Switching mode power supply using saturable reactors

Claim 1

A switching mode power supply comprising: means for producing an output voltage having a controlled relationship to a dc input voltage applied across a positive terminal and a negative terminal; means for sensing a variation in the output voltage from a desired value; means for producing a control signal in response to said variation in said output voltage from a desired value; a first and a second saturable reactor means connected to receive said input voltage, said first saturable reactor means being arranged to receive a signal representing said input voltage on said positive terminal while said second saturable reactor means is disconnected from said negative terminal and said second saturable reactor means being arranged to receive a signal representing the negative of said input voltage on said negative terminal while said first saturable reactor means is disconnected from said positive terminal; means for switching so as to connect cyclically and repetitively said first saturable reactor means to said positive terminal while said second saturable reactor means is disconnected from said negative terminal and to connect said second saturable reactor means to said negative terminal while said first saturable reactor means is disconnected from said positive terminal; means for passing said control signal through said first saturable reactor means and said second saturable reactor means thereby to control the flux in said first saturable reactor means and said second saturable reactor means at the beginning of the connection of said first saturable reactor means to said positive terminal and at the beginning of the connection of said second saturable reactor means to said negative terminal thereby to control the time necessary for said first saturable reactor means and said second saturable reactor means to saturate and thereby to control the time during which current is applied to the load of the structure and thus control the output voltage of the structure to a desired value; wherein said means for producing said control signal includes an inductor comprising a secondary winding on a core said core having a primary winding connected in series with a parallel connected load resistor and filter capacitor; and means for introducing a control voltage in series with both said secondary winding and said means for passing said control signal through said first saturable reactor means and said second saturable reactor means thereby to generate said control signal as the difference between said control voltage and the voltage on the secondary winding of said inductor, thereby to allow the initial flux in the first and second saturable core to be varied in response to a change in the current through the primary winding of said inductor.