PMP10344: TVS Diode

Arion Doneda

Prodigy 60 points

Part Number: PMP10344

I would like to know the purpose of this part of the circuit, in PMP10344:

And how can I shrink the Power Supply size, if possible.

Regards.

Arion

over 3 years ago

0 Robert Taylor1 over 3 years ago

TI__Expert 6670 points

Hi Arion,

D2, D4 and R1 are the clamp circuit that limits the voltage in the flyback primary MOSFET. This is used to limit the voltage spikes due to the leakage inductance of the transformer.

To reduce the size is a much more difficult question, are there any specifications that are different from this design?

Thanks,

Robert

0 Arion Doneda over 3 years ago in reply to Robert Taylor1

Prodigy 60 points

Hi Robert.

Thank you for the answer.

Can I reduce the size of the varistor, using a SMD for example? Or reduce the size of the 0.01uF/1000V capacitor?

Thanks.

Arion

0 Robert Taylor1 over 3 years ago in reply to Arion Doneda

TI__Expert 6670 points

Hi Arion,

My initial thought is no, but I am looping in the original design to comment.

Thanks,

Robert

+1 Brian King over 3 years ago in reply to Robert Taylor1

TI__Intellectual 2885 points

Hi Arion,

The varistors are there for surge protection, and do not play role in the actual power conversion. I don't think you will find any varistors that are significantly smaller, but if you already have surge protection elsewhere in your system you could remove them.

I think 0.01uF capacitor could possibly be removed. It is there to help suppress conducted EMI at higher frequencies, but there is plenty of margin above 10MHz.

thanks,

Brian

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PMP10344: TVS Diode