Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Mar 2013 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Energy Harvesting Use Cases] Date Submitted: [March 19th, 2013] Source: [Reghu Rajan] Company [Microsemi] Address [15822 Bernardo Center Dr, Ste B, San Diego, CA, 92127] Voice:[+01-858-675-3465] FAX :[+01-858-675-3450] E-Mail:[reghu.rajan@microsemi.com ] Abstract: [This presentation presents use cases and requirements for the energy harvesting market] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Reghu Rajan (Microsemi) Slide 1

2. Energy Harvesting Use Cases March 19th, 2013 Reghu Rajan, Microsemi Mar 2013 Reghu Rajan (Microsemi) Slide 2

3. Mar 2013 Abstract This presentation presents use cases and requirements for the energy harvesting market. Reghu Rajan (Microsemi) Slide 3

4. What is Energy Harvesting? Definition: Energy from ambient sources harvested for useful purposes Common sources Light (Photo Voltaic) Vibration/movements (Piezo-electric, electromagnetic) Heat flow (Thermo-electric generators) Benefits Zero Maintenance (deploy and forget, sealed locations) Extremely long operating life Long-run cost saving Mar 2013 Reghu Rajan (Microsemi) Slide 4

5. Types of EH Systems Energy harvester assisted devices Requires Battery EH extends battery life Long-run average power consumption greater than EH power Finite life (battery) Energy harvester with storage (WSN) Harvested energy is used to charge battery/storage device Long-run average power consumption equal to or less than EH power Duty-cycled systems that require more power than EH power Life of battery is the life of node Energy harvester without long-term storage Does not require battery Device works only when energy is available Extremely long life Ex: EH based switches Mar 2013 Reghu Rajan (Microsemi) Slide 5

6. Typical EH Topology Mar 2013 Reghu Rajan (Microsemi) Slide 6

7. Requirements for EH based systems Energy harvester efficiency and energy availability V-I characteristics Source Impedance Average power availability Low aging effects (Mechanical and chemical factors) High-efficiency power management Capture every micro-joule possible from the EH transducer Adapt to various I-V characteristics Extremely low leakage High-efficiency buck-boost converters Handle battery chemistries with protection High efficiency regulators to run application Mar 2013 Reghu Rajan (Microsemi) Slide 7

8. Requirements for EH based systems, cont. Low-power sensor and front-end Low voltage/low noise analog sensor front-end ULP Radio and efficient wireless protocol Low peak current and low voltage (radio & processor) ULP processor (leakage, standby/sleep currents, RTC) Efficient protocol Mar 2013 Reghu Rajan (Microsemi) Slide 8

9. EH Transducers (PV) Photovoltaic cells Most common energy source Power ranges from micro-watts to watts Low power management requirements (Peak-power tracking) Mar 2013 Reghu Rajan (Microsemi) Slide 9

10. Photo Voltaic Panel Use Cases Mar 2013 • PV based smart card • Solar-based wireless environment monitoring • Indoor/outdoor PV based wireless sensors for security and building automation PV Smart Card Example: • System peak current requirement <5 mA (radio + CPU) • System average current 15 uA (1 min duty cycling) • Sub-GHz radio • Efficient protocol (Point-to-point or mesh) • Onboard thin-film battery • Long battery life (>10 years) • TX Power less than 0dBm typically Reghu Rajan (Microsemi) Slide 10

11. EH Transducers (Piezo) Piezo-electric Transducers Impulse energies Transient V-I characteristics Demanding power management Uses Remote control Lighting control Vibration sensing (Sense machine wear & tear) TPS (Tire Pressure Sensor) Mar 2013 Reghu Rajan (Microsemi) Slide 11

12. Piezo Transducer based Use-case Mar 2013 • Harvested energy per click: 10 to 30uJ • 10uJ -> 5mA for 1ms at 2V • Transducer life cycle: >10 Million • Typical payload ~ 11 bytes Reghu Rajan (Microsemi) Slide 12

13. Piezo Transducer based Use-case Mar 2013 • Piezo based floor tiles • Building automation (lighting, climate) • Foot traffic logging and occupancy sensing • Security • Industrial monitoring • Vibration monitoring (Wear and tear) • Fitness industry Reghu Rajan (Microsemi) Slide 13

14. EH Transducers (TEG) Thermo-electric generators (TEG) Steady source Low power management demand Low aging Solid state (no moving parts) Withstands extreme environments (Military) Mar 2013 Reghu Rajan (Microsemi) Slide 14

15. EH Transducers (TEG) Thermo-electric generators (TEG) I-V Curves Example: Industrial transducer Mar 2013 Reghu Rajan (Microsemi) Slide 15

16. TEG Transducer based Use-case Mar 2013 • Industrial and plant monitoring • Thermal runaway sensing • Heat flow monitoring • Security • Medical/fitness monitoring based on body heat • 30uW to 200uW (5mA @ 2V for 3ms at 1 sec duty cycling) • Radio and system peak current is critical (<5mA) • Dynamic duty cycling based on harvested power Reghu Rajan (Microsemi) Slide 16

17. Key Radio requirements Mar 2013 • Low voltage operation (~1.2V) • Low peak current (<5mA for complete system) • Low leakage and deep sleep mode (<1uA) • High data rate for duty-cycling, but tradeoff with peak current (~400 kbps) • Lean protocol with low overhead (PPDU < 30 Octets) Reghu Rajan (Microsemi) Slide 17