I am working on a PV cell energy harvest chip, and transfer efficiency of the ADP5091 cannot reach even 50%. We manage to measure Vin, Iin(pin: VIN), Vout and Iout(pin: REG_OUT) to calculate the efficiency. When Vin is about 0.5V(typical voltage of single PV cell), and Vout has been set at 3.3V, the efficiency of it come to only 30%, which is far from that on datasheet.
Here's my question:
1.figure 11 on datasheet. What's the difference of "INPUT VOLTAGE" and "Vin" ? And how does INPUT VOLTAGE reach 100V high?
2.the same figure. I'd like to learn the right way to calculate the efficiency at Y_axis of ADP5091. And how to get the highest transfer efficiency of ADP5091? We tried 10Ohm~20kOhm load, but nothing help. It is only 30%.
Thank you for reading.