Mosfets gate driver IC criteria

Question

I am designing a driver circuit to drive 4 mosfets connected in parallel as shown in figure below (4 mosfets instead of 3).

Mosfet data sheet : http://www.infineon.com/dgdl/Infineon-IPT020N10N3-DS-v02_00-en.pdf?fileId=db3a30433e9d5d11013e9e58035b0158

I have look around the internet and there are a few criteria to look into for selecting a suitable gate driver.

1. Maximum average output current of the driver must be higher than calculated from the mosfet. (How do I calculate this?)

2. Peak gate current must be higher than calculated. I peak=(Vdr-V_plateau)/(Rg+Rg_internal)?

3. Switching frequency. (assume to be 20 kHz)

QUESTION!

1. How do I calculate the average current?

2. Is the peak gate current formula above correct? If not, how should I calculate it?

3. Is there anything else I should look into?

Got stuck with this for quite some time, searching around google and my question is still unsolved. Please guide me through this. Thanks in advance! Regards, Brandon Lok Toong Yin

Answer 1

1. Take the gate charge and multiply it by the frequency. This is Coulombs per second, aka Amps. As long as you're fully filling the gate capacitor every cycle, this is correct.

2. I believe Ipk is (Vgon-Vgoff)/Rg, which is the charge flowing into the gate capacitor right when you flip it on.

3. Keep reading those app notes! There's lots of info packed in there.