LT3999 Sim failure

Hi JimPrince,

It is difficult to pinpoint where the problem is. Can you provide your LTspice file and schematic?

Hi my company policy forbids my from publishing any design files. I can describe the circuit in this text.....

2 stage converter 17V input -> LT8609S converter ( RT 86.6K, SS 1u ) -> 10u inductor, feedback to gen 15.7V -> 30uF -> LT3999 push-pull (Rdc open, SS 0.01u, Rt 28K, -> 100uH pri, 2 secondaries, 1) dual 156u, 100V schottkeys, 20uH, 20uF, 85 Ohm 2) Dual 25uH, 10uH, 20uF, 10 Ohm 1st stage PG to LT3999 UVLO 100K pull up. 

Hi my company policy forbids my from publishing any design files. I can describe the circuit in this text.....

2 stage converter 17V input -> LT8609S converter ( RT 86.6K, SS 1u ) -> 10u inductor, feedback to gen 15.7V -> 30uF -> LT3999 push-pull (Rdc open, SS 0.01u, Rt 28K, -> 100uH pri, 2 secondaries, 1) dual 156u, 100V schottkeys, 20uH, 20uF, 85 Ohm 2) Dual 25uH, 10uH, 20uF, 10 Ohm 1st stage PG to LT3999 UVLO 100K pull up. 

Hi JimPrince,

In that case, it's better to connect with local FAE or I can help connect you to one if you can provide project details and estimated annual usage.

This does not look like anyone is interested in actually fixing the issue.