Author Topic: EEVblog #357 - USB Supply Power-up Testing  (Read 35928 times)

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Offline EEVblog

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EEVblog #357 - USB Supply Power-up Testing
« on: September 21, 2012, 05:38:33 pm »


Dave.
 

Offline JoannaK

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #1 on: September 21, 2012, 06:00:17 pm »
Yep... I know the feeling, component with 3 legs, definitely too many to get right each time..

As an quick quiz I'd like to ask how many ways simple normal led can be put at the similat sot23 3 legged package..  ;D
 

Offline andyg

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #2 on: September 21, 2012, 06:06:51 pm »
Ah, i know why there is no stock of the FTDI X series chips, as I got caught out myself too in a design.

FTDI found a silicon bug which caused the chip to lock up unexpectedly (there is workaround by using a keep-awake pin) and pulled all the devices off the shelf. I bought a heap from Digikey and got an email, and they offered to return all the parts at their cost and to they were to send me replacements also at their cost.

The details are here:
http://www.ftdichip.com/Support/Documents/TechnicalNotes/TN_139_FT230X%20Errata%20Technical%20Note.pdf
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Offline EEVblog

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #3 on: September 21, 2012, 06:12:51 pm »
Ah, i know why there is no stock of the FTDI X series chips, as I got caught out myself too in a design.

FTDI found a silicon bug which caused the chip to lock up unexpectedly (there is workaround by using a keep-awake pin) and pulled all the devices off the shelf. I bought a heap from Digikey and got an email, and they offered to return all the parts at their cost and to they were to send me replacements also at their cost.

The details are here:
http://www.ftdichip.com/Support/Documents/TechnicalNotes/TN_139_FT230X%20Errata%20Technical%20Note.pdf

Ah, that explains it!
Thanks.

Dave.
 

Offline samgab

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #4 on: September 21, 2012, 07:20:31 pm »
Ah, i know why there is no stock of the FTDI X series chips, as I got caught out myself too in a design.

FTDI found a silicon bug which caused the chip to lock up unexpectedly (there is workaround by using a keep-awake pin) and pulled all the devices off the shelf. I bought a heap from Digikey and got an email, and they offered to return all the parts at their cost and to they were to send me replacements also at their cost.

The details are here:
http://www.ftdichip.com/Support/Documents/TechnicalNotes/TN_139_FT230X%20Errata%20Technical%20Note.pdf

Ah, that explains it!
Thanks.

Dave.

Ahh, well that was just bad luck, picking that particular chip. I was wondering if your mentioning of that chip had inspired keen young EEV hobbyists to go out there and buy up all the available stock!!
 

Offline klinkerstein

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #5 on: September 21, 2012, 07:26:33 pm »
Dave, you can easily omit the schottky diode coming from the battery around Q1. See
http://ww1.microchip.com/downloads/en/DeviceDoc/51746a.pdf
Page 5

 

Offline Mercator

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #6 on: September 21, 2012, 08:42:54 pm »
How about the MCP2200 from Microchip? When I did the research for my own project, it was a lot cheaper than the FTDI ones. Or do you need some special feature, only the FTDI ones have?
 

Offline Skippy

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #7 on: September 21, 2012, 09:47:20 pm »
Are there any more documents/ circuit diagrams/ other stuff as well as the videos? I think I've watched all of the videos, and I'm still a bit unclear as to what it does and how it works. Last time you were looking at a DC/DC converter, suddenly now an entire constructed PCB appears!
 

Offline EEVblog

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #8 on: September 21, 2012, 10:06:21 pm »
Are there any more documents/ circuit diagrams/ other stuff as well as the videos? I think I've watched all of the videos, and I'm still a bit unclear as to what it does and how it works. Last time you were looking at a DC/DC converter, suddenly now an entire constructed PCB appears!

Yeah, magic!
The plan was to do the schematic videos etc first, but the board got rushed through so I decided to shoot it and mix it up a bit.

Dave.
 

Offline Thor-Arne

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #9 on: September 21, 2012, 10:50:50 pm »
Hm, where's the tutorial mentioned at 6:20 in the video?  :)
 

Offline free_electron

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #10 on: September 21, 2012, 11:11:19 pm »
Ah, i know why there is no stock of the FTDI X series chips, as I got caught out myself too in a

The details are here:
http://www.ftdichip.com/Support/Documents/TechnicalNotes/TN_139_FT230X%20Errata%20Technical%20Note.pdf

Ah. That explains why i saw occasional lock ups with those.. I scored a few of their demo boards at ces last year. When playing with them it would go wonky sometimes. I blamed it on the breadboard at that time...
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Offline nitro2k01

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #11 on: September 22, 2012, 12:46:20 am »
Hm, where's the tutorial mentioned at 6:20 in the video?  :)
He has added an annotation link now, but here it is for good measure:

Whoa! How the hell did Dave know that Bob is my uncle? Amazing!
 

