Switchable Reactor Circuit for Fast RF Impedance Matching

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Solution Overview

Problem

Existing impedance-matching arrangements in RF-excited plasma processes face challenges in rapidly matching impedance due to the rapid variability of reactances, leading to overloading and potential destruction of switching elements, especially when handling high currents and voltages.

Innovation Solution

A switchable reactance unit with a parallel switching arrangement, where each switching element is connected in series with an individual reactance, allowing simultaneous control to evenly distribute current and prevent overloading, using transistors like MOSFETs with body diodes to manage high voltages and currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple switching elements are connected in parallel to handle high currents, then the current handling capacity is improved, but the current distribution becomes uneven due to tolerance variations, leading to overloading and destruction of switching elements

Engineering Contradiction:

Improvecurrent handling capacityVSAvoidswitching element reliability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent divides the single large reactance into multiple smaller individual reactances, each connected in series with a switching element. This segmentation allows the total current to be distributed across multiple parallel branches, with each branch handling a portion of the total current. The individual reactances are designed to have matched impedance values, which helps ensure uniform current distribution among the parallel switching elements, preventing any single element from being overloaded.

Inventive Principle:

Principle #1Segmentation

2Speed

If reactances are dynamically adjusted to match rapid impedance changes, then the impedance matching speed is improved, but the switching elements are subjected to high voltage and current stress, causing potential destruction

Engineering Contradiction:

Improveimpedance matching speedVSAvoidswitching element durability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent incorporates individual reactances in series with each switching element before the high current and voltage conditions occur. These reactances act as protective elements that limit the current through each switching element and help distribute the voltage stress. This beforehand cushioning prevents the switching elements from being directly exposed to the full brunt of high voltage and current during rapid impedance adjustments, thereby preventing destruction while maintaining fast response capability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS12556153B2Switchable-reactor unit, variable reactor, high-frequency generator, and impedance adjustment assembly having a switchable-reactor unit

Publication Date: 2026.02.17 TRUMPF PATENTABTEILUNG

AI summary

A switchable reactance unit includes an RF terminal configured to connect to a transmission line for transmitting a signal at a frequency in a range of 1-200 MHz, and a switching arrangement comprising a plurality of switching elements used in parallel. Each switching element has a control terminal, and is connected to the RF terminal via at least one individual reactance assigned to the switching element and connected in series with the switching element. The switching elements are controllable or controlled via their control terminals in such a way that they switch simultaneously.