Catherine Dehollain

An 11-Mb/s 2.1-mW Synchronous Superregenerative Receiver at 2.4 GHz

This paper presents a low-voltage low-power high-speed superregenerative receiver operating in the 2.4-GHz industrial-scientific-medical band. The receiver uses an architecture in which, thanks to the presence of a phase-locked loop, the quench oscillator is operated synchronously with the received data at a quench frequency equal to the data rate. This mode of operation has several benefits. Firstly, the traditional problem of poor selectivity in this type of receiver is to a large extent overcome. Secondly, considerably higher data rates can be achieved than with classical receivers. Thirdly, the bit envelope can be matched to the superregenerative oscillator, which improves sensitivity. The receiver includes an RF front end optimized to support high quench frequencies at low supply voltages, responding to todays increasing demand for high speed and low power consumption. The prototype implemented is very simple and achieves a data rate of 11 Mb/s with a current consumption of 1.75 mA at a supply voltage of 1.2 V - an excellent tradeoff between cost, performance, and power consumption.

A low-power 1-GHz super-regenerative transceiver with time-shared PLL control

A Low-Power transceiver for ISM applications in the 900MHz band has been integrated in a 0.8µm BiCMOS technology. The receiver with its PLL draws 3.6mW for a sensitivity of -105dBm and the Emitter current consumption is 6mA for a 0dBm output power.

Improvement of power efficiency of inductive links for implantable devices

This paper presents the analysis of inductive links for remote powering of implantable devices and a method to improve the power link efficiency by modifying the geometrical parameters of planar spiral inductors. The analysis of the inductive links includes a model for the inductors, which is more accurate for larger bandwidths. The corresponding equations for the power and voltage transfer functions in the inductive links are solved by using MATLABpsilas Symbolic Math Toolbox. These equations are verified in Agilent ADS, and the results perfectly match. Besides the analysis, a method to improve the power efficiency by changing the geometrical parameters of the spiral inductors is proposed.

Inductive Power Link for a Wireless Cortical Implant With Two-Body Packaging

This paper presents an inductive power link for remote powering of a wireless cortical implant. The link includes a Class-E power amplifier, a gate driver, an inductive link, and an integrated rectifier. The coils of the inductive link are designed and optimized for remote powering from a distance of 10 mm (scalp thickness). The power amplifier is designed in order to allow closed-loop control of the power delivered to the implant, by controlling the supply voltage. Moreover, a gate driver is added to the system to drive the power amplifier and to characterize the gate losses. A new packaging topology is proposed in order to position the implant inside a hole in the cranial bone, without occupying a large area, but still obtaining a short distance between the remote powering coils. The package is fabricated by using biocompatible materials such as PDMS and Parylene-C. The power efficiency of the remote powering link is characterized for a wide range of load power (1-20 mW) delivered from the rectifier and is measured to be 24.6% at nominal load of 10 mW.

A System for Wireless Power Transfer of Micro-Systems In-Vivo Implantable in Freely Moving Animals

A system for wireless power transfer of micro-systems in-vivo implantable in small animals is presented. The described solution uses a servo-controlled transmitter moved under the animal moving space. The solution minimizes the power irradiation while enabling animal speeds up to 30 cm/s. An x-y movable magnetic coil transmits the required power with a level able to keep constant the received energy. A permanent magnet on board of the implantable micro-system and an array of magnetic sensors form a coil tracking system capable of an alignment accuracy as good as 1 cm. The power is transferred over the optimized remote powering link at 13.56 MHz. The received ac signal is converted to dc voltage with a passive full-wave integrated rectifier and the voltage regulator supplies 1.8 V for the implantable sensor system. Experimental measurement on a complete prototype verifies the system performance.

