LTspice sim of LT8312 BCM Boost PFC wont work

[ocset]

Hello,
Do you think the attached LTspice sim and pdf schem  shows  an acceptable way to control the LT8312 BCM Boost PFC controller in an "open loop" kind of way?

I am trying to adjust the output power by setting the Vc pin voltage by setting up the internal  error amplifier as an inverting opamp, and inputting voltages into that.


LT8312 datasheet
https://www.analog.com/media/en/technical-documentation/data-sheets/8312fa.pdf

[SiliconWizard]

To begin with, why did you put a voltage source at the output of the converter?

[ocset]

Thanks, thats a representation of a battery...we have these batteries which are always 400v +/-5v no matter what the state of charge.

[ocset]

The OTA inside the  LT8312 has a maximum possible output current of 63uA.....at least the LTspice sim model of LT8312 does.
How, from the datasheet, could this figure of 63uA possibly be calculated?

LT8312 datasheet
https://www.analog.com/media/en/technical-documentation/data-sheets/8312fa.pdf

[SiliconWizard]

I suppose you're talking about VC, the output of the error amplifier?
If so, I haven't seen any spec. regarding the output current capability in the DS, only a couple typical compensation networks (since it's meant to be used as a compensation pin.)

I'd also suggest looking at the output voltage of your converter on a pure resistive load (instead of the voltage source you're using to simulate a battery, which BTW is probably not the right way of simulating one properly) to see how it behaves. Wild oscillations. (I used a 1k resistor as load, and had to change the coupling coefficient - for your transformer - from 1 to 0.99 to avoid convergence problems.)