Gamecube mA measurements for individual voltage lines.

Post by **Triton** » Thu May 24, 2007 11:54 pm

its useful as hell and i am workin on a cp i just dont have the power to sticky lol, i do have a question tho, can i run the cube from 7.2v through the original power board and run a seperate supply for 12v like a smal batt pack or wil that not work

Post by **Gamelver** » Fri May 25, 2007 12:41 am

This thread sucks....why should we sticky it

.

, I'm kidding, of course

. Sorry, adding it to the thread now...

Post by **marshallh** » Sat May 26, 2007 8:12 pm

I'd like to point out something very important...

You might look at the 1.9v line and think "Wow that's a ton of current" but it's not really.

2000mA @ 1.9v does NOT equal say 2000mA @ 7.2v.

The solution to finding total power draw is to multiply current x voltage to get power, or wattage.

1.9 x 2100mA = 4 W
3.3 x 800mA = 2.6 W
5 x 350mA = 1.7 W
12 x 5mA = 0.5 W

Add these together... you get 8.8 W

To get current, divide this by your battery voltage. Using a DVD player battery with Li-poly cells, 8.8W / 7.4v = 1.19 amps. (or 1190 mA)

This might not make sense. It seems kind of low actually, but there's lots of room for error. Remember that this amount is at peak effiency (using several voltage regulators will decrease efficiency, drawing more current)

edit: if all the regulators are at a hopeful 80% effiency (expect less frmo a linear regulator) then the total draw is upped to nearly 1500mA.

Electric Rain · Post by **Electric Rain** » Sun May 27, 2007 5:56 am

Triton wrote:its useful as hell and i am workin on a cp i just dont have the power to sticky lol, i do have a question tho, can i run the cube from 7.2v through the original power board and run a seperate supply for 12v like a smal batt pack or wil that not work

Yes. According to their datasheet, the two dual output LM2643MTD regulators on the 'cube's PSU can be powered off of as little as 4.5v.

...Actually, that's the datasheet for the LM2645MTD. I think they're very similar... but I could be wrong. I can't find ANYTHING on the LM2643MTD.

Gamelver wrote:This thread sucks....why should we sticky it .

, I'm kidding, of course . Sorry, adding it to the thread now...

Cool, thanks man.

It feels so nice having TWO threads stickied.

I'm actually starting to feel important around here now... do you guys think I'm important...?

marshallh wrote:I'd like to point out something very important...

You might look at the 1.9v line and think "Wow that's a ton of current" but it's not really.

2000mA @ 1.9v does NOT equal say 2000mA @ 7.2v.

The solution to finding total power draw is to multiply current x voltage to get power, or wattage.

1.9 x 2100mA = 4 W
3.3 x 800mA = 2.6 W
5 x 350mA = 1.7 W
12 x 5mA = 0.5 W

Add these together... you get 8.8 W

To get current, divide this by your battery voltage. Using a DVD player battery with Li-poly cells, 8.8W / 7.4v = 1.19 amps. (or 1190 mA)

This might not make sense. It seems kind of low actually, but there's lots of room for error. Remember that this amount is at peak effiency (using several voltage regulators will decrease efficiency, drawing more current)

edit: if all the regulators are at a hopeful 80% effiency (expect less frmo a linear regulator) then the total draw is upped to nearly 1500mA.

I am SO stupid... I... never really thought about that... wow... so, what you're saying is... two 10,000mAh poly li-ions from batteryspace (what I was planning on getting for my GC laptop) is probably COMPLETE overkill then...?

Especially considering the fact that I won't be using the disk drive (CF card hack all the way, baby!)...

P.S. Oh, and Marshall... since you're here and seem to know... well, stuff... as you usually do, do you think the 'cubes 1.9V line would do okay on 1.8V? Or don't you think I should risk it, since it's a sensitive (CPU) voltage? It's just that I'm trying to build my own, ultra-efficient all-in-one PSU for my laptop, and my screen uses 1.8V, 3.3V, and 5V, so I'd like to avoid a separate line that's only .1V higher.

Plus, 1.8V regs are more common.

Post by **marshallh** » Sun May 27, 2007 7:53 am

This looks like a good pack for N64/ GC portables:
http://www.batteryspace.com/index.asp?P ... rodID=2271

7.4 - 8.4v, 4800mAh. Charger included. $55
Each cell is skinnier than a C cell, you can cut the pack in half if necessary.

