# US 12,763,301 B2 · Capacitance as control of power applied by a bias-power-supply > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,763,301 B2 - Document ID: US12763301B2 - Status: Granted - Kind: B2 - Application number: 18/096,478 - Filed: 2023-01-12 - Published: 2024-07-18 - Granted: 2026-10-13 - Earliest claimed: 2023-01-12 - Assignees: Advanced Energy Industries, Inc. - Applicants: Advanced Energy Industries, Inc. - Inventors: Hien Minh Nguyen; Daniel Carter - Web page: https://patentgrep.com/patent/US12763301B2 ## CPC - H01J 37/3299: {Feedback systems} - H01J 37/32935: {Monitoring and controlling tubes by information coming from the object and/or discharge} - H01J 37/32174: {Circuits specially adapted for controlling the RF discharge} - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract A bias supply system and methods are disclosed. The bias supply system comprises an output node, a return node, and a bias supply configured to apply an asymmetric periodic voltage waveform between the output node and the return node. A variable capacitance is coupled between the output node and the return node, and a controller is coupled to the variable capacitance. The controller is configured to receive a setting that defines a slope of a workpiece voltage, monitor electrical parameters at the output node to obtain an indication of an actual slope of the workpiece voltage, and control the variable capacitance so the actual slope of the workpiece voltage approaches the slope defined by the setting. ## Claims ### Claim 1 An apparatus to produce a waveform, the apparatus comprising: a first node; a switch configured to apply a peak voltage of the waveform to the first node before a voltage step of the waveform is applied to the first node; a power supply coupled to the first node to apply, after the voltage step, a ramped voltage of the waveform at the first node; and a capacitor coupled to the first node and a second node. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the capacitor is a variable capacitor. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the capacitor comprises: a first variable capacitor coupled between the first node and the second node; and a series combination of a second capacitor and a dissipation resistor coupled between the first node and the second node. ### Claim 4 (depends on 2) The apparatus of claim 2, comprising: a controller configured to adjust the variable capacitor to adjust the ramped voltage. ### Claim 5 (depends on 1) The apparatus of claim 1, comprising a housing enclosing the switch, the power supply, and the capacitor. ### Claim 6 A system for producing a waveform comprising: a bias supply configured to apply an asymmetric periodic voltage waveform to a first node, the asymmetric periodic voltage waveform comprising a peak voltage, a voltage step following the peak voltage, and a ramped voltage; and a capacitor coupled between the first node and a second node. ### Claim 7 (depends on 6) The system of claim 6, wherein the capacitor comprises a variable capacitor coupled between the first node and the second node. ### Claim 8 (depends on 7) The system of claim 7 comprising: a controller coupled to the variable capacitor, the controller configured to: monitor one or more electrical parameters at the first node; and control the variable capacitor to control the ramped voltage. ### Claim 9 (depends on 8) The system of claim 8, wherein the controller is configured to control the variable capacitor and a frequency of the asymmetric periodic voltage waveform to control the ramped voltage. ### Claim 10 (depends on 9) The system of claim 9, wherein the controller is configured to: initially adjust a frequency of the asymmetric periodic voltage waveform to control the ramped voltage; and adjust the variable capacitor if adjusting the frequency does not achieve a desired ramped voltage. ### Claim 11 (depends on 8) The system of claim 8, wherein the controller is configured to: receive a synchronization signal and set a frequency of the asymmetric periodic voltage waveform to a synchronization frequency indicated by the synchronization signal; and control the variable capacitor to control the ramped voltage. ### Claim 12 (depends on 6) The system of claim 6, wherein the capacitor is located outside of a housing of the bias supply. ### Claim 13 (depends on 6) The system of claim 6, wherein the capacitor is located inside of a housing of the bias supply. ### Claim 14 (depends on 6) The system of claim 6, wherein the capacitor comprises: a first variable capacitor coupled between the first node and the second node; and a series combination of a second capacitor and a dissipation resistor coupled between the first node and the second node. ### Claim 15 (depends on 6) The system of claim 6, wherein the bias supply comprises: a switch configured to apply a peak voltage of the waveform to the first node before a voltage step of the waveform is applied to the first node; a power supply coupled to the first node to apply, after the voltage step, a ramped voltage of the waveform at the first node; and a capacitor coupled to the first node and a second node. ### Claim 16 (depends on 7) The system of claim 7, comprising: a series combination of a second capacitor and a dissipation resistor coupled between the first node and the second node. ### Claim 17 (depends on 7) The system of claim 7 comprising: a controller coupled to the variable capacitor, the controller configured to: monitor one or more electrical parameters at the first node; and control the variable capacitor to control the ramped voltage. ### Claim 18 (depends on 15) The system of claim 15, comprising a housing enclosing the switch and the power supply, wherein the capacitor is located outside of the housing. ### Claim 19 (depends on 15) The system of claim 15, comprising a second switch coupled to the first node via a diode, a combination of the second switch and the diode is configured to apply the voltage step. ### Claim 20 (depends on 15) The system of claim 15, wherein the switch comprises a plurality of switches configured to be synchronously driven to open and close simultaneously.