Superconductor-Semiconductor Readout Circuit for Current-to-Charge Conversion
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Solution Overview
Problem
There is a need for an efficient interface that can rapidly and with low energy convert supercurrents in superconducting wires to charge on a capacitor, enabling the integration of superconducting devices with conventional semiconductor electronics for signal readout.
Innovation Solution
A superconducting-semiconductor circuit that uses a transistor circuit to transduce current in a superconducting wire to charge on a capacitor, employing a nanocryotron gate element to detect a threshold value and switch the cryotron channel, allowing for low-noise readout and decoupling the current addition from the readout process, integrating Josephson junctions with MOSFETs for scalable and low-voltage signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional interface is used to convert supercurrent to charge, then the conversion can be achieved, but the process is slow and energy-consuming
Solution Approach 1:
The patent changes the operating parameters by using superconducting transistors that operate at low voltages and temperatures, enabling rapid charge conversion with minimal energy loss. The superconducting state allows for near-zero resistance operation, dramatically improving both speed and energy efficiency compared to conventional interfaces.
Solution Approach 2:
The patent replaces conventional semiconductor transistor mechanisms with superconducting transistor mechanisms. This substitution enables the system to exploit superconducting properties such as zero resistance and Josephson effects, achieving faster switching speeds and lower power consumption in the current-to-charge conversion process.
2Adaptability or versatility
If superconducting devices are integrated with conventional semiconductor electronics, then interface compatibility is achieved, but signal conversion efficiency is reduced
Solution Approach 1:
The patent introduces superconducting transistors as intermediary elements between superconducting devices and conventional semiconductor electronics. These transistors act as a bridge that maintains signal integrity while enabling efficient coupling, converting supercurrents to charges with minimal energy loss and preserving compatibility with conventional CMOS readout circuits.
Solution Approach 2:
The patent employs composite structures combining superconducting materials with semiconductor materials in the transistor fabrication. This composite approach allows the device to simultaneously exhibit superconducting properties for efficient signal processing and semiconductor properties for compatibility with conventional electronics manufacturing and readout.
3Productivity
If current pulses are added to the superconducting wire, then the signal is updated, but the readout process is limited by the pulse temporal extent
Solution Approach 1:
The patent segments the readout process from the signal accumulation process. Superconducting transistors accumulate current charges continuously in the superconducting wire, while the readout operation can be triggered independently at any time. This segmentation allows the readout to be decoupled from the temporal constraints of incoming current pulses, enabling flexible timing and faster overall operation.
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
This approach enables low-noise, scalable readout of superconducting current-storage elements, converting low-voltage superconductor signals to semiconductor-level voltages, facilitating integration with conventional silicon electronics and allowing for independent signal addition and readout processes.
Implementation Method 1
a cryotron switching element comprising a cryotron gate and a cryotron channel, wherein the cryotron switching element is positioned to receive the third current through the cryotron gate and a fifth current through the cryotron channel, wherein the cryotron switching element switches the cryotron gate and the cryotron channel from a superconducting state to a normal metal state at a threshold value of the third current
Implementation Method 2
In order for these circuits to interface with conventional semiconductor electronics, these currents must be converted into voltages that can be detected by semiconductor circuits
Data Source
AI summary
Embodiments of the present invention relate to a superconducting signal storage circuit for integrating and/or storing signals locally as current that can be stored indefinitely in a superconducting wire or inductor. Low-noise readout is accomplished through a transistor circuit that transduces the integrated current signal to a charge on a capacitor. A nanocryotron element generates a voltage across its channel when a sum of the integrated current and a ramp current applied by the transistor circuit reaches a threshold value. This generated voltage switches the gates of an inverter, which terminates the current flow to the capacitor. The accumulated charge on the capacitor is proportional to the current in the storage element that was present when the nanocryotron sensing gate switched from the superconducting state to the resistive state. The charge on capacitor is read by opening a transistor to provide an access line to the capacitor.