Key Engineering Materials Vol. 698

Abstract: The purpose of this research is to reduce the measurement time of the first-order mass moment estimation method proposed by us previously. In the previous method, the loads at the three points of the board are measured one by one using one piece of an expensive scale (model: GX-30KR, resolution: 0.1 g, price: 2,542 USD). The relative standard uncertainly of measurement using a rigid body is estimated to be 1.7% and the measurement time is approximately 10 minutes. In this research, three pieces of inexpensive scales (model: HD-660, resolution: 100 g, price: 17 USD) are used to reduce the measurement time. The relative standard uncertainly of measurement is estimated to be 1.9% and the measurement time is approximately 1 minute. In previous measurement, when changing the position of the scale, the position of the frame has been deviated slightly. However, in this method, this kind of error does not occur, since measurements of three points are simultaneously conducted.

Abstract: At present, a method for evaluating dynamic characteristics of force sensors against small and short-duration impact forces has been developed. In this method, a small mass collides with a force sensor and the impact force is measured with high accuracy as the inertial force of the mass. A pneumatic linear bearing is used in order to realize linear motion with sufficiently small friction acting on the mass, i.e., the moving part of the bearing. Using this method, the dynamic characteristics of the force sensor are evaluated in detail: small and various-duration impact forces with maximum values of approximately 0.4-6.0 N and full width at half maximum (FWHM) of approximately 0.6-2.8 ms are applied to the force sensor and the impact responses of the force sensor are evaluated.

Abstract: Bamboo shinai is a practice sword for kendo which is the Japanese traditional fencing. The effectiveness of the shock absorption of the bamboo shinai has been shown in our previous study. Although shinai is usually made of bamboo, it is also made of carbon fiber reinforced plastic (CFRP). The impact response of bamboo shinai and CFRP shinai is compared. As a result, the difference of peak value of impact force between bamboo shinai and CFRP shinai against similar initial velocity is small. Impact response measurement of each shinai has been carried out using the Levitation Mass Method (LMM) which has been proposed by us. In this method, a mass, which is levitated with a pneumatic linear bearing and hence affected by negligible friction, is made to collide with a shinai under test. Because bamboo is natual product, resource of suitable bamboos for shinai is limited. On the other hand, carbon-fiber-reinforced-plastic (CFRP) can be designed to be suitable for a shinai, which has a fixed shock absorption characteristic for an application to the structure of robot arms. Therefore, if the shock absorption characteristic of CFRP shinai is the same as that of bamboo shinai, CFRP shinai is more suitable for the structure of robot arms.

Abstract: This paper presents a theoretical yet practical device targeting method to extract typical model parameters of MOSFET devices on wafer for RF analog integrated circuit design. This method employs skewing algorithms with model parameters of existing typical device which are selected by using inter-lot process electrical test parameters. Although this technique can be applied for both n-channel and p-channel MOSFETs, only n-channel devices could be prepared for our experiments in this research. To demonstrate the plausibility of this method, a cascode amplifier is designed to simulate frequency characteristic of S₂₁ with this method.

Abstract: The goal of this research is to model the drain current and 1/f noise degradation characteristics of n-channel MOSFETs. In this paper, we present the implementation of hot carrier degradation into drain current equations of BSIM4 model. We show simulation results of the DC drain current degradation, and then 1/f noise voltage density simulation results affected by the drain current degradation. We have extracted BSIM4 model parameters extensively with the measured data including I-V and 1/f noise measurement of our TEGs. Especially for 1/f noise degradation characterizations, the input referred noise has been calculated after extracting the 1/f noise parameter degradations.

Abstract: In this research, a novel SPICE model of an Insulated-Gate-Bipolar-Transistor (IGBT), which is often used to handle high power signals in automotive electrical circuits, has been developed. The model consists of basic SPICE elements. Thus, it can be used in any SPICE-compatible simulators without any source code modification. This paper presents the results of DC, small signal AC, and transient characteristics considering the temperature dependence by using the proposed IGBT macro-model for SPICE. In addition, turn-on and -off time verifications are presented by using a switching test circuit provided by an IGBT manufacturer.

Abstract: This paper describes a redundant Successive Approximation Register Analog-to-Digital Converter (SAR ADC) design method which enables high-reliability and high-speed AD conversion by using digital error correction. Especially we introduce to apply Fibonacci sequence and its property called Golden ratio to SAR ADC design to improve conventional redundant search algorithms. We also present some derived equations and many beautiful properties for well-balanced redundancy design for SAR ADC

Abstract: A time-to-digital converter (TDC) based on residue number system is presented. This architecture can reduce hardware and chip area as well as power significantly compared to a flash-type TDC while keeping comparable performance. Its proof-of-concept prototype was implemented on FPGA, and the measurement results validate the effectiveness of the proposed architecture

Abstract: This paper discusses a digital control method for efficiency improvement of switching power circuit at light load by using C2000 Series DSP (Texas Instruments Inc.). In this work, we alter the module in DSP to adjust the link voltage between a bridgeless PFC AC/DC converter and a phase shift full bridge DC/DC converter, as well as to control the PWM frequency of power circuit in order to improve the power efficiency in a suitable way. Our experiments result show that the efficiency of the power circuit at half or light load improves by adjusting the link voltage and/or PWM frequency

Abstract: This paper describes multi-band low noise amplifiers (LNAs) utilizing input matching transformers. We investigate a conventional dual-band LNA circuit utilizing a transformer, and show our analysis and simulation results for its circuit. Based on this, we propose a triple band LNA with transformers. We have calculated characteristics of the dual-band and triple-band LNAs. As the results, the LNAs show gain of 20dB while maintaining good input matching, in the frequencies at 2.59GHz, 3.50GHz and 5.41 GHz. Then we discuss configuration and design of coupling coefficients of the transformers.