SLLA618 October   2023 ATL431 , ATL431LI , TL431 , TL431LI , TLVH432

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Designing for SSR With a Shunt Reference
    1. 2.1 Setting the Output Voltage
    2. 2.2 Biasing a Shunt Reference
    3. 2.3 Designing for Transient Response
  6. 3Power Considerations
  7. 4Methodology
    1. 4.1 Shunt Reference Implementation
    2. 4.2 Accuracy Comparison
    3. 4.3 Power Consumption Comparison
    4. 4.4 Transient Response Comparison
  8. 5Results
  9. 6Summary
  10. 7References

Abstract

Flyback converters are widely used in AC/DC power adapters and provide key advantages compared to other conventional AC/DC converters, such as isolation and competitive cost. Shunt references enable high-precision SSR (Secondary Side Regulation) in flyback converters and, when implemented properly, can make sure low standby power dissipation, high output accuracy, and quick transient responses to the flyback controller. When incorporating a shunt reference into a flyback feedback loop, designers must consider biasing, power dissipation, and transient response, and select their components accordingly. This application note outlines the key specs of shunt references in flyback design and explains how to effectively use these shunt references in the flyback control loop for SSR. Furthermore, these explanations are demonstrated with the implementation and comparison of the TL431, TLVH432, ATL431, TL431LI, and ATL431LI in the feedback loop of a flyback converter, which are some of the popular designs for SSR. This application note does not discuss the impacts of different types of compensation on the flyback feedback network.