Integrated circuit high voltage DC converter

Claim 1

A high voltage DC converter comprising: a low voltage DC supply; a rectangular wave oscillator of constant duty cycle comprising a high current silicon transistor connected to said supply and controlled for oscillation or non-oscillation by the condition of a control signal applied thereto; a two-winding high voltage step-up transformer matched to the duty cycle of said oscillator; power amplifier means having an input circuit driven by said oscillator and an output circuit connected through the primary winding of said transformer to said supply; a voltage comparator having switching hysteresis; a reference voltage source derived from said supply; means for applying a constant voltage derived from said reference voltage source and a voltage representative of the output voltage from the secondary winding of said transformer to control switching in said voltage comparator to selectively provide a high voltage condition or a low voltage condition at the output of said comparator in response to the relative magnitudes of said applied voltages, and means for coupling the switching output of said comparator as said control signal to control on-off switching of said oscillator, said oscillator and said power amplifier are switched to be inactive at substantially low current condition for the high voltage output condition of said comparator, wherein said oscillator, said power amplifier, said reference voltage source and said comparator comprise a single chip silicon integrated circuit with an oscillator terminal and a power amplifier output terminal and including: frequency controlling circuit means connected to said oscillator terminal; and a circuit connecting to said primary winding from one terminal of said DC supply to said output terminal.