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UC2844: flyback controller compatible with SiCFET

Howard Zou
Genius 12365 points
Part Number: UC2844

Hi,

my customer need to make a flyback converter with SiCFET, and the drive voltage need to be at least 18V.

And they don't want to add external gate driver, they hope that the flyback controller's output could directly drive the SiCFET.

Do we have such flyback controller? Thanks.

  • 0
    TI__Mastermind 32995 points

    Hi Howard,

    TI has 44 controllers listed as flyback specific. UC2844 is a generic PWM that can certainly be used for a general purpose flyback and the PWM output is unregulated according to VCC. VCC can be as high as 36 V, so operating at VCC=18 V will provide the +18 V gate drive to the SiC. Is it ok to operate the SiC from 0 V to +VCC because many SiC applications require -VEE during turn-off? Also, while this would be a low-cost approach many of the safety and reliability features that come from a dedicated SiC gate driver would be missing. In addition to -VEE capability, DESAT, active miller clamp and soft-stop are a few important features necessary for protecting the SiC during fault conditions and unique to SiC gate drive. SiC are low gain, discretes with dynamic characteristics quite different compared to SJ MOSFETs. SiC MOSFETs use smaller die, have short short circuit withstand times and behave more like voltage controlled resistors as opposed to "ideal" low/high impedance switches and this is why there are dedicated SiC gate drivers.

    Regards,

    Steve M