I'm using a power nfet to as a brake on my Hall wiper slot car controller. The gate voltage swing needed to give brake adjustment about 1/3 of a volt. I am having a hard time creating that small of a swing with a pot.
Question: can you think of a better way to this? control the fet in ohmic region? is there an op amp circuit that could do it?
Second question: I tried PWM at the gate and it works but is problematic: any higher current motor blows the nfet. I better flyback diode solved it on the bench but in real conditions the brake fet blew. Question: would more fets in parallel help?
Diagram: the brake fet is show next to the motor and the gate control pot is as shown This linear set up is trouble free but all of the adjustment comes in 1/10 of a turn. I want to spread the control out over the whole pot. I want the fet to go from less than one ohm to about 10 ohms.
Question: can you think of a better way to this? control the fet in ohmic region? is there an op amp circuit that could do it?
Second question: I tried PWM at the gate and it works but is problematic: any higher current motor blows the nfet. I better flyback diode solved it on the bench but in real conditions the brake fet blew. Question: would more fets in parallel help?
Diagram: the brake fet is show next to the motor and the gate control pot is as shown This linear set up is trouble free but all of the adjustment comes in 1/10 of a turn. I want to spread the control out over the whole pot. I want the fet to go from less than one ohm to about 10 ohms.
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