LMG2650: Reverse current, what happens to current sense

Nicholas Carley

Genius 10075 points

Part Number: LMG2650

Tool/software:

Hello,

If current flows in reverse on the GAN FETs, how will the current sense output respond? Will it get damaged?

Nick

3 days ago

0 Pratik Adibatla 3 days ago

TI__Expert 7683 points

Hi Nick,

Thanks for reaching out. It won't get damaged; it just doesn't sense it. It's designed for unidirectional current sense.

Best,

Pratik A.

0 Nicholas Carley 3 days ago in reply to Pratik Adibatla

TI__Genius 10075 points

Thanks Pratik! Will the output CS pin just clamp to 0, or is there other behavior we need to account for on the CS pin?

Is there any fault or indicator we could use when current is flowing in reverse?

Nick

0 Pratik Adibatla 3 days ago in reply to Nicholas Carley

TI__Expert 7683 points

HI Nicholas,

Nicholas Carley said:
Will the output CS pin just clamp to 0, or is there other behavior we need to account for on the CS pin?

The CS pin has internal clamp, it will just go to that voltage

Nicholas Carley said:
Is there any fault or indicator we could use when current is flowing in reverse?

No, to sense the current in reverse conduction, they need to use external CS mechanism.

Best,

Pratik A.

0 Nicholas Carley 3 days ago in reply to Pratik Adibatla

TI__Genius 10075 points

Hi Pratik,

Okay, that wasn't what I was expecting. Just to confirm, in reverse conduction it will clamp high rather than clamp low?

Nick

0 Pratik Adibatla 3 days ago in reply to Nicholas Carley

TI__Expert 7683 points

Hi Nick,

Apologies for the confusion. The 2.55V is the max limit, it can't exceed that. For the reverse conduction, the voltage will be close to 0 or some leakage current times Rcs which should be very small or close to 0V.

Best,

Pratik A.

Power management

Power management forum

LMG2650: Reverse current, what happens to current sense