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A median filtering circuit using clocked CMOS neuron inverters for implantable electronic medical devices
(2017-01-01)
Eguchi, Kei
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Wongjan, Anan
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Julsereewong, Amphawan
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Harada, Yujiro
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Fujimoto, Kuniaki
In the past few years, implantable electronic medical devices are receiving much attention in the field of biomedical engineering. In the design of the implantable electronic medical devices, not only small size but also low power consumption are required to achieve long working-life. In this paper, we present a complementary metal oxide semiconductor (CMOS) median filtering circuit using clocked neuron CMOS inverters. The aim of this work is to develop a CMOS implementable preprocessing circuit realizing low power consumption for implantable electronic medical devices such as a retinal prosthesis system. By controlling the duty cycle of clock pulses in the clocked neuron CMOS inverters, the proposed median filtering circuit can suppress the through current of inverters. Therefore, the proposed circuit can realize smaller power consumption than conventional median filtering circuits. Moreover, without arithmetic logic circuits, the median filtering based on the binary search algorithm is achieved in the proposed circuit. Therefore, the proposed circuit can offer the simple circuit configuration. Concerning the proposed circuit, the operation principle and theoretical design method are discussed in detail. Furthermore, the effectiveness of the proposed circuit is confirmed by simulation program with integrated circuit emphasis (SPICE) simulations. The simulated results demonstrate that the proposed median filtering circuit can reduce about 37% power consumption from the conventional circuit using CMOS neuron inverters.
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Power saving techniques to improve efficiency of a parallel-connected negative DC-DC converter
(2013-09-02)
Eguchi, Kei
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Pongswatd, Sawai
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Thepmanee, Teerawat
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Fujimoto, Kuniaki
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Sasaki, Hirofumi
A parallel-connected negative DC-DC converter using power saving techniques has been proposed in this paper. Unlike conventional negative converters, the proposed converter consists of four negative heap converters connected in parallel, where the power switch is driven by non-overlapped four-phase pulses cyclically. In two of the four negative heap converters, a part of the electric charge in parasitic capacitances is reused in each clock cycle. For this reason, the proposed converter can reduce energy loss than the conventional converters. The validity of the proposed technique was confirmed by simulation program with integrated circuit emphasis (SPICE) simulations and theoretical analysis. When the output load is 1 km, the proposed converter was able to improve power efficiency more than 11% compared to the conventional converter. © 2013 IEEE.
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A step-up/step-down SC DC-DC converter and its power saving techniques
(2013-09-02)
Eguchi, Kei
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Pongswatd, Sawai
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Thepmanee, Teerawat
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Fujimoto, Kuniaki
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Sasaki, Hirofumi
To improve power efficiency, a power saving technique for the ring-type DC-DC converter is proposed in this paper. By reusing a part of the electric charge in stray parasitic capacitances, the proposed converter can achieve higher power efficiency than the conventional converter. The results of the simulation program with integrated circuit emphasis (SPICE) simulation showed that more than 8% of the power efficiency was improved by the proposed converter when the output load is 10km. Furthermore, a handy equation to estimate the maximum power efficiency of the proposed converter is provided by theoretical analysis. © 2013 IEEE.
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Simple resistance-to-frequency converter with lead-wire-resistance compensation
(2013-03-28)
Julsereewong, Amphawan
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Petchmaneelumka, Wandee
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Rungkhum, Tipparat
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Yahara, Mitsutoshi
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Fujimoto, Kuniaki
This article presents a simple technique to realize a resistance-to-frequency converter for single resistive sensor-based remote measurements. The proposed realization method uses commercially available devices to generate output frequency, which is linearly proportional to sensing resistance deviation. Experimental results are shown that not only the good circuit operation but also the effective lead-wire-resistance compensation of the proposed technique can be obtained. © 2013 ICIC International.
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A dickson-type adder/subtractor dc-dc converter realizing step-up/step-down conversion
(2013-01-16)
Eguchi, Kei
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Julsereewong, Prasit
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Julsereewong, Amphawan
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Fujimoto, Kuniaki
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Sasaki, Hirofumi
In this paper, a Dickson-type adder/subtractor DC-DC converter realizing step-up/step-down conversion is proposed. Although the conventional Dickson converter cannot achieve step-up/step-down conversion, the proposed converter can provide not only the stepped-up voltage but also the stepped-down voltage by combining the battery energy and the clean energy. Moreover, the proposed converter can achieve many con-version ratios by utilizing hybrid inputs. Therefore, by choosing the optimal combination of conversion ratio, the proposed converter can alleviate the energy loss caused by the output regulation. To evaluate circuit properties, theoretical analyses, simulations and experiments were performed concerning a simple example of the proposed converter. Cir-cuit simulations and experiments showed the following results: (1) The circuit design is appropriate, because the step-up/step-down conversion was confirmed by the experimen-tal circuit. (2) The number of conversion ratios of the proposed converter is three times as large as that of the conventional three-stage ring-type converter. (3) The proposed converter can reduce more than 25% hardware cost than the conventional converter. (4) The derived theoretical formulas are useful to estimate the characteristics of the proposed converter, because the theoretical result corresponded well with the simulated result. © 2013 ICIC International.
