TPS40200: With the P-FET for small parasitic capacitance

ACGUY

Part Number: TPS40200

Hello E2E,

When with small the parasitic capacitance of P-FET, VGDRV goes to under 10-V from VDD at FET turn-ON.

Questions;
What Is cause?
Is there any countermeasures?
Vin 24V - 36V, Vout 12V, Iout 1A, What is the recommended P-FET?

Regards,
ACGUY

over 5 years ago

0 Daniel Li14 over 5 years ago

TI__Mastermind 27470 points

you can refer TPS40200 EVM's mosfet, and put a zener between P-fet GS to protect the drive. it should be 8V, make sure there is no osiliation happened at GS when high side turn on

Thanks

0 ACGUY over 5 years ago in reply to Daniel Li14

Guru 11170 points

Hello,

Thank you for suggest a countermeasure.

I think that TPS40200 has a 8-V zenner between GDRV and VDD in gate driver circuit, that zenner max Iz is not so large current conducting.
Is it correct?

How much the maximum current for voltage clamping zenner?

Regards,
ACGUY

0 Daniel Li14 over 5 years ago in reply to ACGUY

TI__Mastermind 27470 points

you can follow the Zener used in EVM board which is around 200mA.

Thanks

Daniel Li

0 ACGUY over 5 years ago in reply to Daniel Li14

Guru 11170 points

Hello,

How much the maximum current of inculded voltage clamping circuit for GDRV?

Regards,

ACGUY

0 Daniel Li14 over 5 years ago in reply to ACGUY

TI__Mastermind 27470 points

Hi ACGUY:

Do you mean the GDRV max current capability? if it is, I don't have this data.

thanks

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TPS40200: With the P-FET for small parasitic capacitance