• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 64 subscribers
  • Views 164 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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:

UCC28950-Q1: Centre tapped or Full bridge synchronous rectifier

UCC28950-Q1: ICs or reference design for full bridge rectification

Nicolas Murguizur
Prodigy 140 points
Part Number: UCC28950-Q1
Other Parts Discussed in Thread: UCC24624, UCC27710, UCC27211, UCC27712, UCC27714, UCC27211A, UCC24612

Tool/software:

Hi,

I want to develop a 100kHz-300kHz synchronous rectifier (60V, 15A). I don't want to use a center tapped secondary because to my understanding, that allows me using twice as much copper for the same volume thus halving the power dissipation in the windings. I think the losses in the semiconductors for a full bridge rectifier are twice as much as in a center tapped rectifier but I don't think that will offset the power dissipation savings from using the entire secondary windings. Let me know if my understanding so far is wrong.

I have seen some LLC rectifiers which use the center tapped secondary but I have seen no full bridge synchronous rectification IC.

Can you please indicate if you have such a device or maybe using several devices to achieve such purpose. Also, any reference regarding such a system is welcome.

Regards

  • 0
    TI__Intellectual 2350 points

    Hi Nicolas,

    Yes, you are correct. With full bridge rectifier on secondary, instead of center-tapped secondary, the conduction losses in the secondary winding of transformer can be halved. 

    Full bridge rectifier may be generally recommended for high output voltages. Where this additional conduction losses in semiconductor are not major part of total loss.

    Full bridge rectifier with synchronous rectifier may be chosen at high output voltages and high currents. 

    I do not know a design, where the full bridge rectifier with SRs is used to provide a direct reference.

    • However, you can consider UCC24624 SR driver for this purpose. 
    • Connect UCC24624 to drive two lower MOSFETs on each leg.
    • Use these two gate drives to drive the alternate leg's high side FETs (Top1+Bottom2 and Bottom1+Top2) as well through a half bridge gate driver.
    • Chose the gate driver based on voltage requirement (example: UCC27211/ UCC27211A for 100V; UCC27710 /UCC27712 / UCC27714 for 600V rating etc).

    Regards

    Hemanth

  • 0 in reply to Hemanth Sreeperumbudur
    Prodigy 140 points

    Hi Hemanth,

    Thanks for your answer. So there's no full bridge SRs in all TIs AN?

    What would be the recommendation for implementing a current doubler rectifier?

    Regards

  • 0 in reply to Nicolas Murguizur
    TI__Intellectual 2350 points

    Hi Nicolas, 


    We don't have a full bridge SR controller to recommend.

    To implement current doubler with SRs, please consider UCC24612 (single channel) controller. As UCC24624 doesn't allow to turn-on both the gate drives at the same time.

    Regards
    Hemanth