Other Parts Discussed in Thread: TINA-TI
Tool/software: TINA-TI or Spice Models
Good afternoon,
As the thread title suggests, I am having trouble simulating the UC3846 model in LTSPICE. I have gone through the process of creating the chip and adding it to the simulation space, but when configured in a similar way to the "Typical Application Diagram" from the data sheet it doesn't create any output oscillation. The system runs up to certain voltages then remains constant through the rest of the operation.
I have adjusted the values of Rt and Ct to give me an output frequency of a theoretical 20kHz. I thought the soft start might be the issue, so I added a pulse current and pulse voltage that overlap by 1us. I have attempted a few different setups, including adding in the bjt/diodes/transformer output in the data sheet diagram, but nothing changes. Here are my plots and output waveforms. You may notice that the run-time only goes up to 4ms, I halted the process before the end of the run as I should have already seen some oscillation by that point. If anything is unclear, please ask whatever questions you might have.
