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OPEN Power

I didn't have enough to buy a Lab Bench PSU... So I made one.

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Open Power is about providing makers and students with a Portable, Versatile Intuitive and Cheap (under $2.50) power supply for all their projects.

Prototype 1: Simple and Cheap Constant Voltage/ Constant Current Power Supply variable from 0.6V to 12V with led voltage indication. USB Load sharing powered and Lipo backup.

Prototype 2: A Constant Voltage Constant Current Power Supply 0.6V to 12V In addition to an adjustable Negative Rail. Voltage and current Monitoring Provided by a OLED Display.

Prototype 3: Utilizes a Boost Inverting IC to get +-13V and LDO's to Reduce the voltage between 0 and 12V. Both +- Rail Voltage Current and Power will Be displayed on a Full Color LED Display.

The goals of OPEN Power is to produce 3 final Prototypes. All Power Supplies will have USB Charging of Lithium polymer batteries and a Load Sharing and Uninterruptible power when disconnected.

Prototype 1a:

---------------------
Status
(COMPLETED)
Simple Constant voltage Power Supply
Variable from 0.6V to 12V
.
Will Include 5V and 3V Rails.
Voltage indicator will be achieved using
comparators and LED Array.
This was chosen to reduce cost
as much as possible and keep each
board with components under $2.75.



Schematic (LINK)

BOM (LINK)

Gerber Files (LINK)
Prototype 1a: Rendering
Prototype 1a: Rendering
Prototype 1a: Assembled
Prototype 1a: Assembled
Voltage Test
Voltage Test
Load Sharing and Quick disconnect Test
Load Sharing / Uninterruptible Test
Prototype 1b:
---------------------
Status
(Sent To
 the Fab)
Revision 1b The Led arrays are
switch from a linear array to a
polar array
around the Voltage
and Potentiometer
trimmers have been added to calibrate.

Schematic (LINK)

BOM (LINK)

Prototype 1B: Rendering
Prototype 1B: Rendering
Prototype 1B: Rendering
Prototype 1B: Rendering
Prototype 1B: Traces
Prototype 1B: Traces
Prototype 1B: Schematic
Prototype 1B: Schematic
Prototype 1c:Revision 1c will add an additional 
Constant Current 
Knob to allot
user to limit and see around what
current is being drawn. 

Prototype 2:A Constant Voltage Constant current
Power Supply 0.6V to 12V.
In addition to an adjustable Negative Rail.
Voltage, Current and Power
of the positive Rail will be displayed
on a compact OLED. Negative Rail
Voltage will also Be displayed
as well as the Battery Voltage.

Prototype 3:
---------------------
Status (COMPLETED)
Utilizes a Boost Inverting IC to get
+-13V and LDO's to Reduce the
Voltage between 0 and 12V.
Both +- Rail Voltage, Current
and Power
will Be displayed
on a Full Color 0.96" LED Display.


(COMPLETED Some errors see Schematic)


Schematic (LINK)
Prototype 3A - Render
Prototype 3A: Rendering
Prototype 3A: Assembled
Prototype 3A: Assembled
Prototype 3A: Load sharing Test
Prototype 3A: Load sharing Test
Prototype 3A: Constant Current Test
Prototype 3A: Constant Current Test
Prototype 3b:
--------------------- 
Status 
(Sent To
the Fab)
Revision 3b will have a DAC
Output,  2 Analog input
and 4 DIO Pins
.

The implementation of a 16-Bit ADC
Will improve the Current Readout


                (Sent to the Fab)

Schematic (LINK)
Prototype 3B: Rendering
Prototype 3B: Rendering
Prototype 3B: Layout
Prototype 3B: Layout
Prototype 3B: PCB Traces
Prototype 3B: PCB Traces
Prototype 3B: Schematic
Prototype 3B: Schematic

Prototype 3c:
---------------------  
Status  
(Layout Mock-up)
Revision 3c will switch from the
Samd21 to the Samd51 for faster
Procecesing power and additional IOs. 
The LCD will also be upgraded
 to a 1.3" IPS 240x240 LCD. 
Since the circuit is completely
analog the MCU can perform 
Double duty and Potentially  be
used as a Crude Oscilloscope
or Logic Analyzer.
Prototype 3C: Layout Mockup
Prototype 3C: Layout Mock-up

Open Power - Prototype1A - Gerber.zip

OPEN Power - Prototype 1B - Gerber Files Formatted for JLBPCB

Zip Archive - 435.96 kB - 08/25/2019 at 03:11

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Open Power - Prototype 1B.pdf

OPEN Power - Prototype 1B - Schematic

Adobe Portable Document Format - 662.95 kB - 08/25/2019 at 02:59

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Open Power - Prototype 1B - BOM.pdf

