Hello,
my charging circuit (schematic below) works as expected, except of the charger IC which becomes much too hot - around 100°C at lab conditions.
The circuit is configured for two serial Li-Ion cells (8.4V) which shall be charged at 2.7 amps.
As reference circuit for searching errors, I took the bq24171EVM evalboard which showed the same electrical behavior in the following measurement:
SW pin: 1.6MHz, 68%high, 14.2Vmax, -2.8Vmin
The evalboard works fine at 700mW less power consumption than my own designed circuit board.
Because the switching signal (at SW pin) for the buck converter is the same at both designes, it seems the 700mW is only heat production at the BQ24171 IC.
Now my question:
Can you see any errors in my schematic or is my heat sink for the charger IC not sufficient (PCB layout snipped doublelayer also below).
Thanks for helping
regards
Marius
