Steady-State Error Reduction by Digital Offset Control for Dc-to-dc Converters

T. Kuroki,T. Sato,T. Nabeshima,K. Nishijima 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper presents a novel algorithm of a digital control that improves a steady-state error of a dc-to-dc switching converter. Instead of the conventional Integral control, the offset control is employed in which the base-duty-cycle of Pulse Width Modulation (PWM) is updated at constant intervals so that the error of the output voltage might become small. The principle of the proposed algorithm is described in detail. The implementation of the algorithm is very simple and the code size becomes small that yield the shortest execute time. Characteristics of the proposed controller are examined, and it is found that the controller has the same characteristics as the conventional integral control. As a result, the steady-state error has been reduced to almost zero.

Prenatal nicotine exposure decreases the release of dopamine in the medial frontal cortex and induces atomoxetine-responsive neurobehavioral deficits in mice

Alkam, T.,Mamiya, T.,Kimura, N.,Yoshida, A.,Kihara, D.,Tsunoda, Y.,Aoyama, Y.,Hiramatsu, M.,Kim, H. C.,Nabeshima, T. Springer Science + Business Media 2017 Psychophamacology Vol.234 No.12

<P>Increased risk of attention-deficit/hyperactivity disorder (AD/HD) is partly associated with the early developmental exposure to nicotine in tobacco smoke. Emerging reports link tobacco smoke exposure or prenatal nicotine exposure (PNE) with AD/HD-like behaviors in rodent models. We have previously reported that PNE induces cognitive behavioral deficits in offspring and decreases the contents of dopamine (DA) and its turnover in the prefrontal cortex (PFC) of offspring It is well known that the dysfunction of DAergic system in the brain is one of the core factors in the pathophysiology of AD/HD. Therefore, we examined whether the effects of PNE on the DAergic system underlie the AD/HD-related behavioral changes in mouse offspring. PNE reduced the release of DA in the medial PFC (mPFC) in mouse offspring. PNE reduced the number of tyrosine hydroxylase (TH)-positive varicosities in the mPFC and in the core as well as the shell of nucleus accumbens, but not in the striatum. PNE also induced behavioral deficits in cliff avoidance, object-based attention, and sensorimotor gating in offspring. These behavioral deficits were attenuated by acute treatment with atomoxetine (3 mg/kg, s.c.) or partially attenuated by acute treatment with MPH (1 mg/kg, s.c.). Taken together, our findings support the notion that PNE induces neurobehavioral abnormalities in mouse offspring by disrupting the DAergic system and improve our understanding about the incidence of AD/HD in children whose mothers were exposed to nicotine during their pregnancy.</P>

High Efficiency Operation for H-Bridge DC-DC Converter

K. Okura,T. Nabeshima,T. Sato,K. Nishijima,H. Yajima 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper presents two methods of switching operation for higher conversion efficiency and seamless control for wide range of the input voltage in a H-Bridge DC-DC Converter. This converter consists of buck and boost blocks and a feedforward control from the input voltage is employed for the boost block to realize seamless transition between step down and step up operation mode. From the view point of the conduction loss and the switching loss, two methods of the desirable duty ratio of the boost section and different switching frequencies are examined. As a result, higher efficiency was obtained by minimizing the duty ratio of the boost block for wide range of the input voltage and by decreasing the switching frequency of the buck block without increasing output ripple voltage.

A Two-Phase High Step Down Coupled-Inductor Converter for Next Generation Low Voltage CPU

K. Matsumoto,K. Nishijima,T. Sato,T. Nabeshima 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

In this paper, a novel two-phase high step down coupled-inductor converter for next generation low voltage CPU is proposed. This converter has a very high step down characteristic as Vo/Vi = D/4. The switching loss and noise of all switching elements are sufficiently reduced because the drain-source voltages at switching periods are reduced to a quarter of the input source voltage. Low withstand voltage MOSFETs with low on resistance and low Qg(total gate charge) characteristics are possible to use for the all switching elements because the maximum voltage stresses of the main switches and the synchronous rectifier switches are reduced to a half and a quarter of the input source voltage respectively. Further, the branch currents flowed through the paralleled converters are automatically and mostly balanced without the current detection and balance control. The above fine characteristics are simply achieved with three additional capacitors.

Novel Low Cost Ripple Based Controlled Pulse Width Modulator for Fast Transient Response

S.Hirose,K.Ono,T.Sato,T.Nabeshima,K.Nishijima 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper presents novel pulse width modulation circuit for fast transient response. In the proposed modulator, C-MOS logic inverters are used instead of high speed comparators. Four types of new modulator are proposed and operating principle described in detail. The proposed modulator is applied to a buck converter, and steady state characteristics and frequency response of the proposed modulator are measured with the bread board circuit. From the experimental result, it is found that the proposed modulator has the derivative characteristics as hysteretic PWM controller that has good transient performance. Excellent load and line regulation are obtained. By using C-MOS inverter, compared with conventional hysteretic PWM controller with fast comparator, cost is reduced to one-fifth.

