Hi
I have a query need your help.
1, The selected solar panel has a rated voltage of 5V and a rated current of 80mA. According to the solar panel information, I set the input current to 70mA and the voltage threshold to 4.4V.
2, When I use the power supply of 5V from the power box as the input VBUS to charge the battery with a current voltage of 4.1V, the current is 70mA, which is the same as the theoretical value.
3, When I use the solar panel as the input VBUS to charge the battery with the same voltage of 4.1V, the current is 1mA. When I disconnected the solar panel from the board, the voltage of the solar panel was measured to be 4.7V, but when the board was connected as the input voltage for charging, VBUS was pulled down to about 4.42V. Later, when I opened VDPM as tracking mode. The solar panel will still produce a voltage drop to about the threshold voltage (VBAT+100mV). At this time, the charging current is still 1mA. Why does the voltage always drop to the threshold voltage? Below is the schematic.
Please help check it.
Thanks
Star
