Ultra-Low Power Wireless SoCs Enabling a Batteryless · PDF file 2015-08-21 ·...

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Transcript of Ultra-Low Power Wireless SoCs Enabling a Batteryless · PDF file 2015-08-21 ·...

  • August 2015

    Ultra-Low Power Wireless SoCs Enabling a Batteryless IoT

    Dr. Benton Calhoun and Dr. David Wentzloff co-CTOs

  • ©PsiKick 2015 2

    Today’s IoT… is messy

    The “Internet of Things”

    Figure from venturescanner.com

  • ©PsiKick 2015 3

    Today’s IoT… is limited by hardware

    Most wireless IoT devices use:  … MCU at 10s of MHz and 1s of mA  … Radio at 5-10s of mA (e.g. BLE)  … Battery  … Active power in 10s to 100s of mW  … Achieve “Low Power” by duty cycling, or

    turning OFF for large fractions of time  Limited in functionality or lifetime

  • ©PsiKick 2015 4

    Next Wave of Computing: “Internet of Things”

    1960s

    1980s

    1990s

    2010s

    2000s

    2015

    2025: 1 trillion wireless sensors

    2020: 50 billion connected devices

    Today’s IoT Devices –

    NOT going to get

    us to 1 Trillion

  • ©PsiKick 2015 5

    Powering 1 Trillion Sensors...

    BATTERIES

     Today’s RF ICs = 10s to 100s mW ACTIVE

     with current batteries 

    hours/days/months

     No “Moore’s Law” for energy density

     1T x 10 yr. batteries = 275M

    replacements/recharges per day

     THE ANSWER, but...

     It only delivers 10s of µWs / cm2

     Versus 10s to 100s of mWs

     Need 2-3 order of magnitude

    improvement

     So, power target of 20-30 µWs

    Need wireless SoCs @ 1/1000th of today’s power consumption

    Piezo

    Indoor Solar

    Thermal Gradient

    RF Induction

    ENERGY HARVESTING

  • ©PsiKick 2015 6

    Harvested Power = PHARV(t)

    Consumed Power

    = PLOAD(t)

    Estorage (cap)

    PLOAD may exceed PHARV for some time periods

    Constraint on power used over any time period:

    Good: PHARV ↑ Estorage↑ PLOAD ↓

    VKILL EUSABLE

    dttPtPEt HARV

    t

    LOADUSABLE )]()([, 0

     

    Self-powered Operation

  • ©PsiKick 2015 7

    Power Limitations for IoT

    Harvestable power: ~10s of µW/cm2

  • ©PsiKick 2015 8

    Power Limitations for IoT

    ACTIVE power today: ~1s to 100s of mW

    Harvestable power: ~10s of µW/cm2

  • ©PsiKick 2015 9

    Power Limitations for IoT

    ACTIVE power today: ~1s to 100s of mW

    Harvestable power: ~10s of µW/cm2

    Need to reduce power active power by ~1000X to < 20-30µW

  • ©PsiKick 2015 10

    What can you do with 20 – 30 µW ACTIVE power?

  • ©PsiKick 2015 11

    Agenda

     Proof of Concept: Self powered University SoCs  Self-powered Wakeup Radio  Self-powered SoC for the IoT

  • ©PsiKick 2015 12

    What can you do with 20 – 30 µWs? A lot.

    19 µW Wearable ECG / EEG / EMG 6.46 µW Wireless Activity Monitor

     Activity Monitor Demo:  3-axis accelerometer data  Extract posture, activity  Build histogram of activity Stream

    raw data over TX (10m range)

     Harvest from PV with MPP tracking and 75% efficiency end-end

     No battery

     6.46 µW total power  ISSCC 2015

     Wearable ExG  Continuous ECG  Extract heart rate intervals  Detect atrial fibrillation  RF updates every ~3-5s  Powered by body heat with

    Thermoelectric Generator  No battery

     19 µW total ACTIVE power  ISSCC 2012

  • ©PsiKick 2015 13

    Digital Sub- Threshold Circuit

    Operation

     Low-voltage, sub- threshold digital circuits

     Devices are “off”, resulting in 10X power savings

    Low-Power RF Expertise

     Extremely low power radio frequency

     10+ years developing low-power/high- performance RF

    System-level Integration

     Tight system integration dramatically improves efficiency

     “Un-blocks”

     Understand and optimize for lowest joules per operation

    Approach to Achieving Ultra Low Active Power

    Key breakthroughs in...

    …resulting in a new paradigm of circuit design

    Trade-offs

     RF Range – sweet spot between 1 m and 4 km; data rate between 1 Mb/s and 1 kb/s

     Processor Speed – sweet spot between 100s kHz and 10s MHz

  • ©PsiKick 2015 14

    Agenda

     Proof of Concept: Self powered University SoCs  Self-powered Wakeup Radio  Self-powered SoC for the IoT

  • ©PsiKick 2015 15

    Self Powered Wakeup Chip (PK1001) Application

    Existing

    IoT Device

    (Main RF Chipset)

    PK1001 GO!