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Self-statable integral type astable multivibrator using CMOS-XOR/XNOR gates
(2012-01-01)
Sasaki, Hirotoshi
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Isoguchi, Hiroshi
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Yahara, Mitsutoshi
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Fujimoto, Kuniaki
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Julsereewong, Amphawan
The astable multivibrator of the integral type operation using 2 CMOS-XOR/XNOR gates doesn't oscillate only by the power supply's being turned on. On the other hand, the proposed astable multivibrator of the integral type operation by 3CMOS-XOR/XNOR gates oscillates surely when the power supply is turned on. © 2012 The Institute of Electrical Engineers of Japan.
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A step-down switched-capacitor AC-DC converter for energy harvesting system using vibration-based energy
(2011-07-01)
Eguchi, Kei
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Pongswatd, Sawai
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Tirasesth, Kitti
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Fujimoto, Kuniaki
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Sasaki, Hirofumi
To realize battery-free operation employing energy harvesting, a step-down switched-capacitor-based converter has been used as a vibration-to-electricity converter. In this paper, to improve power efficiency, an AC-DC converter realizing 1/N× (N = 2; 3,...) step-down is designed by using switched-capacitor techniques. Although conventional converters offer a DC output by regulating the stored energy in a big capacitor, the proposed converter generates a DC output by realizing AC-DC conversion. Thus, the proposed converter can improve power efficiency. To clarify effectiveness of the proposed converter, theoretical analysis is performed concerning power efficiency and equivalent circuit. When the AC input is a rectangular-wave voltage, the theoretical results obtained by the theoretical analysis are consistent with SPICE simulated results. Furthermore, SPICE simulation results show that the proposed converter can improve power efficiency about 32 % from the conventional converter when R<inf>L</inf> = 100Ω. Next, the validity of the circuit design is confirmed by experiments. The experiments show that the proposed converter can offer stepped-down DC voltage from sinusoidal voltage. © 2011.
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A study on differential type monostable multivibrator using CMOS-XOR/XNOR gate
(2011-01-01)
Sasaki, Hirotoshi
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Julsereewong, Amphawan
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Isoguchi, Hiroshi
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Yahara, Mitsutoshi
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Fujimoto, Kuniaki
In the differential type monostabel multivibirator using CMOS-XOR/XNOR gates, there is a circuit configuration that the operation of two elements becomes the same in stable sate and the metastable state. And, these circuits has the up mode and down mode operations. Furthermore, the metastable state is not influenced trigger repetition rate, and it is shown by a simple formula expression. © 2011 The Institute of Electrical Engineers of Japan.
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A cross-coupled 3 × /4× step-up AC-DC converters for RFID tags
(2010-07-30)
Eguchi, Kei
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Pongswatd, Sawai
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Watanabe, Toshiya
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Fujimoto, Kuniaki
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Tirasesth, Kitti
Due to the threshold voltage drop caused by diode-switches, conventional AC-DC converters for RFID tags cannot be applied to mobile applications which require higher voltages. To make matters worse, the power efficiency decreases by the influence of threshold voltage. To solve these problems, two types of cross-coupled AC-DC converters for RFID tags are proposed in this paper: the 3× step-up converter and the 4× step-up converter. By using negative step-up converters and cross-coupled connection of CMOS switches, the proposed converters are able not only to offer higher output voltages but also to improve power efficiency. The characteristics of the proposed converters are clarified by theoretical analyses. Furthermore, the SPICE simulation and the experiment showed the validity of theoretical formulas and circuit design.
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Accurate dual slope analog-to-digital converter using bootstrap circuit
(2009-12-01)
Julsereewong, Amphawan
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Pongswatd, Sawai
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Riewruja, Vanchai
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Sasaki, Hirofumi
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Fujimoto, Kuniaki
This paper presents a simple and inexpensive implementation of the accurate dual slope analog-to-digital converter (ADC). The proposed technique with positive reference voltage takes advantages of a bootstrap circuit to function as a precise noninverting/inverting integrator. To achieve the constant reference voltage during integrating analog input voltage interval, a sample/hold (S/H) circuit is employed. Experimental results are given to confirm the operation of the proposed ADC. © 2009 IEEE.

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