A high-voltage SFQ-to-DC driver for wide-range digital SQUID magnetometer based on flux quanta counting scheme

IF 1.3 3区物理与天体物理 Q4 PHYSICS, APPLIED

Physica C-superconductivity and Its Applications Pub Date : 2025-04-08 DOI:10.1016/j.physc.2025.1354708

Mengfei Zhao , Yongliang Wang , Pusheng Yuan , Shuna Wang , Lingyun Li , Lixing You

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引用次数: 0

Abstract

Superconducting quantum interference devices (SQUIDs) exhibit flux-modulated current–voltage characteristics and are widely used as magnetometers for ultra-low noise magnetic field measurements in biomagnetism and geophysics. Compared to the conventional flux-locked loop (FLL) readout scheme, the flux quanta counting (FQC) scheme offers a wider flux measurement range and a higher slew rate. The challenge of the FQC scheme lies in the matching of voltage levels and response speeds between the SQUID and room-temperature circuits. Typically, the FQC scheme utilizes an SFQ-to-DC converter (Q2D) for signal conversion. However, the output voltage of Q2D is only a few hundred microvolts, which prevents it from operating at high speeds and limits the slew rate of the magnetometer. Moreover, the low amplitude output of Q2D also increases the burden on the subsequent semiconductor amplifiers. Therefore, a high-voltage, high-speed SFQ-to-DC driver is essential for the application of FQC schemes. We developed an SFQ-to-DC driver with high voltage output for the asynchronous FQC scheme. This driver is designed to capture voltage pulses from the DC-SQUID and convert them into DC voltages for reading by semiconductor digital devices. The asynchronous FQC scheme based on this driver was introduced and simulated, and the quantized flux counting signal closely matches the input flux signal with a quantization error of

1 Φ_{0}

. The test results of the driver demonstrate an output swing of up to 6.9 mV and an operating speed of up to 15 Gbps. This is promising for the wide-range and high-slew-rate digital SQUID magnetometer for geophysics, which faces challenges in the airborne platform due to the Earth’s magnetic field.

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基于磁通量子计数方案的宽量程数字SQUID磁强计高压sfq - dc驱动器

超导量子干涉器件（squid）具有磁通调制的电流-电压特性，被广泛用作生物磁学和地球物理领域的超低噪声磁场测量磁强计。与传统的磁通锁定环路读出方案相比，磁通量子计数方案具有更宽的磁通测量范围和更高的转换率。FQC方案的挑战在于SQUID与室温电路之间的电压水平和响应速度的匹配。通常，FQC方案利用sfq - dc转换器（Q2D）进行信号转换。然而，Q2D的输出电压只有几百微伏，这阻碍了它在高速下工作，并限制了磁力计的摆速。此外，Q2D的低幅值输出也增加了后续半导体放大器的负担。因此，高压、高速的sfq - dc驱动器对于FQC方案的应用至关重要。我们为异步FQC方案开发了一种具有高压输出的sfq - dc驱动器。该驱动器设计用于从DC- squid捕获电压脉冲并将其转换为直流电压以供半导体数字设备读取。介绍了基于该驱动器的异步FQC方案并进行了仿真，量化磁链计数信号与输入磁链信号吻合较好，量化误差为1Φ0。测试结果表明，该驱动器的输出摆幅高达6.9 mV，运行速度高达15 Gbps。这对于大范围、高转速的数字SQUID地球物理磁强计来说是很有希望的，因为地球磁场对机载平台造成了挑战。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Physica C-superconductivity and Its Applications 物理-物理：应用

CiteScore

2.70

自引率

11.80%

发文量

102

审稿时长

66 days

期刊介绍： Physica C (Superconductivity and its Applications) publishes peer-reviewed papers on novel developments in the field of superconductivity. Topics include discovery of new superconducting materials and elucidation of their mechanisms, physics of vortex matter, enhancement of critical properties of superconductors, identification of novel properties and processing methods that improve their performance and promote new routes to applications of superconductivity. The main goal of the journal is to publish: 1. Papers that substantially increase the understanding of the fundamental aspects and mechanisms of superconductivity and vortex matter through theoretical and experimental methods. 2. Papers that report on novel physical properties and processing of materials that substantially enhance their critical performance. 3. Papers that promote new or improved routes to applications of superconductivity and/or superconducting materials, and proof-of-concept novel proto-type superconducting devices. The editors of the journal will select papers that are well written and based on thorough research that provide truly novel insights.