Using constant current source as voltage regulator

[jan.didden]

Originally Posted by CBS240

I do this often and it works great. But like Jan said, any variance in current pulling off of the voltage reference will vary the reference. So I like to use it in this manner...

Cascode the low Gm J-fet with the high Gm J-fet to get a more acurate Idss. Use a J-fet gate as the load on the voltage reference to steer the differential. (the N-Jfet and the P-Jfet act like a diff amp in this arrangement) If much higher output voltage is needed, you can always add another cascode to the J201. Way better than using noisy Zeners for a voltage reference IMO.

Nice. Any measurements for us to compare to a purpose-designed voltage reference driven by a CS? I would be interested in Zout over freq and nosie levels.

Note to Phisci: this is also a reference build from a current into a resistor, but the difference with your idea is that here there is a negative feedback loop that modifies the current source 'strength' to compensate for reference changes with load changes (and a few other things), and thereby stabilizes the ref voltage.

jan