Post by **Triton** » Sun May 27, 2007 10:10 am

this news gladdens me greatly! so according to this i should get like 2 hours off of one 3300mah battery?(including lcd) AWESOME! also ive made huge progress on my gamecube portable, expect an update to my progress thread today

Electric Rain · Post by **Electric Rain** » Sun May 27, 2007 3:38 pm

My screen draws 1.5 amps @ 12V though...

Well, that's the wall-wart rating, anyway. I'm sure it takes less than that... I'll have to measure each of its voltage lines...

timmeh87 · Post by **timmeh87** » Mon May 28, 2007 9:14 am

re: undervolting the CPU line.

you should be fine, I did the same thing to my n64. it makes it save a bit of power (current goes up at lower voltage but its not linear) and therefore it should run a bit cooler.

of course, it might just not work if you go too low. or become unstable.

if you want to get experimental, then hook up a variable voltage source to the 1.9v line and make us a graph of voltage/current, with the dropout point marked.

.

Electric Rain · Post by **Electric Rain** » Mon May 28, 2007 4:01 pm

Hmm... I'll bet only the Gecko and/or Broadway use the 1.9V line... so what I need to do to be sure is look up their datasheets... hmm... I know Corscaria somehow found the Gecko datasheet, but I haven't had much luck getting in contact with her.

Anyone else know how to find either of their datasheets? It's not gonna be easy...

Post by **Triton** » Wed Jun 13, 2007 6:55 pm

just thought i would let you all know that i have basically confirmed that the gamecube will NOT run off of 7.5v through the daughterboard, i tried it and it was nothin doin, the fan spun because its powered before the board but that was it (this was done with a psone power adapter run to a unmodified gamecube via a cable i made)

Electric Rain · Post by **Electric Rain** » Wed Jun 13, 2007 11:50 pm

... Interesting... hey, that's actually good news to me...! That means that there's actually a good reason for me building a new PSU other than the fact that I'm anal and want all of my power related circuits all on one, nice and neat little central PSU board.

But... it's still odd to me that the 'cubes PSU won't take 7.5v. The only thing that shouldn't work on 7.5v is the audio.

Wait... how much mA can the PSone screen's A/C adapter put out? Maybe that's the problem... Ah... I'm sure you're smart enough to have already thought of that.

Interesting "problem" we have here...

Well, at the very least, I'm pretty sure my mA measurements are right.

Edit: I have news... I just found out that there appears to be another, un-accounted for voltage regulator; it's not on the PSU.

I was looking around on my GC mobo, trying to find out what this anti-7.5v problem could be, and I noticed a chip that ACTUALLY wasn't some DOL Nintendo proprietary chip.

I was actually looking for the amp chip... the audio chip that seems to be needing 12v, in hopes that I could trace from the input pin on that, to something else that might also be needing 12v. So, I came across the Sharp 070XZ1H. It's a 1.5A, adjustable voltage LINEAR regulator. I can't trace what it's powering, but what I do know is that it's putting out a steady 2.868V, and it's powered from the 3.3v line; the second highest current drawing line... I don't know what it's powering, I don't know how much current it's drawing, and I sure as **** am not going to find out at 1:30AM, but we all know that linear regulators are inefficient. So tell me... am I just nit-picking at this point, or do you all think it's worth it to build a 2.85v line into my ub3r efficient custom PSU to replace this mystery regulator to cut down on current draw? I need a 2.5v line for my screen anyway... I wonder if I could use the same line for the 2.85 line... hmm... *mind wanders off*

vskid · Post by **vskid** » Thu Jun 14, 2007 9:28 am

Electric Rain wrote:Wait... how much mA can the PSone screen's A/C adapter put out? Maybe that's the problem... Ah... I'm sure you're smart enough to have already thought of that. Interesting "problem" we have here... Well, at the very least, I'm pretty sure my mA measurements are right.

If that is the problem, you can get more amps from a computer PSU (just use the 12v and have 5v be ground, 7v is close enough).

timmeh87 · Post by **timmeh87** » Thu Jun 14, 2007 12:16 pm

the amount of power lost in that linear reg cant be much, if its only dropping 0.5v. I wouldnt risk breaking things, personally

Electric Rain · Post by **Electric Rain** » Thu Jun 14, 2007 2:37 pm

timmeh87 wrote:the amount of power lost in that linear reg cant be much, if its only dropping 0.5v. I wouldnt risk breaking things, personally

*nod nod* Yeah, okay. I see your point... you're right. I'll leave it alone... Its existence off the PSU board still bugs me a little bit though.

Post by **Triton** » Thu Jun 14, 2007 5:20 pm

psone power adapter i was using outputs 7.75v (at no draw, probably 7.5 under draw) and 3ah so i dont think it was starved for amperage