You may want to consider other topologies, such as flyback. I spent a *LOT* of time debugging the DC-DC converter for my wristwatch project, with simulations and bench-testing. In the end, I got it working but my simulations were way-off because I did not have proper modeling of my transformer.
The main problem I had was saturation, because I used such a small transformer due to space-constraints. Lesson-learned: Use an oversized inductor and stay well-away from Isat. You'll know it's saturating because it will get warm, and even warmer while under load. Another area you need to be careful about is the kick-back when the switching device shuts off. Depending upon the topology, your switch should be rated at the max output of your converter, NOT the DC input supply voltage. If you go with a flyback transformer (I used a 10:1 ratio), the kickback is *ideally* lowered by the turns ratio; in reality it's substantially higher due to leakage inductance and other factors. Be mindful of the ESR of the capacitor you are using for output filtering. Simulators, such as LTspice, will display the RMS current of device (a very handy feature). Expect to spend a lot of time on the bench with a scope. Monitoring the current thru the inductor/switch with a scope can be tricky, because noise will couple into the scope's ground lead and make you think you have horrible ringing/overshoot when you really dont. There are some good techniques online, such as removing your scope's ground lead and probe-shroud, and connecting the ground at the exposed metal ring near the probe tip. Lastly, you will find that DC-DC converters work beautifully under almost no load. Once you start loading them down, they dont work *as* nicely, but they definitely *do* work. Welcome to the real world..... Most importantly, when you do get it working, congratulate yourself on your accomplishment. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/83819c9a-f249-4dfc-b7c3-b57ea3d06e8f%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
