Author Topic: EEVblog #1030 - $20 DIY Bench Power Supply!  (Read 27747 times)

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Offline raul320

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #50 on: October 07, 2017, 09:06:05 am »
i have embedded such module in ups case. it works pretty well
 
 

Offline CJay

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #51 on: October 07, 2017, 11:00:10 am »
i have embedded such module in ups case. it works pretty well

Nice, I have an APC SmartUPS which would work well for that, thanks for the idea
M0UAW
 

Offline electronic_eel

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #52 on: October 07, 2017, 04:35:59 pm »
When reading about the open source firmware replacement for these units here https://johan.kanflo.com/opendps-design/, it seems like the CC mode control is just done in software by reading the current with the ADC and adjusting the set voltage with the DAC.

Is this true for the stock firmware too or is the open firmware just missing a hardware control loop for CC mode?

How bad is the CC mode with quickly varying resistances? Did anyone test it with an e load with pulse mode?

 

Offline bitseeker

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #53 on: October 07, 2017, 05:13:21 pm »
i have embedded such module in ups case. it works pretty well

That is a neat idea, raul. :-+
I TEA.
 

Offline ez24

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #54 on: October 07, 2017, 07:58:36 pm »
...  I can power it via a Dell laptop PSU ...

How do you handle the "third" wire?   The center pin.

thanks
YouTube and Website Electronic Resources ------>  https://www.eevblog.com/forum/other-blog-specific/a/msg1341166/#msg1341166
 

Offline German_EE

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #55 on: October 07, 2017, 08:25:01 pm »
If Dell (or their sub-contractor) have done it right then the center pin or PE should be connected to negative on the output, this means that the chassis of the notebook is then grounded. Notebook supplies are however strange beasts and at least half of them from any manufacturer will have the output floating, with ground only used for the filters on the mains side and maybe the screens.

As a test measure using a 10M impedance voltmeter between negative output and mains earth with the supply running. If you see half mains voltage then your output is probably floating. Note that this voltage is normally quite safe, it's just leakage current from the capacitors.
Should you find yourself in a chronically leaking boat, energy devoted to changing vessels is likely to be more productive than energy devoted to patching leaks.

Warren Buffett
 

Offline plazma

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #56 on: October 07, 2017, 08:45:18 pm »
...  I can power it via a Dell laptop PSU ...

How do you handle the "third" wire?   The center pin.

thanks
I leave it unconnected. My workplace uses Dell laptops and all original PSUs have worked fine.
 

Offline Bratster

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #57 on: October 07, 2017, 09:51:19 pm »
...  I can power it via a Dell laptop PSU ...

How do you handle the "third" wire?   The center pin.

thanks
That third wire on Dell power supplies is just an ID wire that tells the computer the wattage of the power supply, and if it is genuine.

The power supply itself just sends out power it doesn't care.

Sent from my Nexus 6 using Tapatalk

 

Offline Rolo

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #58 on: October 08, 2017, 06:18:10 am »
When reading about the open source firmware replacement for these units here https://johan.kanflo.com/opendps-design/, it seems like the CC mode control is just done in software by reading the current with the ADC and adjusting the set voltage with the DAC.

Is this true for the stock firmware too or is the open firmware just missing a hardware control loop for CC mode?

How bad is the CC mode with quickly varying resistances? Did anyone test it with an e load with pulse mode?

I have plans to test it with pulsing loads. I think I have the parts laying around to build this:


   
« Last Edit: October 08, 2017, 08:40:35 am by Rolo »
 

Offline German_EE

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #59 on: October 08, 2017, 08:35:41 am »
Shariar over on The Signal Path has done some tests as well, he worked on the DPH3205 buck/boost module:

Should you find yourself in a chronically leaking boat, energy devoted to changing vessels is likely to be more productive than energy devoted to patching leaks.

Warren Buffett
 

Offline Fungus

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #60 on: October 08, 2017, 10:45:55 am »
But sorry i can't understand english very well, so with this device i can't limit current? only voltage?  :-\

You can limit current and voltage with these.
 

Offline halexa

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #61 on: October 08, 2017, 01:21:26 pm »
My attempt, got it finished 15min before the Patreon video was released.  :scared:

It based on a server PSU that I scored from a dumpster. 240VAC supplied with 24DC output.
I manage to fit the switch-modul, binding post and on/off button in the PSU casing.






 

Offline Rolo

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #62 on: October 08, 2017, 02:38:20 pm »
My attempt, got it finished 15min before the Patreon video was released.  :scared:

It based on a server PSU that I scored from a dumpster. 240VAC supplied with 24DC output.
I manage to fit the switch-modul, binding post and on/off button in the PSU casing.

Nice, I do like the red panel, witch module did you choose for this PSU?
 

Offline StillTrying

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #63 on: October 08, 2017, 03:12:50 pm »
It based on a server PSU that I scored from a dumpster. 240VAC supplied with 24DC output.

How have you arranged the GNDs between the input, output and case ?

