UCC24612: Ciss selection

Charles Zhang1

Part Number: UCC24612

Hi Team,

My customer wants to drive 2 paralleled MOSFETs, I have known that MOSFET's RDSON is the key concern as described in the datasheet, then how about Ciss?

Is there any selection guide for choosing the proper MOSFET Ciss? How do we ensure that the driving capability of UCC24612 is enough for the MOSFETs?

Thanks.

over 1 year ago

0 Manikanta Pallantla over 1 year ago

TI__Genius 12875 points

Hi Charles,

The SR Controller expert is currently out of office. He will be coming back on 6th. Please expect the reply to thread on 6th.

Regards

Manikanta P

0 Wesley Hsu over 1 year ago

TI__Expert 3431 points

Hi, Charles:

May I know what which MOSFET and what kind of topology that your customer would like to use?

Generally, UCC24612 provides 1A peak souring capability to drive MOSFET.

You may using the equation as below to check the Ciss charging/discharging time is meet your expectation or not.

Since Ciss is variable, you may also use dT= Qg(total)/I, where Q = C*dV, to check if MOSFET can turn on/off in time.

Regards,

Wesley

0 Charles Zhang1 over 1 year ago in reply to Wesley Hsu

TI__Intellectual 2810 points

Hi Wesley,

Customer is using BSC093N15NS5, and the topolgy is forward.

Thanks.

0 Wesley Hsu over 1 year ago in reply to Charles Zhang1

TI__Expert 3431 points

Hi, Charles:

Unfortunately, UCC24612 is not recommended for forward converters. Because the rectifier current shape in forward converters in CCM, the Vds sensing may not be able to turn off without shoot through. I think it could be some risk here.

Thanks.

Regards,

Wesley

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UCC24612: Ciss selection