TPS40200: Recommended Zener diode between source and gate of MOSFET

Hide

Guru 21045 points

Part Number: TPS40200

Hi Katelyn-san,

You use BZX84C12T (Diode, Zener, 12-V, 350mW) at Figure 31 (8 V to 12 V Input, 3.3 V to 5.0 V at 2.5-A Output).

Could you please let us know the recommended parts at “24V Input 5.0V Output at TBD output current”?

I would be grateful if you could reply as soon as possible.

Regards,

Kanemaru

over 6 years ago

0 Robert Blattner over 6 years ago

TI__Expert 6245 points

Hello Kanemaru,

The purpose of D3 is to protect the gate of Q1 and level shift the sync signal. D3 will not need to be changed. Be sure that Q1’s drain can sustain VDD.

Regards, Robert

0 Hide over 6 years ago in reply to Robert Blattner

Guru 21045 points

Hi Robert-san,

I'm sorry for confusing you.

I would like to know about D1.

Could you please let us know the recommended parts at “24V Input 5.0V Output at TBD output current”?

Regards,

Kanemaru

0 Robert Blattner over 6 years ago in reply to Hide

TI__Expert 6245 points

Hello Kanemaru,

The purpose of D1 is to protect both the gate of Q2 and the gate drive circuitry in the TPS40200 from large transient voltages cause by, amongst other things, Q2’s miller charge. Since Q2’s tolerance of high voltage as well as that of the IC’s gate drive circuit does not change with input voltage, this diode should not be changed when you redesign for higher input voltage.

Regards, Robert

0 Hide over 6 years ago in reply to Robert Blattner

Guru 21045 points

Hi Robert-san,

Thank you for your prompt reply.

I understand. Thank you very much.

Regards,

Kanemaru

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TPS40200: Recommended Zener diode between source and gate of MOSFET