AC Power Switch based on Back-to-Back MOSFETs

Gadi Fishel2

Other Parts Discussed in Thread: UCC5350

Greetings,

Design AC switch requirements for 80VAC to 250VAC and currents: up to 80VAC to 130VAC - 5A, 130VAC to 250VAC - 3A;

I want to use back to back MOSFETs pair installed on PCB ( as a cheap option);

Please advise isolated driver for the application and * *(!) more important - way to calculate PCB built in heat sink ( as a copper plane area around MOSFETs drains on top side of PCB and also at bottom side copper plane connected to each other through vias.

Thank you,

over 6 years ago

0 Robert Taylor1 over 6 years ago

TI__Expert 6540 points

Hi GF,

We have many isolated gate drivers that would be appropriate for driving your FETs. UCC5350 is a good one to start with.

As for the power dissipated in the PCB. A simplified calculation for the temp rise is delta T = P * 166 / SA. Power is in watts and surface area in square inches. You can account for both sides of the PCB.

Thanks,
Robert

0 Gadi Fishel2 over 6 years ago in reply to Robert Taylor1

Prodigy 120 points

Robert,
Thank you for your recommendation. I am going to try UCC5350.
Regarding delta T = P * 166 / SA. Can you please point the source of the equation. It should be also calculation of vias ( number, diameters etc) and also what parameter represent number 166?
Thanks a lot,
GF

0 Robert Taylor1 over 6 years ago in reply to Gadi Fishel2

TI__Expert 6540 points

HI GF,

Please check the paper at this location:

Thanks,

Robert

0 Gadi Fishel2 over 6 years ago in reply to Robert Taylor1

Prodigy 120 points

Robert,
Thank you!

Power management

Power management forum

AC Power Switch based on Back-to-Back MOSFETs