L6565 modeling and Quasi-resonant (QR) ZVS flyback converter simulation

Sophia Li

Introduction:
Switch mode control is widely used in power converters and motor drives. The key controllers are Pulse Width Modulation (PWM) ICs. This QR ZVS flyback converter example comes from ST Microelectronics application note AN1326. L6565 quasi-resonant (QR) controller is used in this design. L6565 modeling is the key point for this simulation. In this example, hierarchical schematic of l6565 is created based on datasheet block diagram. Starter and line forward function are accomplished by MAST hardware description language (HDL). Blanking time is inputted by Table Look-Up (TLU) tool.
In the circuit test process, use experiment to run time domain analysis, checked the output voltage changes to load changes and input voltage changes. Also check the switch voltage to make sure the circuit is working in Zero Voltage Switch (ZVS) mode.

Circuit Snapshot:
Refer to the attached snapshot “l6565_flyback.png”

How to use the example:
Download the attached l6565_flyback.zip file and unzip the contents. Open the l6565_flyback.ai_dsn in SaberRD and run “time_domain_test” in the Experiment Analyzer tool. After simulation, look at the generated graph and experiment report.

For more details of the design, how to run the design, etc., refer to the README.pdf file in the folder.

Note:
This design works only in SaberRD commercial edition 2015.03 and above.