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WIRELESS  CHARGING  PAST,  PRESENT  AND  FUTURE  

Meng He, (Maxim Integrated)

SPEAKER Meng He

Executive Business Manager, Maxim Integrated Not  only  an  engineer  focused  on  power  products,  but  also  a  passionate  leader  full  of  crea6ve  ideas  

Led  efforts  across  system  engineering,  product  management,  business  development,  and  marke6ng  to  define  strategies  

Over  10  publica6ons  covering  power  system  op6miza6on,  mixed  signal  system  designs,  capaci6ve  touch  sensing  and  analog  basics “Challenging  the  impossible  to  change  the  world.”  

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EFFORTLESS  CHARGING  PAST,  PRESENT  AND  FUTURE  

Meng He, (Maxim Integrated)

Why Should We Care?

Look into your backpacks or suitcases…

There are at least two chargers And they are often bigger than the device itself

We Are Trying…

•  The  number  of  wireless  power  systems  in  mobile  devices  will  grow  from  3.74  million  in  2012  to  27.63  million  in  2016  (Source:  Pike  Research)  

•  Smartphone  manufacturers  began  integraUng  wireless  charging  features  as  early  as  2013    •  Intel  has  promised  the  world  its  first  completely  wireless  computer  by  2016  

•  Companies  have  begun  to  include  in-­‐vehicle  wireless  chargers    in  automobiles  

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“An inexpensive instrument, not bigger than a watch, will enable its bearer to hear anywhere, on sea or land, music or song, the speech of a political leader, the address of an eminent man of science, or the sermon of an eloquent clergyman, delivered in some other place, however distant. In the same manner any picture, character, drawing, or print can be transferred from one to another place. Millions of such instruments can be operated from but one plant of this kind. More important than all of this, however, will be the transmission of power, without wires, which will be shown on a scale large enough to carry conviction.”

-----Nikola Tesla 1908

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Nikola Tesla demonstrated wireless lighting over short distances in 1891

In 1890s…

Basic Principle

TransmiDer   Receiver  

The Vision: World-Wide Wireless Electricity

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Near Field Inductive Charging System

•  The frequency in the coil changes based on the amount of power needed by the receiver•  The communication signal is superimposed onto the power signal •  The most efficient transfer of power but is highly sensitive to coil misalignment•  The coupled coils need to be tuned to a slightly “off-resonance” frequency

AC#to#DC# Driver#and#Amplifier#

Controller#

Voltage##Rec6fier#

Buck#Converter#

Ba:ery##Charger#

Controller#

Transmi(er* Receiver*Power#

Communica6on#

Near Field Resonant Charging System

•  Precise frequency matching is required between the receiver(s) and transmitter •  Transferred power will decrease with the number of connected devices and distance •  A separate bidirectional communication channel is required

AC#to#DC# Driver#and#Amplifier#

Controller#

Buck#Converter#

Ba6ery##Charger#

Controller#

Transmi(er* Receiver*Power#

Voltage##Rec>fier#

Wireless#Protocol#

Near Field Charging Standard

Each standard defines the type of coil coupling, configuration, and the communications protocol

    Qi  (WPC)  AirFuel  Alliance  

PMA   Rezence  (A4WP)  

Power  Frequency   100  to  205kHz   277  to  357  kHz   6.78MHz  

Communica6on   Superimposed   Superimposed   BLE:  2.4G  

Receiver  Free  Posi6on   No   No   Yes  

Mul6ple  Receiver   No   No   Yes  

Incompliance Introduces Adoption Barriers

Great product does not guarantee user adoption

Why Our Current Solution Is Not Enough

Place On ≈ Plug in ≠ Effortless

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Far Field Resonant Charging System

“I#am#here!”#

Energy#Hub#

Receiver# “Con8nuous#link#established!#Power&

Receiver#

Receiver#

Receiver#

Receiver#

How Does It Work?

RF (e.g. WattUpTM, CotaTM)•  The  coil  magne6c  front  end  in  the  near  field  charging  methods  is  replaced  with  one  or  mul6ple  antennas  •  These  micro  energy  beamed  then  add  up  to  a  charging  current  for  the  baDeries.    

