AFEC_ACR.IBCTL controls the ADC bias current with the nominal setting IBCTL = 10.
IBCTL = 10 is the mandatory configuration suitable for a sampling frequency of up to 1 MHz. If the sampling frequency is below 500 kHz, IBCTL = 01 can be used to reduce the current consumption.
If the sampling frequency is more than 1 MHz, then the setting must be IBCTL=11.