Self-Powered Processors

1. Self-Powered Processors Bryna Hazelton UC Santa Cruz Dept. of Physics Andrew Putnam, Luis Ceze University of Washington Computer Science & Engineering

2. What if processors powered themselves? • No need to cluster around electrical outlets at conferences AS PLOS • Use all of those power pins for something useful • Run all the speculative and helper threads you want • Stop worrying about power management

3. 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? Energy Independence! I’m graduating: offer me a job and get your company logo here! Researchers lead the way with self-powered processors

4. On-Chip Power Generation • Chip-Scale nuclear reactors • Fission • Alpha decay • Use heat energy from the environment • Silicon Solid-state “Wiggler”

5. Chip-Scale Nuclear Power Glow-in the Dark Processors

6. Chip-Scale Nuclear Reactor • Radioactive isotopes have incredible energy densities • Uranium-235: • 11.4g (0.60 cm3) provides 50W for 10 years

7. 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%

8. Fission Generator • Thermally isolated by 5mm Aerogel • Lithium-6 bath converts neutrons to gamma rays • 50W continuous power Cold Chamber Surgeon General Warning: Gamma rays can be hazardous to your health. These processors should come nowhere near any living organism. 3cm Fission Chamber Hot Chamber Aerogel CPU

9. Alpha Decay Generator • Heat from radioactive alpha decay from larger decay chamber • Alpha decay is easilyshielded Cold Chamber 9cm Decay Chamber • 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 Hot Chamber Aerogel CPU

10. Silicon “Wiggle” Generator Shake it like a Poloroid Picture

11. Spring – Capacitor Circuit Spring Battery Capacitor

12. Spring – Capacitor Circuit • Charge builds up on capacitor plates

13. Spring – Capacitor Circuit • Charge builds up on capacitor plates • As charge builds, plates are attracted to each other Attraction

14. 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

15. 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

16. 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

17. 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

18. 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

19. Spring n-doped Hammer Battery p-doped Anvil Capacitor

20. Cantilever Depletion Region 0.6V Capacitor

21. Charge n-doped Hammer p-doped Anvil

22. Attraction

23. Discharge

24. Recoil

25. 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 • -173°C for Silicon E-Field E-Field - - + +

26. 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 100°C of heat energy per second • 1 ft3 : 3.7°C / second air conditioner @ 46 MW • Solar cells: 4.8 GW / m3 (170 W/m2 0.35 mm thick)

27. Duracell Powering Nano-Devices 2200 μm 6100μm 10 μm MEMS / NEMS Device

28. Powering Nano-Devices

29. Thank You Questions?

31. 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 isn’t a perpetual motion machine – it will stop working with the heat death of the universe

32. Energy Density • Solar cells: 170 W / m2 • 0.35 mm thick • Power density = 4.8 GW / m3

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

38. Cantilever n-doped Hammer Depletion Region p-doped Anvil Gap