Other Parts Discussed in Thread: LM3478, LM3481, LM5155
After a first failed attempt with the LM3478, quite probably because of a bad assembling process on my end, I bought a CNC router and used WeBench designer to to craft a flyback transformer using the LM3481 that would in theory produce +15V at the output from a regular Li-Po battery.
Sadly, I still don't get +15V out but barely 2V under no load and I also noticed that I need to switch the circuit quickly off and back on to start some switching.
Now power electronics is not my strong suit and I can't figure out if it could be some Isense limiting, the Comp feedback loop that doesn't respond properly, or simply my assembly which is flawed.
So here's the design, straight from WeBench, and mine updated with the component I had :
You can also see my build here :
And here is some measurement I took (With about 4V steady at the input) :
- Output voltage :
- The Gate signal :
- The primary winding output :
- The secondary winding :
- The Comp pin :
- And finally the Isense (both peak to peak and a close up)
So there it is : I have several doubts of possible problems, but the fact that I tried to follow exactly the Webench design sort of throws me of. Do you have a clue of what could go wrong ?
Thanks in advance for your help !