I want to use a solar panel to extend the use time of 3 NiMH AA's in series to power a microcontroller.
The solar panel is rated at 1 W with a max load voltage of 6.4 V and the product page is here.
The battery capacity is 2450 mAH with a nominal 1.2 V per cell and the datasheet is here. (I plan to use three, for ~3.6 V to power a microcontroller that needs 3.3 V)
My confusion is about trickle charging the battery vs. fast charging it. I know that the trickle charging rate for a NiMH is between C/10 and C/40, which comes out to 245 mA and 61 mA, respectively, and fast charging is between C/2 and 1.2C.
My problem is finding an IC that can do both, specifically for NiMH batteries.
For slow charging, I want the input to be solar panels (varies between 0 to 5.5 V max).
For fast charging, I want the input to be a wall charger (fixed at 5 or 9 or 12 V).
Is there an IC that can take an input voltage between 250 mV - 5 V (at least, but up to 12 would be even better) and output a current between C/10 and C (but between C/40 and 1.2 C would be perfect), with automatic charge termination and switching between the two modes I mentioned above?
If such an IC doesn't exist, how can I modify an existing one to do this?