Hello
I am using the BQ24072 charger with a lithium polymer battery. The EN1, EN2 and /CE pins are connected directly to the GPIO of a MSP430 (no pull-down resistors). The MSP430 and the rest of the circuit is powered through a 3.3V buck-boost, with an UVLO of 2.7V. (I.E. the load circuit switches off if the battery reaches the minimum voltage of 2.7V).
I have experienced an intermittent problem when the battery is fully discharged (2.7V) and the circuit is switched off. If I plug in the charger (USB), I am expecting the output of the BQ24072 to go to 3.4V and the load to switch back on. This doesn't always happen. I end up having to unplug the battery and reconnect the battery for the circuit to reset.
Am I correct in thinking that the EN1, EN2 and /CE lines are effectively floating when I have a flat battery, as the MSP430 is unpowered? Do I require pull down resistors on these three signals to give them an initial defined state when the load circuit is switched off?
Thank you for your assistance.
Regards,
Geoff