Hello,
I have been trying to implement a way to utilize the fuel-gauges functionality and parts. The end goal is to use the fuel-gauge as both protection, and a soft-latch power switch.
This is entirely feasible to some degree, by utilizing the Emergency FET Shutdown capability. Contrary to the name, it doesn't have to be an emergency to use this feature. This feature allows me to press a momentary button for ~1s to tell the fuel-gauge to either turn ON or OFF the CHG and DSG FETs. They can even be turned back on at the presence of a charger, so that you don't have to press the button to allow the battery to be charged. This is great, except...
If the battery is integrated into a system, the entire system turns on when charging commences and does not turn off when the charger is removed. So if the CHG FET could simply always be on (unless a fuel-gauge protection gets tripped) but the DSG FET be command-able, this problem could be avoided.
So if I could press a button for 1 second to turn ON or OFF the DSG FET alone, I could have exactly what I am trying to do. The alternative is to implement external circuitry to be a high or low side switch but this suddenly increases cost and valuable space (especially for a high current application). This seems entirely wasteful when the parts and capability already exist in the fuel-gauge circuit.
I know that the DSG and CHG FETs can be individually controlled, but only through I2C commands and only when the Firmware FET control is disabled..
So I am at a loss. The function that I am looking for should be technically possible. There must be a way for me to manually command the DSG FET ON or OFF. Preferably through one of the GPIO pins. Any help with this would be hugely appreciated. It's the last design obstacle in this project.
Thank you,
-Chris
