Thread: Good designs for 12v to 19v/3.5A for powering laptops

Originally Posted by PhilG

CanuckMart, where did you get your components from and what was the total cost if you don't mind me asking? I might take a run at building this instead of shelling out 150 for a Carnetix. Thanks!

In all honesty it wasn't cheap (all from Digikey), but it was an experiment that I was working on anyway. I can't recall the exact total cost as the parts were in a larger order with other stuff.

There is an update on this - I had significant ground loop noise issues. Granted it was not the final install (just a test rig for the moment), but the common ground in this design caused a loop issue severe enough to make me rethink the final design. Final wiring would address ground resistance issues on the analog audio side but not on internal computer/USB losses. This is where the inverter/transformer setup has an advantage as it breaks that ground loop - that will probably be the final design in my rig.

Originally Posted by upspace

Hi PhilG

I have used such an Carnetix for laptop powering in the past. Now I have an Archos for my car.

You can have it for 20$ (plus shipping costs) if you are interested

Thank you for the offer, upspace, but you are not in North America, correct? If thats the case, can it be shipped reliably to Canada at a reasonable expense? Is it the P1900?
Thanks.

Originally Posted by CanuckMark

In all honesty it wasn't cheap (all from Digikey), but it was an experiment that I was working on anyway. I can't recall the exact total cost as the parts were in a larger order with other stuff.

There is an update on this - I had significant ground loop noise issues. Granted it was not the final install (just a test rig for the moment), but the common ground in this design caused a loop issue severe enough to make me rethink the final design. Final wiring would address ground resistance issues on the analog audio side but not on internal computer/USB losses. This is where the inverter/transformer setup has an advantage as it breaks that ground loop - that will probably be the final design in my rig.

Thank you for the answer on this CanuckMark, I guess prefab will be the way to go for me, I do have the ability to assemble but not design or modify design. It sounds like you have the ability to isolate the ground issue and redesign if necessary, good luck with it!

yes it is the p1900. shipping to canada is possible (i am in switzerland) and costs are approx. 30-35$ so in total 50$.

Originally Posted by upspace

yes it is the p1900. shipping to canada is possible (i am in switzerland) and costs are approx. 30-35$ so in total 50$.

I am interested. Is it a version 2.2?
How would we do the transaction, Paypal? I guess this would require "a leap of faith" on my part? Can the package be insured and have a tracking number?
Thanks!

i think http://www.mini-box.com/DCDC-USB is your best option

Originally Posted by sergatiuk

i think http://www.mini-box.com/DCDC-USB is your best option

Thank you for the heads up on this PS. I will investigate this option as well. It's well priced and has a USB output without an add on component that the Carnetix requires. I presume I can hack this one into the power switch of a laptop just like the Carnetix?
I just Emailed them to ask if they would ship USPS as UPS is BRUTAL for cost to ship to Canada.

duplicate message

I know this page has been brought back from the grave once, but I found it relevant in 2011. If anyone wants the English version of the schematic & parts list on page 1, it's here:
Laptop Power Supply Adapter 95W