XMOS-based Asynchronous USB to I2S interface - Page 51

robertopisa · 24th March 2012, 11:16 PM

Hello Douwe, I'm interested how you got 3.3V with LifePo4-batteries: which brands of batteries, how many mA, which circuit for controlling charge/discharge you attached to them, which charger are you using, where you bought, etc.

Thanks for helping
Roberto

Quote:

Originally Posted by Douwe01nl

Hi Lorien, would it be possible to feed the board with 3,3V in stead of 5V? The specs of the xmos chip allow 3,3v. It would be nice when we could use LifePo4-batteries, works great on my current Hiface.
regards, Douwe

qusp · 25th March 2012, 07:25 AM

umm every lifepo4 battery ive used is 3.3v nominal as its normal voltage. at fully charged it will be 3.6 but this drops to 3.45 very quickly and spends the rest of its charge between 3.45 and 3.2 before falling off a cliff, which is where you should cut it anyway. so you dont really need a regulator as generally most parts will allow this much tolerance in the supply as long as its steady

A123 ANR26650A and the new updated ANR26650B is the best IMO but levinpower is supposed to be pretty much the same, dont buy from ebay its too risky. current you say? lol these things are insane, they will put out an extended pulse of 140A, but will run at 40A all day long. yes you read that right

carsten.witt · 25th March 2012, 12:51 PM

@Lorien,

this is the "working area" and music comes out.

More later ......

Lorien · 25th March 2012, 03:09 PM

Quote:

Originally Posted by Douwe01nl

Hi Lorien, would it be possible to feed the board with 3,3V in stead of 5V? The specs of the xmos chip allow 3,3v. It would be nice when we could use LifePo4-batteries, works great on my current Hiface.
regards, Douwe

Unfortunately WaveIO card does not offer this feature! I know that XMOS I/O ports are working with 3.3V BUT you forgot that there are voltage regulators before XMOS chip (in fact there are all over the place). AFAIK minimum voltage applied to external PSU connector must be between 5V and 6V. There could be a chance to wire those batteries to this card by means of using few diodes between the two... just to drop the voltage to suggested levels. I remember that it was someone willing to try this path but no news so far ... so I don't know if it will work as expected.

Quote:

Originally Posted by carsten.witt

@Lorien,

this is the "working area" and music comes out.

More later ......

Nice setup you got there Carsten! One small thing I will do is to short the wires of PH regs - if possible. Thank you for sharing!
Kind regards,
L

carsten.witt · 25th March 2012, 03:28 PM

Hi,
thank you.

Quote:

Originally Posted by Lorien

Nice setup you got there Carsten! One small thing I will do is to short the wires of PH regs - if possible.
L

Yes, i will do so when the final setup/case is ready. There are some things to do, like a own power supply for WaveIO (5v), changing to none isolated I2S, ....

qusp · 03:35 PM

I was about to say the same thing; using such expensive high performance regulators and leaving long leads and a connector between them and the load will destroy all benefit of having them. I would get rid of the connector and hard wire them as well.

i was meaning to supply directly, couldnt he plug the batteries directly in? they are pretty much perfect voltage and most 3v3 compliant parts will allow +/-5% not for the faint hearted though as these things will literally melt themselves and the load if shorted

and @ Lorien: I saw your reply, no problem about taking it to PM, i'm sorry i let it go on as long as I did. as for my application, i'll send you some info and pics privately rather than in the thread.

triode_al · 25th March 2012, 04:24 PM

Quote:

Originally Posted by carsten.witt

Hi,
thank you.
There are some things to do, like - - - changing to none isolated I2S, ....

Carsten
Why is this? I had the impression one would like optimum isolation between power domains. . as that is said to reduce jitter-induced distortion.
The isolator behaves pretty well I understand. (there was a post on that).

[That is why I would expect an isolator on the USB input, but that is just my rambling].

robertopisa · 25th March 2012, 04:45 PM

Thanks cusp for the info, the A123 is not easy to find in Europe but I have probably found an Internet store.

-Roberto

Quote:

Originally Posted by qusp

umm every lifepo4 battery ive used is 3.3v nominal as its normal voltage. at fully charged it will be 3.6 but this drops to 3.45 very quickly and spends the rest of its charge between 3.45 and 3.2 before falling off a cliff, which is where you should cut it anyway. so you dont really need a regulator as generally most parts will allow this much tolerance in the supply as long as its steady

A123 ANR26650A and the new updated ANR26650B is the best IMO but levinpower is supposed to be pretty much the same, dont buy from ebay its too risky. current you say? lol these things are insane, they will put out an extended pulse of 140A, but will run at 40A all day long. yes you read that right

qusp · 25th March 2012, 04:54 PM

if they are selling to the public, then i would not trust them to be real. more likely grey market or flat out fakes as these are a highly sought after product and the company normally only sell to OEMs. i do know where to get legit new product though. where are you talking about? i dont want to post the company's info in public as i dont know whether they are acting within their agreement and i want to continue to be able to get them

robertopisa · 25th March 2012, 05:22 PM

They can be legally found (sometimes rebranded) in stores selling Radio Control products.

-Roberto

Quote:

Originally Posted by qusp

if they are selling to the public, then i would not trust them to be real. more likely grey market or flat out fakes as these are a highly sought after product and the company normally only sell to OEMs. i do know where to get legit new product though. where are you talking about? i dont want to post the company's info in public as i dont know whether they are acting within their agreement and i want to continue to be able to get them

25th March 2012, 03:33 PM	#506
qusp diyAudio Member Join Date: Oct 2009 Location: Brisbane, Australia	I was about to say the same thing; using such expensive high performance regulators and leaving long leads and a connector between them and the load will destroy all benefit of having them. I would get rid of the connector and hard wire them as well. i was meaning to supply directly, couldnt he plug the batteries directly in? they are pretty much perfect voltage and most 3v3 compliant parts will allow +/-5% not for the faint hearted though as these things will literally melt themselves and the load if shorted and @ Lorien: I saw your reply, no problem about taking it to PM, i'm sorry i let it go on as long as I did. as for my application, i'll send you some info and pics privately rather than in the thread. Last edited by qusp; 25th March 2012 at 03:35 PM.

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25th March 2012, 07:25 AM	#502
qusp diyAudio Member Join Date: Oct 2009 Location: Brisbane, Australia	umm every lifepo4 battery ive used is 3.3v nominal as its normal voltage. at fully charged it will be 3.6 but this drops to 3.45 very quickly and spends the rest of its charge between 3.45 and 3.2 before falling off a cliff, which is where you should cut it anyway. so you dont really need a regulator as generally most parts will allow this much tolerance in the supply as long as its steady A123 ANR26650A and the new updated ANR26650B is the best IMO but levinpower is supposed to be pretty much the same, dont buy from ebay its too risky. current you say? lol these things are insane, they will put out an extended pulse of 140A, but will run at 40A all day long. yes you read that right

25th March 2012, 04:54 PM	#509
qusp diyAudio Member Join Date: Oct 2009 Location: Brisbane, Australia	if they are selling to the public, then i would not trust them to be real. more likely grey market or flat out fakes as these are a highly sought after product and the company normally only sell to OEMs. i do know where to get legit new product though. where are you talking about? i dont want to post the company's info in public as i dont know whether they are acting within their agreement and i want to continue to be able to get them