Tool/software:
Hi,
I am trying to use this evaluation board in combination with 5 18650-Lithium cells wired serially. But whenever I start the charging process (connecting CHGEN), the ACDRV, BATDRV and PG LEDs are flickering and on the oscilloscope I observe a rapid alternation of BATDRV and ACDRV. Upon further investigation I noticed that the VCC voltage is dropping as soon as fast charging begins (see attached Image). At the moment VCC is lower than VBAT, the controller is switching back to BATDRV and thus stopping the charging process. The latter behaviour is to be expected, but I can't figure out, why VCC is dropping.
VBAT : green, VCC: orange, IBAT(1 A/V): blue
On the evalboard I only replaced R12 with 7k1 in order to limit the charging current to just above 1 A. The batteries cells are all around 3.6V. Other than that I connected a 15k resistor between TS an GND.
I also tried this setup with almost fully charged batteries (around 4 V) so that the charger is operating in constant voltage mode and there are no problems. Also no problems in precharge mode. There is no significant change when I raise the input voltage. The battery cells are internally protected, but i doutbt that this is interfering, especially after I reduced the charging current. There is also no qualitative change when I connect a load to the SYS terminal.
Do you have any hints or suggestion on how to prevent the charging interruption?
Kind regards and thank you very much in advance.
