UCC28710: Using the UCC28710 in a low voltage input DC-DC Converter

Stephen Oberholzer

Intellectual 895 points

Part Number: UCC28710

Good morning,

I want to use the UCC28710 in a Flyback application with an input voltage range of 12V - 36V DC.

I am confident it will work but would like to have your consent.

I am asking because Webench does not allow me to input this voltage range.

I will not be using the HV pin of the UCC28710 and will leave it floating.

I want to use the UCC28710 because of its constant voltage constant current capability.

Thank you.

over 7 years ago

0 Kuan Wei Chen (Kevin Chen) over 7 years ago

TI__Genius 9710 points

Dear Stephan,

Thanks for interested in TI's solution.
Did you notice that VDD turnon threshold is 21V?
What are your Vout and Iout?

Best Regards
Kevin

0 Stephen Oberholzer over 7 years ago in reply to Kuan Wei Chen (Kevin Chen)

Intellectual 895 points

Dear Kevin,

Thank you for your quick reply.
Yes, I have noticed the turn-on threshold of 21V which is fine in my application.
Vout is 1.5kV and Iout is 5mA.

I intend using the primary winding for feeding back the information about Vin and Vout - there will be no additional auxiliary winding for this.

Can you please refer to my original post for the questions I have asked?

Is the UCC28710 not a wonderful ic!

Best regards,

Stephan.

0 Kuan Wei Chen (Kevin Chen) over 7 years ago in reply to Stephen Oberholzer

TI__Genius 9710 points

Dear Stephan,

Thanks for your information.
If VDD turnon threshold 21V is ok for you, I think it should be good to go.
But I am not sure what you mean no auxiliary winding.

Best Regards
Kevin

0 Stephen Oberholzer over 7 years ago in reply to Kuan Wei Chen (Kevin Chen)

Intellectual 895 points

Dear Kevin,
Thank you for your reply.
To explain what I am saying: I will need no additional auxiliary winding on my transformer to supply VDD and VS of the UCC28710 - I will use the primary winding for this. In other words, I will connect the DRAIN of the primary side MOSFET via a small linear regulator to the VDD pin, and I will connect the DRAIN of the primary side MOSFET through a resistor divider to the VS pin. This can be done because Vin of my power supply is 36V max.
Regards,
Stephan.

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UCC28710: Using the UCC28710 in a low voltage input DC-DC Converter