Power Matters.

Power Matters

ULP Wireless Technology for Bio-sensors and Energy Harvesting Reghu Rajan

September, 2012

Power Matters.

Presentation Overview

Overview of wireless telemetry and sensors in healthcare

Radio requirements for sensors in wireless healthcare

Applications & energy harvesting

Conclusion

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Implanted Medical Telemetry • Communication with implanted medical devices

External Medical Telemetry • Communication with patient sensors located near or on the skin

– Sensors/instrument Bedside monitor Remote station

Network classifications • (a) Body or Personal Area Network (BAN or PAN)

– Transmission into or around body

• (b) Human Area Network (HAN)

– Transmission using body

Key Areas in Medical Telemetry

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Operating Room

Home Monitoring

Doctor’s Office

Typical Applications And Improvements to Patient’s Quality of Life

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Improving quality-of-life for an

aging population

– Increasingly mobile, independent population

driving demand for home-based healthcare

– Pain or symptom management for

range of diseases

– Enabling new, breakthrough treatments

Reducing healthcare costs

– Preventative diagnostics

– Shorten surgery time, eliminate some

surgical procedures

Enable new wireless applications and therapies to improve

patient care and lower healthcare costs

Functional stimulation

Hearing assistance

Cardiac pacemaker/ Energy harvesting

Defibrillator

Drug delivery/ Insulin pump

Bladder control

Wireless endoscopy

Deep brain stimulation/ Neurostimulator

Applications with Sensing and Therapies

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Wireless Monitoring is a Key Element of the Transition

Involves implant and non-implant radio

Technology used by

healthcare facilities

– To lower costs

– To improve patient outcomes

Healthcare delivered outside

formal institutions

– Aging world population

– Need for better management

of chronic diseases

Explosive growth predicted

for developing countries

– Enabled by remote healthcare

Moving the Cycle of Care from Hospital to Home

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Ultra Low Power QoS Reliable Secure Medical Quality

External Sensing- Use Cases and Technology

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Common key requirement:

Low power for long battery life

Low peak current due to high impedance power source

External Sensing- Continuous Monitoring Sensors

Energy Harvesting

• Body heat energy harvesting (Seebeck effect based)

• Motion energy harvesting

Disposable sensors

• Temperature plaster

• Ovulation detection etc.

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Radio Requirements for Ultra Low-power Wireless Sensors

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ULP Radio

Supply Voltage

Peak & Average current

Network protocol

Link Frequency Antenna

Impedance

Footprint

Streaming Capability & data

rate

Wake-up feature

Key Considerations for Radios in Wireless Sensors

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Supply Voltage

Sub 2 Volts operation

– For single cell applications

(sometime down to 1V)

– Different battery chemistries

Maintain TX and RX performance

– PA and matching network design

– Power supply rejection

Current profile without excessive peaks to fit supply impedance

Key Features for Radios in Wireless Sensors

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Peak and Average Current

Low peak current

While average low power can be achieved

by extreme duty-cycling, this may not work

with energy sources that have higher

impedance such as thin-film , zinc-air

batteries and energy harvesting

transducers etc.

Good power-supply rejection

Efficient sniff or wakeup features

For non streaming application that require

waking up of radio, sniffing can be a

significant source of average power

consumption

Key Features for Radios in Wireless Sensors

TZ1030/53 – Toumaz

CC11/24xx – Texas Instruments

ZW0301 – Sigma Designs

EnOcean – 868MHz modules

ZL70250 – Microsemi ULP RFIC

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Link frequency

Application dependent frequency and choice of radio

The band frequency can affect the link quality and power consumption for

medical telemetry. The MICS band, 402-405MHz, is ideal for implant

telemetry due to low tissue absorption.

For non-implant applications ISM band at 900MHz and 2.4GHz are

available, but for lower path loss, less directivity and lower power

consumption 900MHz maybe better suitable than 2.4GHz.

Free-space path-loss is 8.7dB higher for 2.4GHz compared to 900MHz

High data-rate may require 2.4GHz at the cost of power

Key Features for Radios in Wireless Sensors

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Antenna Impedance

Non-standard antenna impedance is becoming more common due to

specialized antenna size requirements and low supply voltage.

Careful planning of TX/RX circuits and antenna can minimize requirement

on matching network and hence the insertion loss between the radio and

the antenna and cost.

Non-standard impedance helps more efficient PA design for given supply

voltage

Key Features for Radios in Wireless Sensors

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Network Protocol

Several standards are currently available for network protocol such BLE,

Ant, Zigbee etc.

Medical data varies from a applications that requires few bytes/s to few

Mbps

Most of standard protocols have huge over heads that decrease the

payload efficiency for small data rates and packet sizes

Therefore ‘one size fits all’ strategy

does not work for optimum power

consumption in medical telemetry!

Key Features for Radios in Wireless Sensors

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Efficient wake-up strategies can be crucial for

low average power consumption, especially for

implant radios and low-power sensors.

Multi-stage wake-up scheme with smart Rx

correlation for progressive waking up of stages

to save power from false wake-ups.

Wake-up feature

Key Features for Radios in Wireless Sensors

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Applications and Energy Harvesting

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Relative

Market Share

Reliability

Possible Future Trends as

IEEE 802.15.6 emerges

Faster Growth as cost

lowers for 802.15.6 & 15.4 Limited into implant market

Low Power Bluetooth

Custom

IEEE 802.15.6 & 15.4

Reliability Low Medium High High

Wireless Cost Low Low Medium High

Environment Consumer,

home,

rehabilitation

Aged Care,

General

Hospital

Operating

Room,

Intensive

Care

Implant

Examples Fitness Monitor Temperature,

Weight

ECG, Blood

Oximeter

Implant

Devices

Wireless Sensing and Radio Technology Trends

Energy Harvesting

applications

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Source St Jude

Annual Report

2009

Growth Area: Neuro-sensing and Modulation

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Example: Remote Sensing and Pacing

ZL70102 Integrated Circuit

• Transceiver designed for base stations and Implanted Medical Device (IMD)

RF Modules

• Fully tested, implantable RF modules

Reference Designs

• IMD and base station

Design Tools

• Software, documentation, app notes

• Evaluation kits

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Growth are: Baroreflex Activation Therapy for Blood Pressure

Startup CVRx • Minneapolis (largest VC financing in state) • Electrically activates the carotid baroreceptors, the body’s

natural cardiovascular regulation sensors

• Brain senses stimulation and regulates both sympathetic and parasympathetic activity in the heart, blood vessels and kidneys

• These changes result in maintained or improved cardiac output at a reduced blood pressure thereby reducing the load on the arteries and heart.

Mircosemi wireless transceiver used for communication in the Barostim neo™

system

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Healthy Small Bowel

Example: Wireless Camera Capsule- Given Imaging

Size: 11 x 26 mm

Weight: < 4 gram

View angle: 140o

at each end

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Example: Wireless Camera Capsule- Given Imaging

World’s First Swallowable Wireless Camera Capsule, from Given Imaging, including Microsemi’s ULP RF Transmitter

Approximately 57,000 pictures transmitted over 8 hours

Second generation incorporates technology to define

pill location

Microsemi’s RF

IC

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Example: Wireless Hearing Aid- Remote Sound Sensing

Continuous wireless stereo audio steaming to hearing aids: Uses

Microsemi’s ULP ISM RF Transceiver

Microsemi’s

ISM RF IC

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Energy Harvesting based Wireless sensor

Block diagram of typical EH based sensor

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Energy Harvesting based Wireless sensor

Practical sensor based on ZL70250 ULP radio and Perpetua Thermo-Electric Generator

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Thank You