I've spent sometime checking the principle of your new circuit, and I think I finally understood it. Here is my explanation:
CC Loop:
you have an op-amp which has Vout+ as its positive terminal and it is always above the negative terminal by a voltage that equals exactly the voltage difference around the current shunt resistor. For 1A output current -> 100mV drop voltage which means the positive terminal of the CC op-amp is 100mV more than the negative one at all times.
Now to set a constant current limit, you need to inject this 100mV in the negative input to make it equal to the positive one (or slightly above) to get the diff amp to put the negative rail as its output and thus drive the MOSFET gate down to the negative rail (-5V) which is a CC operation.
To do so, you put a current source of 1mA --> 1mA*100R = 100mV which makes the negative terminal of the op-amp equals (V_I+) - 100mV at all times. Meaning, you only allow a 100mV drop voltage to exist on the current shunt (=1A) and if it exceeds this then it won't be allowed.
Now that is a brilliant idea! and it is so damn accurate even in very tiny currents!
Aside from that, I didn't understand the purpose of the other current sources (to make minimum current or stability) but since they are fixed currents I can make them using the famous LM334! No worries!
However, the problem is making the current source I4 which is the critical one! how to make it adjustable and software controlled? LM334 won't do it here plus I need something like 1uA resolution...
I thought of making an op-amp comparator (or something like a dummy load constant current sink) but I didn't get a good idea. I want something to be controlled via MCU as well as reading the output current to the MCU. Do you have any idea? I tried just adding a voltage below the 100R but it didn't work properly.
Is this the only thing left in the circuit? I hope xD
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now please see this image of your circuits:
http://imgur.com/a/AK6PkI ran the ac analysis and probed the points in the image. Where and what are the points that you spoke of? I mean how do you probe to see what you seek in the bode plot?
You spoke about the output impedance being 1v AC/1A AC but what is the point that you drew on the plot? and the other schematic as well. This is the only thing I am still totally confused with until now. You've been cooperating nicely with me and I am doing much effort in learning and trying but this portion is still not understandable for me.
To further explain the core of my questions: how did you know that the circuit behaves well above 5mA?
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Domo Arigatou gozaimasu Kleinstein-sensei!