Circuits similar to this can be found in this section. This is from 1967 General Electric documentation. The main SCR must be fitted with a heat sink.
This circuit is from 1964 documentation but can be easily implemented based on current components....
This circuit, which can generate voltages up to 25 V, was found in the December 1992 issue of...
Found in National Semiconductor documentation from the 90's, this circuit has an output current of...