Electrical circuit for producing controlled high voltage AC output

Claim 1

A power supply for producing high voltage AC output power at a relatively low base frquency from relatively low voltage DC input power, comprising: a pulse-width modulated inverter for converting the DC input power to a pulse width modulated power signal, said inverter chopping the DC input power at a frequency relatively high with respect to the base frequency; a voltage step-up transformer having high inductive and capacitive reactance at the chopping frequency, said transformer including a primary winding connected to said inverter for receiving said power signal and a secondary winding for developing the high-voltage AC output power, the reactance of said transformer serving to filter the high-frequency component of said power signal while raising to high voltage the base frequency component of said power signal; means for sensing the voltage magnitude of said AC output power and for generating a voltage signal representative thereof; a reference voltage source for producing a reference voltage representative of a desired voltage magnitude of the AC output power; and means for comparing said voltage signal to said reference voltage, said comparing means providing a signal to said inverter for varying the duty cycle of said power signal as a function of the difference between the magnitude of said reference voltage and the magnitude of said voltage signal thereby to adjust said voltage magnitude of said AC output power in a manner to minimize said difference.