Author Topic: EEVblog #259 - PSU Rev C Schematic - Part 12  (Read 57972 times)

0 Members and 1 Guest are viewing this topic.

Offline samarkh

  • Contributor
  • Posts: 13
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #100 on: July 05, 2012, 09:46:21 pm »
I know that there is a PDF of the project, but is there any chance of the original altium files being posted? I would find this useful to show my students some of your workings and 'what ifs' using the live cad file.

Yours Simon M.
 

Offline Kevin.D

  • Frequent Contributor
  • **
  • Posts: 290
  • Country: england
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #101 on: July 14, 2012, 11:42:17 am »
Are you going to finish this off Dave. ?  Your 90% there to a finished project.
I really could have done with one of these small portable supply's the other day.
 

Offline MarSik

  • Newbie
  • Posts: 2
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #102 on: September 20, 2012, 06:59:39 pm »
Hi Dave,

I was trying to design a supply for my needs and used your videos as inspiration. But I have noticed one issue which haven't been mentioned in the forums (I think..) yet.

The issue with your rev C schematics is the power supply for your U3A (voltage control). The LM358 datasheet states Output voltage swing to be 26V with Vcc = 30V and only 5mV when Vcc is 5V.

In the digital case, it changes the calculations a bit as you have to account for the limit in the DC-DC control algorithm.

However, when combined with your attempt at analog control loop for the SMPS preregulator part, it would not allow the supply to start, am I right?

(Vbat = 3.7V, Vset doesn´t really matter here => V+ = 3.7V, LT3080 adj pin is less than 5mV => SPMS control transistor is less than 2.005V which is less than battery voltage and will stay that way => V+ = 3.7V)

This all means that in both cases the power dissipation of lt3080 will be a bit higher (V+ needs to be about 5V higher than the desired voltage) than expected. I suppose it is a limitation of the used opamp and is solvable by using a rail-to-rail one though.
 

Offline wrayman

  • Newbie
  • Posts: 3
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #103 on: September 22, 2012, 11:53:59 pm »
Hello all,

I am new, and since Dave's vBlogs are extensive, I don't think I have time to catch up....

On this PSU I don't understand why there can't be an option to run this off the power supply that will charge the battery.

Please let me know (you die hard fans that have followed this from the beginning) I watched the Rev C blog and it wasn't covered, or I missed it,.

Would an idea of running if off your notebook power supply be stupid??  I have used my notebook supply as a base for other projects before. You can make or buy a splitter for your notebook (mine is a 5.5 mm 2.1) but on your splitter you could always make one that has the size for your notebook and the standard 5.5 on the Y, which it seems to be a "standard". 4

Here a One Hung Lo brand concept photo:



 

Offline wrayman

  • Newbie
  • Posts: 3
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #104 on: September 24, 2012, 02:46:01 am »
Thanks for the warm smartass welcome....

It is a appreciated.

Like I can't read a data sheet or I don't know the voltage.

Components are coming and going so I suppose, duh, another part could be used, but I guess I should check with you first to see if I am allowed to have an opinion or suggestion.

I suppose your the type that has to police the conscious of all so that one singular set of conformal behavior can be had for all.

I think your advice should be heeded. Check before you speak, you might piss someone off.
 

Offline baljemmett

  • Supporter
  • ****
  • Posts: 665
  • Country: gb
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #105 on: September 24, 2012, 11:43:13 am »
Check before you speak ...

Maybe you missed the bit where this is the thread about the big boys' PSU project, not the USB one...
 

Offline nathancrum

  • Contributor
  • Posts: 29
  • Country: us
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #106 on: February 08, 2013, 09:36:10 pm »
Is this project dead?  Dang - I finally got through all 12 videos in detail and was hoping something more had been brewing elsewhere for the last 11 months. 

Here's to hoping Dave makes another video installation on this project...
 

Online EEVblog

  • Administrator
  • *****
  • Posts: 37664
  • Country: au
    • EEVblog
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #107 on: February 08, 2013, 10:00:50 pm »
My current effort is going into the battery powered "USB" version.

Dave.
 

Offline inderpreet

  • Newbie
  • Posts: 2
  • Country: 00
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #108 on: February 10, 2013, 11:53:45 am »
I was wondering if the LTC3115 can be used instead of the Micreal. I was hoping to get a suggestion based on LTC devices since my experience with their sample service is great.

In the Battery powered version of the PSU i was hoping to use an external USB type battery/ power pack solutions available in the market and use the one best suited to my power requirements. This means that i can use the PSU with
a. The USB port of my PC/Laptop
b. Use the Battery power pack solution used to charge mobiles and stuff during travel
c. Use the USB type chargers that come with cellphones.

Additionally I would like to keep the option for a 12V adaptor and use the LTC3115 to buck the voltage in that case.

