Impedance Matching Device Staggered Switch Timing
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Solution Overview
Problem
Existing impedance matching devices for high frequency power supplies experience unstable ON/OFF operations of semiconductor switches due to noise caused by electromagnetic coupling, particularly when multiple PIN diodes are controlled simultaneously.
Innovation Solution
An impedance matching device and method that includes a variable capacitor with series circuits of capacitors and semiconductor switches, a calculation unit to determine impedance or reflection coefficients, and a control unit to adjust the ON/OFF states of the switches, ensuring a time difference in control timing between switches to prevent interference and stabilize operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple PIN diodes are controlled to be turned on or off at the same time, then impedance matching adjustment speed is improved, but noise is superimposed on the electrodes due to electromagnetic coupling between choke coils, causing unstable ON/OFF operation
Solution Approach 1:
The patent applies periodic action by sequentially switching PIN diodes in a time-division manner rather than simultaneously. The control unit switches each PIN diode at different time points in a predetermined sequence, creating periodic switching actions that avoid electromagnetic coupling noise while maintaining efficient impedance matching adjustment.
Solution Approach 2:
The patent segments the simultaneous switching operation into multiple sequential switching operations. Instead of controlling all PIN diodes at once, the control unit divides the switching process into discrete time steps, controlling each PIN diode individually in sequence. This segmentation eliminates the electromagnetic coupling issue while preserving the overall impedance matching function.
2Ease of operation
If choke coils are used to separate DC voltage application circuit from high frequency signal electrodes, then DC voltage control is achieved, but electromagnetic coupling between choke coils causes noise interference
Solution Approach 1:
The patent uses periodic action to sequentially activate different PIN diodes connected to different choke coils at different time points. This time-division multiplexing approach allows DC voltage control capability while preventing simultaneous electromagnetic coupling noise from multiple choke coils.
Solution Approach 2:
The control unit acts as an intermediary that coordinates the switching timing between multiple PIN diodes and choke coils. By introducing this control intermediary, the system achieves DC voltage control while mediating the timing to prevent electromagnetic coupling noise.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents unstable ON/OFF operations by synchronizing the control timing of semiconductor switches, reducing noise interference and ensuring efficient impedance matching between high frequency power supplies and loads.
Implementation Method 1
a choke coil (inductor) is used to separate a DC voltage application circuit in a high frequency manner from an electrode to which a high frequency signal is applied
Implementation Method 2
a variable capacitor in which a plurality of series circuits of capacitors and semiconductor switches are connected in parallel
Implementation Method 3
The semiconductor switches are P-Intrinsic-N (PIN) diodes. The impedance matching device is configured to perform impedance matching by adjusting the capacitance of the variable capacitor by switching (turning on and off) the semiconductor switches
Data Source
AI summary
An impedance matching device includes: a variable capacitor in which a plurality of series circuits of capacitors and semiconductor switches are connected in parallel; a calculation unit that calculates an impedance or a reflection coefficient on the load side using information regarding impedance acquired from the outside; and a control unit that determines ON/OFF states to be taken by the semiconductor switches included in the variable capacitor using the impedance or the reflection coefficient calculated by the calculation unit and turns on or off the semiconductor switches based on the determined states. The control unit changes an ON/OFF control timing between one and another of the semiconductor switches.