SLUAB13 April   2025 UCG28826

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2VCC Self-Bias at Different AC Line and Load Conditions
  6. 3VCC Capacitor Configuration
  7. 465W AC-DC USB PD Charger Based on VCC Self-Biasing GaN Flyback
  8. 5Summary
  9. 6References

Abstract

This application note addresses how to size the VCC capacitor for a VCC self-biased gallium nitride (GaN) integrated flyback converter. This document first addresses the benefits of VCC self-bias in USB PD charger applications. Subsequently, the document explains VCC self-bias under different AC line and load conditions, emphasizing the VCC self bias role in maintaining a stable VCC voltage and the impact on no-load power consumption. The discussion further extends to the design calculations for appropriate VCC capacitance, verifying both a stable VCC voltage and a minimized no-load power consumption, targeting as low as 30mW. This comprehensive analysis provides essential guidelines for improving the performance and efficiency of GaN-based flyback converters in power-sensitive applications.