    PK1001 powered from

    a harvested energy

    source and charges an

    energy storage device

    RF signal addressing

    detected. PK1001

    issues interrupt to

    Main RF chipset

    1

    Main RF chipset

    communicates with

    handset. Decides when

    to go to sleep

    2 3

    http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=CwHZWChOSuix_M&tbnid=bW44k_uLQvvtjM:&ved=0CAUQjRw&url=http://mermodynamics.com/calmdown/iphone.html&ei=QyMcUsf3NbPH4APouoGgAQ&psig=AFQjCNGVKuZk00tlvp9Vq1ZbqM7xMM-6KA&ust=1377662109854638 http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=U1PMMvIVgqzu2M&tbnid=dYIFAInULDTUYM:&ved=0CAUQjRw&url=http://www.clker.com/clipart-wireless-antenna-1.html&ei=gyQcUprDOu364AOxi4HwAw&bvm=bv.51156542,d.dmg&psig=AFQjCNGQXGMQu8OuE9jr3-RGsv08alVrOw&ust=1377662444568646 http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=5X4_VGlpbE3eDM&tbnid=uDkl02tAfOSLTM:&ved=0CAUQjRw&url=http://www.psdgraphics.com/psd-icons/battery-levels-icons/&ei=oSYcUrzcGrH94AOO1IGIBw&psig=AFQjCNEIwyu_-PaPeXIX6kslJu-mEvgv0g&ust=1377663000139374 http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=BeX7FLDlZzMoJM&tbnid=vd8B_n0_AoLCnM:&ved=0CAUQjRw&url=http://www.northcoastirwmp.net/Content/10369/2/Solar.html&ei=uCEcUo__H5P84AP1kYGICA&bvm=bv.51156542,d.dmg&psig=AFQjCNFwZXkdYuQt6YY3BsLMB5T0Ib4nDw&ust=1377661735336939 http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=U1PMMvIVgqzu2M&tbnid=dYIFAInULDTUYM:&ved=0CAUQjRw&url=http://www.clker.com/clipart-wireless-antenna-1.html&ei=gyQcUprDOu364AOxi4HwAw&bvm=bv.51156542,d.dmg&psig=AFQjCNGQXGMQu8OuE9jr3-RGsv08alVrOw&ust=1377662444568646

  • ©PsiKick 2015 16

    PK1001 Main Features

     World’s lowest-power wake-up radio solution – A self-powered wireless trigger – ~500nW ACTIVE system power measured

    • No radio duty cycling – 3-7 meter wireless range – Retrofit existing IoT devices to reduce power from mW to

  • ©PsiKick 2015 17

    Block Diagram of Wakeup Radio Chip

    Clock generation

    psikick

    Multiple VDDs 0.5V, 1.0V, 2.5V

    Off-chip battery Or cap

    SPI Slave

    Regulator Interrupt Handler

    Boost converter

    Harvesters

    Clock out

    Clock ext

    VDDs

    PMU

    4b

    INT_OUT

    32.768 kHz XTAL

    RF

    ULP RX (path 1,2)

    BLE Wakeup RF harvest

    INT_IN 31b Code Wakeup

    Data processing

    Counters

    Memory Mapped Register File

    Reset Handler

    General Purpose Driver

    RESET_BAR

    GPD

  • ©PsiKick 2015 18

    Block Diagram of Wakeup Radio Chip

    Clock generation

    psikick

    Multiple VDDs 0.5V, 1.0V, 2.5V

    Off-chip battery Or cap

    SPI Slave

    Regulator Interrupt Handler

    Boost converter

    Harvesters

    Clock out

    Clock ext

    VDDs

    PMU

    4b

    INT_OUT

    32.768 kHz XTAL

    RF

    ULP RX (path 1,2)

    BLE Wakeup RF harvest

    INT_IN 31b Code Wakeup

    Data processing

    Counters

    Memory Mapped Register File

    Reset Handler

    General Purpose Driver

    RESET_BAR

    GPD

    Clock Gen: 32kHz clock with counters for interrupt generation and time keeping

  • ©PsiKick 2015 19

    Block Diagram of Wakeup Radio Chip

    Clock generation

    psikick

    Multiple VDDs 0.5V, 1.0V, 2.5V

    Off-chip battery Or cap

    SPI Slave

    Regulator Interrupt Handler

    Boost converter

    Harvesters

    Clock out

    Clock ext

    VDDs

    PMU

    4b

    INT_OUT

    32.768 kHz XTAL

    RF

    ULP RX (path 1,2)

    BLE Wakeup RF harvest

    INT_IN 31b Code Wakeup

    Data processing

    Counters

    Memory Mapped Register File

    Reset Handler

    General Purpose D