N. Joehl

Bio: N. Joehl is an academic researcher from École Polytechnique Fédérale de Lausanne. The author has contributed to research in topics: BiCMOS & Phase-locked loop. The author has an hindex of 11, co-authored 23 publications receiving 2356 citations.

A 4-MHz CMOS continuous-time filter with on-chip automatic tuning

Abstract: A third-order elliptic low-pass continuous-time filter with a 4-MHz cutoff frequency, integrated in a 3- mu m p-well CMOS process, is presented. The design procedure is based on the direct simulation of a doubly terminated LC ladder filter by capacitors and fully balanced, current-controlled transconductance amplifiers with extended linear range. The on-chip automatic tuning circuit uses a phase-locked loop implemented with an 8.5-MHz controlled oscillator that matches a specific two-integrator loop of the filter. The complete circuit features 70-dB dynamic range (THD >

A 4-MHz CMOS Continuous-Time Filter with On-Chip Automatic Tuning

Abstract: This paper presents a 3rd order low-pass continuous-time filter with 4 MHz cut-off frequency, integrated in a 3 ?m CMOS process. The design approach is based on the direct simulation of a doubly-terminated LC ladder using capacitors and fully-balanced, current-controlled transconductance amplifiers with extended linear range. PLL techniques, involving a 8.5 MHz controlled oscillator that matches a specific part of the filter, are used to realize on-chip automatic tuning. The complete circuit features 71 dB dynamic range and consumes only 16 mW from a single 5 V supply.

Remotely powered addressable UHF RFID integrated system

Abstract: This paper presents a fully integrated remotely powered and addressable radio frequency identification (RFID) transponder working at 2.45 GHz. The achieved operating range at 4 W effective isotropically radiated power (EIRP) base-station transmit power is 12 m. The integrated circuit (IC) is implemented in a 0.5 /spl mu/m silicon-on-sapphire technology. A state-of-the-art rectifier design achieving 37% of global efficiency is embedded to supply energy to the transponder. The necessary input power to operate the transponder is about 2.7 /spl mu/W. Reader to transponder communication is obtained using on-off keying (OOK) modulation while transponder to reader communication is ensured using the amplitude shift keying (ASK) backscattering modulation technique. Inductive matching between the antenna and the transponder IC is used to further optimize the operating range.

A model for /spl mu/-power rectifier analysis and design

Abstract: This paper proposes a linear two-port model for an N-stage modified-Greinacher full-wave rectifier. It predicts the overall conversion efficiency at low power levels where the diodes are operating near their threshold voltage. The output electrical behavior of the rectifier is calculated as a function of the received power and the antenna parameters. Moreover, the two-port parameter values are computed for particular input voltages and output currents for the complete N-stage rectifier circuit using only the measured I-V and C-V characteristics of a single diode. To validate the model a three-stage modified-Greinacher full-wave rectifier was realized in an silicon-on-sapphire (SOS) CMOS 0.5-/spl mu/m technology. The measurements are in excellent agreement with the values calculated using the presented model.

Design and Optimization of Passive UHF RFID Systems

Abstract: Radio Frequency IDentification (RFID) stores and retrieves data using devices called RFID tags: objects attached to or incorporated into a product, animal or person which communicate with an RFID reader or interrogator. This book proposes a linear two-port model for an N-stage modified-Greinacher full wave rectifier, predicting the overall conversion efficiency at low power levels where the diodes are operating near their threshold voltage. Included is an experimental procedure to measure how impedance modulation in the tag affects the signal at the reader, and a useful tool for choosing the most appropriate impedances.

Design of Analog CMOS Integrated Circuits

Abstract: The CMOS technology area has quickly grown, calling for a new text--and here it is, covering the analysis and design of CMOS integrated circuits that practicing engineers need to master to succeed. Filled with many examples and chapter-ending problems, the book not only describes the thought process behind each circuit topology, but also considers the rationale behind each modification. The analysis and design techniques focus on CMOS circuits but also apply to other IC technologies. Table of contents 1 Introduction to Analog Design 2 Basic MOS Device Physics 3 Single-Stage Amplifiers 4 Differential Amplifiers 5 Passive and Active Current Mirrors 6 Frequency Response of Amplifiers 7 Noise 8 Feedback 9 Operational Amplifiers 10 Stability and Frequency Compensation 11 Bandgap References 12 Introduction to Switched-Capacitor Circuits 13 Nonlinearity and Mismatch 14 Oscillators 15 Phase-Locked Loops 16 Short-Channel Effects and Device Models 17 CMOS Processing Technology 18 Layout and Packaging

Wireless Networks With RF Energy Harvesting: A Contemporary Survey

Abstract: Radio frequency (RF) energy transfer and harvesting techniques have recently become alternative methods to power the next-generation wireless networks As this emerging technology enables proactive energy replenishment of wireless devices, it is advantageous in supporting applications with quality-of-service requirements In this paper, we present a comprehensive literature review on the research progresses in wireless networks with RF energy harvesting capability, which is referred to as RF energy harvesting networks (RF-EHNs) First, we present an overview of the RF-EHNs including system architecture, RF energy harvesting techniques, and existing applications Then, we present the background in circuit design as well as the state-of-the-art circuitry implementations and review the communication protocols specially designed for RF-EHNs We also explore various key design issues in the development of RF-EHNs according to the network types, ie, single-hop networks, multiantenna networks, relay networks, and cognitive radio networks Finally, we envision some open research directions

Circuit techniques for reducing the effects of op-amp imperfections: autozeroing, correlated double sampling, and chopper stabilization

Abstract: In linear IC's fabricated in a low-voltage CMOS technology, the reduction of the dynamic range due to the dc offset and low frequency noise of the amplifiers becomes increasingly significant. Also, the achievable amplifier gain is often quite low in such a technology, since cascoding may not be a practical circuit option due to the resulting reduction of the output signal swing. In this paper, some old and some new circuit techniques are described for the compensation of the amplifier's most important nonideal effects including the noise (mainly thermal and 1/f noise), the input-referred dc offset voltage as well as the finite gain resulting in a nonideal virtual ground at the input.

Efficient Far-Field Radio Frequency Energy Harvesting for Passively Powered Sensor Networks

Abstract: An RF-DC power conversion system is designed to efficiently convert far-field RF energy to DC voltages at very low received power and voltages. Passive rectifier circuits are designed in a 0.25 mum CMOS technology using floating gate transistors as rectifying diodes. The 36-stage rectifier can rectify input voltages as low as 50 mV with a voltage gain of 6.4 and operates with received power as low as 5.5 muW(22.6 dBm). Optimized for far field, the circuit operates at a distance of 44 m from a 4 W EIRP source. The high voltage range achieved at low load current make it ideal for use in passively powered sensor networks.