Hi;
I am designing the battery charger circuit with BQ24074 for a battery-powered piece of equipment. I'd like to use the USB port for two functions: 1) Communicate with the MCU for configuration, 2) Charge the battery from a 5V /1A wall adapter that has a USB Type-A connector for power output. I'd like the charger to be standalone so that it can function even when the unit is not powered up.
The question: How can I limit the charging current to 100 mA or 500 mA from the USB host while using the USB port for MCU communications, yet enable a fast charge (>1.25 A) when the USB power adapter is plugged to the USB port of the device? I can see how this could be done using the MCU to manage the charging process with the EN inputs, but it is not clear to me how this could be achieved in a standalone mode of operation without some kind of external supervisory circuit.
Any help and ideas would be appreciated.
Best regards.
Omer
