• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 64 subscribers
  • Views 866 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.

UCC28019A current sensing using CT

mechaniK
Prodigy 180 points
Other Parts Discussed in Thread: UCC28019A, UCC28180, UC3854

Is it possible to use a CT[1:100] instead of shunt resistor for current sensing for UCC28019A PFC chip?

If yes, then is it possible to use one CT in series with drain of switching mosfet or I would need to have one in series with drain of the mosfet and one in series with boost diode and then sum the secondary outputs in negative going format feeding Isense pin of the PFC chip ?

  • 0
    TI__Expert 3200 points
    I have sent your question to an AE who will help you soon.
  • 0
    TI__Genius 9790 points

    Hi, 

    UCC28019A needs total current information of PFC inductor, so it is possible to use two CTs, which like your comment. One CT in series with drain of Mosfet is not possible.

    Could you let me know why do you want to use two CTs? If for the efficiency, we have UCC28180 which is new generation based on UCC28019A. UCC28180 has lower current protection threshold which need smaller shunt. The current protection threshold of UCC28019A is 1V, but it is only 0.4V with UCC28180.

    Regards,

    Yunsheng 

  • 0 in reply to Yunsheng Qu
    Prodigy 180 points

    Thank you Yunsheng for the current sense information and suggestion on using new chip, I will try it.

    I am designing a Bidirectional PFC with common source connection of mosfets, drains between AC line after coupled boost inductors , followed by fast recovery bridge, in which the current sensing is easily done with CTs and gate driver is already using isolated drivers. This UCC28019A chip doesn't need multiplier input IAC/MULT like typical UC3854 types hence wanted to use it just by giving Vsense+Gatedrive+Current sensing information to it and get the resultant output. 

    Best Regards,

    Abhishek

  • 0 in reply to Yunsheng Qu
    Prodigy 180 points

    Hello Yunsheng,

    Can we use one resistor in series with boost inductor instead of CT, I plan to use isolation amplifier to sense the current across the resistor and then feed it to the pfc controller , hence it will sense the current image of both FET and Boost diode combined?

  • 0 in reply to mechaniK
    TI__Genius 9790 points
    Hi, mechaniK

    The PFC topology with Bi-directional MOSFET only need one inductor, so it is good proposal to use one resistor in series with boost inductor.

    But normally, the output signal of isolation amplifier is two differential signals, you need transfer the two differential signals to meet UCC28109A.



    BR,

    Yunsheng