What will happen if the drain voltage in the below image increases up to 200V? (the Mosfet could be IRF9640 or could be p-ch mosfet in IRF7105) I want to know if the Mosfet temperature goes up and also if the Drain current
is almost zero.
P-ch Mosfet behavior During Drain Load
mosfet
Related Solutions
those look like you have saturation and a high gate voltage above Vt, so VDSat approx is sqrt(Is *Isat)/Ut (that's the behavior, not the complete equation), where Ut is the thermal voltage. The drain current would decrease as the temperature goes up.
As the temperature increases, the meantime of collisions goes up, which causes those "higher order effects" that slows down mobility.
If we had a benefit from higher temperatures, we wouldn't need heatsinks.
The limit is the total of Vgs(max) and Vds(max), added with appropriate signs, unless otherwise specified, as with this 2N7000 datasheet.
You cannot just connect a voltage source between drain and gate and crank it up to 800V or whatever the MOSFET is rated for- you must constrain the gate-source voltage to remain within the acceptable range (the example above indicates a resistor so Vgs~= 0V).
Driving a MOSFET 'on' means the magnitude of the drain-gate voltage is less than the drain-source voltage. It can be more if you drive the gate 'off' - in the 2N7000 example you might have -15V on the gate, in which case the drain voltage should be less than 45V.
Best Answer
It will heat up, and if you indeed manage to get it up to 200V it will probably violently blow. The internal body diode is forward based and causes excessive current to flow. It'll probably be destroyed long before you actually reach 200V.