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How to replace LT3083 with opamp+pass transistor
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AloyseTech:
Hi,

I've been able to work a little bit on this project again.

I added the current limiter option. Is this a good solution ?



Kleinstein:
The shown circuit is a rather poor solution. It has quite a few bad points:
The voltage control loop (U9B) has no added compensation and thus only relies on the speed of the OP. Chances are it will oscillate, especially with the extra buffer and LT3083 used as a "power transistor" and the extra delay via C1. Chances are U9B will work as a kind of comparator, making it a kind of "controlled" triangle, on-off type regulation.

The current loop is also poor, with added gain from the transistor. So some kind of oscillation is nearly guarantied.
Because of C1 the current limit would also be very slow.

The chose OPs are also rather noisy for the small voltage relevant to the current regulation.

Precision wise the differential amplifier at the shunt is also bad - it heavily depends on resistor accuracy.
AloyseTech:
Thanks @Kleinstein for your comments. What improvements would you suggest ? Would you happen to know where to find a proven DAC controlled PSU design?
prasimix:

--- Quote from: AloyseTech on November 19, 2018, 10:40:58 am ---Would you happen to know where to find a proven DAC controlled PSU design?

--- End quote ---

Take into account that proven DAC controlled PSU design goes beyond hardware alone for simple reason that DAC require firmware for control. And proven firmware can easily goes beyond simply set output voltage and/or current :). We spent much more time on developing solid software (firmware) then on developing hardware for EEZ H24005, despite our core competence is software development.
AloyseTech:
I'm only looking for the hardware part of the system. I don't want the software to be responsible for regulation, only for settings voltage and current. I understand that a lot of work is needed for the software if the regulation is not done in hardware.
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