Jayaram Ya Tong Yu Original Assignee Jayaram Sheshakamal H Ya Tong Yu Priority date (The priority date is an assumption and is not a legal conclusion.
Google Patents WO2011017802A1 - High voltage square wave and spwm wave generator You're not trying to generate a high-voltage supply, you're trying to generate short sparks, so getting a nice smooth power transition from primary to secondary side in these transformers isn't at all what you want – I don't know, but I guess the transformers thermally aren't designed to continously transport power, but really just short impulses.WO2011017802A1 - High voltage square wave and spwm wave generator If you want to drive ignition coils, also, you typically want the highest \$\frac\$ possible, so, you'd also want hard switching in that case, and not a sine wave or anything else. It's always "easiest" to switch something on and off – it's where transistors waste the least power. So, I guess it's most likely you'd want to end up unipolar. The spark as is doesn't care, but in reality, the vehicle ground usually closes the circuit, so you typically can't choose an arbitrary virtual ground, and hence would need your amplifier or its power supply to generate a negative, 20A-average-capable supply – that's a hard job. Possibly, but what's worse is that the output filter of that amplifier will never allow you to get sufficiently steep signal edges.ĭoes uni vs bipolar square make a difference?ĭepends on how the wiring of your ignition actually looks like. One problem might be(?) that I want to use a square wave, will the dc filtering remove this? And that doesn't mean anything's sufficiently linear at 100W. Looking at that ebay offer, there's positively no way imaginable the amplifier depicted comes close to 600W output power. You need an amplifier with a linear in/output relationship – and at 5V/20A, ie. In other words: getting a set of MOSFETs to do the switching is exactly the right (and only) thing you should do if you need to amplify a square wave.įor a sine wave, things look drastically different. So, you want the actual power transistor part of that amplifier, but nothing else of that amplifier. An amplifier is always bandwidth-limited, and especially a class-D amplifier only works by smoothing out a square wave until it doesn't look square anymore. So, in reality, they are limited to some finite slew rate – you'll need to figure out what that is, but I'm pretty certain it's above audio frequency levels. Problem is that square and triangular waves have theoretically infinite bandwidth. So this is a set of three different waveforms you need to amplify. Hope that helps a little, and thanks again.Ī square wave (normally unipolar) sine, triangle Will use any power supply that's required for the amp stage, not the transformers/rectifiers Again, the 8 MJ11032's in parallel that I tried were fine, they just didn't last. I just want to replace the darlington section with something that an engineer actually built. If it helps here's a link to the coil specs I'm using-, 4 in parallel, and an 8" phanotron plasma tube, I will be using one switchable vintage spark "tube" instead of the spark plugs. Yeah that's all there is really to these, usually. There's too many types of amplifiers out there here's the basic idea Does uni vs bipolar square make a difference?.One problem might be(?) that I want to use a square wave, will the dc filtering remove this?.So what I'd like to do is just take advantage of the many amp boards offered on ebay such as. I used 8 MJ11033's in parallel, which was sufficient, but I apparently didn't bias them right and they all burned eventually. Usually people use one or two darlingtons and the power is not sufficient. I need to supply 4 MSD ignition coils with a square wave (normally unipolar) sine, triangle wave at 5v and amplify that signal up to say… 20A MAX.