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Kinnar
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CEO
Re: harvested power
Kinnar   12/17/2013 1:36:12 AM
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The rough estimation of the power requirement of smart dust will vary a lot during evolution phase, but the previous threads in the discussions are quite right,  IC is a very good design for providing power to these kind of devices, as yes instead of batteries a smart capacitor will also be able to provide power in dark conditions, this way the life of the device will become virtually endless. This is really amazing.

RichQ
User Rank
CEO
Re: harvested power
RichQ   12/16/2013 1:58:47 PM
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Given the dependence on light availability, it seems that a device would always need some form of energy storage to take it through the "dark times." It might be able to be a supercapacitor instead of a battery, though.

krisi
User Rank
CEO
Re: harvested power
krisi   12/16/2013 1:39:30 PM
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thank you Rich, that strikes me as a high number but I wish you are correct in your math...plenty of devices could be battery-less if you are right

RichQ
User Rank
CEO
Re: harvested power
RichQ   12/16/2013 1:31:22 PM
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A quick look found this solar panel (http://www.mouser.com/ProductDetail/Parallax/750-00031/?qs=Pc4kzEvJlcRIqSNmZk3pdQ%3D%3D&gclid=CO3n0ryttbsCFaQl4godlCkAtA) that is about 5 inches square and puts out 1W at 9V. So, something about watch sized would have about 1/4W, or around 25 mA at 9V. An individual cell produces about a half volt open circuit, so you could wire the array to produce 3V and you would get the 75mA, if my mental math is correct. So, the 70 mA spec seems perfectly suited to a watch sized solar array, to me.

krisi
User Rank
CEO
Re: harvested power
krisi   12/16/2013 1:01:06 PM
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I think we all understand that the amount of harvested power depends on sun exposure conditions...but the article talks about usage in wearable devices so presumably the size of the battery is constrained...having the spec of 70mA in that context is somewhat puzzling to me as watch sized solar battery will harvest orders of magnitude less than 70mA...Kris

RichQ
User Rank
CEO
Re: harvested power
RichQ   12/16/2013 12:51:00 PM
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I would think that the amount of power involved depends on the size and configuration of the solar panel and the quality and intensity of the light striking it. What is important about this device is that it efficiently handles the highly variable power that the panel is generating and saves it to battery storage with minimal loss in the conversion process.

goafrit
User Rank
Manager
Re: Very good Input Voltage Regulation
goafrit   12/16/2013 12:29:55 PM
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>> 
This is really a remarkable design by STMicroelectronics, the input voltage regulation is very good, i

ST has a really good design team. Just as they now control the MEMS gyro and XL market, they continue to show innovation sparks in many areas. This is a new growth market and it is evident that will create new solid business here.

goafrit
User Rank
Manager
Re: harvested power
goafrit   12/16/2013 12:28:33 PM
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>> Ho wmuch power can be harvested this way? 

There are many variants to consider - the sun, the capacity, the charge rate. For different applications, they can have different amounts of power which they can harvest and will be dependent on many factors

krisi
User Rank
CEO
Re: harvested power
krisi   12/16/2013 10:24:28 AM
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70mA sounds like a lot...very impressive if you can really achieve it under normal operating conditions...how large the solar battery is required to get to that level?

waaromikke
User Rank
Freelancer
Re: harvested power
waaromikke   12/16/2013 8:19:45 AM
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I was also missing the more interesing bit of information; power number. I hope it is more than some solar charged lamps that must be charged for days to give minutes of lights.

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