Hello, my question of how to do a professional consumer electronics cut off / shut down the overall system before over-discharge kicks in?
Looking at a reference design of https://www.ti.com/tool/TIDA-01182#3 by Texas I see protection circuits, charger, and fuel-gauge but I am still thinking how the product will shut off itself properly?
For instance, on my system, I would probably not want the battery to drop below 3.2v as my system is using 5V domain which is OTG boost supplied by BQ25895 which based on the datasheet battery voltage falling below 3V will cut off 5v boost voltage. The problem I see here is that my 5V domain will shut off earlier than my SYS out voltage so that means there might be some part of the system are not working while low voltage things like my MCU will be running fine till further discharge. The problem I would want to solve is to sync the cut-off, 5V(OTG) collapse and the entire system to shut off till charger is present ? how to achieve this efficiently?
One idea I have in mind is to add the comparator and p-channel FET source directly to SYS output and setting the threshold voltage at 3.2V to cut off SYS output, likely to tie the reference voltage from the battery directly with a divider but I am open to much more efficient idea if there's