In this study, a dead-time control circuit is proposed to generate independent delays for the high and low sides of half-bridge converter switches. In addition to greatly decreasing the losses of ...power converters, the proposed method mitigates the shoot-through current through the application of superimposed power switches. The circuit presented here comprises a switched capacitor architecture and is implemented in AMS 0.35 <inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> technology. In the implementation, the proposed dead-time control circuit occupies a silicon area of <inline-formula> <tex-math notation="LaTeX">70\,\,\mu \text{m}\,\,\times 180\,\,\mu \text{m} </tex-math></inline-formula>. To realize the technique, a two-sided wide swing current source is employed. Each sides of the current source comes with two capacitors, two Schmitt triggers, and three transmission gates. Results show that the low and high sides of the projected half-bridge converter switches respectively require delays of 35 and 62 ns. The performance of the proposed dead-time circuit is evaluated by assembling it with the half-bridge converter. The proposed dead-time prototype achieves a 40% drop in power losses in the half-bridge circuit.
Given the fact that MEM gyroscopes can provide a better solution for inertial sensors in terms of size and cost, increasing their performance will remain an important issue in the development of that ...field. Researchers seek enhancing different performance measures, mainly the bias stability, Angle Random Walk and sensitivity. Nevertheless, different amplification techniques unfortunately decrease the signal to noise ratio (SNR) and thereby decrease the gyroscope’s precision. In this context, parametric excitation methods emerged to have positive effects on both the gyroscope’s sensitivity and SNR, this is based on the fact that the amplification is achieved mechanically.
However, parametric amplification is conventionally limited to the resonant frequencies. This limitation affects the efficiency of the control methods used to tune the excitation frequency. This can be, however, overcome by introducing a broadband parametric amplification method. This parametric excitation method is described in this paper in detail. It is based on inducing a modal-coupled phase-shifted parametric excitation in multi-degree of freedom dynamic systems. Using this excitation method the system can be subjected to destabilization on a broad frequency band, i.e. not only at resonant frequencies. In that way the parametric excitation can then offer a negative-damping effect thus mechanically increasing the amplitude and the device’s sensitivity.
In this paper, a micro-ring gyroscope is subjected to a bimodal coupled phase-shifted parametric excitation. The system’s differential equations were derived using Hamilton’s principle and discretized using Galerkin’s method. Afterwards, the aforementioned excitation method is applied through a suggested control circuit. The whole system is analyzed by a semi-analytical method, namely, the method of normal forms and verified numerically using the Floquet method. Using the data of a realistic micro-ring gyroscope we could then achieve broadband amplification under certain conditions.
Display omitted
•A parametrically excited micro-ring gyroscope is modeled using Hamilton’s principle and discretized using Galerkin’s method.•The effect of the phase-shifted coupled parametric excitation in micro gyroscopes is introduced.•An electronic control circuit is suggested to induce the required phenomenon, i.e. the broadband amplification.•A realistic model of a micro-ring gyroscope is analyzed and the results are discussed.•A broadband parametric amplification is obtained, that is also at the nonresonant frequencies.
Controllers are mission-critical components of any electronic design. By sending control signals, they decide which and when other data path elements must operate. Faults, especially Single Event ...Upset (SEU) occurrence in these components, can lead to functional/mission failure of the system when deployed in harsh environments. Hence, competence to self-heal from SEU is highly required in the control path of the digital system. Reconfiguration is critical for recovering from a faulty state to a non-faulty state. Compared to native reconfiguration, the Virtual Reconfigurable Circuit (VRC) is an FPGA-generic reconfiguration mechanism. The non-partial reconfiguration in VRC and extensive architecture are considered hindrances in extending the VRC-based Evolvable Hardware (EHW) to real-time fault mitigation. To confront this challenge, we have proposed an intrinsic constrained evolution to improve the scalability and accelerate the evolution process for VRC-based fault mitigation in mission-critical applications. Experimentation is conducted on complex ACM/SIGDA benchmark circuits and real-time circuits used in space missions, which are not included in related works. In addition, a comparative study is made between existing and proposed methodologies for brushless DC motor control circuits. The hardware utilization in the multiplexer has been significantly reduced, resulting in up to a 77% reduction in the existing VRC architecture. The proposed methodology employs a fault localization approach to narrow the search space effectively. This approach has yielded an 87% improvement on average in convergence speed, as measured by the evolution time, compared to the existing work.
This paper presents a robust nonlinear current-mode control approach for a pulse-width modulated DC-DC Cuk converter in a simple analog form. The control scheme is developed based on the ...reduced-state sliding-mode current control technique, in which a simplified equivalent control equation is derived using an averaged power converter model in continuous conduction mode. The proposed controller does not require an output capacitor current sensor and double proportional-integral compensators as in conventional sliding-mode current controllers; thus, the cost and complexity of the practical implementation is minimized without degrading the control performance. The simplified nonlinear controller rejects large disturbances, provides fast transient response, and maintains a constant switching frequency. The nonlinear control scheme is developed using an analog circuit with minimal added components, which is suitable for low-cost industrial applications. The control law derivation, control circuit design, controller gains selection, and stability analysis are provided. The proposed control methodology is verified via simulating the closed-loop nonlinear power converter model in MATLAB/SIMULINK under abrupt changes in load current and input voltage. The simulation results show that the proposed control scheme provides robust tracking performance, a low percentage overshoot, fast transient response, and a wide operating range. The maximum percentage overshoot and settling time of the closed-loop power converter response during line disturbance are 5.6% and 20 ms, respectively, whereas the percentage overshoot and settling time during load disturbance are 2.8% and 15 ms, respectively.
Contribution to Special Issue on Fast effects of steroids.
