Self-exciting push-pull inverter having reduced dielectric strength requirements

Claim 1

A self-exiciting push-pull inverter comprising: input means connectable to a DC source; a boosting transformer composed of an input coil having two input coil section connected at a center tap, the center tap being connected to said input means for receiving DC current from the DC source, an output coil for supplying power to a load and a feedback coil inductively coupled to said input coil so that an alternating voltage is generated across said feedback coil; and first and second switching elements each having a control electrode connected to said feedback coil to be alternatingly turned on and off in dependence on the direction of the voltage across said feedback coil, wherein current through one of the input coil sections is switched on and off by operation of said first switching element and current flow through the other one of said input coil sections is switched on and off by operation of said second switching element so that an alternating voltage is output from said output coil, said self-exciting push-pull inverter being characterized in that: said output coil of said boosting transformer comprises two output coil sections and a conductor section connecting said two output coil sections together and circuit-arranged so that said conductor section is at a negative potential of the DC source; said inverter further comprises at least one capacitor; and said output coil has two ends, each of which is an end of a respective output coil section, and the load is connectable between said two ends of said output coil, with said at least one capacitor in series between said output coil and the load, so that a voltage drop is created across said at least one capacitor and a voltage which is the difference between the sum of voltages generated in said two output coil sections and the voltage drop across said at least one capacitor is applied to the load, and a load current generated by the voltage applied to the load flows over a series path composed of said output coil, said at least one capacitor and the load, whereby said inverter has effective insulation and breakdown voltage characteristics.