• Journal of IKEEE
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• v.19 no.4
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• pp.573-582
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• 2015

This paper presents the design of dual mode boost converter for energy harvesting. The designed converter boosts low voltage from energy harvester through a startup circuit. When the voltage goes above predefined value, supplied voltage to startup circuit is blocked by voltage detector. Boost controller makes the boosted voltage into $V_{OUT}$. The proposed circuit consists of oscillator for charge pump, charge pump, pulse generator, voltage detector, and boost controller. The proposed converter is designed and fabricated using a $0.18{\mu}m$ CMOS process. The designed circuit shows that minimum input voltage is 600mV, output is 3V and startup time is 20ms. The boost converter achieves 47% efficiency at a load current of 3mA.

• Journal of IKEEE
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• v.21 no.1
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• pp.66-69
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• 2017

In recent year, energy harvesting technologies from the ambient environments such as light, motion, wireless waves, and temperature again a lot of attraction form research community [1-5] due to its efficient solution in order to substitute for conventional power delivery methods, especially in wearable together with on-body applications. The drawbacks of battery-powered characteristic used in commodity applications lead to self-powered, long-lifetime circuit design. Thermoelectric generator, a solid-state sensor, is useful compared to the harvesting devices in order to enable self-sustained low-power applications. TEG based on the Seebeck effect is utilized to transfer thermal energy which is available with a temperature gradient into useful electrical energy. Depending on the temperature difference between two sides, amount of output power will be proportionally delivered. In this work, we illustrated a low-input voltage energy harvesting circuit applied discontinuous conduction mode (DCM) method for getting an adequate amount of energy from thermoelectric generator (TEG) for a specific wearable application. With a small temperature gradient harvested from human skin, the input voltage from the transducer is as low as 60mV, the proposed circuit, fabricated in a $0.6{\mu}m$ CMOS process, is capable of generating a regulated output voltage of 4.2V with an output power reaching to $40{\mu}W$. The proposed circuit is useful for powering energy to battery-less systems, such as wearable application devices.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.520-523
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• 2016

This paper describes a DC-DC converter with MPPT control for thermoelectric energy harvesting. The designed circuit converts low voltage harvested from a thermoelectric generator into higher voltage for powering a load. A start-up circuit supplies VDD to a controller, and the controller turns on and off a NMOS switch of a main-boost converter. The converter supplies the boosted voltage to the load through the switch operation. Bulk-driven comparators can do the comparison under low voltage condition and are used for voltage regulation. Also, bulk-driven comparators raise system's efficiency. A peak conversion efficiency of 76% is achieved. The proposed circuit is designed in a 0.35um CMOS technology and its functionality has been verified through simulations. The designed chip occupies $933um{\times}769um$.