UCC21750: Gate driver power supply control power budget.

Anoop kumar N

Part Number: UCC21750

Dear experts,

Is there any analytical method to determine the control power budget required for the gate driver power supply ? My power supply is capable of delivering 80mA at 20V. My peak current requirement is 4.5A, calculated based on the equation given in the datasheet of UCC21750 for the selected Rg. How to calculate the rms current taken from the power supply ? LTSpice simulation can help i know, but is there any analytical method available, pls help. (the purpose is, incase of paralleling of mosfet required, whether this power supply alone can meet the power demand)

Thanks and regards

Anoop kumar N

over 2 years ago

0 Pratik Adibatla over 2 years ago

TI__Expert 7473 points

Hi Anoop,

Thanks for the interesting question. For my better understanding, do you want to calculate the rms current from the DC power supply which provides the 20V to VDD pin of UCC21750? You want to see if you can power up the VDD of two UCC21750 devices using the same power supply, right?

Best,

Pratik

0 Anoop kumar N over 2 years ago in reply to Pratik Adibatla

Intellectual 998 points

Actually not paralleling 2 UCC21750, paralleling two mosfet with common gate drive. at that time whether my power supply can able to meet the power demand ?

+1 Pratik Adibatla over 2 years ago in reply to Anoop kumar N

TI__Expert 7473 points

Hi Anoop,

I see your question. You want to calculate the current drawn from power supply IVDD during normal operation for one UCC21750 which is driving two MOSFETs. You have to know the gate charge for both the FETs (Qg1 & Qg2) and the switching frequency (Fsw). Then IVDD = (Qg1+Qg2)*Fsw. And if this value is less than 80mA you should be good. Hope this helps!

Best,

Pratik

0 Anoop kumar N over 2 years ago in reply to Pratik Adibatla

Intellectual 998 points

Thank you pratik for ur time.

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UCC21750: Gate driver power supply control power budget.