RSFQ Synchronous Gate Structure for Single-Cycle Complex Logic
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Solution Overview
Problem
Rapid Single Flux Quantum (RSFQ) logic circuits require clock input signals for even static gates, limiting the number of logic functions that can be performed within a clock cycle and preventing the implementation of complex gates within a single clock cycle, which restricts their high-speed and low-power consumption potential.
Innovation Solution
Implementing complex logic gates using a combination of synchronous and asynchronous logic gates, where synchronous gates provide inputs to an asynchronous gate without a clock signal, allowing for the operation of complex functions within a single clock cycle, reducing clock latency and circuit size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional synchronous logic gates are implemented in RSFQ logic with clock input signals to each stage, then synchronous operation is achieved, but the number of clock stages increases and circuit complexity increases
Solution Approach 1:
The patent segments the logic circuit into two distinct parts: synchronous logic gates that require clock signals for reliable operation, and asynchronous logic gates that do not require clock signals. This segmentation allows each type of gate to operate optimally according to its requirements, reducing overall circuit complexity while maintaining synchronous operation where needed.
Solution Approach 2:
The patent introduces asynchronous logic gates as intermediaries between synchronous logic stages. These asynchronous gates receive inputs from synchronous gates and can drive subsequent synchronous gates, acting as a mediator that reduces the need for clock signals at every stage and thereby reducing circuit complexity.
2Reliability
If conventional synchronous logic gates are implemented in RSFQ logic with clock input signals to each stage, then synchronous operation is achieved, but clock speed is limited to around 10 GHz
Solution Approach 1:
By segmenting the circuit into synchronous and asynchronous sections, the patent allows the asynchronous sections to operate without clock signal constraints, enabling faster operation beyond the 10 GHz limit that constrains fully synchronous designs.
Solution Approach 2:
The patent introduces dynamic operation modes where logic gates can switch between synchronous and asynchronous operation depending on the specific logic function being performed. This dynamic approach allows the circuit to optimize speed for critical paths while maintaining synchronous reliability where needed.
3Productivity
If complex logic functions are implemented within a single clock cycle in RSFQ logic, then clock latency is reduced and productivity is improved, but the circuit requires more clock stages and larger layout size
Solution Approach 1:
The patent uses asynchronous logic gates as intermediaries that can process complex logic functions without requiring additional clock stages. These asynchronous gates handle the complexity internally, allowing the circuit to maintain a compact layout while achieving high productivity through reduced clock latency.
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
Enables the implementation of complex logic functions at clock speeds exceeding 10 GHz, reducing clock stages and circuit layout size by allowing complex operations within a single clock cycle, thereby enhancing the performance of RSFQ logic circuits.
Implementation Method 1
A Josephson junction (JJ) is a quantum mechanical device that includes two superconducting materials with another non-superconducting material (e.g., dielectric, metal, semiconductor, ferromagnet) sandwiched between them. A Josephson junction switches or generates flux when current passes through it.
Implementation Method 2
Superconducting integrated circuits are based on Josephson-junction technologies. A Josephson junction (JJ) is a quantum mechanical device that includes two superconducting materials
Data Source
AI summary
A superconducting multi-stage synchronous logic circuit structure includes a first clocked logic gate, a second clocked logic gate, and an unclocked logic gate. Each of the logic gates includes Josephson junctions. The first clocked logic gate has a single first clocked logic gate output; the second clocked logic gate has a single second clocked logic gate output. The unclocked logic gate has a first input connected in electrical communication with the first clocked logic gate output and has a second input connected in electrical communication with the second clocked logic gate output, and has a single output. The Josephson junctions of the unclocked logic gate are arranged such that, in a single clock cycle that drives the first clocked logic gate and the second clocked logic gate, the unclocked logic gate produces a single signal in response to the inputs of the first and second clocked logic gates.