US Patent 11942309 Bias supply with resonant switching

Bias supplies and plasma processing systems are disclosed. One bias supply comprises an output node, a return node, and a power section coupled to the output node and the return node. A resonant switch section is coupled to the power section at a first node, a second node, and a third node wherein the resonant switch section is configured to connect and disconnect a current pathway between the first node and the second node to apply an asymmetric periodic voltage waveform at the output node relative to the return node. The asymmetric periodic voltage waveform includes a first portion that begins with a first negative voltage and changes to a positive peak voltage, a second portion that changes from the positive peak voltage level to a third voltage level and a fourth portion that includes a negative voltage ramp from the third voltage level to a fourth voltage level.