TINA/Spice/TPS92692-Q1: Sim Model Not Boosting to give constant current output

Tool/software: TINA-TI or Spice Models

Hello Team,

My customer is having trouble with the TPS92692-Q1 simulation model where the output isn't boosting to a high enough voltage to get the expected current running through the LED string.

It seems that the boost fet gate drive will only run in short pulses and turn off instead of boosting up to the expected voltage. Also the Fault output seems to trip for very short periods of time.

I've attached the simulation model, the calculation sheet used for the design, and an example that the model is outputting.

Any suggestions on what we can change to get this working?

So far I've tried:

- Replacing the boost fet with a logic controlled switch

- Replacing the LED model with a string of 18 LEDs

- Removing the dimming FET

Thanks!

DavidTPS92692_Boost_Design_16_18LEDs_Calculator.xlsxtps92692.TSC