Thank you very much to share your videos, i'm building my own power supply and i have followed your circuit for the voltage regulation which works realy well. For the 5v referenve i've used a 7805, works fine. Without this regulator the output voltage was droping a lot on big loads, but now it's working really well. Perhaps i will try the current regulation later. My transformer is a toroidal 12/24V AC so i've used a 3pin switch to switch the secondary when needed so the transistor doesnt disipate all the power when working with low voltages. I can go 0 to 15V and 0 to 28.8V with the switch. Anyway thanks a lot for sharing.
can't you connect second opamp to the middle of voltage divider and switch it's inputs (- to Vref). When ever the current gets too high it'll rise voltage divider voltage and the first opamp will reduce the output. You can also put a gain (negative feedback) on the second opamp because it works like a comparator and it might not be much stable. Use gain of 30-50 for example. Maybe also an integrating cap between - and opamp output. P.S. Because opamps have push pull output it'll also drop the voltage of divider to 0 if the current is below the threashold. So on the second opamp you need a diode with the anode facing the output of the opamp.
If you are aiming to dissipate the least amount of heat and thus stay quiet, did you consider if having a switching pre-regulator that tracks the desired output voltage by a small offset might be a fun thing to try once you have the main regulation working?
For some reason I always felt you'd come back to the diy power supply(probably because you either said that or hinted it in a previous video :P). Looking forward to the next video. A little bit off topic, what would you have done to the other power supplies to reduce the noise?
Looking at the size of these PSUs,I don't think they support fans larger than 80mm, which means even a good fan at that size would still be too noisy for his application.
Is it better to use a transistor (for the constant voltage side of the powersupply) instead of a mosfet? I'm trying with a logic mosfet and the output is not that good
dont use a discrete diff amp for the current control. Even a 1% or less mismatch in the resistors will ruin your CMRR by a huge margin and degrade accuracy. use a diff amp IC!
I am really excited to see more of this project. I am planning my own PSU right now also. I was thinking on making a take on this one. tuxgraphics.org/electronics/201005/bench-power-supply-v3.shtml you can even find an early schematic. tuxgraphics.org/common/images2/article379/powersupply.gif
So happy you are getting back to making fundamental useful equipment. Can't wait to follow along with this project! CC and CV....awesome
next part please. I'm very excited about seeing this circuit working in practice
Thank you very much to share your videos, i'm building my own power supply and i have followed your circuit for the voltage regulation which works realy well.
For the 5v referenve i've used a 7805, works fine. Without this regulator the output voltage was droping a lot on big loads, but now it's working really well. Perhaps i will try the current regulation later.
My transformer is a toroidal 12/24V AC so i've used a 3pin switch to switch the secondary when needed so the transistor doesnt disipate all the power when working with low voltages. I can go 0 to 15V and 0 to 28.8V with the switch.
Anyway thanks a lot for sharing.
Fellow Dane really looking forward to this series, your explanations are great :) I need a CV/CC PSU, so I might build this alongside you
can't you connect second opamp to the middle of voltage divider and switch it's inputs (- to Vref). When ever the current gets too high it'll rise voltage divider voltage and the first opamp will reduce the output. You can also put a gain (negative feedback) on the second opamp because it works like a comparator and it might not be much stable. Use gain of 30-50 for example. Maybe also an integrating cap between - and opamp output.
P.S. Because opamps have push pull output it'll also drop the voltage of divider to 0 if the current is below the threashold. So on the second opamp you need a diode with the anode facing the output of the opamp.
If you are aiming to dissipate the least amount of heat and thus stay quiet, did you consider if having a switching pre-regulator that tracks the desired output voltage by a small offset might be a fun thing to try once you have the main regulation working?
First!! :O
Welcome back.
Nice explanation. Thanks.
boa explicação , Abraços
Great video. Thanks!!!
For some reason I always felt you'd come back to the diy power supply(probably because you either said that or hinted it in a previous video :P). Looking forward to the next video. A little bit off topic, what would you have done to the other power supplies to reduce the noise?
Looking at the size of these PSUs,I don't think they support fans larger than 80mm, which means even a good fan at that size would still be too noisy for his application.
And next comes the water cooling for the power supplies with the loud fans?
very good
Is it better to use a transistor (for the constant voltage side of the powersupply) instead of a mosfet? I'm trying with a logic mosfet and the output is not that good
Any reason you chose a bjt over a mosfet for the switching?
dont use a discrete diff amp for the current control. Even a 1% or less mismatch in the resistors will ruin your CMRR by a huge margin and degrade accuracy. use a diff amp IC!
why not do a buck converter instead? much less heat to be dissipated
Was thinking the same :-/ But maybe its to keep it simple, and get les noise.. most buck generate noise in the 1-4mhz range :-/
bucks or smps are very noisy
sir when you post the next video
I am really excited to see more of this project. I am planning my own PSU right now also.
I was thinking on making a take on this one. tuxgraphics.org/electronics/201005/bench-power-supply-v3.shtml you can even find an early schematic. tuxgraphics.org/common/images2/article379/powersupply.gif