Shinya Terada

A ring type switched-capacitor (SC) programmable converter with DC or AC input/DC or AC output

We have already proposed a ring type switched-capacitor (SC) converter. This converter consists of capacitors which make a ring connection switches. In this paper, we propose programmable converter of DC-DC, DC-AC, AC-DC and AC-AC using a ring type SC converter. The SPICE simulations show that the power efficiency is more than 80%. This converter can provide to some combination of DC or AC input/DC or AC output.

Development of Switched-Capacitor bi-directional DC-AC converter for inductive and capacitive loads

This paper presents a research for Switched-Capacitor (SC) bi-directional DC-AC converter for inductive and capacitive loads. The proposed converter keeps high efficiency even if the phase of the load is changed widely, since the output energy returns to the input. The validity of the proposed converter is confirmed by SPICE simulations. The SPICE simulations showed that (1) the output voltage is kept a sinusoidal for the capacitive load and/or the inductive load, (2) the power conversion efficiency η is 93% or more regardless the phase θ of the load (−72≪θ ≪72) without output regulation, and (3) the efficiency η<inf>reg</inf> is 80% or more (−54≪θ ≪54) with regulation.

A switched-capacitor (SC) AC-DC or AC-AC converter with arbitrarily output voltage using the same circuit configuration

In this paper, switched-capacitor (SC) AC-DC / AC-AC converter with arbitrary output voltages using same circuit configuration is proposed. This converter can reduce voltage drop even if load currents are large, and can choice DC output or AC output by changing signal patterns of switches in the same AC input. The validity of the proposed converter is confirmed by SPICE simulations. The SPICE simulations showed that the output voltage and the output frequency can be determined arbitrarily.

Switched-capacitor (SC) DC-DC converter with fine tune control outputs

A switched-capacitor (SC) converter is in the spotlight as a coilless converter that consists of capacitors and switches. The SC converters have a weak point that the voltage ratio cannot change linearly, because the output voltage is determined by the voltage dividing ratios of the capacitors. In this paper, we propose SC DC-DC converter with fine tune control outputs. This circuit consists of 2 converter blocks. The output voltage with fine tune control can be obtained by the sum of the output of each converter. Thus, the proposed circuit can provide more numbers of output voltages than conventional converters. As an example, the circuit which has 25 types of outputs in the range 0.75 ~ 2.3V from 3.6V input is designed. The SPICE simulations show that the power efficiency is 85 ~ 70% when the output current is about 160 to 360mA

Design of a Digitally Controlled Inductor-Less Voltage Multiplier for Non-Thermal Food Processing

Abstract—For non-thermal food processing systems utilizing an underwater shockwave, a digitally controlled voltage multiplier is proposed in this paper. The proposed voltage multiplier based on Cockcroft-Walton voltage multiplier (CWVM) has a bipolar structure. Unlike the conventional CWVM, the output voltage of the proposed multiplier is expressed by sum of the output voltage of positive and negative voltage multiplier blocks. Therefore, the number of stages of the proposed multiplier is about a half of that of the conventional CWVM. Furthermore, by utilizing high-low side drivers and a microcontroller, the diode switch of the proposed multiplier is driven by high-speed rectangular pulses. For these reasons, the proposed multiplier can achieve not only high voltage efficiency but also high speed operation. The validity of the circuit design is confirmed by theoretical analysis, simulation program with integrated circuit emphasis (SPICE) simulations, and experiments. The simulation results show that the settling time of the proposed voltage multiplier is less than 1/400 of that of the conventional CWVM. Furthermore, the experimental results show that the proposed voltage multiplier can improve voltage efficiency more than 21% from the conventional CWVM when the input voltage is 10V@60Hz and the output capacitor is 10μF.

A Symmetrical Digital Selecting Type DC-DC Converter with Power Saving Techniques

To achieve various conversion ratios with high power efficiency, a symmetrical digital selecting type switched-capacitor (SC) DC-DC converter with power saving techniques is proposed in this paper. Unlike conventional SC DC-DC converters, the voltage ratio of capacitors is expressed as the ratio of a power of two. By combining some of these capacitors in series, the proposed converter can achieve a larger number of conversion ratios than conventional converters. Furthermore, by employing a symmetrical structure with power saving techniques, the proposed converter can alleviate energy loss due to stray parasitic capacitance. The theoretical analysis and SPICE simulations show the effectiveness of the proposed converter.

Parallel-Connected High Voltage Multiplier with Symmetrical Structure

A high voltage multiplier is proposed for non-thermal food processing systems utilizing an underwater shockwave. Unlike conventional Cockcroft-Walton Voltage Multiplier (CWVM) providing a DC output from an AC input, the proposed multiplier consists of two switched-capacitor-based DC-DC converters with different polarities. Owing to the symmetrical bipolar structure without magnetic component, the proposed multiplier can achieve faster response speed and lower voltage drop than the conventional CWVM. The theoretical analysis and simulation program with integrated circuit emphasis (SPICE) simulations show the effectiveness of the proposed voltage multiplier.

Design and Analysis of a Generalized Dual Fibonacci Converter Using Improved Charge Reusing Techniques

For energy-harvesting systems utilizing thermoelectric energy, a dual Fibonacci converter using power saving techniques is proposed. Compared with conventional converters, the proposed converter can provide higher output voltages without magnetic components. The output voltage of the proposed converter is expressed by the k-step (2, 3, 4 ...) Fibonacci numbers. Furthermore, a novel control technique is proposed to utilize the energy stored in stray parasitic capacitances effectively. The result of simulation program with integrated circuit emphasis (SPICE) simulations shows that the proposed converter can provide higher output voltages than conventional converters. Furthermore, more than 8.4% of power efficiency is improved by the proposed technique.

Design of a Charge-Pump Type AC-DC Converter for RE-ID Tags

In this paper, a charge-pump type AC-DC converter for RF ID tags is proposed. Since the proposed converter employing novel bootstrap circuits can avoid the threshold voltage drop caused by diode-switches, it can achieve an AC-DC conversion at high efficiency. The SPICE simulations showed that the power efficiency of the proposed converter is more than 85% and the electric power is about 5 mW when an output load is 500Omega. Furthermore, the characteristics concerning power efficiency and ripple voltage are analyzed theoretically