Patent ID: 8866400

Claim:
A plasma supply device comprising: an inverter connected to a DC power supply, wherein the inverter has at least one switching element, and wherein the inverter is configured to convert DC power from the DC power supply into AC power greater than 500 W at an essentially constant basic frequency greater than 3 MHz; and an output network comprising an input and an output, the input being electrically coupled to the inverter, the output being electrically coupled to a plasma load, wherein the output network is configured to provide the AC power from the inverter to the plasma load and filter reflected power that is returned from the plasma load, and wherein the output network includes a transformer comprising primary and secondary windings, and the capacitance formed by one or more conductor paths between one or more turns of the secondary winding of the transformer, together with the inductance of the secondary winding, forms an LC filter of the output network; wherein the output network includes an inductance that has a magnetic field strengthening element that is a Perminvar ferrite, and wherein the magnetic field strengthening element encloses the inductance.