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# TPS54618C-Q1: Power loss calculation

Part Number: TPS54618C-Q1

Hi experts,

The TPS54618C-Q1 datasheet give us some instruction on power dissipation estimate, but I'm a little confused about the gate drive loss.

In 10.3 Power Dissipation Estimate, the gate drive loss is estimated by Pgd = 2 × Vin × ƒsw× 10 × 10–9

Could you please help to explain this formula and parameters? From my understanding, the gate drive loss should be related to VGS, MOSFET gate charge and frequency, but why there use Vin in this formula? What does 10× 10–9 mean? Is it the sum Qg of High-side and Low-side MOSFET?

Thanks.

Arie

• Hello Arie,

I recommend zou have a look at the attached paper >

In order to chrage and discharge the BOOT capacitor, an internal circuit will be used.

When charged the BOOT capacitor will see VIN accross its pin.

I think it is a reasonable assumption to say that, 2*10*10-9 is the sum of Qg of High-side and low-side.

Thanks a lot!

Regards,
Dorian

• Hello Arie,

I haven't back from you!

Do you have any further questions?

Let me know.

Thanks a lot!

Regards,
Dorian