RE: The Modular Bench Power Supply ++, Integration theory and practical

napiza — Thu, 12 May 2022 06:07:24 GMT

Thanks you Peter for all the tutorial. It have been really interesting and helpfull, and it have engaged me to start my own PSU. I don't quite very well undestand the operation of the V control and I control points againts Vgate that you show in the second picture. As far as I undestand, the integrator goes from -12 to 12 depending on the output of the previous state of sensing. Take it for example that I have a setpoint of 3V and I am sensing 3V on the output of my PSU. The output of the integrator will this case do nothing and remain at 0V, turning off the mosfet because not voltage is being put into the gate (all is going to the integrator because of the diode's direction).

Now, let's imagine that I have a setpoint of 3V and I am sensign 5V (-5V in differential amp), so the summing junction will be -2V--> It will generate a decreasing ramp on the integrator output until reaching the -12V. As this voltage is lower than the 6V that we have in the Vgate path, this will turn off the Mosfet.

On the other hand, if I would have a setpoint of 5V and I am sensign 3V (-3V in differential amp), the summing junction will be 2V--> It will generate an increasing ramp on the integrator output until reaching the 12V. When it exceeds the 6V, because the direction of the diode, it will allow the mosfet to turn it on, allowing the 6 V on the Vgate path to go into its gate.

I don't know if this is correct, I was not pretty sure before starting to write, but while writing it has been usefull to me to clear my ideas (sorry ;) ). In this case, we will all the time be working with the mosfet in a saturation mode, where it is either fully ON or fully OFF right? The question is--> ¿Is this a switching mode PSU or a linear mode PSU? I think it is linear because based on what i have understood and taking the latest example, where I needed to increment the output voltage of my PSU from 3V to 5V, once it has reached those 5V, is going to be 0V into the integral amp's input, generating no ramp in its output, so keeping its output in 12V until another setpoint is set?

What is the difference then between a setpoint of 4V or 5V, because the integral output is always 12 V or -12 V, I don't very well understand how the Vds of the Mosfet changes in order to put the PSU's output higher or lower. Because if we work in saturation mode, is always going to be the same voltage in the source right?

I don't know if i am right, and if it is a switching mode PSU, what is its frequency?

I am sorry for my explanations and my english. I hope I have explain myself clearly enough to understand my questions. Let me know if it is not like that

Another question, what is the purpose of the analogue 0V that you have in common on all your amps in your final schematic of this tutorial?, and where do you take it from?

Thank you so much

Nagore

RE: The Modular Bench Power Supply ++, Integration theory and practical

savvo — Tue, 02 Jun 2015 15:30:29 GMT

Thanks for sharing your work. I have nothing to add but a bit of nit-picking; "…studying 30 year old agilent power supply schematics…" didn't sound right to me so I looked it up: Agilent is only 16 years old.