Circuits and Systems

Circuits and systems research encompasses the analysis, design and implementation of interconnected electrical and electronic components that process power and information. At its core lies the study of how voltages, currents and electromagnetic fields propagate through networks of resistors, capacitors, inductors and active devices, giving rise to desired signal-processing or power-conversion functions. Analogue circuits govern continuous signals and exploit feedback to achieve stability, bandwidth and linearity, while digital circuits encode information in discrete levels for computation and storage. Mixed-signal systems bridge these domains via data converters, enabling the capture of real-world phenomena and their manipulation by digital logic. In power-electronics applications, converter topologies and control techniques manage energy flow with high efficiency and fast transient response. On a larger scale, electrical-network models address system-level stability, modal behaviour and the integration of renewable sources. Advances in semiconductor technologies and in compact, low-loss passive components continue to expand the performance envelope of circuits and systems, driving innovations from portable electronics to smart grids and autonomous sensors.

Research from Nature Portfolio

A new method employs voiceprint analysis to extract time–frequency singular-value features from acoustic emissions of high-voltage circuit breakers. By integrating an improved S-transform with singular-value decomposition and support-vector-machine modelling, this approach achieves over 92 % accuracy in identifying faults under varying operating conditions, demonstrating the potential of non-intrusive acoustic diagnostics. In a separate study, a hybrid energy and leakage-current monitoring system has been developed for electrical appliances. It combines rule-based classifiers with multiclass support-vector machines to distinguish normal operation, overcurrent faults and leakage-current anomalies. The system relies on remotely-collected mains measurements and long-range communication, offering a scalable platform for real-time safety monitoring without per-appliance sensors.

Research from all publishers

Ultrafast transient control in buck converters has been realised by embedding transient-acceleration loops and V-cubic frequency-stabilisation techniques. Fabricated in 0.18 µm BCD, the design achieves a recovery time of 1.6 µs, overshoot and undershoot below 20 mV, and peak efficiencies exceeding 90 %. This work combines optimum-damping control, slope-compensation circuitry and adaptive on-time logic to minimise voltage excursions under rapid load changes.

Wave digital filter (WDF) structures have been extended to model rate-dependent hysteresis in magnetic components by encapsulating recurrent neural-network based scattering relations into one-port blocks. This data-driven WDF approach retains passivity and real-time performance, enabling accurate emulation of nonlinear transformer behaviour in virtual-analogue audio applications.

At millimetre-wave frequencies, a fully integrated 24 GHz frequency-modulated continuous-wave radar transceiver has been demonstrated in 65 nm CMOS. It features a fractional-N PLL with programmable chirp generation, a bridged attenuator for precise gain control, and a direct-conversion I-Q receiver with noise-cancelled low-noise amplifiers, mixers and biquad filters. The monolithic design delivers 13 dBm output power, 100 dB receiver gain, and consumes 220 mW in a 4.8 mm² die, illustrating the trend towards compact, high-performance radar front ends.

Circuits and Systems publication trend

The graph below shows the total number of articles in circuits and systems across all publications each year (not limited to Nature Index journals).

Technical terms

Feedback: A mechanism by which a portion of a circuit’s output is routed back to its input to regulate gain, bandwidth or stability.

Buck converter: A step-down DC–DC topology that uses a switch, inductor and capacitor to regulate output voltage efficiently.

Wave Digital Filter (WDF): A digital emulation framework that maps analogue circuits into lossless digital structures using wave variables and scattering junctions.

Frequency-modulated continuous-wave (FMCW): A radar technique where the transmit frequency is varied linearly over time to measure range and velocity via beat-frequency detection.

S-transform: A time–frequency analysis tool that generalises the short-time Fourier transform with frequency-dependent resolution.

Support-vector machine (SVM): A supervised learning classifier that separates data by maximising the margin between classes in a high-dimensional feature space.

References

1. Research on fault identification of high-voltage circuit breakers with characteristics of voiceprint information. Scientific Reports (2024).
2. An energy and leakage current monitoring system for abnormality detection in electrical appliances. Scientific Reports (2022).
3. A New Improved Ultra-Fast-Response Low-Transient-Voltage Buck Converter With Transient-Acceleration Loops and V-Cubic Techniques. IEEE Access (2022).
4. Deep learning-based wave digital modeling of rate-dependent hysteretic nonlinearities for virtual analog applications. EURASIP Journal on Audio, Speech, and Music Processing (2023).
5. Fully Integrated 24-GHz 1TX-2RX Transceiver for Compact FMCW Radar Applications. Sensors (2024).