Please suggest.
Many Thanks in advance.
 

Offline Pilot3514

  • Contributor
  • Posts: 28
  • Country: us
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #109 on: March 14, 2013, 12:20:17 pm »
"What's a SOC4?" Answer: To keep your foot warm.

You need to be and old fart (like me) to get that one.
I'm not cheap, I'm frugal
unlike those wasteful Scotch.
 

Offline Pilot3514

  • Contributor
  • Posts: 28
  • Country: us
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #110 on: March 14, 2013, 12:33:35 pm »
I'm no engineer and but I feel I am leaning a lot from the video blog (Thanks you crazy Auzzie).

In many places, such as R30-R32, you are using 0.1% resisters.  They are in circuits that are either controlled or send data to the microcontroler.  I would think that you could have "calibration constants" stored in the controller to compensate for the variations in resistor values.  I would think the the more important aspect is consistency over time and temperature.

I started thinking about this when I watched the teardown video on the HP multimeter and the comment was made that if the battery were disconnected, the calibration values would be lost.

I'm cheap and I don't want to spend extra on resistors if I can use a few bytes of EEPROM and a little code to get the same results.
I'm not cheap, I'm frugal
unlike those wasteful Scotch.
 

Offline KuchateK

  • Regular Contributor
  • *
  • Posts: 78
  • Country: us
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #111 on: March 14, 2013, 01:46:53 pm »
I'm cheap and I don't want to spend extra on resistors if I can use a few bytes of EEPROM and a little code to get the same results.
With this method you need to calibrate each unit, spend extra time on coding. Calibration equipment is required, often with custom made jigs. For small run it may be cheaper to use more precise components and skip labor intensive coding and calibration. If you'll look at the whole picture sometimes expensive parts are the cheapest and certainly quickest solution.
 

Offline Pilot3514

  • Contributor
  • Posts: 28
  • Country: us
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #112 on: March 15, 2013, 08:23:42 pm »
With this method you need to calibrate each unit, spend extra time on coding. Calibration equipment is required, ...

So then my assumption is correct, that you could use lower tolerance (read 'cheaper') components and compensate in software.

Without a micro this is not an option.  I recall a blog where Dave was ranting mentioning that he received components that were out of spec from his supplier.  If the unit had a microcontroller, the errors  could have been accounted for in sortware.

I agree that this calibration could be difficult.  I wonder if you could build a test/calibration jig that could work with software in the PS.  The PS could talk over it's serial bus telling what voltage it is sending and the test jig could tell what voltage it is getting.  The PS could then log that bit of information.  Do this for several voltages.  Then make an other pass, this time with adjustment factors applied.

After the voltage then do current in much the same way.

I would think that this sort of calibration could be performed in about the same amount of time as a functional test would take.

I have not thought this all the way through but just off the top of my head.  Therefore, there may be large problems that I have not considered.
I'm not cheap, I'm frugal
unlike those wasteful Scotch.
 

Offline wigman27

  • Regular Contributor
  • *
  • Posts: 143
  • Country: au
    • Wiggins Wonderful Websites
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #113 on: June 02, 2013, 12:15:21 pm »
Hi Dave,

It's been a while on this topic I know so its all probably gone out of your head now, did you end up building it? and where you happy with it? I have notice a few videos lately that you a re working on the rev C board but haven't yet seen it done.

A couple of questions, did you do a video on the board design for the rev C? and is there somewhere I can download the software you programmed to Micro with?

Thanks Mate, Great job! :-+
Need a website designed? Check out my Australian based web development business www.wigweb.com.au for affordable fixed price packages
 

Offline wigman27

  • Regular Contributor
  • *
  • Posts: 143
  • Country: au
    • Wiggins Wonderful Websites
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #114 on: June 06, 2013, 04:24:25 am »
Just a little bump to hopefully get someone that may not have seen the post. Any ideas??
Need a website designed? Check out my Australian based web development business www.wigweb.com.au for affordable fixed price packages
 

Offline mwilson

  • Contributor
  • Posts: 42
  • Country: us
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #115 on: July 11, 2013, 08:59:18 pm »
Something I noticed between the Rev B and Rev C schematic as I start planning on designing my own PS and find this video series extremely educational (thanks, Dave!):

Starting with RevC, the Vcontrol pin of the LT3080 is tied to V+ instead of Vin. I assume that decision was to improve the dropout voltage of the LT3080. However, according to Page 8 of the LT3080 datasheet, "the current flow into this [Vcontrol] pin is about 1.7% of the output current." Does that mean that since you're still just measuring the current into the Vin pin, the current measurement of the supply is going to be 1.7% low?
 