Offline Thor-Arne

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #12 on: September 22, 2012, 01:01:29 am »
Hm, where's the tutorial mentioned at 6:20 in the video?  :)
He has added an annotation link now, but here it is for good measure:



Great, thanks. :)
 

Offline OndraSter

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #13 on: September 22, 2012, 01:52:25 am »
Don't worry, I have used LM2936's footprint instead of regular 1117-3v3 LDO. I had to bodge it up on the first revision of the board as well.

Also, why are you using FTDI? There are AVRs and PICs with USB built-in.

I bet that xmega32a4u would be cheaper than the mega you have there (or at least it looked like Atmel's logo on it) + FTDI. Not Arduino compatible though.
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Offline Mr Smiley

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #14 on: September 22, 2012, 02:30:38 am »
I'm confused  ???

Wasn't the original idea;

Isolated from USB supply.
NO USB communication because it couldn't be isolated, and would considerable up the cost if it was.
Fits into a small box with switches and display on the top.
No battery backup.
As simple but efficient as it can be.

Lots and Lots of No's to other posters suggestions of control from the pc/laptop.

Now we have buttons on the side, USB interface chip, battery backup, menu options and a soft on/off switch.

Or has it been sooooooooooooooo long since Dave started this that I've missed something major.

Mr Smiley  :)
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Offline firewalker

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #15 on: September 22, 2012, 02:37:39 am »
I think this is a merge of the two power supplies.

Alexander.
Become a realist, stay a dreamer.

 

Offline DarkPrince

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #16 on: September 22, 2012, 04:41:19 am »
Unfortunate that it had to be rushed but at the same time it is really nice to see an update about the project. Woke up this morning seeing that you had a new video, and pertaining to the power supply projects; awesome!

Now, I like this design. Low power supply but with alternate battery source. Good idea. Anything high powered, in my case, i'd just use an outlet anyway. Makes sense. Hope there will be another update sooner than later. :)

Thanks Dave!

Craig.
 

Offline dolabra

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #17 on: September 22, 2012, 11:27:16 am »
Don't worry, I have used LM2936's footprint instead of regular 1117-3v3 LDO. I had to bodge it up on the first revision of the board as well.

Also, why are you using FTDI? There are AVRs and PICs with USB built-in.

I bet that xmega32a4u would be cheaper than the mega you have there (or at least it looked like Atmel's logo on it) + FTDI. Not Arduino compatible though.

Because to sell it  he would have to get a vendor id, or beg Microchip/Atmega  to use thiers. Its a lot easier to use FTDI
 

Offline dolabra

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #18 on: September 22, 2012, 11:32:00 am »
Am I wrong that most if not all sot-23 transistors have the same pinout?
 

Offline EEVblog

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #19 on: September 22, 2012, 01:40:11 pm »
Also, why are you using FTDI? There are AVRs and PICs with USB built-in.

There needs to be electrical isolation. Doing so with USB is generally not cheap.

Dave.
 

Offline gxti

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #20 on: September 22, 2012, 01:48:44 pm »
Last I checked MCP2200 is a bit cheaper than any FTDI part, although you do have to add a crystal.
 

Offline nitro2k01

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #21 on: September 22, 2012, 04:35:43 pm »
Dave, what's in it to use that new shiny XS series? Surely a good ol' FT232 would do the job fine for this project?
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Offline EEVblog

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #22 on: September 22, 2012, 06:58:18 pm »
Dave, what's in it to use that new shiny XS series? Surely a good ol' FT232 would do the job fine for this project?

IIRC:
a) It was the cheapest solution
b) It was the smallest solution. No need for external xtal and EEPROM.

I knew it was new-ish, but didn't know how new, and I swear there were many thousands in stock at Digikey at the time. So seemed pretty safe.

Dave.
 

Offline David_AVD

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #23 on: September 22, 2012, 07:04:28 pm »
The FT232RL is almost zero external parts count and a reasonably small package.
 

Offline dda

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Re: EEVblog #357 - USB Supply Power-up Testing
« Reply #24 on: September 22, 2012, 07:14:39 pm »

I knew it was new-ish, but didn't know how new, and I swear there were many thousands in stock at Digikey at the time. So seemed pretty safe.

Dave.

Trap For Young Players.

Are you picking an alternative or do you expect to get your hands on some soon?
 


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