The LTC3588-1 converts the voltage from a Pezosensor or from other sources as well to a usable 3.3V. Then the its stores the energy in capcitors and there is also 4 recargeble AA batteries which feed energy to the LTC3588-1 and get charged. Then the energy goes into a 5V step-up regulator. The output voltage goes out on a USB line charging devices through a USB-A conector.
So what do you think?
Well, the LTC3588 max current output is only 100mA, even if you can manage to squeeze that from the piezo (good luck) by the time you have converted your 3.3V@100mA to 5V you will have only a small current to work with, maybe 50mA or so.
But what about the backup batteries which output 2,500mA?
What do you mean, you want to recharge a 2500mAH battery with this circuit?
No! It has 4 backup batteries and it gets charged while it supplies energy to the harvester!!!
SparkFun is planning on doing a BOB for this IC. No idea when it is set to release though.
The BOB is in the works.
Nice work! Looks interesting.
Have you calculated/measured an energy budget or done any load testing?
I recently have been messing around with the LTC3588, two CPC1822 solar cells (http://www.sparkfun.com/commerce/produc … ts_id=9962), and aerogel super caps on both the input and output. I have yet to get the energy budget in the positive region (i.e. circuit gains energy) with a small load attached (ATtiny in sleep mode).
I have not tried to use a rechargeable battery at the input either, so I will probably try that next.
What kind of pezo are you using?
The LTC3588 still works great though as just an efficient switching regulator for low power applications.
-Aaron