Low-Voltage Super class AB CMOS OTA cells with very high slew rate and power efficiency

The electrification of transportation and the continued expansion of cloud based computing are two drivers for optimizing power efficiency. The automotive power requirements focus on highly efficient transfer from DC to AC (and vice versa), at very high power levels. Current IGBT switching devices are packaged in large modules with extensive cooling capacities. Reductions in size/weight require increased efficiency at higher frequency and current density. The desire for higher efficiency in datacenters is aimed at cost reduction of the total compute environment. Each individual server requires the most efficient power conversion from high voltage distribution lines to very low voltage boards. Switching devices again are packaged in modules, operating at very high power density, requiring co-optimization of devices, connections and packages. To realize the desired combination of size, speed and density, wide bandgap materials may be needed to advance the roadmap of these power management products. We will review some of the recent progress and challenges in materials innovation to optimize device and package and circuit.

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Evaluation of the mechanical properties of Inconel 718 to SCM 440 dissimilar friction welding through real-time monitoring of the acoustic emission system

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/1464420721993838 ◽

2021 ◽

pp. 146442072199383

Author(s):

Yu Sik Kong ◽

Muralimohan Cheepu ◽

Jin-Kyung Lee

Keyword(s):

Acoustic Emission ◽

Friction Welding ◽

Inconel 718 ◽

Low Voltage ◽

Dissimilar Materials ◽

Average Frequency ◽

Very High Frequency ◽

Cumulative Count ◽

Emission System ◽

Very High

Friction welding was chosen for its versatility in the joining of dissimilar materials with high quality. The aim of this study is to determine the optimal welding conditions for attaining quality joints by using online monitoring of acoustic emission system signals. During friction welding, the formation of cracks, defects, or any abnormalities in the joining process which have a detrimental effect on the joints quality was identified. The most widely used materials in the aerospace industry—Inconel 718 and molybdenum steel—were joined by friction welding. The precision of the joints, internal defects, and quality are major concerns for aerospace parts. The results of the present research determined the optimal welding conditions for high tensile strength by nondestructively inducing acoustic emission signals. During friction time and upset time periods, the typical waveforms and frequency spectrum of the acoustic emission signals were recorded, and their energy level, average frequency, cumulative count, and amplitude were analyzed. Both cumulative count and amplitude were found to be useful parameters for deriving the optimal welding conditions. In the initial stage of friction welding, a very high voltage of continuous form was generated with frequency characteristics of 0.44 MHz and 0.54 MHz. The signals generated during the upset stage had a low voltage, but a very high frequency of 1.56 MHz and 1.74 MHz with a burst-type signal. The amplitude of the signal generated for the optimally welded joints was about 100 dB at the friction time and about 45 dB at the upset time.

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A 0.3 V Rail-to-Rail Ultra-Low-Power OTA with Improved Bandwidth and Slew Rate

Journal of Low Power Electronics and Applications ◽

10.3390/jlpea11020019 ◽

2021 ◽

Vol 11 (2) ◽

pp. 19

Author(s):

Francesco Centurelli ◽

Riccardo Della Sala ◽

Pietro Monsurrò ◽

Giuseppe Scotti ◽

Alessandro Trifiletti

Keyword(s):

Low Power ◽

Low Voltage ◽

Supply Voltage ◽

Cmos Process ◽

Slew Rate ◽

Large Signal ◽

Output Stage ◽

Ultra Low Power ◽

Input Stage ◽

Rail To Rail

In this paper, we present a novel operational transconductance amplifier (OTA) topology based on a dual-path body-driven input stage that exploits a body-driven current mirror-active load and targets ultra-low-power (ULP) and ultra-low-voltage (ULV) applications, such as IoT or biomedical devices. The proposed OTA exhibits only one high-impedance node, and can therefore be compensated at the output stage, thus not requiring Miller compensation. The input stage ensures rail-to-rail input common-mode range, whereas the gate-driven output stage ensures both a high open-loop gain and an enhanced slew rate. The proposed amplifier was designed in an STMicroelectronics 130 nm CMOS process with a nominal supply voltage of only 0.3 V, and it achieved very good values for both the small-signal and large-signal Figures of Merit. Extensive PVT (process, supply voltage, and temperature) and mismatch simulations are reported to prove the robustness of the proposed amplifier.

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