Integrated circuit high voltage DC converter

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.