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Wanted CC CV Regulated POwer Supply Circuit For construction

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message4guru

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Hi to all!!!!

I want to construct CC CV Regulated POwer Supply Circuit For Laboratory Bench use. I am Totally Confused of Circuits available in Google. Every time i construct and Obtain Magic smoke out of it..


Please Give Circits with CC CV Regulated POwer Supply Circuit for specification of

input voltage 34v after filtering from centre tap transformer 12-0-12 @ 5 Ampere.
output voltage 0-30V and 0-5ampere Variable
It should work in constant Current mode and constant voltage made.

Help me in this regard....
 

Are you wanting the supply, or are you wanting the experience
of making one?

Because you can get "Dr. Meter" supplies of about this voltage
and current capacity, with both modes, for about 40 bucks.
The switcher based ones (HY3005M) are nice, quiet, cool.
I bought 4 of them for my lab. You just have to shop the
various resellers and be patient.

I doubt you could make one as cheap as you can buy
one, just the parts cost alone. How bad do you want
to play at this?
 

You are repeating a question that has been already discussed in a previous thread https://www.edaboard.com/showthread.php?t=368036

I notice you also got reasonable circuit suggestions. As long as you don't have the knowledge to decide which of the "Circuits available in Google" are promising and which should be better avoided, you better follow the given advise.

Your volt and ampere calculation is however flawed.

A 24V/5A rated transformer can't supply more than 5/1.6 = 3.1A filtered DC through a bridge rectifier + filter capacitor. Voltage drops must be considered, thus 24V/3A can be a safe output specification for the lab supply. May be up to 28 or 30V at reduced current.
 

A 24V/5A rated transformer can't supply more than 5/1.6 = 3.1A filtered DC through a bridge rectifier + filter capacitor. Voltage drops must be considered, thus 24V/3A can be a safe output specification for the lab supply. May be up to 28 or 30V at reduced current.

Could you clarify why the AC current rating of the transformer was divided by a factor of 1.6?
 

1.6 is so called form factor, current into bridge rectifier with filter is non-sinusoidal, RMS value is higher than average DC output by this factor.
 

The maximum power from your transformer is 24V x 5A= 120VA and can drive a 120W load.
The power supply has a peak DC voltage of 34V and a load of 5A so it needs 34 x 5= 170W. Your transformer is too small.

The rectifiers have a 2V loss, the main filter capacitor has a 2V loss, the emitter-follower pass and driver transistors have a 4V loss and maybe the current sensor has a 1V loss so the max output voltage at 5A with a 24V transformer is only 25V, not 30V.
There is a Chinese kit available for a very old 30VDC/3A power supply that did not work. Here is that circuit but it is fixed and improved. If R7 is changed to 0.27 ohms, a 3rd output transistor added and the transformer changed to 28VAC/7.2A (202VA).

This power supply will produce a lot of heat if the output voltage is low and the current is 5A. The maximum heating in the output transistors will be about 180W so a huge heatsink with a fan and maybe some liquid nitrogen will be needed.
 

Attachments

  • 0-30V Schematic Rev6 Jul 2014.gif
    0-30V Schematic Rev6 Jul 2014.gif
    23.4 KB · Views: 420
  • 0-30V Parts List Rev6 Jul 2014.png
    0-30V Parts List Rev6 Jul 2014.png
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LM723 and Variable Current Control Technique????

Hi to all!!

This was a circuit Taken from google search.

the doubt is first circuit , how does the current control knob operates that is 1Kohm 10 turns potentiometer in the first circuit?

the second circuit contain potentiometer of 500ohm which control the current in output of regulator Circuit?

the third circuit contain potentiometer across a Diode, How does it make Current variable regulator?

Please help me in such way i could understand Variable current control circuit LM723 Voltage regulator.

I have also Discussed this in my previous thread topic, current limiting is not happening in LM723???...


So i am totally confused with these circuit. Please make me to understand the Technique behind Current control transistor in LM723 for Variable current control in power supplies.or give some ideas to build cc cv power supply design.

Help me in this regard.. I think i have conveyed my thoughts.if any thing is incomplete,please ask me .

Correct me if i am wrong..
 

Attachments

  • LM723_Variable_CurrentControl_Circuit_1.jpg
    LM723_Variable_CurrentControl_Circuit_1.jpg
    77.2 KB · Views: 334
  • LM723_Circuit_2.jpg
    LM723_Circuit_2.jpg
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  • LM723_Circuit_3.jpg
    LM723_Circuit_3.jpg
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None of the three circuits looks really good to me. A simple, but at first sight better LM723 based variable current limiting circuit (Elektor PSU) has been posted by prairiedog in your previous same topic thread https://www.edaboard.com/showthread.php?t=368036.

As a general restriction, the LM723 current limit function is temperature dependent and has no accurate threshhold. Most linear CC CV power supplies are using operational amplifiers for CC control. So does the circuit posted by AudioGuru below.
 

Re: LM723 and Variable Current Control Technique????

Hi to all!!

This was a circuit Taken from google search.

the doubt is first circuit , how does the current control knob operates that is 1Kohm 10 turns potentiometer in the first circuit?

the second circuit contain potentiometer of 500ohm which control the current in output of regulator Circuit?

the third circuit contain potentiometer across a Diode, How does it make Current variable regulator?

Please help me in such way i could understand Variable current control circuit LM723 Voltage regulator.

I have also Discussed this in my previous thread topic, current limiting is not happening in LM723???...


So i am totally confused with these circuit. Please make me to understand the Technique behind Current control transistor in LM723 for Variable current control in power supplies.or give some ideas to build cc cv power supply design.

Help me in this regard.. I think i have conveyed my thoughts.if any thing is incomplete,please ask me .

Correct me if i am wrong..

configuration for LM 723 as a CC/CV professional grade lab power supply also have look to my favorite LM317 CC/CV power supply national app note improved and redesign for better CC/CV control from R.Quan **broken link removed**
 

Attachments

  • LM 723 CC-CV Lab Power Supply.pdf
    321.4 KB · Views: 235
Last edited:

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