Current Issue : January-March Volume : 2025 Issue Number : 1 Articles : 5 Articles
This paper presents a modified current-mode vertical-cavity surface-emitting laser (VCSEL) driver as a transmitter for short-range light detection and ranging (LiDAR) sensors, where a stable bias generator is suggested with a regulated cascode current mirror circuit to provide the bias current of 1 mA with a trivial deviation of 5.4%, even at the worst-case process–voltage–temperature (PVT) variations. Also, a modified current-steering logic circuit is exploited with N-type MOSFET (NMOS) switches to deliver the modulation currents of 0.1~10 mApp to the VCSEL diode simultaneously, with no overshoot distortions. Post-layout simulations of the modified current-mode VCSEL driver (m-CMVD), using 180 nm CMOS technology, demonstrate very large and clean output pulses with significantly reduced signal distortions. Hereby, the VCSEL diode is transformed into an equivalent circuit with a 1.6 V DC voltage and a 50 Ω resistor for circuit simulations. The proposed m-CMVD consumes a maximum of 11mWfrom a 3.3 V supply voltage and the chip core occupies an area of 0.196 mm2....
A novel Gm-C structure of a second-order continuous-time filter is proposed that allows for the independent control of the filter’s natural frequency (ω0) and quality factor (Q). The structure consists of two capacitors and four transconductors. Two transconductors together with the capacitors form a lossless second-order circuit with tunable ω0. The other two transconductors form a variable gain amplifier (VGA) which realizes an adjustable loss and thereby adjustable Q. The proposed solution can be used to implement low-voltage and low-power tunable front-end filter banks for fully integrated CMOS cochlear implants and edge intelligence accelerators. An example filter bank powered by 0.5 V and consuming 40 nW of power per single filter is designed and simulated using a 180 nm CMOS process. Circuitries for the adaptive control of transistor bias at a reduced supply voltage are proposed. The ω0 and Q control circuitries are also proposed: a delay-locked loop (DLL)-based system for fine ω0 tuning and a binary-weighted current mirror for Q adjustment. The proposed solution allows for the independent regulation of ω0 and Q within the ranges of 0.25–8 kHz and 1–14, respectively, with a relative tolerance of up to 5% across a filter bank....
Gamification is being incorporated into university classrooms due to its educational benefits for students learning, including encouraging student behavior and engagement, and consequently improving learning outcomes. Despite gamification being increasingly used in education, little has been developed related to Very-Large-Scale Integration (VLSI). In this article, we describe two different gamification experiences applied to integrated circuit processing and design in an introductory VLSI design course for Electronic Engineers. While gamification in universities is still not very mature and our experience spans only two academic years, we observed that, with the practice of gamifying part of our course, the topics treated in games were profoundly learned and the experience was very positive in every aspect of the teaching–learning process....
In this study, the use of Cr/CrN+CrCN/Cr-C:H, Cr/W-C:H, and Cr/CrN+Ag/Cr-C:H coatings deposited on copper beryllium were investigated. These protective coatings were prepared using the Magnetron Sputtering Physical Vapor Deposition (MSPVD) method. The tests were carried out in order to qualify the outer DLC (Diamond-Like Carbon) layers for use as the protective function and for regulating the thermo-optical properties. The objective of this study was to compare the properties of chromium and chromium nitride-based coatings. The microstructure, architecture, and chemical composition were studied using scanning electron microscopy (SEM), Photo Diode BackScattered Electrons (PDBS), and X-ray dispersion spectroscopy (EDX). The adhesion was evaluated using a scratch test and a peel and pull-off method. The level of protection against the cold welding effect was tested. Thermo-optical, microhardness, and surface electric resistivity tests were performed. It was found that in cases where increased resistance to cold welding is required, DLC2 and DLC3 proved to be the best solutions. An example of such an application is tubular boom antennas, which are stored in a rolled-up form until deployed in space. They are susceptible to cold welding due to vibration during rocket launch and subsequent exposure to high vacuum....
The paper presents the original structure of a processing unit for multiplying quaternions. The idea of organizing the device is based on the use of fast Hadamard transform blocks. The operation principles of such a device are described. Compared to direct quaternion multiplication, the developed algorithm significantly reduces the number of multiplication and addition operations. Hardware implementations of the developed structure, in FPGA and ASIC, are presented. The FPGA blocks were implemented in the Vivado environment. The ASICs were designed using 130 nm technology. The developed scripts in VHDL are available in the GitHub repository....
Loading....