Marcio Bender Machado

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This paper presents the fundamentals for the design of MOS analog and digital circuits that can operate at very low supply voltages. Operation of the MOS transistor in the triode region is highlighted owing to the limited voltages available. Special attention has been given to the properties of the zero-VT transistor due to its high drive capability at low(More)
This paper presents a very simple methodology for determining the threshold voltage. The procedure is based on the expressions of the Advanced Compact MOSFET (ACM) model, valid in all regimes of operation, which assures physical meaning, consistency and reliability for the results. The extraction of the threshold voltage is accomplished over a single(More)
—In this paper, we present a MOSFET-based Colpitts oscillator based on a " zero-threshold " transistor operating at a supply voltage below 20 mV. The circuit was carefully analyzed and expressions relating the start-up conditions and the voltage supply, as well as the oscillation frequency were developed. Measurement results obtained on a discrete prototype(More)
This paper presents a brief discussion on the main MOSFET definitions of threshold voltage available in the literature and associated extraction methodologies. We have taken advantage of the Advanced Compact MOSFET (ACM) model, which accurately relates surface potential φ S to inversion charge density I Q′ in all regions of operation. A new robust and(More)
This paper presents an ultra-low-voltage step-up converter for energy harvesting applications, which is able to operate from supply voltages below the thermal voltage kT/q. The operation of the main blocks of the converter, namely an enhanced swing ring oscillator and a Dickson charge pump, both operating at ultra-low voltage, is described. The extremely(More)
— In this paper, we present a fully-integrated step-up converter for energy-harvesting applications able to operate from supply voltages below 4kT/q ≅ 100 mV. Expressions for the operation of the main blocks of the topology, the enhanced swing ring oscillator and the Dickson charge pump operating at ultra-low-voltages, are derived. A fully-integrated(More)
This paper presents a very simple methodology for determining the effective channel length and width, which is independent of the determination of the threshold voltage. The procedure is based on measurement of the transconductance-to-current ratio (g m /I D) characteristic of the MOSFET in the linear region, from weak to moderate inversion. For the(More)