UCC27201: Max current required for UCC27201 in the worst case

Ella KIM

Part Number: UCC27201
Other Parts Discussed in Thread: LM34927,

Hi Team,

I'm looking into the possible max current required for UCC27201 (VDD) to see if designing power supply with LM34927 (600mA DCDC) is okay.

It looks the IC itself consumes approximately 1.6mA (0.8mA+0.8mA) under f 500kHz and no load on PWM outputs. And this device is max 3A source capability with load. Does this mean UCC27201 VDD pin requires the current of 1.6mA + 3A in the worst case? If so, it looks I cannot use LM34927 to supply VDD of UCC27201. Could you advise?

over 3 years ago

+1 Richard Herring over 3 years ago

TI__Mastermind 21325 points

Hello Ella,

The current required from the bias supply will be the average current required for the IC quiescent current plus the average current required for the gate drive losses. The driver peak currents are sourced from the VDD and HB capacitors which are located close to the IC pins.

To estimate the average current for driving the MOSFETs it is simply Iavg=Qg x Fsw, where Qg is the total gate charge of MOSFETs on both the LO and HO outputs, and Fsw is the maximum switching frequency of the converter.

The bias supply you mention of 600mA is likely more than adequate for the average current, unless there is very high gate charge and/or high switching frequency.

Regards,

0 Ella KIM over 3 years ago in reply to Richard Herring

TI__Expert 3932 points

Thanks Richard for your clear & kind information.

0 Richard Herring over 3 years ago in reply to Ella KIM

TI__Mastermind 21325 points

Hello Ella,

Thank you for confirming, if you can confirm this resolved your questions we would appreciate.

Regards,

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UCC27201: Max current required for UCC27201 in the worst case