This circuit is the old and well-known NE555 integrated circuits based. DC to DC circuit is not complicated, little parts, and doing pretty much stable voltage. It produces with the 12V DC voltage of 30V to voltage. The NE555 constant operating frequency is set. The 3 pin voltage convert of 30V. D1- D4 and C1-C5 voltage tripler circuit. DC to DC converter is use in similar tube circuit.