I’ve had mostly reasonable results running TI unencrypted PSPICE models in QSPICE, though sometimes due to poorly written models with sharp discontinuities there are convergence problems.
The model for the TPS63805 buck-boost converter is different though. There are no convergence problems, it runs quickly, but the output is nothing like the PSPICE output (which seems correct).
As a new user I can’t upload files, but any hints would be welcome. My QSPICE schematic is the same as the PSPICE schematic, but the output from QSPICE is a step from 0 mV to about 5 mV instead of the 3.3 V set output of the buck-boost .
What should I look for in the PSPICE model that might be incompatible with QSPICE?
Well, it doesn’t seem like the maximum timestep fixed the issue. It gave different results, and looked like it might be starting along the right path, but it is still giving incorrect results.
Exported netlist from Pspice example and using the library file “TPS63805_TRANS.lib”, Qspice cannot run the same result as Pspice. However, also tested this netlist and library in LTspice, it returns same result as Qspice.
Here is netlist file and library if anyone try to run it from SPICE program. pspice_netlist_TPS63805.cir.txt (524 Bytes)
(Forum not allow .cir extension, remove .txt to return netlist file as .cir) TPS63805_TRANS.txt (48.7 KB)
Here is where the problem lies. The operator “^” in Qspice represents the power function (same as **). In Pspice, “^” represents XOR in an if() condition. Line #892 in TPS63805_TRANS.lib has a subckt for an XNOR gate, and this function relies on “^” to perform as XOR. In Qspice (also LTspice), it performed as power instead of XOR.
Update to latest version of Qspice, Mike implemented a new operator for boolean XOR (^^)
08/21/2025 Implememted boolean XOR (symbol ^^ in analogy to boolean AND(&&) and boolean OR(||)) in the simulator
In general, QSpice can accept PSpice syntax netlists. However, the caret (^) is more commonly used to refer to power in modern syntax. Mike decided to implement a new operator (^^) for the boolean XOR operation.
So, if you are working with a PSpice netlist that contains XOR (^), simply change it to (^^) for use in QSpice. This will ease the modification. Here is an example of a modified TPS63805 netlist.
