Search

This paper presents a class-AB amplifier with enhanced transconductance and slew rate using adaptive biasing technique and new drivers. The adaptive biasing configuration provides a tail current linked to the input signal in order to increase the slew rate during slewing phase. In addition, the new structure benefits from new drivers to enhance the transconductance which are supported by adaptive biasing configuration. These enhancement techniques lead to the input and output class-AB operations for fast settling applications. The proposed structure is simulated in 65-nm complementary metal-oxide semiconductortechnology which shows a 16.2-dB enhancement in the DC gain and a 72% reduction in the settling time compared to the conventional structure. [ABSTRACT FROM AUTHOR]

Laser wire-feed metal additive manufacturing (LWMAM) is a promising additive manufacturing technology that is well suited to build from various materials near net shape mid- to large-size complex components with a high deposition rate and high material usage. It could find applications in diverse industrial sectors such as aerospace, automotive, oil and gas, and rapid tooling. To further gain the acceptance of this technology, the development of process planning software is identified as one of the main challenges. LWMAM has several specific features that complicate the process planning compared to other similar additive manufacturing processes. LWMAM is still in its infancy. In this study, key features involved in the LWMAM process were first identified by building a prismatic block. The corresponding strategies were proposed and tested. Then, a MATLAB-based process planning software was developed that consisted of modules for volume slicing, contour filling, track trimming/elongating, stairstep effect compensation, and post-processing. Free-form contours and a propeller were successfully built by using the developed software. The as-built shapes were measured and compared to the CAD models. [ABSTRACT FROM AUTHOR]

This paper presents a two-stage bulk-driven operational transconductance amplifier operating in weak-inversion region. The proposed amplifier is upgraded using recycling structure, current shunt technique, positive feedback source degeneration and indirect frequency compensation feedback to enhance transconductance under a reasonable stability. Combining these approaches leads to an ultra-low-power high performance amplifier without increasing power dissipation compared to the conventional one. Simulation results in 0.13-µm complementary metal-oxide-semiconductor technology show the proposed structure achieves a 63-dB DC gain at 0.25-V supply voltage with just 20-nW power dissipation. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This article presents a chip designed for wireless intra-cardiac monitoring systems. The design consists of a three-channel analog front-end, a pulse-width modulator featuring output-frequency offset and temperature calibration, and inductive data telemetry. By employing a resistance boosting technique in the instrumentation amplifier feedback, the pseudo-resistor exhibits lower non-linearity, leading to a total harmonic distortion of below 0.1%. Furthermore, the boosting technique enhances the feedback resistance, leading to a reduction in the size of the feedback capacitor and, consequently, the overall size. To make the modulator's output frequency resilient to temperature and process changes, coarse and fine-tuning algorithms are used. The front-end channel is capable of extracting the intra-cardiac signal with an effective number of bits of 8.9, while exhibiting an input-referred noise of less than 2.7 μV rms , and consuming 200 nW per channel. The front-end output is encoded by an ASK-PWM modulator, which drives an on-chip transmitter at 13.56 MHz. The proposed System-on-Chip (SoC) is fabricated in a 0.18 μm standard CMOS technology and consumes 4.5 μW while occupying 1.125 mm 2 .