Hi,
I'm new to PCB design, and I'm building a synchronous buck converter PCB using Altium Designer. My design is heavily based on an evaluation kit designed by CREE (attached below). The problem is that the gate drivers in the circuit generate +22V and -5V bias to drive SiC MOSFETs (Cool-MOS). I want to use the same gate drives to to drive a GaN-HEMT devices which require +5V and 0V bias.

Is it possible to add a voltage regulator to adjust the gate bias for the GaN-HEMT devices, or do I have to use a different gate driver? I'm doing this as a project for my dissertation and I'm running out of time and options. I would be grateful if you could provide me with a quick solution (if there is) for this problem.

Thanks

Amar

 

Have no an experience with GaN, but Google for AN (application notes), it Must Be from producer of Your devices, and trust them well.

 

Dear Janis59,

Thanks for the reply, appreciate it. I did find an application note on how to drive GaN devices, but I want to know if it's possible (and how) to modify the attached circuit to use it for both GaN and SiC/Si devices. I will take your advice and look for more Application notes maybe I'll find a solution.

Thanks

 

You should be able to reduce the voltage from U3 and U4 to reduce the +22V but I don't see where the -5V is coming from.

 

You should be able to reduce the voltage from U3 and U4 to reduce the +22V but I don't see where the -5V is coming from.

For the high driver stage, the ZD6 forms a virtual common voltage for the source of the Power MOS transistors.

With the U4 power supply's basic load through the R12 and ZD6, I wonder a bit over the "clamping circuit" R23 and ZD7?

 

You should be able to reduce the voltage from U3 and U4 to reduce the +22V but I don't see where the -5V is coming from.

It doesn't say -5V, but it's indicated as -VEE_mid_HS.

How would you edit the circuit to adjust the voltage bias and make it, say, +6V and -4V?