Current-Mode RF Pulse Generator Path for Low-Distortion Qubit Control
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Solution Overview
Problem
Quantum computing systems face challenges with high power consumption and distortion in signal generation due to voltage mode representations, leading to reduced coherence time of qubits and inefficiencies in scaling quantum systems.
Innovation Solution
Implementing a current-mode end-to-end signal path from the digital to analog converter (DAC) through the output stage, utilizing PMOS switching transistors and a current subtractor with a diode-connected transistor, to reduce power consumption and enhance linearity, allowing for current reuse and adjustable gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If voltage mode representations are used in signal generation, then the signal generation function is achieved, but power consumption is high and distortion occurs
Solution Approach 1:
The patent replaces voltage mode signal generation with current mode signal generation throughout the signal chain. This substitution fundamentally changes the operating mode from voltage-based to current-based, enabling lower power consumption and reduced distortion by eliminating the need for high voltage swings and reducing capacitive loading effects that cause distortion in voltage mode systems.
Solution Approach 2:
The patent changes the fundamental parameter representation from voltage to current throughout the signal path. By using current mode representations instead of voltage mode, the system achieves lower power consumption (P=IV vs P=V²/R) and reduced distortion, as current mode operation naturally provides better linearity and lower sensitivity to parasitic capacitances.
2Productivity
If n-type metal-oxide semiconductor (NMOS) switching transistors are used, then switching performance is achieved, but power consumption increases
Solution Approach 1:
The patent changes the transistor type from NMOS to PMOS for the switching transistors in both the DAC and upconverting mixer. PMOS transistors have higher threshold voltages and lower leakage currents compared to NMOS, resulting in lower dynamic power consumption while maintaining adequate switching performance for the application requirements.
3Stability of the object's composition
If static-to-dynamic current ratio is high at the output stage, then bias stability is maintained, but power efficiency decreases
Solution Approach 1:
The patent segments the current path by introducing a current subtractor that separates the static bias current from the dynamic signal current. The current subtractor removes the static component before it reaches the output stage, allowing the output stage to operate with lower static current while maintaining bias stability through the filtered dynamic current component, thereby improving power efficiency.
Solution Approach 2:
The patent extracts and removes the static bias current component from the signal path using the current subtractor. By taking out the static component separately, the output stage receives primarily dynamic current, reducing the static-to-dynamic current ratio and improving power efficiency while the static bias is maintained independently for stability.
Data Source
AI summary
One or more systems, devices and/or methods of use provided herein relate to a device that can support a signal generation. A current-mode end-to-end signal path can include a digital to analog converter (DAC) operating in current-mode and an upconverting mixer, operating in current-mode and operatively coupled to the DAC. Analog inputs and outputs of the DAC and upconverting mixer can be represented as currents, and the DAC can generate a baseband signal. The DAC and upconverting mixer each can comprise switching transistors of the same type, such as p-type metal-oxide semiconductor (PMOS) switching transistors. In one or more embodiments, a current source and a diode-connected transistor can be arranged in parallel in the current-mode signal path, and the current source passes a static current, while the diode-connected transistor passes both a static current and a dynamic current.