LM723 Based bench PSU

[zeus_threat]

I know this is a place for SMPS but i wanted to build a transformer based bench psu. I just completed testing of this prototype: . Current and voltage regulation are working fine i need to scope the output to see how clean it is. Currently its giving 20V 6A max continuous and >11A max in very short bursts before everything starts cooking like hell. Its enough for my purpose and it can be beefed up to give 20A continuous and 37V max.

The dc output is taken from C4

Am planning to add a pic + LCD for voltage and current monitoring as well as temperature sensor + fan.

Later on maybe digital potentiometers controlled by the pic for current and voltage control.

The project is a taken from this one and adjusted according to the components i had handy:http://sentex.ca/~mec1995/circ/ps3010/ps3010a.html

 

[MicrosiM]

Zeus

Very good project

Thanks for sharing

 

[zeus_threat]

Voltmeter ammeter successfully tested with prototype bench psu

Succesfully built an ammeter and voltmeter based on a pic16F877A and a HD44780 LCD to show current and voltage difference from voltmeter is acceptable but can be further fine tuned:

 

[Rogelio]

I've also built same kind of psu but only with 7 to 13V variable voltage and current limit of max of 5Amp.

It's good that you share 723 psu circuit. I'll add the 0 to 6V circuit to my 723 variable dc supply.

Thanks for sharing.

 

[zeus_threat]

Welcome am studying studier bench psu which are entirely based on comparators will see where it takes me digitally controlled psu is also interesting

 

[DCPreamp]

LM723 0-15V, 0-50A Astron Power Supply Schematic

Hi There,

I don't know if you're still working on this project, but your description reminded me of an Astron power supply I used to use at work. It was an adjustable, 0 to 15VDC and 0 to 50ADC power supply. It was very stable, very clean, but was very heavy. It used a huge EI transformer and had four large heatsinks to keep the eight TO-3 series-pass transistors cool. It used an LM723 as the main control for the entire supply. Attached is the schematic. If you were to basically copy the entire power stage, but use a programmed PIC working as a D/A to adjust the voltage and current, you would have a fantastic, very powerful, digital power supply that could power just about anything up to 1/2KW designed to run on a car battery. I hope this helps!

 

[zeus_threat]

Hi thanks a lot for the post i came back into this thread after a long time. Thanks for the schematics. I was actually rebuilt my ugly dead bug style into a cleaner protoype board PSU. The voltmeter and ammeter code is there and is working i just need to create a potential divider and put it into a circuit. Its not impossible to drive the LM723 with a DAC but that ic was not built to be controlled that way also given the time the ic was designed which was in the seventies i think. I am building a an opamp CC/CV linear PSU in one of my threads which will lend itself more easily to DAC control and ADC reading for a microcontroller. I did do some test on my prototype LM723 circuit and it could burst 8AMP @22V. I did modify it to run at 5AMP though by adding some current limiting around each series pass transistor. The way i tested the load was with a quick built electronic load. I will open another thread on that. The reason for all this work i am doing around bench PSU is the current need to power my test digital audio circuits with clean power and the CS8416 e.g. needs a very clean 3V and the range it accepts is very very narrow. The digital pins only accepts 3.13 to 3.46 volts to power the device on, a slight millivolt outside this range and the devices immediately shuts off. I'll keep posted