• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 2 answers
  • Subscribers 63 subscribers
  • Views 215 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.

Synchronous rectifier control chip

Danilo A.
Mastermind 24715 points
Other Parts Discussed in Thread: UCC24612, UCC24624

Hi Team,

Our customer is looking for a synchronous rectifier control chip. According to the customer,

The synchronous rectifier control sits on the secondary and I need one which work with a full bridge topology but does not require a signal from the primary side.

Also need to work if the output is 3.2v or lower. Generally this mean the chip's power supply Vdd, needs to work at 3.2v are less.

FYI we can use a chip with one or two output meaning it can be the half wave type or the center taped type. quote both if possible.

Hope to hear from you soon. Our project has been dead for over a month because none of the chips we try work. They all seem to be for the flyback topology which we don't have.

Can you please suggest a device that fits the customer's requirements.

Thank you for your support!

Regards,

Danilo

  • 0
    TI__Mastermind 26840 points

    Hello Danilo,

    I will enquire with colleagues about your application.

    Please allow a day or two for a reply.

    Regards,

    Ulrich

  • 0 in reply to Ulrich Goerke
    TI__Mastermind 26840 points

    Hello Danilo,

    It seems that there are not many options for non-primary SR control for this application.
    I've been advised to concentrate on independent controllers if both SRs will be one at the same time as some full-bridge topologies do.

    I suggest to try the UCC24612 (if you have not already done so), one on each output leg.
    If that works, and if the output configuration does not have current in both SRs at the same time, then consider the UCC24624 as well.
    The UCC24624 will not allow >50% duty cycle in either output, however, so it my not be applicable.

    In any case, it is unlikely that an SR controller can work from an output voltage much lower than 5V, so some secondary-side auxiliary circuit will be needed to provide appropriate bias power to the controller(s).   

    Regards,
    Ulrich
       

  • 0 in reply to Ulrich Goerke
    TI__Mastermind 24715 points

    Hi Ulrich,

    Thank you for your suggestions. Our customer has a follow up inquiry below.

    Can you recommend a full bridge SR chip with a wide input voltage range?  
    We could make that work with some extra secondaries. 
    Something like 8-15v Vdd range would be good.  
    Regards,
    Danilo
  • 0 in reply to Danilo A.
    TI__Mastermind 26840 points

    Hello Danilo,

    I am not aware of a single IC that will control all four SR-MOSFETS of a full bridge output.

    The part I mentioned earlier, UCC24612, works on a single SR-FET and has a VDD range from 4V to 28V.
    The -1 version can accommodate low levels of CCM, and may work in your application. 
    I suggest that you can try it.

    Regards,
    Ulrich