Gate resistors in MOSFET

Discuss hardware related to the VESC such as the NRF nunchuk.
jbc
Posts: 2
Joined: 14 Dec 2017, 11:13

Gate resistors in MOSFET

Postby jbc » 14 Dec 2017, 11:17

Hi everyone,

what is the functionality of the 4,7ohm resistors in the gate of mosfets exactly?

Thank you
regards

ThierryGTLTS
Posts: 86
Joined: 09 Aug 2017, 11:10

Re: Gate resistors in MOSFET

Postby ThierryGTLTS » 14 Dec 2017, 11:23

1. To limit the driver current.

2. To improve switching and stability, less ringing.

So it's very important.

Have a Nice Day.

Thierry

pf26
Posts: 309
Joined: 28 Mar 2016, 14:37
Location: FR Valence

Re: Gate resistors in MOSFET

Postby pf26 » 16 Dec 2017, 13:36

When you want to control the MOSFET turn ON and OFF times, the gate resistor limit the gate currents and increase MOSFET switching times.
Otherwise, the dV/dt would be higher, would generate larger RF emissions, and could be destructive (because of components and pcb parasitic inductance and capacitances, playing unexpected role at higher frequencies).
So you need to find a compromise between higher efficiency (requiring low switching times) and safety (especially that turning ON the low side FET never makes the high side also turn on due to some coupling).

jbc
Posts: 2
Joined: 14 Dec 2017, 11:13

Re: Gate resistors in MOSFET

Postby jbc » 15 Jan 2018, 13:00

Now it is clear.

Thank you very much
regards


Return to “Related Hardware”

Who is online

Users browsing this forum: No registered users and 1 guest