OrCad Capture Convergence Problem Full Bridge Amplifier

[loki3118]

Thank you everyone for you help with my earlier post regarding a half bridge amplifier. I got that simulation to work beautifully.

My next task is to model a full bridge amplifier. This design is giving me a lot more trouble than the previous iteration. No matter what recommendations that the online resources suggest I cannot get the circuit to converge. I'm at the point that there must be something completely wrong with my circuit design. I've looked for something obviously wrong with the circuit but I believe that I am too close to see the error.

Does anyone see something obviously wrong with the circuit? Also does anyone have any suggestions that I could try to get it to converge?

Thank you for your help!

 

[FvM]

There are several circuit faults, LO2 and HO2 interchanged, both HS pins that are necessary for bootstrap operation unconnected. So at present, the circuit can't work.

But convergence problems aren't unlikely with MOSFET switching circuits, thorough tuning of transient analysis parameters may be required to get the circuit work after correcting the errors.

 

[loki3118]

Dear FvM,

In order to get current to flow both ways through the resistor wouldn't the top left MOSFET need to be at the same time as the bottom right? Interchanging LO2 and HO2 would cause both the top MOSFETs to be at the same time, i.e. no current through the resistor.

What would be the best way to feed the right side MOSFETs with the inverse drive signal of the left side? My first thought would be to use a NOT gate since the output signals from the driver chip is just discrete pulses of a specific voltage.

 

[FvM]

HO and LO are dedicated high- and lowside driver outputs. To reverse the output polarity, interchange HI and LI.