I have a project where its power from 3.7V, 300mAH Li-Poly Battery. Currently its having USB based Charging by MCP73831T. I want to add a Solar Cell based Charging in adding with USB. My Board dimension 32mm Diameter which is very small hence I chooses a small Solar Cell. Below is the specification of Solar Cell:
But this is not working. DCDC Boost voltage dropped to less than 1v. I understand MCP73831T is tuned for 100mA charging currents due to that Boost Voltage dropped as Solar Cell not able to provide 100mA.
I like to have your advise:
The way of my design is Ok? or what is the best design idea to do a Li-Poly charger from such small Solar Cell.
A deeply discharged cell might well drag the boost output
down that far. Why don't you concentrate on the converter
for now, see what kind of load-line it delivers with a solid
battery / power supply feed, and then what giving it a very
limited input current does.
There might be nothing wrong, besides needing time to
deliver coulombs. But you should characterize things to get
that understanding.
We also found MCP73831 consume around 500uA, even no battery. Is there any other Charging chip which will be better choice for Solar Based Charging than MCP73831?
Or how is, if connect the Solar Cell directly to Li-Poly through a Diode?
A diode is not a complicated proper charging circuit. A diode does not limit the charging current to the charging ratings of the battery cell, and it does not limit the charging voltage to 4.20V.
The Li-Po might blow up or catch on fire if it is charged wrongly. Also it might be damaged.