SLUSD49A September 2017 – January 2019 UCC256303
PRODUCTION DATA.
Refer to the PDF data sheet for device specific package drawings
This function provides a way to shut down the system by an external signal. When the FBreplica is less than the burst mode threshold, stop LLC switching. When FBLessThanBMT is true for more than 200 ms, go to startup state and try to re-start. Before LLC starts switching, the system has to make sure that FBLessThanBMT is not true. If FBreplica is constantly held low by an external signal, the system will not start again.
This function can be used for system on/off control or any other fault shut down which isn’t included in UCC25630. To implement this function, an external biased optocoupler is needed. The schematic below is an example of such implementation.