Cryogenic Power Converter Layout for Low-Leak Quantum Circuits
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Solution Overview
Problem
Existing quantum computing circuits face challenges due to thermal leaks and parasitic capacitance/inductance from power bus wires, limiting their operation at low temperatures and accessibility.
Innovation Solution
A power supply system is integrated within the cryogenic chamber, using high-voltage power transfer and localized power converters to minimize thermal leaks and parasitics, with through-silicon vias and fusion bonding for efficient power delivery to quantum circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power bus wires are used to supply power from external environment to cryogenic environment, then power delivery is achieved, but thermal leaks are introduced into the cryogenic environment
Solution Approach 1:
A cryogenic-rated DC-DC converter is introduced as an intermediary device within the cryogenic chamber to convert power locally. This eliminates the need for long power bus wires extending from the external environment, thereby removing the thermal leak pathway while still achieving power delivery to the quantum computing circuit through localized power conversion.
Solution Approach 2:
The power delivery system is segmented into two parts: a power source outside the cryogenic chamber and a DC-DC converter inside the chamber. This segmentation allows the power conversion function to be performed locally within the cryogenic environment, reducing thermal leaks by minimizing the physical connection between warm and cold environments.
2Length of stationary object
If long power bus wires are used, then power delivery distance is increased, but parasitic capacitance and inductance increase
Solution Approach 1:
The DC-DC converter acts as an intermediary that receives power through a short connection and converts it locally. This eliminates the need for long power bus wires, thereby removing the source of parasitic capacitance and inductance that would otherwise be present in extended wire configurations.
Solution Approach 2:
The power delivery architecture transitions from a direct linear wire connection to a localized conversion approach. By placing the converter within the cryogenic chamber, the system changes the dimensional relationship between power source and load, reducing the physical distance and associated parasitics.
3Temperature
If quantum computing circuits are directly coupled to cold head, then low temperature operation is achieved, but accessibility to circuit is limited
Solution Approach 1:
The quantum computing system is segmented into the quantum circuit on the cold plate and separate control/readout electronics in the warm environment. This allows the quantum circuit to operate at ultra-low temperatures while maintaining accessibility through standardized interfaces and modular architecture.
Solution Approach 2:
A DC-DC converter and associated interface circuits serve as intermediaries between the cold quantum circuit and warm control systems. These intermediaries enable accessibility and control while allowing the quantum circuit itself to remain directly coupled to the cold head for optimal temperature 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
Reduces thermal leakage and parasitic effects, enabling efficient and responsive power delivery to quantum circuits, enhancing their operation at cryogenic temperatures.
Implementation Method 1
A circuit board (CB) includes a power converter configured to convert input power received from a cryogenic chamber feedthrough to one or more DC voltages
Implementation Method 2
The EC die includes at least one through silicon via that couples the output power from the power converter to the QC die
Implementation Method 3
In some embodiments the QC die and the EC die are fusion bonded together
Data Source
AI summary
A quantum device includes a cryogenic chamber and a quantum computing module positioned within the cryogenic chamber. The quantum computing module includes a silicon substrate and a quantum circuit (QC) die including a qubit integrated circuit. The QC die is attached to the silicon substrate. An electronic circuit (EC) die including an electronic integrated circuit is attached to the QC die such that the qubit integrated circuit and the electronic integrated circuit face each other. The QC die can be fusion bonded to the EC die. A circuit board (CB) includes a power converter configured to convert input power received from a cryogenic chamber feedthrough to output power that is coupled to the QC die and to the EC die.