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Can we use opamp as a driver circuit for a MOSFET

Can we use opamp as a driver circuit for a MOSFET?

Using an op-amp is possible but may not be the best solution depending on the switching speeds involved.

if you drive the mosfet in linear mode or if you change gears (10 khz), an op-amp can be a great solution.

The problem with an operational amplifier driving a mosfet of power is the charging and the discharge of the capacity of the grid. The op-amp can not usually provide a lot of source or absorption current.

The dedicated electrical mosfet drivers are essentially designed with an operational amplifier to drive heavy loads and switch between full activation and deactivation.

These drivers can handle currents of one or more amps to quickly charge or discharge grid capacity as quickly as possible. in fact, in some cases, a resistor is used between the driver and the gate to slow down the switching and eliminate the high-speed switching noise.

It is also important to use a mosfet power driver when switching strong currents (5 amperes), because you do not want to heat the mosfet by slowly passing it from one state to another.

A high current can cause a mass rebound if the voltage between the earth seen by the op-amp and the voltage seen by the source of the mosfet is different.

This may cause the mosfet to be weakly biased when it is supposed to be turned off and heated.

I am a fan of opto-isolated mosfet drivers because they allow you to directly connect the mosfet driver’s mass to the source of the mosfet without the control circuit sharing the same connection to the noisy earth.

I used lm393 comparators to create power mosfets with great success. In circuit, the mosfets are deactivated when the excess current flows. the mosfet is kept de-energized for a minimum period (0.5 seconds or more) and turned back on. the low switching speed and the good current absorption capacity of the lm393 work well in the application.

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