Electronics > Beginners
10 Amps power supply with LM723
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mike_mike:

--- Quote from: imo on April 12, 2019, 04:21:53 pm ---For example a simulation with 10k the top resistor, 1k pot, 120ohm bottom, AND a 10k resistor from pot's wiper to gnd
POT's wiper       CLimit
top                   23mA
mid                  1.8A
down                3.8A

--- End quote ---

I used the modification specified above and it works a little bit better, but at mid, the output current is about 1.20A, instead of 1.8A, and the maximum output current is 3.06A. The current starts to rise from only at about 1/4 of the pot course.
For the tests I used only one TIP3055 and only one 4700uF capacitor.v Also, for the tests I did not used D1 and D2.

Is the Rwiper connected correctly ?
Please have a look at the schematic and at the results above and tell me what you think.
iMo:
I would play with those 3 caps see below.
Also I would make the Voltage setting at the Vref side around the +IN (fixed divider at the output).
mike_mike:
The role of those caps is to filter the voltage, for example the 10uF polarized capacitors is to filter the the voltage reference for voltage regulation and current regulation ?
The results of the output current pot are good ?
What are the advantages of using the pot at the Vred side ?
iMo:
Yes.
Yes.

The output divider values contribute to the feedback control loop dynamic parameters.
When changing them the feedback response is changing.
Therefore it is better to have the Voltage regulation at the IN+ side.

For example with fixed 9k/1k output divider (/10) the output voltage will be aprox. 10*V(IN+).

mike_mike:
I tested the attached schematic, but the minimum output voltage is about 9V, and if I reduce the R3 to 0 ohms, the minimum output voltage is about 7V.
I also tested with R12=8k2, R10=2k2, R1=0R and R3=680, and the minimum output voltage vas 3.5V and the maximum was about 29.5V. The voltage pot has a part where if the voltage is at maximum (29.5V) then the output voltage does not go down until the pot is at 1/4 of the course. I found those values on a schematic on the internet: http://www.electroniq.net/power-supply/lm723-variable-power-supply.html
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