Using ISO6521Figure 2-5 Half Bridge LLC Stage Using ISO6521

PWM control for the hot-side from controller 2 can employ a basic isolator such as ISO6741 to ensure the system isolation requirements are met.