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I've gotten the new schematic thrown together, next up is assigning footprints to everything and laying out the board. I'm definitely considering a PCB assembly service for this one, that's something like 35 components, most of them 0603, and I really don't want to have to put it together.

Well, you said "Professional" and while that certainly doesn't describe me, it made me reconsider the hack that probably wouldn't work that I was going to try to get this working, so I went back to the drawing board and started over. Instead of trying to put two switching regulators in parallel for the 5v line, I'm going the proper route and designing it with a controller and mosfets per the suggestion of TI's WEBENCH Power Designer application. I'm still going to have to do some tweaking to make their suggested circuit into something I can reasonably hope to assemble, however. As an added benefit, my new 5v circuit will definitely support the power requirements of the xbox, and won't be prone to the same issues that the 160xt apparently has.

This is a copy of portions of my thread over at BitBuilt https://bitbuilt.net/forums/index.php?threads/xboxdvi.3304/ As some of you may know, the original xbox is really lacking in video output modes for the modern era. It is only capable of analog video out, and doesn't even support VGA through that. Early versions of the xbox use a CX25871 as the video encoder, which can take a variety of digital inputs and in turn outputs analog video. https://html.alldatasheet.com/html-pdf/153349/CONEXANT/CX25871/384/1/CX25871.html My suspicion is that the xbox uses the highest quality of these potential inputs, RGB24. If that turns out to be the case, I should be able to use the Texas Instruments TFP410 to turn these signals into DVI https://www.ti.com/product/TFP410 End goal is to have a board with a BOM of under $20 that I can then install in my absurd stack of xboxen. The catch: This is my first circuit design project and my first PCB design project, so I'm starting out way over my head. Wish me luck, I guess. -------------------------------------------------- I've since found that my initial assumptions were incorrect, and I've made it to my second prototype. It still has issues, but I'll find out soon enough if I'm on the right track. --------------------------------------------------

This is going to start out as just being copied directly over from my thread on BitBuilt about the project. https://bitbuilt.net/forums/index.php?threads/xboxpsu.3387/ The xbox has some mildly odd power requirements. It uses the same 20 pin Molex MiniFit Jr connector that an ATX PSU output, however the pinout is completely different. As it stands, the typical solution is to use a PicoPSU, a small ATX PSU, a modify it to work with the original xbox. PicoPSUs can be had for around $15, the power supplies for them can be had for around $10. It's a very inexpensive solution. Traditionally when this is done, the Power OK and Power On lines are ignored, the PSU is set to always on, and the wires are run all catywumpus to get to where they need to go. While this solution works, it's definitely a hack, and I believe we can do better. So what are the xbox's actual power requirements? While I haven't actually cut up a power supply and tried to get the xbox to full load while measuring the current draw, I have a V1.1 PSU here that handily has the power requirements right on the label. Max Output Power: 96W DC Output: +5V -- 13.2A +3.3V -- 4.8A +12V --1.2A +3VSB -- 0.045A I hope it's safe to assume that further revisions of the xbox had similar or lower power draw. Regardless, this seems like a good starting point. So, how do I plan to accomplish this? With 4x LM2678 Regulators from Texas Instruments. http://www.ti.com/product/LM2678 Why 4 regulators for 3 voltages? The LM2678 is a 5A regulator. I need 13.2A on the 5V line. Having looked at the specs for the PicoPSUs that seem to work just fine, they're rated for 8A on the 5V line. This leads me to believe that 10A should suffice, so I'll need two regulators for 5V. I'll also need a 12V regulator, as I plan to run this off of an easily obtainable laptop power supply rather than needing to source an 8A 12V supply. I will also be designing a smaller footprint alternative that runs off of 12v for when space is of the highest concern. I'll likely also break down the xbox's power requirements even further at some point to see if I can't design a PSU that allows for aggressive trimming, but that's much further down the road. -------------------------------------------- I've designed the first iteration of the 24v board, it's 60*32mm. Now that it's done, I don't like it for a variety of reasons. I'm going to try again, putting the low profile components on the backside of the board and the tall components on the topside of it. Maybe I'll be able to squish it down a bit more in the process. -------------------------------------------- There, that's a little better. 27.5*49.25 mm -------------------------------------------- Oh, hey, I worked on this a bit. I ditched the 12v regulator and changed it to 12v in. I also had to source different inductors, which are sadly larger, so the whole board got a couple of mm wider in the process. 26.5mm*57.2mm I think I'm gonna actually order this one, and see if it works. -------------------------------------------- I've since looked at the most recent revision and noticed a couple of flaws in it. I've repaired those flaws, and I'm gonna sleep on it again, look at it with fresh eyes tomorrow, and probably order it.