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Power Management and Communication for Remotely Power Management and Communication for Remotely
Powered Sensor NodesPowered Sensor NodesMehrdad Azizi, and Catherine Dehollain
Radio Frequency Integrated Circuit Group (RFIC), Ecole Polytechnique Fédérale de Lausanne (EPFL)
IntroductionThis research focuses on development of wirelessly powered integrated circuits (ICs).This research focuses on development of wirelessly powered integrated circuits (ICs).
The circuits should be able to wirelessly communicate with the base station and read
the data from various sensors or control different actuators.
The Main Challenges:
Implementing the internal circuits of the sensor node with low power consumption.
Increasing the efficiency of wireless power transmission.
Example ApplicationsECG Monitoring SystemBlood Pressure Monitoring System
J. Yoo, et al., “A 5.2 mW Self-Configured Wearable Body Sensor
Network Controller and a 12 μW Wirelessly Powered Sensor for a
Continuous Health Monitoring System,” IEEE Journal of Solid-State
Circuits, Jan 2010.P. Cong et al., “A Wireless and Battery less 10-Bit Implantable Blood Pressure Sensing Microsystem
With Adaptive RF Powering for Real-Time Laboratory Mice Monitoring,” IEEE Journal of Solid State Intraocular Pressure & With Adaptive RF Powering for Real Time Laboratory Mice Monitoring,” IEEE Journal of Solid State
Circuits, Dec. 2009.
Cardiac PacemakerCochlear Implants
Intraocular Pressure &
Temperature Monitor
S.Lee, et al., "A Programmable Implantable Micro-Stimulator
SoC with Wireless Telemetry: Application in Closed-Loop
Endocardial Stimulation for Cardiac Pacemaker,“ in ISSCC cochlearamericas.com
Y. C. Shih, T. Shen, and B. P. Otis, “A 2.3 uW
wireless Intraocular pressure/temperature
monitor,” IEEE Journal of Solid State Circuits, vol.
System Building Blocks
Endocardial Stimulation for Cardiac Pacemaker
Digest of Technical Papers, Feb. 2011, pp 44-45.
” IEEE Journal of Solid State Circuits
46, no. 11, pp. 2592-2601, Nov. 2011.
System Building Blocks
Implantable
SensorsADC
Sensor
Interface
Processing
Unit
Power & Clock
Power
ManagementCommunication
Data @ VDC@ 13.56 MHz
Data @
868 MHz Remotely Powered Integrated Circuit
Receiver
Base Station
PowerPA
Base Station
VS
VDC
Remote Powering Remote Powering Main Blocks for Wireless Power Transfer:
Functions of Different Blocks:PA is converting the DC power from
Level AdaptivWireless Voltage Regulation PA is converting the DC power from
the battery to AC power for
coupling.
L1 & L2 are coupling energy from
base station to remotely powered
VDD
Level
Detector
Adaptiv
Supply
base station to remotely powered
side.
Rectifier is converting coupled AC
voltage to DC voltage.
L1 L2
PAC1
C2
Rectifier
CL
RegulatorM12
VS Class E
Processing
Blocks
T PA Coupling Re ctifier Re gulatorη = η ×η ×η ×ηTotal Link Efficiency:
voltage to DC voltage
Regulator is stabilizing the voltage for
processing blocks.
Wireless Voltage Regulation can be
used to compensate the variation of
Base Station Remotely Powered Node
Skin
T PA Coupling Re ctifier Re gulatorη = η ×η ×η ×ηTotal Link Efficiencyused to compensate the variation of
the coupling between the inductors.
Performance of the Fabricated Rectifier:
Bias Vb1
m
VRec
Rectifier Performance
Technology 0.18 um
Frequency 13 56 MHz
CL
Mp1MN1C4C1
MN2 Mp2C3 C2
Bias Vb2
250 um
105 u
m
10 ns
500 mV
VIN+
VIN-
VIN=2.1 VP
RL=9.1 KOhm
GND ref
Frequency 13.56 MHz
Output Power 300 uW
Output Voltage 1.65 V
Peak Input Voltage 2 1 VPeak Input Voltage 2.1 V
PCE (Simulated) 85 %
PlaCiTUSPlaCiTUSPlaCiTUSPlaCiTUS RTD 2010PlaCiTUSPlaCiTUSPlaCiTUSPlaCiTUS
Power Management and Communication for Remotely Power Management and Communication for Remotely
Powered Sensor NodesPowered Sensor NodesMehrdad Azizi, and Catherine Dehollain
Ecole Polytechnique Fédérale de Lausanne (EPFL)
Low Power Communication Standard Transmitter Low Power TransmitterStandard Transmitter: Low Power Transmitter:
Free Running
Oscillator
Digital
ModulatorDAC
Mixer
PAData from
Data from
SensorsFrequency
Synthesizer
Data from
Sensors
Standards transmitters are sutiable for high data
rates and require power hungry blocks like
frequency synthesizers and power amplifiers
Low data rate of biomedical signals and short
communication range make it possible to use low
precision transmitter by directly modulating the
free running oscillatorfrequency synthesizers and power amplifiers.
Performance of the Fabricated Transmitter:
free running oscillator.
RAdjust
M4
M1
C1
M2
M3
120 u
m
Digital
Control
VSupply
M3 M4
Oscillator PerformanceC2
190 umL1
Off Chip
C2C1Technology 0.18 um
External Inductor 27 nH
Frequency 700 – 802 MHz (5 Bit) M1 M2
RAdjust1.5 cm
External Inductor as
Transmitter Antenna Supply Voltage 1 V
Supply Current 65 – 176 uA (4 Bit)
Data
Demonstration of the Concept
V
L1 L2
PAC1
C2 CLReg.
M12
VS Class ETransmitter
VDC
L3 ReceiverSensor
Interface
Base Station Sensor Node Base Station
Interface
Remote Powering Data Communication
Performance of Different Blocks:
Data Transmitter
Operation Frequency 868MHz
Power Consumption 840 uW
Data Rate 12 Kbps
Data Receiver
Class E PA
Operation Frequency 13.56 MHz
Power Consumption 370 mW
Data Receiver
Operation Frequency 868 MHz
Data Rate 12 Kbps
Sensitivity -85 dBm
Power Consumption 152 mW
Data Link Operation Distance 40 cm
System Setup:
Rectifier & Clock generationRectifier & Clock generation
Rectified Voltage 4 V
Regulated Voltage 3 & 1.8 V
Clock Frequency 192 KHz
Transmitter
Sensor
Remotely
Powered
Power
Amplifier
Receiver
Received Data
Power Link Operation Distance 1.5 cm
4.3 %Link Efficiency: PA+ Coupling+Rectifier
Clock Frequency 192 KHz
Powered
Module
4.3 %Link Efficiency: PA+ Coupling+Rectifier
Expected Contributions
This research aims to improve the already existing platforms with:This research aims to improve the already existing platforms with:
Intelligent usage of the harvested power by modifying the system level design.
Extending the system operation to multiple implantsExtending the system operation to multiple implants.
