A comparative study of charge pumping circuits for flash memory applications

2015 IEEE International Symposium on Circuits and Systems (ISCAS)

2015

The superior electrical characteristics of the heterojunction III-V Tunnel FET (TFET) devices can outperform current\ud technologies in the process of energy harvesting conversion at ultra-low power supply voltage operation (sub-0.25 V). In this work, it is\ud shown by simulations that a cross-coupled switched-capacitor topology with GaSb-InAs TFET devices present better conversion\ud performance compared to the use of Si FinFET technology at low temperature variations\ud (¿T < 3 ºC) when considering a thermo-electric energy harvesting source (with a = 80 mV/K). At higher ¿T, the conversion process is\ud degraded with the increase of the transistor losses. Considering a ¿T of 1 ºC (2 ºC), one cross-coupled stage with TFET devices can\ud achieve 74 % (69 %) of power conversion efficiency when considering an output load of 0.4 µA (6 µA). At the same conditions, the\ud FinFET charge pump is shown inefficient.Postprint (published version

Section: Simulation Resultsmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Pespectives of TFET devices in ultra-low power charge pumps for thermo-electric energy sources

2015 IEEE International Symposium on Circuits and Systems (ISCAS)

2015

“…5 (a). With conventional MOSFET devices, this charge-pump was shown to present better conversion performance at low input voltage values compared to other converter topologies [17]. > REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT) < The principle of operation of the GCCCP converter can be divided into two regions of operation as shown in Fig.…”

Section: A State-of-the-art Tfet-based Charge-pumpsmentioning

confidence: 99%

Insights Into Tunnel FET-Based Charge Pumps and Rectifiers for Energy Harvesting Applications

2017

IEEE Trans. VLSI Syst.

Abstract-In this work the electrical characteristics of Tunnel FET (TFET) devices are explored for energy harvesting frontend circuits with ultra-low power consumption. Compared to conventional thermionic technologies the improved electrical characteristics of TFET devices are expected to increase the power conversion efficiency (PCE) of front-end charge-pumps and rectifiers powered at sub-μW power levels. Under reverse bias conditions the TFET device presents particular electrical characteristics due to the different carrier injection mechanism. A negative differential resistance (NDR) is observed at low reverse bias and high drift diffusion (DD) current is observed at high reverse bias, thus degrading the efficiency of low-power front-end circuits and limiting their operation range. Therefore, in order to take full advantage of the TFET electrical characteristics in front-end energy harvesting circuits, different circuit approaches are required. In this work we propose and discuss different topologies for TFET-based charge-pumps and rectifiers for energy harvesting applications.Index Terms-Charge-Pump, Energy Harvesting, Passive Rectifier, Thermogenerator, Tunnel FET, Ultra-Low Power. I. INTRODUCTIONHE emerging Tunnel Field-Effect Transistor (TFET) has been considered an attractive alternative to replace conventional CMOS technologies in ultra-low power and energy efficient computing applications [1][2][3][4][5][6][7]. In contrast to thermionic devices, the high energy filtering of the band -toband tunneling (BTBT) carrier injection mechanism characterizes the TFET device with a sub-threshold slope (SS) below 60 mV/dec (at room temperature) and lower leakage current.Simulation results show that TFET devices present better electrical characteristics than conventional technologies at sub-0.25 V operation [8]. On the other hand, TFETs conduct less current at voltages around 1 V, and thereby their use is envisioned for low voltage, low performance applications.T his paragraph of the first footnote will contain the date on which you submitted your paper for review. This work was supported by the Portuguese funding institution FCT (Fundação para a Ciência e a T ecnologia) and Spanish Ministry of Economy (MINECO) and ERDF funds through project T EC2013-45638-C3-2-R (Maragda).D. Cavalheiro and F. Moll are with the Department of Electronic Engineering, Polytechnic University of Catalonia, Jordi Girona, 31, 08034, Barcelona, francesc.moll@upc.edu).S. Valtchev is with the Department of Electrical Engineering, New University of Lisbon FCT , Quinta da T orre, 2829-516 Caparica, Portugal (e-mail: ssv@fct.unl.pt).As energy harvesting transducers produce low output voltage values from typical ambient conditions with small temperature gradients (case of thermogenerators) and low RF power (antennas powered by electromagnetic radiation), energy conversion circuits are required to increase these values for use by the electronic systems . Under extreme low voltage scenarios, TFETs appear as an interesting device to implement the...

“…1, the gate cross-coupled (GCC) charge pump topology is presented. This topology has been proved to present better conversion performance at low input voltage values compared to other DC-DC converter topologies [5]. The principle of operation of the GCC converter can be divided into two regions.…”

Section: Gate Cross-coupled Charge Pumpmentioning

confidence: 99%

“…Besides the inherent switching losses that characterize these converters, the main difficulty in achieving a good power conversion performance at low input voltage (sub-0.25 V) and low power levels (sub-µW) is related to the high conduction losses of conventional transistors applied in the conversion process [5]. Thermionic injection transistors as MOSFETs and FinFETs are characterized by a minimum subthreshold-slope swing of 60 mV/dec (room temperature).…”

Section: Introductionmentioning

confidence: 99%

Novel charge pump converter with Tunnel FET devices for ultra-low power energy harvesting sources

2015 IEEE 58th International Midwest Symposium on Circuits and Systems (MWSCAS)

2015

Abstract-Compared to conventional technologies, the superior electrical characteristics of III-V Tunnel FET (TFET) devices can highly improve the process of energy harvesting conversion at ultra-low input voltage operation (sub-0.25V). In order to extend the input voltage/power range of operation in conventional charge pump topologies with TFET devices, it is of the major importance to reduce the band-to-band tunneling current when the transistor is under reverse bias conditions. This paper proposes a new charge pump topology with TFET devices that attenuate the reverse losses, thus improving the power conversion efficiency (PCE) in a broader range of input voltage values and output loads. It is shown by simulations that compared with the conventional gate cross-coupled charge pump and considering an input voltage of 640 mV, the proposed topology reduces the reverse losses from 19 % to 1 %, for an output current of 10 µA. For this case, the PCE increased from 63 % to 83 %.