My FC Twin (SNES only) plus Polycase SL-64 project

Rekarp · Post by **Rekarp** » Fri Jan 09, 2009 3:02 am

Try a 100uF or larger cap across the output of the voltage source. Should mellow out that source.

grahf · Post by **grahf** » Fri Jan 09, 2009 3:23 am

I've tried both things already, isolating it and caps on the output. I even went absolutely crazy tying all the grounds together without any change. Capacitors on the output line reduce it somewhat, so I know it's noise from the DC-DC circuit. I just can't squash it entirely.

I wanted to use this since it has 5v output and also charges via 5v. USB charging is one of my goals with this project. I'm ok with buying a different charger, but is there anything out there that can charge a 7.2v battery back at only 5v input?

Rekarp · Post by **Rekarp** » Fri Jan 09, 2009 9:55 am

grahf wrote: I wanted to use this since it has 5v output and also charges via 5v. USB charging is one of my goals with this project. I'm ok with buying a different charger, but is there anything out there that can charge a 7.2v battery back at only 5v input?

Nope, You need a higher Voltage to charge batteries. You could just use a voltage booster though.

Post by **Triton** » Fri Jan 09, 2009 11:01 am

Try putting an inductor on there somewhere either your power converter or the video itsself (probably the former). it would be more useful for filtering AC noise than a capacitor would be probably

dragonhead · Post by **dragonhead** » Fri Jan 09, 2009 1:37 pm

http://freecircuitdiagram.com/2008/08/0 ... ine-noise/ try that

grahf · Post by **grahf** » Sat Jan 10, 2009 5:21 am

Thanks for the tips Triton and Dragonhead.

Rekarp, the batter pack I have does charge via 5v. There are a lot of "booster pack" type battery packs like that here in Japan, usually used for mobile phones and such. It's got a big all-in-one DC-DC converter IC that bumps the voltage up when charging, so it can charge from a 5v source (USB in this case). Thats why I really wanted to use this thing, since its got everything in one small pcb. I really wanted to make a portable thats USB chargable, so I hope I can get this thing straightened out.

Kurt_ · Post by **Kurt_** » Sat Jan 10, 2009 11:15 pm

Why not just use the age-old secret of shielding?

It's an often-overlooked option. I'm sure you can bend some scrap metal around it and wrap it in electrical tape or something simple.

Rekarp · Post by **Rekarp** » Sat Jan 10, 2009 11:16 pm

Kurt_ wrote:Why not just use the age-old secret of shielding?

It's an often-overlooked option. I'm sure you can bend some scrap metal around it and wrap it in electrical tape or something simple.

Foil covered in packing tape

Kurt_ · Post by **Kurt_** » Sat Jan 10, 2009 11:35 pm

I thought about that, but foil is hard to solder to. The connection to ground would only last so long.

grahf · Post by **grahf** » Sun Jan 11, 2009 5:24 am

Shielding won't work since the noise is in the power line, not emitting from the board. I This thing was only designed as a charger after all, so I guess they didn't really figure noise-free output into the design

.

Kurt_ · Post by **Kurt_** » Mon Jan 12, 2009 10:46 am

Use a little coax?

EPIC PUN!