I'm planning an energy harvesting circuit using LTC3105 (400mA Step-Up DC/DC Converter with Maximum Power Point Control and 250mV Start-Up).
The problem is that my energy source is bipolar, although polarity switch is a matter of seconds (very low frequency). I very much like the 250 mV startup voltage of this chip and such low voltage is required by my application.
The obvious solution would be to use bridge rectifier, but it introduces voltage drop that is significant compared to 250 mV startup voltage. Is it possible to solve it in another way? It is allowed to use two LTC3105 chips.
EDIT: LTC3105 supports only positive voltage with regard to GND. The problem is that I'm using small motor with gearbox as a dynamo which will be turned by hand in both directions. If connected directly and turned in one direction it will produce positive voltage, if turned in opposite direction it will produce negative voltage. The slower you turn the motor the lower voltage you get and the goal is to produce energy from smallest turn speed as possible.
So maybe instead of rectifying the motor input and losing some voltage, there is a method to route each motor polarity to separate LTC3105.