Instrumented Knee Prosthesis for Force and Kinematics Measurements

In this work, we present the general concept of an instrumented smart knee prosthesis for in-vivo measurement of forces and kinematics. This system can be used for early monitoring of the patient after implantation and prevent possible damage to the prosthesis. The diagnosis of defects can be done by detecting the load imbalance or abnormal forces and kinematics of the prosthetic knee in function. This work is a step towards the fabrication of an instrumented system for monitoring the function of the knee in daily conditions. Studying the constraints of commercially available prostheses, we designed a minimal sensory system and required electronics to be placed in the polyethylene part of prostheses. Three magnetic sensors and a permanent magnet were chosen and configured to measure the prosthetic knee kinematics. Strain gauges were designed to measure the forces applied to the polyethylene insert. Kinematic and force measurements were validated on a mechanical knee simulator by comparing them to different reference systems. Embedded electronics, including the A/D converters and amplifier were designed to acquire and condition the measurements to wirelessly transmit them to an external unit. By considering the necessary power budget for all components, the optimum coil for remote powering was investigated. The necessary rectifier and voltage doubler for remote powering were also designed. This is the first system capable of internally measuring force and kinematics simultaneously. We propose to package the system in the polyethylene part, bringing versatility to the instrumented system developed, as the polyethylene part can be easily modified for different types of prostheses based on the same principle, without changing the prosthesis design.

A Closed-Loop Remote Powering Link for Wireless Cortical Implants

This paper presents a closed-loop remote powering link for wireless cortical implants. The link operates from a single power supply at the external reader and delivers power to the implant adaptively under changing load conditions. A feedback information is sent from the implant to the external reader about the power consumption in the implant and the external reader adapts the amount of transmitted power depending on this feedback. In addition, an in vitro measurement setup is fabricated in order to characterize the performance of the wireless energy transfer when the implant is immersed into saline solution. The implant is packaged by using biocompatible materials and the operation of the remote powering link is demonstrated in air and in vitro for a wide range of load power delivered from the voltage regulator. The power transfer efficiency of the overall closed-loop remote powering link is measured to be 10.6% in vitro at nominal load power of 10 mW. Finally, the operation of the implant in vitro is demonstrated over a five-week period.

A Discrete-Components Impulse-Radio Ultrawide-Band (IR-UWB) Transmitter

We describe an impulse-radio ultra-wideband (IR-UWB) transmitter made with off-the-shelf discrete components. It was initially designed to be used in a UWB testbed for measurement and algorithm validation purposes. There already exist several versions of an IR-UWB transmitter, but many of them are made with custom designed integrated chips. For this reason, it is very difficult for anyone other than their designers to test and measure with the same material. We describe all the information the readers would need to build their own IR-UWB transmitter.

A 0.24-nJ/bit Super-Regenerative Pulsed UWB Receiver in 0.18-

This paper describes a receiver system design for impulse-radio ultra-wideband (IR-UWB) that operates at two carrier frequencies-3.494 and 3.993 GHz-with a 10-Mbps data rate. To reduce the power consumption of the front-end amplifiers, a super-regenerative architecture is used. An integrated circuit, implemented in a CMOS 0.18-μm technology and operating with a 1.5-V power supply, exhibits energy consumption of 0.24 nJ/bit with a measured sensitivity of -66 and -61 dBm at 3.494 and 3.993 GHz, respectively, with a BER of 10-3. Also included on the integrated circuit is an automatic tuning circuit based on a digital phase-locked loop that is used to set the resonant frequency of the super-regenerative block.

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Low power impulse radio-ultra wide band(IRUWB) receivers have potential application in the area of wireless sensor networks. In this paper the possibility of super-regenerative receivers for pulse detection is demonstrated. The super-regenerative receiver is implemented in a 0.18 mum CMOS process for a 500 MHz bandwidth (-3 dB) centered at 3.8 GHz. The receiver is operating at 1.5 V and consumes a peak current of 7.5 mA. The receiver shows a 16.5 mV amplitude difference between the presence and absence of a pulse at an average received power of -91.3 dBm at a pulse repetition rate of 1 MHz.