TIDA-010015: LL/SS pin question

Part Number: TIDA-010015

Hi team,

Our customer is referring to TIDA-010015 reference design.

For LLC controller UCC25630, there is a external circuit connected to LL/SS pin, as shown in below pic.

They would like to know what is the purpose for this external circuit.

Thanks

  • Hi Roy,

    This circuit is meant to change the burst mode threshold based on load current. The comparator U11 turns the opto-coupler on or off which puts R70 in parallel to the bottom LL/SS resistor. This circuit was meant to give the design greater precision on when the LLC exits burst mode.

    Best Regards,

    Ben Lough