Question: BQ24072 USB Input Problem

bq24070/1 offers a proprietary boot-up sequence. On the first application of power to the bq24070/1, this feature enables the 100-mA USB charge rate for a period of approximately 150 ms.

For BQ24072, if we fix EN2 EN1 = 0 1, 500mA mode, can it meet the USB IF specification of 100-mA USB current during USB Enumeration? Or EN1 should be changed dynamicly?


Answer: It should probably be done dynamically.  The part does come up in 100mA mode to check for shorts and runs some routines but changes to the EN2/1 setting soon after it is finished with the power up.  If you want it to stay in 100ma mode, then you need to set EN2/1 to 0/0.