Hi Redwire,Thanks for the reply. I guess there is no getting around not having a negative charge pump with this type of design. I'm curious to see how this guy gets around the problem. Considering he is using a .1 ohm resistor, the theoretical load would be substantial before there would be stability. I think from a practical standpoint if there is a heavy load and 0.47 ohm sense reisistor, the ground for the current op amp is pushed low enough down to provide some control.
On the original and fixed version your diode D2 was a resistor with almost NO voltage drop. Now the D2 has a voltage drop that changes when the temperature changes then the output voltage changes when the temperature changes.
Without a negative supply for the current control opamp the output current will not be regulated when it is set to less than about 0.8V/0.27 ohms= 2.96A. The output voltage of the current control opamp must be able to go to -0.7V so that regulation at low currents works. Then its negative supply must be at least -0.9V so use two diodes like I did.
I am also going to re-look at the design on the first post here. I seemed to have the oscillation under control and I could change the voltage smoothly. I was having some current control issues in that the opamps seemed to be fighting each other until the current setting was set to its lowest setting. If I set the voltage at 14V and the current at 100mv, then connect a load of 1.5 A the current control would never kick in. It was like in a runaway mode.