Voltage Controlled Impedance Synthesizer Digital Switching
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Solution Overview
Problem
Existing impedance synthesizers face limitations in power and voltage handling capabilities due to the use of low-power semiconductor circuit elements, making it difficult and expensive to achieve high power or current control, especially in applications beyond instrument calibration.
Innovation Solution
A voltage-controlled impedance synthesizer is developed using a digital approach with multiple two-terminal impedance modules connected in series, where switches are controlled by analog-to-digital conversion and digital processing to provide monotonic and stepwise variable impedance values, allowing for high power efficiency and precise control of impedance, current, and power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional operational amplifiers and active analog devices are used in impedance synthesizer circuits, then the circuit can provide a wide range of impedance values for instrument calibration, but the power and voltage handling capabilities are limited
Solution Approach 1:
The impedance synthesizer is divided into multiple impedance modules, each containing several impedance elements that can be independently switched. This segmentation allows the system to achieve a wide range of impedance values through digital switching combinations while each individual element can be designed for high power handling, thus resolving the contradiction between versatility and power capability
Solution Approach 2:
The patent replaces traditional analog operational amplifiers and active devices with a digital switching architecture. Impedance values are synthesized by digitally controlling switches that connect passive impedance elements in series or parallel configurations. This substitution eliminates the power limitations of analog active devices while maintaining the ability to provide a wide range of impedance values through digital control
2Measurement precision
If more switches are added to increase the number of impedance steps, then the impedance control precision improves, but the device complexity and cost increase
Solution Approach 1:
Multiple impedance elements within each module are connected in series and can be switched together as a group. By merging the control of multiple elements through shared switches and using weighted impedance values across modules, the system achieves fine impedance resolution without requiring an individual switch for every possible impedance step, thus reducing overall complexity while maintaining precision
Solution Approach 2:
The patent uses multiple impedance modules with impedance elements arranged in series across different modules. This multi-dimensional arrangement allows the system to synthesize a large number of impedance values through the combination of switches in different modules, effectively increasing precision without linearly increasing the total number of switches required
Data Source
AI summary
A voltage controlled impedance synthesizer providing stepwise variable impedance values according to a prescribed function of the control voltage, said synthesizer comprises of one or more two-terminal impedance modules connected in series, in each impedance module one or more essentially identical two-terminal impedance elements connected in series, a corresponding number of switches to short out by selection none to all of the impedance elements in the impedance module, and said switches being controlled by the control voltage through analog-to-digital conversion and digital processing means. The values of the impedance elements between the impedance modules in ratios being uniquely defined according to the numbers of impedance elements in the impedance modules, the voltage controlled impedance synthesizer is controlled to provide monotonic and stepwise variable impedance values. Further, through the use of the voltage controlled impedance synthesizer, other electrical parameters such as current and power can be controlled according to any prescribed functions.