# Thread: Ta-Da! Prototype DC-DC PSU

1. Ooo exciting Keep us posted I like overkill and this thing smacks of it

2. Good! I need something different, I'm tired of my m3 not starting with the car, or not putting out enough on the +12 line. I tried to run my wifi router from it, and it would trip up and reset the computer occasionally. Now I've got the router running battery V, which is fine except it can't take the dip from starting and resets, so I've got a 20 sec delay across the networked things in the car. Ideally I'd like everything running from a single power supply, including the Apple TV 2... That one has a sparkfun dc-dc converter running at 3.4 volts right now, draws less than .25 amps from a 12v supply at full power. I wonder if it would run right off the 3.3 rail.

3. Update! The 5v standby power rail is alive!!! I have only populated the minimum components to get it to power up that rail. I had a mistake that I just found, and fixed with 2 0402 resistors strategically placed Below are 2 pictures.

The first shows one shows 2 zoomed out waveforms. The one on top is the 5v rail, and the one in the middle is the input voltage. I had the input voltage around 6.5v and then dipped it to about 5.5v and back in human time (slowly). Cars usually swing down to 6v at a minimum, 8v generally when cranking. As you can see the top waveform, the 5v standby rail gets stlightly more ripple (the line is thicker) but it stays at 5v.

The second one shows the EXTREMELY zoomed in picture of what the 5v rail looks like. The top line is the input voltage, and the squiggly wave is the 5v. Now this may look bad until you look at the scale. Each of the grids is 20mV or 0.02v. If you read the bottom measurements, you will see the average voltage is 4.968v, the maximum is 4.9868v and the minimum is 4.9519. So average regulation of 0.64% with a worst case of 0.962%. That's pretty darned good.

4. Yay
Now we just need a 12V rail

5. And a -12v rail, a 5v non-standby rail, a 3.3v rail, and then a 12v rail

6. Ok so it appears it is good that you are building this thing and not me... apparently I am not quite up on what goes into and out of a psu
Keep up the good work

7. Do we save some kind of idea for a release date.

8. Originally Posted by MagicMan
Do we save some kind of idea for a release date.
As soon as possible lol.

Now that I have figured this out, I hope to populate the rest of it in the next week. If that works, then I would assume a month of testing before ready for beta testing.

9. Just a quick picture update since I have recently been getting more and more PMs on this (which is a good thing )

10. WOW! You must be tedious with soldering.

Page 4 of 5 First 12345 Last