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  • Author Author: Robert Peter Oakes
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The Modular Bench Power Supply ++, Putting it all together, the bare bones

Robert Peter Oakes

I will be putting together the video this week end to go with this schematic but I thought i would share this with you in the mean time

VCC can be as much as 40V (I was powering the test circuit on a breadboard with a bench PSU for now set to 30V, my psu max)

image

In the video I will be reviewing the behaviour of this circuit as well as Identifying a few pitfalls (Nothing serious and probably acceptable for a basic PSU but we do want to evaluate where we can improve on things

If you think you know the potential issues, please post and we will compare notes at the weekend image (There are two primary ones)

 

Here is the video that describes and goes through some basic tests of this circuit

Enjoy, again, a little detailed so its is about an hour long

 

I will be adding notes etc in the next few days

  • Hello,

    I followed closely all your video materials about the modular bench power system
    (My question below might be of interest to your audience here)

    Can you suggest a principal circuit diagram for tracking control of symmetrical slave negative channel, using the same n-channel MOSFET?
    How would the negative part of the circuit would look like?
    I guess -- using again a differential amplifier for voltage control and curent limiter?
    Is it possible the negative part/channel to be controlled by the same potenciometers already present in the positive part/channel?

  • in reply to hacklord

    Did you use the same above circuit diagram,  I posted.

    Do you have the correct voltage out of the VREF

    when you move the voltage adjust, does the input to the op-amp increase in proportion (Make sure the current pot is turned for MAX current, not minimal

    what is the output of the op-amp when you have max voltage selected,

    what it input + and - at  (Pin 2 and 3) ?

     

    I had fully tested this on he bench so I know the above diagram actually works but I suspect you may have a few deviations due to availability of parts etc. can you provide a schematic of what you built and perhaps a picture too to match it

     

    Regards

    Peter

  • Hi i Built this up but it dose not seem toe work the only out put i get is 0.5 volts whet ever the pots are set to?

    i used an IRFP064N (just to check is the pin out G D S)

    also i used a FPR 4-T221 (it has 4 pins dose it matter which ones i used i connected first 2 to ground 3rd to op amp and 4 to output)

    i followed the diagram correctly i think.

    i would be very grate full for any help on this as its my first time building a bench power supply.

  • in reply to Robert Peter Oakes

    I could not see the Vishay four terminal one  at farnell , I did not have the number at the time

    so I bought this one , MULTICOMP  MC14721  Through Hole Current Sense Resistor, MC Series, 0.1 ohm, 5 W, ± 1%, Axial Leaded, Wirewound

    it does the job

     

    garry

  • in reply to Former Member

    What is important about the sense resistor is the ability to know its value and that it is stable

     

    a .1ohm 5W is perfect, you say it is a sense resistor, do you mean it is 4 terminal ? (Kelvin Connections)

     

    the ones I have are Visha Bulk Metal

    VPG - Foil Resistors - FPR 4-T220 T2211

    and

    VPG - Foil Resistors - FHR 4-3825 to 4618

     

    My power sense FPR is also 1% but I can measure it to better than that and as it is very stable it will remain accurate with the measured value