OPEN Power - Prototype 1B - BOM

Adobe Portable Document Format - 37.02 kB - 08/25/2019 at 02:56

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Open Power - Prototype 3B.pdf

OPEN Power - Prototype 3B - Schematic

Adobe Portable Document Format - 816.20 kB - 08/23/2019 at 04:51

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Open Power - Prototype 3A.pdf

OPEN Power - Prototype 3A - Schematic

Adobe Portable Document Format - 715.76 kB - 08/22/2019 at 11:33

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View all 7 files

  • 2 × MT3608 Boost Converter Modified to be a Sepic Boost.
  • 1 × MIC5225-5.0 5V LDO
  • 2 × LED - 0603 - Yellow LED - 0603 - Yellow
  • 2 × LED - 0603 - Orange LED - 0603 - Orange
  • 3 × LED - 0603 - Red LED - 0603 - Red

View all 45 components

  • Prototype 1B: Designed and sent to the FAB

    John Loeffler3 hours ago 0 comments

    Prototype 1B Makes improvement to the 5V boost converter as well as orients the LEDs arroung the potentiometer.  Because the Potentiometer is very inaccurate, a Trimmer potentiometer is used to calibrate the Voltage knob to the LEDs.  Calibration method will be developed.  1b was Fabricated and sent to Manufacture,

  • Open Power - Prototype 3C - Mockup Renderings

    John Loeffler2 days ago 0 comments

    The Samd51 is a bit more complicated than initial thought so i made a Mock-up of Prototype 3 which uses a bigger 1.3in screen which requires the SAMD51 120MHz Clock power.  A demo layout of the UI was included in the Render to show it is capable of being a crude oscilloscope or logic analyses .

  • Open Power - Prototype 3B Finished and sent to be Fabricated

    John Loeffler2 days ago 0 comments

    Prototype 3B made the corrections to the negative rail.  A new 16-bit ADC will improve the current measuring capability to the 100uA level.  Traces were done manually and verified. 


  • Prototype 3A: Load sharing/ Constant Current Test

    John Loeffler3 days ago 0 comments

    Power is drawn from usb until disconnected.  Power remains on an powering LED

    Constant Current Test With an LED

  • Prototype 3A: Design and Assembly

    John Loeffler4 days ago 0 comments

    Prototype 3a:

    I have got the board of  Prototype 3a back from the fab and populated it and uploaded the code.  Most functionality is working.  

    Problems:

    1) Current limiting on negative rail does not work.  There was an error in the Schematic

    2) The Positive rail only goes down to 0.62V when there is No load.  This is because the LT3081 Requires a 5mA Load for line regulation. 

    Prototype 3b: Revision Concept Includes DAC Output, 2X Analog Inputs(0-12V) and 4x Digital Inputs 3.3V (5V Tolerant)

  • Variable Voltage / Load Sharing / Uninterruptible Power Tests

    John Loeffler5 days ago 0 comments

    Testing the SEPIC Converter and LED Feedback of the adjustable rails.  The pot is calibrated by an additional bot on the bottom for accurate voltage readings.  When the LED begins to flicker it is almost at the desired voltage.  When it just becomes solid it is at the desired voltage.

    When USB Power is applied the battery is disconnected and will be charged if needed.  When Usb is disconnected the battery will be enabled allowing continuous operation.

  • Corrected Boards Recieved

    John Loeffler6 days ago 0 comments

    I got the Fixed Boards Back from JLBPCB and the work perfectly

  • Back From the Fab and Assembled

    John Loeffler05/24/2019 at 21:01 0 comments

    I got the boards back from the Fab but... I made a little mistake with Power and Ground.  I made 3 of these boards and they kept failing.  Turns out if you use 5v for ground and ground for 5v thing don't work that great.  I did a wire route and the board works fine.

  • Board Redesign

    John Loeffler04/16/2019 at 15:15 0 comments

    Redesigned Board with bette component placements for was of assembly and more visible silkscreen.

  • Constant Current and Comparitor Test Boards

    John Loeffler04/16/2019 at 14:48 0 comments

    Test boards came back.  Constant Current and Comparitors Work perfectly

View all 12 project logs

  • 1
    Implementation of Open Power for mass production

    One of the biggest goals for Open Power is to provide a cheap power supply for MAKERS and students projects.  

    Because it is cheap, MAKERS can leave the project on the breadboard and use a different one to start a new project.  With a lab Bench PSU you are required to disconnect the wires to do a different board, sensor...  

    Keeping the entry level less then $5 (assembled with battery)  the purchase of multiple units would be a terrific investment for Makers and students.  

