The MOS tubes currently used in the burn-out prevention circuit require Vth (Vgs=Vds, Id=250uA) to be less than 1V, which can be fully controlled by 1.8V GPIO, but there will be problems of large impedance and small Id. If a power MOS tube with smaller impedance and larger Id (Vth of about 2.5V) is used, there will be the problem of insufficient GPIO (1.8V, which may be reduced to 1.2V in the future) voltage control.

 So how do we solve this problem?

Optimization solution 1: Add 2 small signal NMOS tubes

 That is, select NMOS1 and NMOS2 with Vth < 1.2V/1.8V, and use 3.4V power supply (battery or VBOB) to achieve control:

When GPIO=1.2V, NMOS1 is turned on (Vgs1=1.2V), NMOS2 is turned off, and 3.4V voltage is added to the gate of the burn-out prevention MOS tube (Vgs=3.4V), turning it on;

When GPIO=0V, NMOS1 is turned off, NMOS2 is turned on, and the gate voltage of the anti-burn MOS tube is 0 (Vgs=0V), making it turned off.

Optimization solution 2: Add 1 NMOS + 1 PMOS

 Select NMOS and PMOS with Vth < 1.2V/1.8V, combined with 3.4V power supply control:

When GPIO=1.2V, NMOS is turned on (Vgs1=1.2V), which turns on PMOS (Vgs2=-3.4V). 3.4V voltage is added to the gate of the anti-burn MOS tube (Vgs=3.4V), turning it on.

When GPIO=0V, NMOS and PMOS are turned off, and the gate voltage of the burn-out prevention MOS tube is 0 (Vgs=0V), making it turned off.