I am designing a boost converter circuit using a MOSFET and a 555 timer. I have been advised to use a driver circuit with the MOSFET but I am not entirely sure as to what it does. Why is isolation needed between the logic circuit and the power transistor?

 

It's not need for isolation.
It's needed to drive the high gate capacitance of a typical power MOSFET so that it switches rapidly between on and off, minimizing dissipation in the MOSFET.

 

If somebody recommended an isolated driver it is probably because your circuit needs isolatioin.

More generally, drivers are a very good way to drive current into and out of the gates of MOSFETs. The currents can range into the amps in order to get fast switching on high current MOSFETs.

High switching speed is helpful in reducing switching losses in most switchmode power supply topologies

Reduced switching losses means less heatsinkiing is needed and the efficiency is higher than it otherwise would be.

 

It's not need for isolation.
It's needed to drive the high gate capacitance of a typical power MOSFET so that it switches rapidly between on and off, minimizing dissipation in the MOSFET.

Ok thank you!

 

If somebody recommended an isolated driver it is probably because your circuit needs isolatioin.

More generally, drivers are a very good way to drive current into and out of the gates of MOSFETs. The currents can range into the amps in order to get fast switching on high current MOSFETs.

High switching speed is helpful in reducing switching losses in most switchmode power supply topologies

Reduced switching losses means less heatsinkiing is needed and the efficiency is higher than it otherwise would be.

I read about isolation myself. I don't think it is needed. Thank you!

 

It's not need for isolation.
It's needed to drive the high gate capacitance of a typical power MOSFET so that it switches rapidly between on and off, minimizing dissipation in the MOSFET.

May be just semantics but to a certain extent most gate drivers do offer 'isolation'. The actual driver part is isolated from the 'logic' part of the chip. Without this isolation they wouldn't be able to withstand the ~500V that most are capable of. Would they?