SFQ Logic Biasing Circuit Without Feeding JTL
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Solution Overview
Problem
Current superconducting SFQ circuitry, particularly ERSFQ, faces challenges with high power dissipation and complex biasing circuitry due to the need for significant operating current and circuit area, which limits energy efficiency and scalability.
Innovation Solution
The use of a Josephson junction as a current source with a resistor to ground replaces the conventional feeding Josephson Transmission Line (JTL), reducing power dissipation and circuit complexity by eliminating the need for inductors and additional Josephson junctions, thereby minimizing chip area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a feeding Josephson Transmission Line (JTL) is used to implement on-chip voltage regulation, then voltage control precision is improved, but power dissipation and circuit area increase significantly
Solution Approach 1:
The patent extracts and eliminates the feeding JTL from the ERSFQ circuit architecture. By removing this complex voltage regulation component, the invention reduces power dissipation and circuit area while maintaining functionality through alternative biasing approaches using simple resistors and direct current sources.
Solution Approach 2:
The patent replaces the complex, expensive feeding JTL with simple, low-cost resistive biasing elements. These basic components achieve the necessary voltage control without the overhead of sophisticated regulation circuitry, effectively using simpler substitutes to resolve the contradiction.
2Measurement precision
If a feeding Josephson Transmission Line (JTL) is used to implement on-chip voltage regulation, then voltage control precision is improved, but device complexity increases
Solution Approach 1:
The patent removes the feeding JTL and its associated complex control logic from the circuit. This extraction simplifies the overall device architecture while maintaining essential voltage control functions through more straightforward biasing mechanisms.
Solution Approach 2:
Instead of using complex active regulation (feeding JTL) to control voltage, the patent inverts the approach by using simple passive resistive elements with direct current biasing. This inverted strategy achieves voltage control through fundamental circuit principles rather than sophisticated regulation.
3Ease of manufacture
If standard RSFQ logic is used, then ease of manufacture is improved, but power dissipation increases
Solution Approach 1:
The patent changes the operating parameters of SFQ logic by transitioning from resistive biasing (RSFQ) to a different biasing regime. This parameter change enables lower power dissipation while maintaining the superconducting logic functionality, effectively resolving the contradiction between manufacturing simplicity and energy efficiency.
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 results in a logic circuit with significantly reduced power dissipation and circuit area, achieving approximately 10 times lower power consumption and allowing for a smaller die size, while maintaining precise voltage control and reducing component count.
Implementation Method 1
a logic circuit including a first Josephson junction and a second Josephson junction. The first Josephson junction has a first critical current. The second Josephson junction has a second critical current
Data Source
AI summary
Disclosed herein are embodiments including electrical structures that includes a first cell, a first inductor, a first resistor, and a first shunted Josephson junction. The first inductor is connected in series with the first shunted Josephson junction at a first terminal end of the first inductor and a second terminal end of the first inductor is connected to a feed point of the first cell being powered. A first end of the first resistor having connected to ground and a second end being connected to the first shunted Josephson junction at a terminal of the first shunted Josephson junction that is not connected to the first inductor. A source of an electrical current source that is external to the first cell is connected to the first shunted junction and the first resistor at a common point.