    One of the biggest challenges with this will be sourcing parts and manufactures to keep the cost low.   Currently the entry model uses 5x LM339 Comparators.  Even in quantities of 5 is less than the cheapest MCU.  But there is a point where there are enough led and comparators that a simple MCU and OLED Makes Sense.  Prototype 2b will address this. 

    Working with Suppliers, PCB Fab and assembly labs will be a major focus of bringing OPEN Power to the Masses.

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Discussions

Martin wrote 6 days ago point

Why do you use a SEPIC converter for 5V? You power it from a LiIon battery (max. 4,2V) and even disconnect the output while charging from USB. A normal step -up would be sufficient, uses less components and has better efficiency.

  Are you sure? yes | no

John Loeffler wrote 6 days ago point

You are absolutely right i will have to change that.  At one pint i was thinking of putting in a Barrel jack for more power options and decided to take it out but didn't change the SEPIC back to a Boost.  Thank you.

  Are you sure? yes | no

Keith Olson wrote 05/03/2019 at 04:34 point

FWIW, Instead of a knob, using 8 jumpers would give you the ability to set 0.1v - 11.9v directly, by using (modified) binary addition.  The major would be set up as 1-2-4-4 (0 - 11) and the minor would be set up as 1-2-2-4 (0 - 9).  For example, a 3.3v setting could be 1100 1100, while a 7.5v could be [1101 1001].  Making one of the major jumpers 8 instead of 4 would allow going up to 16v, and additional major jumpers would allow for even higher voltages.  LED's wouldn't be needed, as the voltage would be visibly displayed.

Does that make sense?

  Are you sure? yes | no

John Loeffler wrote 6 days ago point

That does make sense for accuracy.  I do however prefer to have a continuously adjustable rail for testing some circuits.

  Are you sure? yes | no

Aiden Fang wrote 04/23/2019 at 01:19 point

Wow! Great job! The color scheme looks very attractive. What software did you use to make the drawing?

Thanks!

Aiden

  Are you sure? yes | no

Ubi de Feo wrote 04/21/2019 at 07:06 point

Lots of great work going on here :)

I mostly use breadboards with 6 columns per side, rather than 5, and most of these adapters are useless in this case.

Not long ago I was wondering if there'd be a way to make the power rails adaptable to multiple sizes.

Food for thought, I guess ;)

  Are you sure? yes | no

John Loeffler wrote 04/21/2019 at 10:10 point

do you have a picture I could use for reference?

  Are you sure? yes | no

Arsenijs wrote 04/20/2019 at 17:09 point

Consider using 4-resistor arrays, it might allow you to save a bunch of board space and simplify the BOM.

https://p.globalsources.com/IMAGES/PDT/BIG/251/B1064309251.jpg

  Are you sure? yes | no

John Loeffler wrote 04/20/2019 at 19:33 point

Thank you that is exactly what i need

  Are you sure? yes | no

John Loeffler wrote 2 days ago point

I have implemented these in my Prototype 1b Design will post Soon

  Are you sure? yes | no

Jan wrote 04/18/2019 at 20:21 point

Nice idea. The LED thing is a bit over the top though and occupies much board space! 4x LM339?!?!?!
I wonder how you want to route that thing, there is next to no space for traces in the current design. Using 4 layer boards might work though...

  Are you sure? yes | no

John Loeffler wrote 04/19/2019 at 01:16 point

It is routed on a 2layer.  I have gotten pretty good at routing manually over the years.  Check out my prototype 3 it uses an 0.96 color Toft display and has loads more features.

  Are you sure? yes | no

Lukas wrote 04/15/2019 at 08:48 point

Great idea, i need this for my breadboard.

  Are you sure? yes | no

testsubj wrote 04/11/2019 at 18:56 point

There's already some similar boards on Aliexpress that do this. I didn't look for an adjustable version, but the ones that only output 3.3/5 cost less than $1 shipped.

  Are you sure? yes | no

John Loeffler wrote 04/11/2019 at 18:59 point

I love those.  This is usb powered with Lipo backup, as well as continuously adjustable and 5v and 3.3v rails

  Are you sure? yes | no

Dan Maloney wrote 04/11/2019 at 15:12 point

Agreed - great idea. You should really enter this is the Hackaday Prize - this would make a great product!

  Are you sure? yes | no

John Loeffler wrote 04/11/2019 at 15:15 point

Thanks I will,  Check out my Prototype 3.  It has more bells and whistles.  This version is a simple non Micro controller version. Right now the cost of components is less than $4 in low quantity.

  Are you sure? yes | no

Lee Wilkins wrote 04/10/2019 at 20:37 point

Great idea!

  Are you sure? yes | no

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