OSH mains to 5V supply? - Page 1
Forum section: electronics / general

author: Johntron
author_rank: Contributor
timestamp: March 12, 2016, 02:29:03 am
content: I was really fascinated by how the little iPhone charger works. Does anybody know of an open source design for these?It would be great if you could start a project by just dropping a design like this into your EDA tool of choice and combine the BOMs.The flyback SMPS with voltage feedback is really slick, and would be great if something this small was readily available.

author: uncle_bob
author_rank: Unknown
timestamp: March 12, 2016, 02:41:33 am
content: Quote from: Johntron on March 12, 2016, 02:29:03 amHiThere are literally thousands of IC's out there doing switching power supply "stuff". At least three dozen companies make IC's that sell into this market. They all provide "open source" app notes on how their parts work and how to get them going.Apple isn't going to open source much of their hardware any time before the sun cools to room temp. You might as well just head off to your vendor of choice and use their chips.Bob

author: Johntron
author_rank: Contributor
timestamp: March 12, 2016, 03:39:34 am
content: Yes, I'm aware of the risks, certification costs, trade secrets, and vendor app notes.Still, app notes are not the same as a communal project. I guess there's really a bigger issue for me. I'm going to open a separate topic for that.

author: uncle_bob
author_rank: Unknown
timestamp: March 12, 2016, 02:17:47 pm
content: Quote from: Johntron on March 12, 2016, 03:39:34 amHiJust for those who might be reading along, a link to that thread might be nice.Bob

author: Richard Crowley
author_rank: Super Contributor
timestamp: March 12, 2016, 02:25:27 pm
content: Quote from: Johntron on March 12, 2016, 03:39:34 amBut because of the CONSIDERABLE risks and downsides and disadvantages, AND because of the dirt-cheap availability of complete product solutions, there isn't really any motivation for a communal project, is there? Or are we missing something here?

author: station240
author_rank: Unknown
timestamp: March 15, 2016, 05:03:28 pm
content: For a 5V supply it's pointless.Heck I got a bare PCB tiny 5V 700mA SMPS from HK for $5 or something.However, a multi output 'brick' SMPS would be real handy as there is really nothing commercially available.say +5V, +/- 15V but as an open design with guides to winding the transformer for different output voltages.Yes I know you can use a PC PSU, but those things are huge.

author: Richard Crowley
author_rank: Super Contributor
timestamp: March 15, 2016, 05:14:43 pm
content: I would love to find a wall-wart or line-lump power supply for +18 and -18. "Universal" SMPS would be great.There are lots of analog audio projects that could use this kind of supply.I am working on some audio "building-block" modules and would welcome having a commercial PS that I could recommend.Yes, I know there are board-level solutions, but they require the user to do mains wiring.Many people are interested in experimenting, but stop at mains wiring (and probably for good reasons).I may just have to settle for using a ~20VAC wall-wart and a couple of half-wave rectifiers to generate the positive and negative rails.That would probably work for low-power, line-level audio gear.But I was also thinking of a solution that uses 10-24VDC and one of the TI "simple switcher" designs.That way users could use whatever redundant laptop computer power supply they had lying about.And it would accommodate operation from 12V batteries, also for portable gear.

author: uncle_bob
author_rank: Unknown
timestamp: March 15, 2016, 10:37:29 pm
content: Quote from: station240 on March 15, 2016, 05:03:28 pmHiIt turns out that multi output supplies are indeed available. They are a bit harder to find that the far more popular single out versions. You generally need to shop a specialty "power supply only" distributor rather than one of the broad line / sell everything guys. The other advantage I've found shopping that way is that their prices are lower ...Bob