Inverter using parallel connected series pre-regulator and a synchronized switch

Claim 1

A power supply for converting an unregulated direct current input voltage of relatively high value to at least one regulated output voltage of relatively low value, said supply comprising: first and second input terminals, the second terminal being a common terminal, said input voltage being applied between said first and second terminals; an inverter connected to said common terminal, said inverter having an input terminal, a control terminal and an output circuit, said regulated output voltage appearing in the inverter output circuit, said inverter producing a control voltage between said control terminal and said common terminal, said control voltage being a pulsating direct voltage containing periodically generated pulses; a series regulator connected to said common terminal and having an input terminal connected to said first terminal and an output terminal, said regulator responding to said input voltage to produce a constant direct voltage between said output terminal and ground; a resistor connected at one end to the output terminal of the regulator; a current carrying bus connected between the other end of the resistor and the input terminal of the inverter whereby current flows through said resistor producing a voltage drop thereacross and thereafter flows into the inverter to supply power thereto; and an electronic switch connected to said common terminal and coupled to said control terminal, said switch having a closed position at which it connects said first terminal to said bus whereby the current on said bus supplied via said resistor is augmented by the current on said bus supplied via said switch, said switch having an open position at which said augmented current is not present on said bus, said switch being placed in the open position whenever a pulse appears in said control voltage and thereafter is placed in the closed position when the pulse disappears and said voltage drop across said resistor is at least equal to a preselected value.