I am currently building a low-voltage cut-off circuit. When the battery is under 10 V, the microcontroller should pull the battery power to ground which will blow the fuse with high current and cut all the power to the loads. (Assuming the micro can blow the fuse at this point)
I have a design in mind that I think will work, but later I found that depletion PMOS transistors are not being manufactured. There is only depletion NMOS being manufactured. However, depletion NMOS requires a negative voltage to turn the gate off (disconnection).
The reason I need the PMOS is to protect the fuse from the battery's inrush current. I have looked into other electronics that limit inrush currents, such as NTC thermistors and LDOs for soft-start functionality. However, I don't have any external power except for the battery and the current used in the system is way too low for the NTC thermistors to work.
I was thinking about solving this problem by using depletion NMOS, but after the fuse is blown and the microcontroller should be cut off the power, the battery will be my only source of power, and I can not think of a way to produce a negative voltage to disconnect Q1.(depletion NMOS need -V to be OFF)
Are there any transistors or devices that act like depletion PMOS that is initially conducting, then apply a positive voltage to open the connection?
Or any other way to solve this issue by replacing the depletion PMOS (since it is not being manufactured)?
I am appreciative of any input.
I have attached a working version of the circuit with PMOS depletion.
