SLUAAQ7A August   2023  – April 2025 UCC256404

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Theory of LLC Topology Design
  6. 3Burst Mode Operating Control Mechanism
  7. 4Potential ZCS Issue When Exiting Burst Mode
  8. 5Design to External Circuit for Solving ZCS Issue at Burst Transition Period
  9. 6Design to Accurate External Circuit for Solving ZCS Issue at Burst Transition Period_(Option)
    1. 6.1 Test Result of External Circuit for Solving ZCS Issue at Burst Transition Period
  10. 7Summary
  11. 8References
  12. 9Revision History

6.1 Test Result of External Circuit for Solving ZCS Issue at Burst Transition Period

Table 6-1 shows setting external circuit components value for auto standby output current level

Table 6-1 Auto Standby Output Current Level
Load Condition Burst Mode Setting Burst Off Period
> 0.25A No burst 0
< 0.25A Burst with higher power than 0.25A Large

The following waveforms show without external auto standby circuit and with external auto standby circuit

Waveform of Low Side Current (Without Circuit)Figure 6-2 Waveform of Low Side Current (Without Circuit)
Waveform of Low Side Current Zoom (Without Circuit)Figure 6-3 Waveform of Low Side Current Zoom (Without Circuit)
Waveform of Low Side Current (With Circuit)Figure 6-4 Waveform of Low Side Current (With Circuit)
Waveform of Low Side Current Zoom (With Circuit)Figure 6-5 Waveform of Low Side Current Zoom (With Circuit)