Ultrasound (uBeam)•  The  receiver’s  transducer  converts  the  ultrasonic  waves  back  into  charging  current  for  the  baDery.    •  The  ultrasound  wave  stresses  the  piezo  device  resul6ng  in  it  genera6ng  the  baDery  charging  current.      

Infrared (Wi-Charge ) •  The  transmiDer  precisely  beams  infrared  to  the  receiver  using  a  laser  diode  •  A  photovoltaic  cell  in  the  receiver  converts  the  light  back  into  electricity  

Piezoelectric Transducer

V/I$

Far Field Charging Methods

All of these technologies aim at beaming focused power to coupled devices at specific locations instead of broadcasting isotropically in space

Technology/Company   Distance   Transmission  Frequency  

WaDUpTM/Energous   15  c*   5.8GHz  unlicensed  ISM  RF  Spectrum  

CotaTM/Ossia   30  c*   Wi-­‐Fi:  2.4G  

UltrasoundTM/Ubeam   15  c*   Ultrasound:  20KHz  

Infrared/Wi-­‐Charge   500  sqc*   NA  

*Please  see  detailed  data  source  in  the  paper  

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Challenges Ahead

Great  technology  does  not  guarantee  great  products,  and  great  products  do  not  guarantee  market  adop6on    

“Design is so simple, that is why it is so complicated.”

Mobility

Safety

System Interference

Cost

Dead Battery Charge

✔  ✔  ✔  ✔  ✔  

Mobility“ …pay attention to what users do, not what they say.”

•  The  ability  to  precisely  locate  and  follow  mul6ple  moving  receivers  is  cri6cal.    •  When  the  user  is  out  of  the  beaming  range  of  a  transmiDer,  another  transmiDer  needs  to  pick  it  up  immediately  

Safety“A great user interface is so seamless that we don’t even think about it… but a poor user experience tends to make us frustrated, impatient, even angry – and we inherently remember that negative experience for a long time.”

The  Specific  Absorp6on  Rate  (SAR)  defines  frequency  range  and  the  amount  of  power  that  can  be  used  near  human    

System Interference“To design is to plan, to order, to relate, and to control. In short, it opposes all means of disorder and accident.”

•  Low  level  analog  signals  or  even  digital  signals  can  be  affected  by  EMI/RFI    •  It's  something  a  designer  is  always  faced  with  and  will  have  to  deal  with  at  some  point      

Method   Subject  to  EMI  Interference  

Near  Field  Resonant   Yes  Induc6ve   Yes  

Far  Field  

WaDUpTM/Energous   Yes  CotaTM/Ossia   Yes  

UltrasoundTM/Ubeam   No  Infrared/Wi-­‐Charge   No  

Cost“Users are not always logical, at least not on the surface. To be a great designer you need to look a little deeper into how people think and act.”

•  The  cost  of  the  power  transmiDer    •  Transfer  efficiency  Does  it  maXer?  

A  30-­‐waD  home  security  system  that  runs  24  hours  a  day      

30w/1000  x  0.09$/hour  x  24hours  =  $0.065    

Dead Battery Charge“Simple is hard. Easy is harder. Invisible is hardest.”

•  Near  field  charging:  the  charger  can  “revive”  a  completely  dead  baDery.    •  Far  field  charging  :  the  control  circuits  on  the  receiving  side  needs  power  to  be  linked  to  the  power  router  

The Tesla Tower Was Demolished In 1917

To Build A Tower That Does Not Fall…

Device    Manufacture  

Charging    Standard  

Near  Field:  Qi,  Rezence  Far  Field:  RF,  Ultrasound  

Technology    Enabler  Semicon-­‐  ductor  

System  Manufacture  

Infrastructure  Restaurants;  Homes;  Offices;  Hotels;  Automobile    

Conclusions

•  Wireless charging is much MORE than cutting the cord 

•  The expansion of wireless charging technology resides in ECOSYSTEM building

•  There is no room for any SUBOPTIMAL user experiences to magnify any health or safety related concerns.

The ultimate goal of wireless charging is to empower the world.

The best is yet to come.

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QUESTIONS?

Thank you!