I have psu with lm723, but it only have voltage control, and I want to modify it so I can control the current. My idea is to put a regulator that can sum the voltage of the sense resistor and the regulator.....I don’t know if you can understand me, but I don’t know how to explain this anymore....
I hope you realise that you can't control both the current and voltage simultaneously. You can design a regulator that will limit the current and effectively become a constant current source once a certain current limit is exceeded.
Please post the schematic.
Given a low current negative supply most regulators can work down to 0V.
Here's a project I designed a while ago which uses the LM317 and a low current negative supply to give 0V to 13.8V.
1-is the voltage regulator(the PSU)
2-the sense resistor is 0.22R/5W
3-summing circuit
4-the low voltage regulator(the one i was asking for)
What I want to do: at 1A the drop down voltage of the sense resistor is 0.22V. So to cut down the output at 1A between pins 2 and 3 there needs to be 0.63V. I want with the other voltage regulator and the sumator the voltage between those two pins to make it to be 0.63V so lm723 can break the output and the other circuit that I am testing can’t burn out....do you get it now??
btw the other part of the circuit isn’t drawn because there was no need to do that..and that 1A current was an example...
So toss a variable linear regulator on the 12 volt line of the ATX supply. Easier than designing one from scratch. Constant current can be done pretty easily with a Mosfet and a current sense resistor.
So toss a variable linear regulator on the 12 volt line of the ATX supply. Easier than designing one from scratch. Constant current can be done pretty easily with a Mosfet and a current sense resistor.
A voltage reference only needs to supply a tiny current into an error amplifier which will have a high input impedance.
Constant current regulation isn't better or worse, it depends on what you're doing: if you want to power a microcontroller then you want voltage regulation and if you want to power an LED you want current regulation but most of the time you'll need voltage regulation.