| .. I am using the MK II design. a 4403 and a | 4401 driving the fet. i am using a sdr1806-101kl 100uh inductor | ..
The 4403 & 4401 are a good choice. They were designed with switching in mind. I use the (MMBT or MPS) A05 & A55, personally, but there shouldn't be a measurable difference in this app. I also use the SDR1806 in my latest design. Its a pretty beefy coil, and seems to hold up well to abuse. The IPD60R380C6 FET is more than plenty for the need at hand. After looking at its datasheet, I do notice that they practice a bit of 'specmanship'. A little more than usual. Its a tad better than a IRF740, but a lot less than the initial highlights suggest. Otherwise, its still plenty good for the job. I'll be curious to see your actualized efficiency, and max current. The RS1G is a 'Fast rectifier' (150nS), as opposed to the 'ultra fast' (50/75nS) types most of us, usually use. If your efficiency measures below 75%, I'd substitute an ultrafast type in its spot, and see if that helps. Your max output current (at 180V) should be ~30mA (+10mA/-5mA), given a solid 12V input. Make sure your input supply can handle ~2 amps. A sagging input supply will throw off your numbers. Going on a tangent, and back to simple bipolar transistors. The old 2N2222, which most of us have used in mass, was originally designed for switching service (Low saturation Vce at significant collector current). With a fairly healthy current rating, that meant relay driving. But somehow, it got to be used as a general purpose device, used more often than not, in linear amplifier applications. If you can find an old datasheet on the 2N2222, you'll notice 'Switching' in its title. Most, if not all, modern datasheets list it as a 'general purpose amplifier'. Moral of the story, is that sometimes you can get away with using a device in some fashion other than originally intended. As long as you stay within the 'Absolute Maximum Ratings' it may actually do the job well enough for the app at hand. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
