LM3409HV: Internal power dissipation reduction with high Vin

James Powell

Part Number: LM3409HV

Dear Ti

Is it possible to feed Vcc of the above part form an external source through a diode?

I have used this technique on several other parts before to reduce internal dissipation when high Vin, high switching frequency, and high Qg of the external mosfet makes internal dissipation too high

Many thanks

James

over 6 years ago

0 Clinton Jensen over 6 years ago

TI__Mastermind 25500 points

Hello James,

I am going to double check with the IC designer to be sure, but if I remember correctly you cannot drive VCC externally with this device since it is VIN referenced rather than ground referenced. I will respond and let you know differently if that is incorrect.

Regards,

Clint

0 James Powell over 6 years ago in reply to Clinton Jensen

Prodigy 70 points

Thanks Clint
This makes sense since the cap on Vcc in the default configuration is referenced to Vin. Think I have found a suitable a suitable FET with much lower Qg that will help.
Regards
James

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LM3409HV: Internal power dissipation reduction with high Vin