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UCC27284-Q1: For which application without interlock is it?

Part Number: UCC27284-Q1
Other Parts Discussed in Thread: UCC27282-Q1,

Hi team, 

For which application without interlock is UCC27284-Q1? UCC27282-Q1 is with interlock and looks this function is needed for general half bridge application. 
If you have any use case for UCC27284-Q1 instead of UC27282-Q1, please let me know.


  • Hi Ochi,

    Thank you for your question. The lack of input interlock is desired in applications that need the two inputs, and therefore the outputs, to overlapped, such as in secondary side full-bridge synchronous rectification.

    The interlock feature is more common in motor driver applications to drive pumps, fans, etc. and it is mainly used as fail-safe option to shutdown the IC when the 2 inputs are high at the same time due to MCU malfunction, software error or noise on the input. 

    Best regards,


  • Hi Leslie, 

    Thank you for your response. Why does secondary side full-bridge allows overlap operation? I though secondary side full bridge synchronous rectifier also needs interlock to prevent shoot-through.


  • Hello Ochi,

    In some SR applications the SR switch is conducting during the active current conduction time and also during the dead time between until the opposite phase SR switch is turned on. This results in overlapping timing of the two SR switches.

    Another topology that requires no interlock is a two switch forward converter.