Zhenghao Lu

A CMOS temperature sensor targeting automotive and industrial applications is presented. The sensor integrates a BJT-based sensing frontend with a second-order $\Sigma \Delta$ ADC. To address the accumulation of common-mode error in the integrator under low supply voltages, which can lead to large input common-mode deviations that reduce the integrator amplifier gain and degrade the ADC SNR, a novel sampling scheme is proposed. By means of a carefully designed sampling sequence, the proposed scheme maintains the amplifier input common-mode voltage within a small and predictable range, thereby stabilizing the amplifier gain and preventing SNR degradation. In addition, the sampling scheme reduces the number of ADC input branches, which effectively minimizes leakage current. To further enhance the measurement accuracy, a finite BJT current-gain compensation resistor and a bitstream-controlled dynamic element matching (BSC-DEM) technique are employed in the sensing frontend. Fabricated in a 180 nm CMOS process, the prototype achieves an inaccuracy of $\pm$1.0 °C (3$\sigma$) from −50 °C to 150 °C. The sensor consumes 6.3 μA from a 1.8 V supply at room temperature, achieves a resolution of 0.018 °C, and occupies an active area of 0.1 mm$^{2}$.

This paper presents a project‐based learning approach to improve students' ability to apply systematic design methodologies during their transition from general Electrical Engineering (EE) courses to Integrated Circuit (IC) design programs. With the advent of Electronic Design Automation (EDA) tools and Artificial Intelligence (AI) techniques, there is a growing need for students to develop a more systematic understanding of circuit design. A structured training program is designed to enhance the ability of mixed IC design of fourth‐year students, who are expected to use open source tools to design key circuit components which are aligned with MATLAB. With these components, the mixed signal system can be built and optimized top‐down, allowing significantly accelerated development and deeper knowledge learning. A team of students is required to design MATLAB‐aligned circuit components and a benchmark testing framework is developed to ensure the alignment of functionality between the proposed work and MATLAB Simulink. The results indicate that the proposed project‐based learning approach effectively supports fourth‐year students in transitioning to IC design, with strong recommendations for its continued implementation in future academic years. The project establishes a comprehensive and free EDA framework for teaching mixed signal IC design, offering significant advantages over traditional commercial tools. Moreover, the use of hardware‐defined code provides greater flexibility in the design environment, allowing students to utilize the EDA framework across multiple platforms without the need for expensive commercial licenses.

As a fundamental component of inertial measurement, micro electromechanical systems (MEMS) gyroscopes are extensively utilized in industrial robotics, drones, and personal navigation systems. Triaxial MEMS gyroscopes, capable of simultaneously measuring angular rates along three axes and providing three-dimensional orientation, have garnered significant attention in recent years. This paper presents three contemporary integration methods for triaxial MEMS gyroscopes: 3D integration of three single-axis gyroscopes, the monolithic single-structure triaxial gyroscope, and the monolithic multi-structure gyroscope array. Furthermore, the methods are compared and analyzed, discussing their respective advantages and disadvantages, while the future applications and development trends of triaxial MEMS gyroscopes are explored.

This article presents an ultrasound analog front-end (AFE) circuit featuring continuous time-gain compensation (TGC) based on a variable-gain current amplifier (VGCA). The AFE comprises a class-AB input current buffer and a current gain stage realized by the translinear (TL) loop principle. The gain of the gain stage is precisely controlled by a novel exponential current generator to achieve the dB-linear gain characteristic. The proposed AFE is fabricated in a 0.13- $\mu $ m CMOS technology with a core area of 0.08 mm². The measurement results show that the VGCA has a dB-linear gain range of 37.3 dB with a gain error of less than ±0.7 dB. Within the gain range, the VGCA consumes an average power of 0.65 mW from a 1.2V supply, with a minimum bandwidth of 1.61 MHz.

A novel low-power MOS-only voltage reference is presented. The Enz-Krummenacher-Vittoz (EKV) model is adopted to provide a new perspective on the operating principle. The normalized charge density, introduced as a new variable, serves as an indicator when trimming the output temperature coefficient. The proposed voltage reference consists of a specific current generator and a 5-bit trimmable load. Thanks to the well-match between the current source stage and the output stage, the non-linear temperature dependence of carrier mobility is automatically canceled out. The circuit is designed in 55 nm COMS technology. The operating temperature ranges from -40 ∘C to 120 ∘C. The average temperature coefficient of the output voltage can be reduced to 21.7 ppm/∘C by trimming. The power consumption is only 23.2 nW with a supply voltage of 0.8 V. The line sensitivity and the power supply rejection ratio at 100 Hz are 0.011 %/V and -89 dB respectively.

In this paper, an event-driven wireless sensor node is proposed and demonstrated. The primary design objective is to devise a wireless sensor node with miniaturization, integration, and high-accuracy recognition ability. The proposed wireless sensor node integrates two vibration-threshold-triggered energy harvesters that sense and power a threshold voltage control circuit for power management, a microcontroller unit (MCU) for system control, a one-dimensional convolutional neural network (1D-CNN) environment data analysis and vibration events distribution, and a radio frequency (RF) digital baseband transmitter with IEEE 802.15.4-/.6 protocols. The dimensions of the wireless sensor node are 4 × 2 × 1 cm³. Finally, the proposed wireless sensor node was fabricated and tested. The alarming time for detecting the vibration event is less than 6 s. The measured recognition accuracy of three events (knock, shake, and heat) is over 97.5%. The experimental results showed that the proposed integrated wireless sensor node is very suitable for wireless environmental monitoring systems.

In this paper, the design methodology of a high-linearity wide-band transimpedance amplifier (TIA) for cable television (CATV) application is addressed. A simple four-stage topology is proposed to maintain a well-balanced linearity over a wide operating band. The regulated cascode (RGC) input stage is used to match an input impedance of 75 Ω, followed by a gain stage with enhanced bandwidth. The high-linearity output stage is able to drive the 75 Ω load directly with high output swing under a high supply voltage. The prototype is implemented with a standard 0.11μm CMOS process while occupying the silicon area of 0.034 mm ² . The measurement results for the prototype show a peak gain of 76.6 dBΩ over a 3-dB bandwidth of 1.1 GHz with a considerably small gain ripple and an OIP ₃ of 20.4 dBm. The whole test chip consumes 447 mW DC power and the measured average input-referred noise current spectral density is 7.9 pA Hz ^−1/2 up to 1 GHz.