Offline wigman27

  • Regular Contributor
  • *
  • Posts: 143
  • Country: au
    • Wiggins Wonderful Websites
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #116 on: July 11, 2013, 10:09:25 pm »
Hi mwilson.

They have discovered a bit of an issue with the Lt3080 in this design. May want to check it out.

https://www.eevblog.com/forum/projects/lt3080-wierdness-dave%27s-power-supply-%28eev224%29-gone-mad/
Need a website designed? Check out my Australian based web development business www.wigweb.com.au for affordable fixed price packages
 

Offline robbag

  • Contributor
  • Posts: 16
  • Country: au
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #117 on: October 31, 2013, 08:02:53 am »
Hi

Does anyone know if there has there been anymore progress with this great project?

Cheers
 

Offline mos6502

  • Frequent Contributor
  • **
  • Posts: 537
  • Country: aq
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #118 on: November 02, 2013, 10:22:53 am »
If you're running off batteries, I think it would be wise to use a switching regulator. Your energy will be very limited, and you don't want to waste most of it on heating the surrounding air. Check out these buck-boost modules available on eBay:

http://www.ebay.com/itm/DC-DC-Auto-Boost-Buck-Step-Down-Converter-Module-Solar-Voltage-LM2577-S9-/141053316479?pt=LH_DefaultDomain_0&hash=item20d76ecd7f

Being Buck-Boost, they can create an output voltage that is either higher or lower (or indeed the same) than the input voltage.

If you need low noise, you could use a linear low drop regulator and set the switcher voltage just 1V higher than the voltage you need. That way you have the best of both worlds: high efficieny and low noise linear regulation.

Now, a neat project would be to have a uC control the voltage setting for both the switcher and the linear reg so you don't have to fiddle with two knobs.
for(;;);
 

Offline kizzap

  • Supporter
  • ****
  • Posts: 477
  • Country: au
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #119 on: November 02, 2013, 11:00:48 am »
If you're running off batteries, I think it would be wise to use a switching regulator. Your energy will be very limited, and you don't want to waste most of it on heating the surrounding air. Check out these buck-boost modules available on eBay:

http://www.ebay.com/itm/DC-DC-Auto-Boost-Buck-Step-Down-Converter-Module-Solar-Voltage-LM2577-S9-/141053316479?pt=LH_DefaultDomain_0&hash=item20d76ecd7f

Being Buck-Boost, they can create an output voltage that is either higher or lower (or indeed the same) than the input voltage.

If you need low noise, you could use a linear low drop regulator and set the switcher voltage just 1V higher than the voltage you need. That way you have the best of both worlds: high efficieny and low noise linear regulation.

Now, a neat project would be to have a uC control the voltage setting for both the switcher and the linear reg so you don't have to fiddle with two knobs.

Last time I checked, he was...
<MatCat> The thing with aircraft is murphy loves to hang out with them
<Baljem> hey, you're the one who apparently pronounces FPGA 'fuhpugger'
 

Offline boffin

  • Supporter
  • ****
  • Posts: 1027
  • Country: ca
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #120 on: March 16, 2015, 03:40:21 pm »
Eagerly awaiting the next instalment.  It's just what my bench needs...
 

Offline mvdswaluw

  • Contributor
  • Posts: 21
  • Country: 00
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #121 on: March 16, 2015, 04:02:22 pm »
The PSU was the trigger for
me to join the forum and subcribe to the youtube channel. Read and watched a lot since and I did buy a ucurrent, but still no supply :-(
 

Offline timofonic

  • Frequent Contributor
  • **
  • Posts: 904
  • Country: es
  • Eternal Wannabe Geek
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #122 on: March 27, 2015, 12:06:29 pm »
Any news? Does using a switching power supply make ripple greater? I see people are obsessed with linear adjustable power supplies because of that.

I lost half information because my spoken English is quite bad, I would love to have subtitles
and I would want to help to translate them to Spanish!
 

Offline boffin

  • Supporter
  • ****
  • Posts: 1027
  • Country: ca
Re: EEVblog #259 - PSU Rev C Schematic - Part 12
« Reply #123 on: April 06, 2015, 06:29:43 am »
Dave;  having re-watched a little bit, I'll add my suggestions/comments

Heatsink:
You're still going to have significant heat across the 3080 when you're using lower voltages.  If you run 2v @ 1a, you're dropping 6.4v (and hence 6.4W) across the regulator as the lowest you'll get on the source is the 8.4 off the LiIons

Controls:
I'd rather see a SINGLE control, one nice rotary encoder & knob (with finger hole) you press and spin to switch between V/A/mode select. One nicer knob rather than two cheap ones and a  bunch of buttons.  That also frees up some front panel space.  The only push button I think might make sense is a load on/off.

Layout of front case:
KNOB (multifunction) --- DISPLAY --- JACKS (vertical)
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf