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TPS40140: Having problems running TINA-TI simulation with provided model

Part Number: TPS40140
Other Parts Discussed in Thread: TINA-TI

Hi,

I am trying to run a simulation using TINA-TI and the TPS40140 model provided by TI.  This simulation is intended to better understand operation of a legacy circuit; it is not for a new design.  The circuit uses a TPS40140 configured as a dual output buck regulator (3.3V and 1.1V).  I entered the circuit schematic into TINA and tried to run a transient simulation.  The simulation did converge, but results did not make much sense.  Several hours were spent checking the circuit schematic for problems and making various circuit simplifications to try to get the simulation to produce meaningful results, without success.

I then tried to run a simulation using the TPS40140 example circuit that is included with the TINA-TI installation.  The example circuit is a two phase, single output, 1.5V buck regulator.  Simulation ran without problems and results made sense.  I decided to convert the example circuit into my circuit a step at a time to gain some insight into the simulation problem.  The output circuit was split into two outputs and a second feedback network was added.  Please see attached .TSC file.  The schematic is not very pretty, but I am only about half way to getting the schematic completely converted;  output voltage and current limits have not been changed and the original circuit uses the 3.3V regulator output as an input to the 1.1V regulator.  Simulating this circuit is successful as-is.  But there is an error in the circuit.  Note that pin CSRT2 is connected to VOUT.  It should be connected to VOUT2.  When this connection is changed, the simulation will not run.  Can this be explained?  Is there a workaround to get the simulation to run?

tps40140_vreg.TSC