There's some discussion about the DPS's input and output GNDs not being the same starting about here:
https://www.eevblog.com/forum/projects/dps5005-portable-mini-lab-psu/msg1288457/#msg1288457
CML+  That took much longer than I thought it would.
 

Offline plazma

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #64 on: October 08, 2017, 03:26:52 pm »
It based on a server PSU that I scored from a dumpster. 240VAC supplied with 24DC output.

How have you arranged the GNDs between the input, output and case ?

There's some discussion about the DPS's input and output GNDs not being the same starting about here:
https://www.eevblog.com/forum/projects/dps5005-portable-mini-lab-psu/msg1288457/#msg1288457
The Dell laptop PSU got floating output. In that picture the? DPS5005 module is powered from the internal battery.
 

Offline halexa

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #65 on: October 08, 2017, 04:02:37 pm »
My attempt, got it finished 15min before the Patreon video was released.  :scared:

It based on a server PSU that I scored from a dumpster. 240VAC supplied with 24DC output.
I manage to fit the switch-modul, binding post and on/off button in the PSU casing.

Nice, I do like the red panel, witch module did you choose for this PSU?

I used DPS5005
 

Offline StillTrying

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #66 on: October 08, 2017, 04:27:33 pm »
The Dell laptop PSU got floating output.

Yep, on a quick check my [Dell + monitor] seems to be floating, just 14VAC when on, 0VAC and OC when off, I didn't measure the current.

Quote
In that picture the? DPS5005 module is powered from the internal battery.

I know yours has battery, have you connected your aluminium case to anything, or just left it floating?
« Last Edit: October 08, 2017, 04:30:12 pm by StillTrying »
CML+  That took much longer than I thought it would.
 

Offline plazma

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #67 on: October 08, 2017, 04:31:35 pm »


I know yours has battery, have you connected your aluminium case to anything ?
The case is floating. I'll probably connect it to input ground when I add the optoisolated USB.
 

Offline StillTrying

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #68 on: October 08, 2017, 04:41:06 pm »


I know yours has battery, have you connected your aluminium case to anything ?
The case is floating. I'll probably connect it to input ground when I add the optoisolated USB.

That's the problem, if the DPS's +Ve or -Ve outputs come in contact with the case - Boom! - possibly.
CML+  That took much longer than I thought it would.
 

Offline plazma

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #69 on: October 08, 2017, 04:58:45 pm »


I know yours has battery, have you connected your aluminium case to anything ?
The case is floating. I'll probably connect it to input ground when I add the optoisolated USB.

That's the problem, if the DPS's +Ve or -Ve outputs come in contact with the case - Boom! - possibly.
I have not put much thought to it yet. That's why the case is floating atm. I have to check the modules ground path. There is at least the low side current measurement shunt. Floating or connection to output- may be better.
 

Offline StillTrying

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #70 on: October 08, 2017, 05:03:55 pm »
"connection to output -Ve may be better."

Yep. I think the only safe use of these is with the inputs +V and -V floating and isolated from everything else.
« Last Edit: October 08, 2017, 05:06:34 pm by StillTrying »
CML+  That took much longer than I thought it would.
 

Offline retrolefty

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #71 on: October 08, 2017, 07:18:37 pm »
Does anyone know how to utilize the M functions?

 Appears you can save specific V/I/CV/CV/CP setups and so forth but the instructions were very vague on utilizing M1, M2 functions. I watched a ton of U-tube videos on these modules but none covered M1/M2.

Bump. Has no one mastered the M functions yet?   :-/O
 

Offline HKJ

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #72 on: October 08, 2017, 07:23:51 pm »
Does anyone know how to utilize the M functions?

 Appears you can save specific V/I/CV/CV/CP setups and so forth but the instructions were very vague on utilizing M1, M2 functions. I watched a ton of U-tube videos on these modules but none covered M1/M2.

Bump. Has no one mastered the M functions yet?   :-/O


I do cover them in my review I linked before:

The device has 9 preset memories. To save a preset adjust the parameters, move the marker to M0, adjust the encoded to desired preset number and hold down the SET button.

Holding down V/A/SET will recall a preset, with V and A it is preset 1 and 2, with SET any of the 9 presets can be selected.





 

Offline Ertew

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #73 on: October 08, 2017, 10:13:28 pm »
My english is poor, but i try to not make mistakes.
 
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Offline bill.coghill

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Re: EEVblog #1030 - $20 DIY Bench Power Supply!
« Reply #74 on: October 09, 2017, 05:45:14 am »
I'm looking to get a couple of DPS3005 comms version to build some automated testing for a product - was about to press go on a Tenma with USB from Element14 and then try and munge a Python script for control and monitoring !

Protocol for the DPS serial seems to be based on ModBus RTU, but I found some Python code someone wrote that can talk to it easily.
There is some good info about remote controlling them here : http://ls-homeprojects.co.uk/dps3005-psu-module-and-modbus-rtu-python-arduino/

Bill.
 


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