Self-Powered Processors

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Self-Powered Processors

• Andrew Putnam, Luis Ceze
• University of Washington
• Computer Science Engineering

Bryna Hazelton UC Santa Cruz Dept. of Physics
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What if processors powered themselves?

• No need to cluster around electrical outlets at
  conferences

AS PL OS

• Use all of those power pins for something useful

• Run all the speculative and helper threads you
  want

• Stop worrying about power management

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How would this change

• Computing in the 3rd World?
• Remote sensing and data collection?
• Cost and management of data centers, cloud
  computing?
• Nano-scale machines?

Im graduating offer me a job and get your
company logo here!
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On-Chip Power Generation

• Chip-Scale nuclear reactors
• Fission
• Alpha decay
• Use heat energy from the environment
• Silicon Solid-state Wiggler

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Chip-Scale Nuclear Power

• Glow-in the Dark Processors

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Chip-Scale Nuclear Reactor

• Radioactive isotopes have incredible energy
  densities
• Uranium-235
• 11.4g (0.60 cm3) provides 50W for 10 years

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Stirling Engine

• Hot chamber absorbs heat energy from surroundings
• Air flows from hot chamber to cold
• Cold chamber cools, compresses air
• Efficiency has recently jumped from 5 to 38

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Fission Generator

• Thermally isolated by 5mm Aerogel
• Lithium-6 bath converts neutrons to gamma rays
• 50W continuous power

3cm
CPU
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Alpha Decay Generator

• Heat from radioactive alpha decay from larger
  decay chamber
• Alpha decay is easilyshielded

9cm

• Polonium-208, 210
• 53W for 5 years
• Plutonium-238
• 55W for 100 years
• Strontium-90
• 35 W for 40 years
• Requires 1cm lead shielding to block gamma rays

CPU
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Silicon Wiggle Generator

• Shake it like a Poloroid Picture

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Spring Capacitor Circuit
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Spring Capacitor Circuit

• Charge builds up on capacitor plates

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Spring Capacitor Circuit

• Charge builds up on capacitor plates
• As charge builds, plates are attracted to each
  other

Attraction
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Spring Capacitor Circuit

• Charge builds up on capacitor plates
• As charge builds, plates are attracted to each
  other
• As plates get closer, attractive force grows

Attraction
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Spring Capacitor Circuit

• Charge builds up on capacitor plates
• As charge builds, plates are attracted to each
  other
• As plates get closer, attractive force grows
• Plates contact, and charges move across the plates

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Spring Capacitor Circuit

• Charge builds up on capacitor plates
• As charge builds, plates are attracted to each
  other
• As plates get closer, attractive force grows
• Plates contact, and charges move across the
  plates
• Spring recoils, disconnecting capacitor plates

Recoil
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Spring Capacitor Circuit

• Charge builds up on capacitor plates
• As charge builds, plates are attracted to each
  other
• As plates get closer, attractive force grows
• Plates contact, and charges move across the
  plates
• Spring recoils, disconnecting capacitor plates
• Charges regenerate

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Spring Capacitor Circuit

• Charge builds up on capacitor plates
• As charge builds, plates are attracted to each
  other
• As plates get closer, attractive force grows
• Plates contact, and charges move across the
  plates
• Spring recoils, disconnecting capacitor plates
• Charges regenerate
• Cycle begins again

Attraction
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n-doped Hammer
p-doped Anvil
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0.6V
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Charge
n-doped Hammer
p-doped Anvil
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Attraction
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Discharge
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Recoil
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Energy Generation

• Charge carriers are thermally regenerated
• Phonon lattice vibration (a.k.a. heat) kicks
  electrons to higher-energy state
• So the energy comes from the ambient heat around
  the device (heat bath)
• Device will operate until freezeout temperature
• -173C for Silicon

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Details

• Piezoelectric converts motion to electricity
• Very high conversion efficiency (50-90)
• Each device 5 nW
• 1 mm3 2.5 W (mobile processor)
• 40 mm3 100 W (high-performance processor)
• 1 m3 2.5 GW (medium-sized city)
• - requires 100C of heat energy per second
• 1 ft3 3.7C / second air conditioner _at_ 46 MW
• Solar cells 4.8 GW / m3 (170 W/m2 0.35 mm
  thick)

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Powering Nano-Devices
2200 µm
6100µm
10 µm
MEMS / NEMS Device
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Powering Nano-Devices
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Thank You

• Questions?

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2nd Law of Thermodynamics

• "Every physicist knows what the first and second
  laws mean, but it is my experience that no two
  physicists agree on them." -- Clifford Truesdell

• 2nd law is a statistical law based on classical
  mechanics
• The applicability of the 2nd Law to quantum
  mechanical domains is hotly debated
• This isnt a perpetual motion machine it will
  stop working with the heat death of the universe

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Energy Density

• Solar cells 170 W / m2
• 0.35 mm thick
• Power density 4.8 GW / m3

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Stirling Engine

• Hot chamber absorbs heat energy from surroundings
• Air flows from hot chamber to cold
• Cold chamber cools, compresses air

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n-doped Hammer
p-doped Anvil