• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 320 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

UCC28070A: Calculation sheet sluc114

UCC28070A: Calculation sheet sluc114

Masazumi Ishii
Genius 3945 points
Part Number: UCC28070A

Hello.

Thank you for the data of Mathcad calculator the other day.

I calculated using this.
Also, we designed the same specifications using WEBENCH.

As a result, it became a big difference design.

Choke coil value is about 10 times (MathCAD: 22 μH versus WEBENCH: 220 μH) There is a difference.

Also, the choke coil selected by WEBENCH has a very small rated current of 3.5 A is selected.

Actually I think that it is necessary to have a peak of 30 A class.

Is it possible to send design data of WEBENCH and MathCAD and see which design is better?

Please let me know your email address if possible.

Thank you.

  • 0
    TI__Mastermind 34465 points
    Hello Masazumi Ishii ,
    A pfc design with only a 22uH boost inductance seems very small.
    In order to check this is an acceptable value I need to know your design specifications.
    What is your power requirements, switching frequency, input voltage range and ripple current requirement ?

    Thanks
    John
  • 0 in reply to John Griffin1
    Genius 3945 points

    Hello.

    thank you for your answer.

    Specification is. It is as follows.
    I brought it from WEBENCH.

    1. Iout 13.0 Maximum Output Current
    2. VinMax 264.0 Maximum input voltage
    3. VinMin 165.0 Minimum input voltage
    4. Vout 380.0 Output Voltage
    5. acFrequency 60.0 AC Frequency
    6. base_pn UCC28070A Base Product Number
    7. source AC Input Source Type
    8. Ta 60.0 Ambient temperature
    9. Frequency 205.479 kHz System

    Regarding ripple current, we do not specifically set it.
    I am thinking with general values.
    Thank you.
  • 0 in reply to Masazumi Ishii
    TI__Mastermind 34465 points
    Hello Masazumi Ishii ,
    There is some issue with the Webench model and it is not giving the correct value for the inductance .
    The values of inductance calculated in Mathcad and in the Excel tools are about 10uH at full load and with 30% current ripple current.
    I recommend that you use the values calculated by Mathcad or Excel
    I will contact the Webench team and inform them of this inaccuracy.
    Thank you for reporting this.
    Regards
    John