Power supply for magnetron and the like loads

Claim 1

A power supply for energizing a self-rectifying load, through which a current flows only when a voltage of predetermined polarity and magnitude is exceeded thereacross, comprising: source means for providing an operating potential; a transformer having a single high-voltage secondary winding connected directly across said load and having an untapped primary winding having a mutual inductance to said secondary winding; a switching device having a controlled-current path coupled, as the only controllable device, in electrical series connection with said transformer primary winding across the operating potential of said source means, said switching device having an input terminal for receiving a periodic signal controlling the flow of current in said controlled-current path and said primary winding; unidirectional current flow means connected in parallel with said controlled-current path of said switching device for conducting to prevent a flow of current through the controlled-current path of said switching device in a reverse direction and for preventing application of voltages of improper polarity across said switching device; an electrical capacitance effectively connected in parallel across the mutual inductance of said transformer and resonant therewith at a predetermined first frequency; and circuit means for driving the input of said switching device with said periodic signal of magnitude sufficient to cause said controlled-current path to heavily conduct a flow of current therethrough commencing while said unidirectional current flow means is conducting and continuing during a first portion of a predetermined time interval; said circuit means providing said periodic signal at a second frequency less than said first frequency and causing said signal to terminate to abruptly end the flow of current through said controlled-current path at the end of said time interval first portion, to cause said capacitance to charge and apply a voltage aross said load causing said load to periodically conduct a flow of current therethrough at said second frequency and during another portion of said time interval after said first portion.