Hassene Mnif

Modeling the self-heating effect in SiGe HBTs

This paper describes a new approach for modeling the self-heating phenomena in silicon germanium (SiGe) heterojunction bipolar transistors (HBT). This approach is based on the physical resolution of the heat transfer differential equation. The model is compared to the electro-thermal model used in most commercial circuit simulators. This new approach produces the better self-heating agreement with measured data. For its validation, it is implemented into a recent compact model.

A power management system for energy harvesting and wireless sensor networks application based on a novel charge pump circuit

ABSTRACT Energy Harvesting circuits are developed as an alternative solution to supply energy to autonomous sensor nodes in Wireless Sensor Networks. In this context, this paper presents a micro-power management system for multi energy sources based on a novel design of charge pump circuit to allow the total autonomy of self-powered sensors. This work proposes a low-voltage and high performance charge pump (CP) suitable for implementation in standard complementary metal oxide semiconductor (CMOS) technologies. The CP design was implemented using Cadence Virtuoso with AMS 0.35μm CMOS technology parameters. Its active area is 0.112 mm2. Consistent results were obtained between the measured findings of the chip testing and the simulation results. The circuit can operate with an 800 mV supply and generate a boosted output voltage of 2.835 V with 1 MHz as frequency.

Transit time parameter extraction for the HICUM bipolar compact model

This paper presents a extraction procedure for the transit time parameters of the HICUM bipolar compact model. The extraction routines use as input the measured small-signal current gain in the -20 dB/decade falloff region as a function of the collector current and the collector-emitter (or collector-base) voltage. All HICUM transit time parameters are extracted in a straightforward manner, no optimisation is necessary. Especially the critical current value ICK is determined in a self consistent way.

An improved MOS charge pump circuit for low voltage operations and wireless sensor applications

This paper proposes a new low-voltage and high performance charge pump circuit suitable for implementation in standard CMOS technologies. The proposed MOS charge pumps is an energy harvesting circuit for wireless sensor. This new pump is an improvement of the basic charge transfer switches (CTSs) to generate higher output voltage. The simulation results show that the proposed circuit have high pumping gain and suitable for low-voltage.

Improved circuit model of photovoltaic cell for energy harvesting application

This paper mainly focuses on model of photovoltaic cell for energy harvesting application (EHV). This model is developed using the standard simulation software LTspice to explore the effect of electrical and physical parameters on Current-Voltage (I-V) and Power-Voltage (P-V) characteristics of photovoltaic cell (PV). The proposed model is based on mathematical equations and is described through an equivalent circuit. The developed model serves to specify the optimal conditions for operating the PV cell and define the maximum power point (MPP). It also allows the prediction of PV cell behavior as a function of temperature and ambient radiation. To demonstrate the validity of the generated model, an experimental test was performed for a PV cell (of type“ASI” from SCHOTT Company). Experimental and technical data display a good agreement with the simulated findings.

A non-coherent high speed IR-UWB receiver for biomedical implants

This paper presents a non-coherent IR-UWB receiver for biomedical implants in the human body. The IR-UWB receiver is designed using 0.18μm CMOS technology. It is based on OOK demodulation. Its bandwidth is between [1;5] GHz. The receiver comprises two main blocks: the low noise amplifier (LNA) and the demodulator. The LNA has a measured maximum voltage gain of 18dB with minimum noise figure of 0.9 dB. Measurements show that the proposed receiver operates with data rate of 4 Gbps.

A novel heuristic for the optimal design of LC voltage controlled oscillators

We propose a heuristic for the optimal sizing of LC VCO. The heuristic is an algorithm driven methodology that allows us determining optimal sizes of inductors, bias current and channel widths that minimizes the VCOpsilas phase noise. The proposed optimization methodology was applied to size a cross-coupled differential voltage controlled oscillator. This latter, designed using AMS 0.35 mum technology, achieves -118.75 dBc/Hz at 1 MHz offset from a 5.4 GHz carrier frequency with 8.0 mW consumption power.

PSO-based charge pump chip area minimization

In this paper a solution of the well-known silicon area/performance dilemma and an energy harvesting circuit for wireless sensor nodes are presented. A PSO-based integrated circuit area optimization methodology is proposed. The study is performed on a charge pump circuit, using a 0.35μm Si-CMOS process. The PSO sizing strategy has been implemented using a Spice kernel and Matlab environment. The chip size has been reduced from 583μm2 to 179μm2 after the optimization process. Simulation results from the 0.35μm parameters are given. When driving a capacitive load of 50pF, the output-generated voltage is 4V from a 1.3V input voltage. The simulated pumping gain is 3.1.

Graphical method for the phase noise optimization applied to a 6-GHz fully integrated NMOS differential LC VCO

This paper describes the design and the optimization in terms of phase noise of a fully integrated NMOS Voltage Controlled Oscillator (VCO) using a 0.25 μm BICMOS SiGe process. A three-dimensional phase noise analysis diagram and a graphical optimization approach is presented to optimize the phase noise of the VCO while satisfying design constraints such as tank amplitude, power dissipation, tuning range and start up conditions. At 2.5 V power supply voltage, the optimized VCO features a simulated phase noise of −118 dBc/Hz at 1 MHz frequency offset from a 6.12 GHz carrier. The VCO is tuned from 6.1 GHz to 7.9 GHz with a tuning voltage varying from 0 to 2.5 V, and a power dissipation of only 7.4 mW.

Design and implementation of an active inductor based LC oscillator

In this paper operation of an LC oscillator in two distinct frequency bands, dedicated respectively to Zigbee standard (2.4GHz–2.483GHz) and RFID standard (860MHz–960MHz) is presented. To perform low power consumption and low silicon area, an LC quadrature controlled oscillator using an active inductance has been used. The proposed topology has been simulated under 1.2V supply voltage using the typical model parameters of the 0.13μm CMOS process from STMicroelectronics. At the two separated frequency bands the phase noise is lower than −83dBcHz with frequency offset of 1MHz. At the same simulation condition the total power consumption is 5.5mW only.