The LTC3588-1 requires the output voltage of the transducer to be above the undervoltage lockout rising threshold limit for the specific output voltage set at the D0 and D1 input pins. For maximum energy transfer, the energy transducer must have an open circuit voltage of twice the input operating voltage and a short-circuit current of twice the input current required. These requirements must be met at the minimum excitation level of the source to achieve continuous output power.
Piezoelectric transducer application Figure 3 shows a piezoelectric system that, when placed in an air stream, produces 100μW of power at 3.3V. The deflection of the piezoelectric element is 0.5cm at a frequency of 50Hz.
Seebeck transducer application Figure 4 shows an energy harvesting system that uses a Seebeck transducer from Tellurex Corporation. A heat differential produces an output voltage that supports a 300mW output load. Connecting the transducer to the PZ1 input prevents reverse current from flowing back into the Seebeck device when the heat source is removed. The 100Ω resistor provides current limiting to protect the LTC3588-1 input bridge.
Harvest energy from the EM field produced by standard fluorescent lights
This application requires some outside-the-box thinking. Figure 5 shows a system that harvests energy from the electric fields surrounding high voltage fluorescent tubes. Two 12” × 24” copper panels are placed 6” from a 2’ × 4’ fluorescent light fixture. The copper panels capacitively harvest 200μW from the surrounding electric fields and the LTC3588-1 converts that power to a regulated output.
The LTC3588-1 allows remote sensors to operate without batteries by harvesting ambient energy from the surrounding environment.
It contains all the critical power management functions: a low loss bridge rectifier, a high efficiency buck regulator, a low bias UVLO detector that turns the buck converter on and off, and a PGOOD status signal to wake up the microcontroller when power is available. The LTC3588-1 supports loads up to 100mA with just five external components.
I have read somewhere that such energy harvesters have some environmental side effects, which may be harmful in the long run. However, I have not seen any empirical results of similar devices, nor for this current device being featured above. Would you be able to provide references to expert opinions, specifically engineers or consultants in the field? It would be great to have some references apart from the ones I find on the web. Books, or journals would be great to have.
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David Patterson, known for his pioneering research that led to RAID, clusters and more, is part of a team at UC Berkeley that recently made its RISC-V processor architecture an open source hardware offering. We talk with Patterson and one of his colleagues behind the effort about the opportunities they see, what new kinds of designs they hope to enable and what it means for today’s commercial processor giants such as Intel, ARM and Imagination Technologies.