I made 4 boards. In my board, I use bq24079 for power management. Name the 4 boards as b1 b2 b3 b4.
For b1, b2 and b3, all functions work right. When I plug a battery in, the battery can be charged no matter the battery is pluged before the USB or after the USB.
But for b4, when the USB is first connected, the board takes 70mA. After that, when the battery is pluged, the battery can not be charged, the current of the board is still 70mA.
If the USB is connected, and the battery is connected, the battery can power the board to work. Then, when I connect the USB, the battery can be charged, the current of the board is 475mA. And in this situation, the board also works well.
In short, the battery can only be charged if the battery is pluged before USB power when I use b4 board!
I'm sure the battery is not full. And I tested the other 3 boards with the same battery, they works well in both situations.
What is the possible cause of this problem?
Thank you.