Role of Mitochondria in Methamphetamine-Induced Dopaminergic Neurotoxicity: Involvement in Oxidative Stress, Neuroinflammation, and Pro-apoptosis—A Review

Shin, E. J.,Tran, H. Q.,Nguyen, P. T.,Jeong, J. H.,Nah, S. Y.,Jang, C. G.,Nabeshima, T.,Kim, H. C. Springer Science + Business Media 2018 Neurochem Res Vol.43 No.1

MK-801, but not naloxone, attenuates high-dose dextromethorphan-induced convulsive behavior: Possible involvement of the GluN2B receptor

Tran, H.Q.,Chung, Y.H.,Shin, E.J.,Tran, T.V.,Jeong, J.H.,Jang, C.G.,Nah, S.Y.,Yamada, K.,Nabeshima, T.,Kim, H.C. Academic Press 2017 Toxicology and applied pharmacology Vol.334 No.-

Dextromethorphan (DM) is a dextrorotatory isomer of levorphanol, a typical morphine-like opioid. When administered at supra-antitussive doses, DM produces psychotoxic and neurotoxic effects in humans. Although DM abuse has been well-documented, few studies have examined the effects of high-dose DM. The present study aimed to explore the effects of a single high dose of DM on mortality and seizure occurrence. After intraperitoneal administration with a high dose of DM (80mg/kg), Sprague-Dawley rats showed increased seizure occurrence and intensity. Hippocampal expression levels of N-methyl-d-aspartate (NMDA) receptor subunits (GluN1<GluN2A<GluN2B), c-Fos and pro-apoptotic factors (Bax and cleaved caspase-3) were upregulated by DM treatment; while levels of anti-apoptotic factors (Bcl-2 and Bcl-xL) were downregulated. Consistently, DM also induced ultrastructural degeneration in the hippocampus. A non-competitive NMDA receptor antagonist, MK-801, attenuated these effects of high-dose DM, whereas an opioid antagonist, naloxone, did not affect DM-induced neurotoxicity. Moreover, pretreatment with a highly specific GluN2B subunit inhibitor, traxoprodil, was selectively effective in preventing DM-induced c-Fos expression and apoptotic changes. These results suggest that high-dose DM produces convulsive behaviors by activating GluN2B/NMDA signaling that leads to pro-apoptotic changes.

The role of system Xc^- in methamphetamine-induced dopaminergic neurotoxicity in mice

Dang, D.K.,Shin, E.J.,Tran, H.Q.,Kim, D.J.,Jeong, J.H.,Jang, C.G.,Nah, S.Y.,Sato, H.,Nabeshima, T.,Yoneda, Y.,Kim, H.C. Pergamon Press 2017 Neurochemistry International Vol.108 No.-

The cystine/glutamate antiporter (system Xc<SUP>-</SUP>, Sxc) transports cystine into cell in exchange for glutamate. Since xCT is a specific subunit of Sxc, we employed xCT knockout mice and investigated whether this antiporter affected methamphetamine (MA)-induced dopaminergic neurotoxicity. MA treatment significantly increased striatal oxidative burdens in wild type mice. xCT inhibitor [i.e., S-4-carboxy-phenylglycine (CPG), sulfasalazine] or an xCT knockout significantly protected against these oxidative burdens. MA-induced increases in Iba-1 expression and Iba-1-labeled microglial immunoreactivity (Iba-1-IR) were significantly attenuated by CPG or sulfasalazine administration or xCT knockout. CPG or sulfasalazine significantly attenuated MA-induced TUNEL-positive cell populations in the striatum of Taconic ICR mice. The decrease in excitatory amino acid transporter-2 (or glutamate transporter-1) expression and increase in glutamate release were attenuated by CPG, sulfasalazine or xCT knockout. In addition, CPG, sulfasalazine or xCT knockout significantly protected against dopaminergic loss (i.e., decreases in tyrosine hydroxylase expression and immunoreactivity, and an increase in dopamine turnover rate) induced by MA. However, CPG, sulfasalazine or xCT knockout did not significantly affect the impaired glutathione system [i.e., decrease in reduced glutathione (GSH) and increase in oxidized glutathione (GSSG)] induced by MA. Our results suggest that Sxc mediates MA-induced neurotoxicity via facilitating oxidative stress, microgliosis, proapoptosis, and glutamate-related toxicity.