I'm using LTC3105 as a trickle charger for a Li-Po battery as shown in the first page of the datasheet, but with a 1W, 5V rated PV panel instead of a single cell one. I'm using a 390k resistor in the MPPC pin because I want the panel to work at 3.9V . Is this correct? When I measure the voltage in the MPPC it varies and usually is around 2.5V and 3V. If the block diagram in the datasheet is correct, there is an internal current source so the voltage should be constant. What is wrong?