US 11,721,523 B2
Control of rail voltage in multi-level pulsing RF power amplifier
Chad S. Samuels, Fort Collins, CO (US)
Assigned to Advanced Energy Industries, Inc., Fort Collins, CO (US)
Filed by Advanced Energy Industries, Inc., Fort Collins, CO (US)
Filed on Sep. 7, 2021, as Appl. No. 17/468,412.
Prior Publication US 2023/0075152 A1, Mar. 9, 2023
Int. Cl. H01J 37/32 (2006.01); H03F 3/21 (2006.01)
CPC H01J 37/32174 (2013.01) [H03F 3/21 (2013.01); H03F 2200/451 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A generator comprising:
a control section comprising:
an RF driver;
an RF controller;
a DC driver; and
a DC controller;
a power generation section coupled to and configured to receive control signals from the control section, the power generation section comprising:
a DC section;
an RF power amplifier coupled to and configured to receive a variable rail voltage from the DC section; and
an output of the generator configured for coupling to a plasma processing chamber and delivering RF power to a nonlinear plasma load, wherein
the RF controller and the DC controller comprise one or more processing portions, one or more memories, and one or more modules stored on the one or more memories and executable on the one or more processing portions to:
for each state in an n-level waveform, raise the variable rail voltage if a target waveform requires a drive voltage of the RF power amplifier to equal or exceed a drive voltage threshold stored in the one or more memories, and make any state that causes the output of the DC section to rise, to become a master state;
at an end of each pulse, assign the master state to a previous state in a current pulse cycle of the target waveform having a greatest drive voltage of the RF power amplifier; and
for each state, check to see if a current state is the master state, and if so, instruct the DC section to lower its output if possible.