USB Syncroized 5V@8A power supply POL. Now Taking Orders!!!

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Originally Posted by turbocad6

ok, so in one of my installs I have used a 5v relay to trip a spare opus power supply from my usb, what will your's do different than that? I mean any power supply can be tripped by usb? am I missing something here other than maybe the use of relays vs solid state?

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thats basically the idea. but its not a ratsnest of wires stuffed in a radio shack project box. Its a small self contained supply capable of supplying more power than I need.

With the OPUS you can only power 1 USB hub for sure. each hub may take up to 2A, so 3A only guarantees 1 works for sure. And I'm not sure if you can connect OPUS in parallel. minor variations betwwen supplies can cause one supply to take the majority of the load and possibly fail by over loading.

Now you could definately keep track of all the power consumption of each device and maximize the OPUS to it fullest capability, but that leaves room for error and mistakes. Say one day your trouble shooting a hardware problem and you accedentally plug in another load to a maxed out OPUS and it blows. now you have 2 problems.

I guess it all boils down to convienience, simplicity and elegance. I could have bought 3 opus, and several relays wired it all up in a box, but it would have cost more, taken up more space, and been more complicated and difficult to install. this answer made more sense to me. my car allready has enough wires and difficult connections, I wanted a commercial quality device that was more than enough to serve my purpose.

Yep, I want one!

please tell me how much and how to pay

Thanks

This looks very promising and I will likely sign up if the price is reasonable. What is the cost, assuming that will cover the cost of the parts and your labor/time?

I have a cobbled together power system with a relay, fuse box, and a hacked-up Kensington 120W power supply that is providing the 19V power for my laptop and the 5V power I need for my Sound Blaster NX and USB ports. However, my USB is underpowered and I cannot add any more to it or get more power out of the Kensington adaptor, so no external DVD or harddrive for me yet...

Price should be $90 thats parts and labor ($15hr) without development time included. I should be able to ship one in a 1-1.5 months. there's some more prototype tweaking before its ready.

Keep checking back on this thread, I'll be posting progress updates in the third post.

Interested, but not ready to buy yet.............

Could you add a 12 regulated to power a touchsreen to the design? That would make for a very nice versatile package in a small form factor.

Or does it already have it and I missed it ? I think I only saw 12 v unregulated........

Very nice by the way.

I'll be watching for developements. Subscribed.

The tricky part about putting a regulated 12V output in an automotive enviroment is maintaining a 1.5-2V headroom required for a simple regulator. In order to opperate an LM7812 voltage regulator the input needs to be ~1.5V above the output. In an automotive environment, where you have to design for worse case, I cannot assume that the cars power system will not drop below that voltage.

So... in a auto environment a DC-DC converter is needed to take the unregulated 12V and make it regulated 12V. A DC-DC converter is much more complicated than a linear regulator.

To add this feature to my design would amount to doubling the existing circuitry to accomodate the two regulated outputs. unfortunately there is not enough room to do this in my design.

Update to the project:
towards the beginning of summer I lost interest and went outside to play in the sun :) but I'm feeling renewed interest and have some part ordering to do. My prototype suffered a devistating blow durring line regulation testing when a test lead shorted the high power switching node (with high voltage sipkes) to a delicate current sensing pin, the controll chip died :(. I have to order almost all the parts again and build another prototype to continue development.

Dude! The railgun is fricken schweet! Upload the pictures on Youtube....it'll save on hosting costs ;-)

I might be interested in the power supply, but not at the moment. I haven't got my car yet or passed my drivers test, but hopefully will do quite soon! woo!

I think this device could be quite popular once it's fully tried and tested. Keep us updated on progress :)

UPDATE!!! 10/23/07

Much work has taken place since my last post.

10A model is dead for now. Unless multiple people start asking for a 10A version it won’t be made. It was proving difficult to create a stable and reliable unit that would fit in the defined space without overheating or raising the price considerably.

I have re-designed the unit and built a 5A model that’s proving to be very capable and tough. I recently tested the 5A model (with pic) and found it to be very efficient (89%) and not suffering the same faults as the 10A model.

I have also determined that 5A should be plenty of power to supply any in-car USB system. Remember that each USB port can supply 0.5A, but most devices use far less. Unless you are using 5 USB powered hard drives at the same time you should be fine.

During testing I cranked the load current to over 6A and let it run for ~30min. After running at that high load I checked the temperature of the power components and found them to be warm, but not hot. This is a good sign for the longevity of the unit.

Electronics break down due to heat. The power components in this design are capable of operating at 125C. The hottest component in the power supply was ~55C.

What can we gather from this information? This design will run safe in any environment. Here’s why; when running in a 27C room, the power components temperature stabilized about 30C above the surrounding environment. The components were releasing heat as fast as they were making it when the components were 30C hotter that the surrounding air.

In the trunk of a car in the hot sun, the trunk might reach 55C (130F), in that case the electronics would again heat up 30C above the surrounding environment. Even if the components raised 35C, the total, 90C is still below the operating temperature of the components. They would still be within a safe operating region.

The other great finding from the test showed great output voltage regulation. At 0A output the voltage was 5.05V, at 5.75A the output voltage was 4.88V. Not very much change for the difference in output current.

Most USB devises will work within 10% of 5V (4.5-5.5V). At 4.88V the output is 2.4% away from the nominal output of 5V, well within spec.

I will spec this design as 5V @ 5A, since a safety margin should be used. If this device is outputting less than 5A it will work in any conditions (except under water!).

Now taking orders
I am proud to offer this product for $80. That price gets you an assembled power supply, with manual.

Once I have 5 confirmed buyers I will make a run of 10.

Speak up to get yours! (soon)

Umm.......

Not to sound negative or anthing, but why would someone pay 85 bucks for a 5v supply when you could buy an 80w m2-atx for the same price?

Just wondering..........