Sex steroid hormones act during early development to shape the circuitry upon which these same hormones act in adulthood to control ...behavioral responses to various stimuli. The “organizational” vs. “activational” distinction was proposed to explain this temporal difference in hormone action. In both of these cases steroids were thought to act genomically over a time-scale of days to weeks. However, sex steroids can affect behavior over short (e.g., seconds or minutes) time-scales. Here, we discuss how testosterone controls birdsong via actions at different sites and over different time-scales, with an emphasis on this process in canaries (Serinus canaria). Our work shows that testosterone in the medial preoptic nucleus regulates the motivation to sing, but not aspects of song performance. Instead, different aspects of song performance are regulated by long-term actions of testosterone in steroid-sensitive cortical-like brain regions and the syrinx, the avian vocal production organ. On the other hand, acute aromatase inhibition rapidly reduces the availability of estrogens and this reduction is correlated with reductions in the motivation to sing and song performance. Thus, testosterone and its estrogenic metabolites regulate distinct features of birdsong depending on the site and temporal window of action. The number of brain areas expressing androgen receptors is higher in species producing learned vocalization as compared to species that produce unlearned calls. An appealing scenario is that rapid effects of steroids in specific brain regions is a derived trait secondary to the widespread genomic effects of steroids in systems where steroids coordinate morphological, physiological, and behavioral traits.
•Testosterone (T) and/or estradiol (E) coordinate suites of traits into an adaptive response.•This coordination occurs over different brain regions and time-scales.•T/E in distinct brain regions regulates different aspects of birdsong.•Acute E synthesis regulates song over short time-scales.•Evolution has shaped steroid-sensitive telencephalic circuitry to control learned complex birdsong.
The high prevalence of internet addiction (IA) has become a worldwide problem that profoundly affects people's mental health and executive function. Empirical studies have suggested trait anxiety ...(TA) as one of the most robust predictors of addictive behaviors. The present study investigated the neural and socio-psychological mechanisms underlying the association between TA and IA.
Firstly, we tested the correlation between TA and IA. Then we investigated the longitudinal influence of TA on IA using a linear mixed effect (LME) model. Secondly, connectome-based predictive modeling (CPM) was employed to explore neuromarkers of TA, and we tested whether the identified neuromarkers of TA can predict IA. Lastly, stressful life events and default mode network (DMN) were considered as mediating variables to explore the relationship between TA and IA.
A significant positive correlation between TA and IA was found and the high TA group demonstrated higher IA across time. CPM results revealed that the functional connectivity of cognitive control and emotion-regulation circuits and DMN were significantly correlated with TA. Furthermore, a significant association was found between the neuromarkers of TA and IA. Notably, the CPM results were all validated in an independent sample. The results of mediation demonstrated that stressful life events and correlated functional connectivity mediated the association between TA and IA.
Findings of the present study facilitate a deeper understanding of the neural and socio-psychological mechanisms linking TA and IA and provide new directions for developing neural and psychological interventions.
The use of high-frequency input signals from room-temperature microwave sources makes it difficult to scale up the number of quantum bits in universal quantum computers. To address this issue, ...superconducting single flux quantum (SFQ) integrated circuits are being explored as suitable candidates for qubit manipulation in universal quantum computers. Previously, we designed a low-power SFQ qubit control circuit (SQCC) to produce an equidistant SFQ pulse train without high-frequency input. It was reported that the fidelity of qubit control could be further improved if the pattern of SFQ pulse train could be adjustable. In this paper, we present optimized designs for different pattern requirements of qubit control, building upon the SQCC without high-frequency input. These designs feature segmented frequency modulation circuits, as well as circuits capable of outputting arbitrary patterns. The circuit capable of generating arbitrary patterns currently achieves a maximum adjustable number of 400, with a corresponding frequency output of 20 GHz. It has been successfully fabricated using the SIMIT Nb03 process and has passed functionality measurement tests. The optimized circuit opens up possibilities for improved qubit control and advancements in quantum computing applications.
This brief presents a high-efficiency inverse Class-F (Class-F-1) monolithic microwave integrated circuit (MMIC) power amplifier (PA) fabricated with 0.25-lm GaN-on-Si technology. The design is based ...on a compact output matching network (COMN), which consists of a harmonic control circuit (HCC), an L-section matching circuit and a bias line. In order to reduce the circuit area that make it suitable for monolithic integration, the HCC uses only three transmission lines to achieve the second and third harmonic control. In addition, the conventional quarter-wave bias line is replaced with a shorter, proper one. The proposed COMN simplifies the matching network while realizing Class-F-1 operation, which improves efficiency, output power and reduce chip size. The maximum power added efficiency of 64.5% is achieved at 3.0 GHz, with an output power of 38.4 dBm and a power gain of 10.3 dB.
This article reports a single-loop full-rate bang-bang clock and data recovery (BBCDR) circuit supporting a four-level pulse amplitude modulation (PAM-4) pattern. We eliminate both the reference and ...the separate frequency detector (FD) by deliberately adding two fixed strobe points in the bang-bang phase detector (BBPD) curve via a clock-selection scheme. As such, we can achieve a wide frequency-capture range in a single-sided FD polarity. The BBPD also incorporates a hybrid control circuit to automate the frequency acquisition over a wide frequency range. Prototyped in a 28-nm CMOS, the proposed BBCDR occupies a tiny area of 0.0285 mm 2 and exhibits a 23-to-29-Gb/s capture range. The acquisition speed 8.2 Gb/s/<inline-formula> <tex-math notation="LaTeX">\mu \text{s} </tex-math></inline-formula> and energy efficiency (0.68 pJ/bit) compare favorably with the state of the art.
