TIDA-01505: start-up circuit (uses of UCC28700-Q1 instead of UCC28C43-Q1)

Hassan KHALIL

Prodigy 90 points

Part Number: TIDA-01505
Other Parts Discussed in Thread: UCC28700, UCC28700-Q1, , UCC28C43, UCC28C43-Q1

Hello,

I has identifie annoter part (UCC28700) which the start up circuit is integrated inside this component.

Can you confirme me if it's possible?

What is the maximum duty cycle for UCC28700?

Thank you.

Best regards

over 3 years ago

0 Xun over 3 years ago

TI__Mastermind 18120 points

Hi Hassan,

Yes, using UCC28700 is possible. The gate driver voltage is clamped to 14V. PMP10415 is an example of such application. I will come back to you regarding the maximum duty cycle. Will need to check internally.

0 Hassan KHALIL over 3 years ago in reply to Xun

Prodigy 90 points

Hi Xun,

Thank you for your response.

I have some question about calculation.

In this equation, what is the fmax? it's the switching frequency?

What is the good value to be considered for VOCBC

My application is to convert an input signal 40V-500V to 16V 6W and 5V 1W without isolation between primary and secondary.

This is converter work in DCM mode, it's right?

when i calculated primary inductance with:

The selected value must be lower than the calculated value, it's righ?

This driver work with input of 40V?

Have you an excel file for calculation?

0 Xun over 3 years ago in reply to Hassan KHALIL

TI__Mastermind 18120 points

Hi Hassan,

I could not see your uploaded images. Could you please check? Thanks.

0 Hassan KHALIL over 3 years ago in reply to Xun

Prodigy 90 points

Hi Xun,

Thank you for your response.

I have some question about calculation.

In this equation, what is the fmax? it's the switching frequency?

What is the good value to be considered for VOCBC

My application is to convert an input signal 40V-500V to 16V 6W and 5V 1W without isolation between primary and secondary.

This is converter work in DCM mode, it's right?

when i calculated primary inductance with:

The selected value must be lower than the calculated value, it's righ?

This driver work with input of 40V?

Have you an excel file for calculation?

0 Xun over 3 years ago in reply to Hassan KHALIL

TI__Mastermind 18120 points

Hi Hassan,

I still could not see your images. But to answer you last question: Both UCC28c43 and UCC28700-Q1 works with input voltage of 40V. I don't have a excel file for the TIDA-01505, but for UCC28700 based design there is an excel file at the link blow: