Journal of Low Power Electronics and Applications

This paper introduces a novel analog-to-digital converter (ADC) employing a passive noise-shaping (NS) technique combined with a chopper-stabilized comparator, enhancing performance and reducing ripple factor while maintaining low power consumption. The NS architecture is built on a cascade-integrator feedforward (CIFF) structure, using both infinite- and finite-impulse response filters to minimize quantization and kT/C noise. Additionally, it employs a low-power two-stage chopper amplifier to compensate for the offset voltage and enhance system stability. Validated according to the 180 nm CMOS process, the proposed ADC has an effective number of bits of 10.6, a signal-to-noise-and-distortion ratio of 68.4 dB, and a signal-to-noise ratio of 59.33 dB. With a compact area of 0.17 mm2 and a power consumption of 650 µW from a 1.8 V supply, the proposal is well suited to biomedical sensor applications requiring strict accuracy and low energy consumption.

Accurate estimation of lithium-ion battery State of Health (SoH) is critical for emerging applications such as reconfigurable battery systems. Although data-driven machine learning methods are promising, they often rely on costly, time-intensive aging experiments and extensive feature engineering. This work proposes a lightweight SoH-prediction framework validated on both physics-informed synthetic aging data and the NASA battery aging dataset. We evaluated Random Forest (RF) and Feedforward Neural Network (FNN) models that use only a limited number of samples from an early segment of the raw discharge voltage curve as input. Results show that RF consistently outperforms FNN across input sizes in deterministic or noise-free environments, achieving an RMSE of 0.07% SoH using just 5 voltage samples. In inherently stochastic experimental data, however, FNN can achieve an RMSE 50% lower than RF (1.28 vs. 2.87), but requires 37× more mathematical operations per inference. These findings emphasize the predictive value of the early-discharge-voltage region and demonstrate that compact, low-feature-complexity models can deliver accurate SoH estimates. Overall, the approach supports a goal of combining informed synthetic data with limited real measurements to build robust, scalable SoH predictors, reducing dependence on labor-intensive degradation testing and feature-heavy pipelines.

The measurement of the magnetic field generated by a flowing current constitutes a non-invasive sensing technique for online energy consumption monitoring. In this work, based on the use of low-cost linear Hall effect sensors, a low-form-factor custom contactless ammeter probe is presented. The differential configuration of the sensor module and the subsequent fully digital programmability in range and sensitivity, together with the included self-calibration and compensation circuits for mismatching, managed by a microcontroller, allow for optimum detection for both continuous and mains current with a resolution of 10 mA for input ranges of 2 A. The proposed ammeter power consumption and measurement accuracy in different scenarios are tested, including the power monitoring of an IoT-based device, obtaining results matched to those featured by a commercial oscilloscope current probe, which validates its suitability and reliability as autonomous low-cost probe for portable contactless power monitoring.

This paper provides a comprehensive analysis of active frequency doubler architectures adopted for efficient generation of millimeter-wave (mm-wave) signals. The operational principles of each topology are explained to address a thorough comparison based on essential performance metrics such as conversion gain, power efficiency, and spectral purity. The review covers several topologies from the standard push–push (PP) doubler to its power-efficient evolution, the complementary push–push (CPP) doubler. Furthermore, this paper focuses on more recent and advanced topologies, including the complementary common gate capacitive cross-coupled (CCGCCC) doubler. Finally, this work proposes and evaluates an improved version of the CCCGCC doubler, offering insights into the state of the art and future directions in mm-wave frequency multiplication.

Distributed energy systems open up a vast field of research in power electronics. Local solar power generation requires DC-DC converters that adapt the energy generated by the panels to on-site distribution buses. In addition, the control of the power converter to obtain the maximum possible energy from the solar source is crucial for the correct deployment of these distributed grids. In this work, system-level solutions are proposed for this application as follows: On the one hand, the use of novel resonant forward-flyback converters allows for a higher energy density than that of a conventional flyback and more relaxed withstand voltages on the switching elements. On the other hand, the implementation of maximum power point tracking algorithms for solar energy using Edge AI enables the deployment of algorithms that maximize the energy obtained locally. These improvements are shown by means of a prototype demonstrator, using cutting-edge microcontrollers and the implementation of a DC-DC power converter based on the proposed topology.