• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 135 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.

UCC28951: Question regarding the design of the UCC28951

Tomohiro Yoshimura
Prodigy 20 points

Part Number: UCC28951

Hello,

I design a phase-shift full-bridge converter useing the UCC28951.

The design condition are as follows:

Input Voltage Min.250V Typ.280V Max. 300V

Output Voltage Typ.5V

Output Current Max. 14A

Output Power Max. 70W

Switching Frequency 106.8kHz (RT=56kohm)

 

I have two questions regarding the calculation formulas listed in the UCC28951 datasheet.

Q1.This is a question about the duty cycle. Is the method for calculating the duty cycle shown in the following diagram's formula correct?

duty.png

Q2. We are currently designing with the circuit below. According to the datasheet calculations, the duty cycle D is 0.3, but in LTspice simulations, D is 0.6. Is it correct to understand that, with the rectification method shown in the following diagram, D becomes twice the value specified in the datasheet? Additionally, are there other parameters similar to D that should be taken into account?

phase-shift full-bridge.png

primary.png

secondary.png