Digital Dreams
Everyone else at work has been very, very busy with production task and I have been waiting a few days for feedback about the latest design project schematic. I have been using the down time to do a little circuit simulation in Altium Designer of critical sub-circuits of the new project with Spice. So far I have successfully simulated the digital drive input actuator circuity which contained analog filters with a digital logic gate!
Spice does not model digital logic very well. The sharp logic transitions plays havoc with the circuit model matrix slowing the math down and causing singularities errors. In the past, I had to break up the circuit into analog and digital sections and only simulate the analog section.
Altium Design solution to the digital logic gate modeling problem is to replace the full Spice model of a digital logic gate with a very simple behavior model of just the input and the output pins written in code. These SimCode models are written in a "C" like code and linking them into the schematic was kludge, but it did work.
Having the ability to model both analog and digital circuitry together is very useful. I have already found that the actuator has large asymmetrical latencies that was caused by the clamping diodes capacitance.
Spice does not model digital logic very well. The sharp logic transitions plays havoc with the circuit model matrix slowing the math down and causing singularities errors. In the past, I had to break up the circuit into analog and digital sections and only simulate the analog section.
Altium Design solution to the digital logic gate modeling problem is to replace the full Spice model of a digital logic gate with a very simple behavior model of just the input and the output pins written in code. These SimCode models are written in a "C" like code and linking them into the schematic was kludge, but it did work.
Having the ability to model both analog and digital circuitry together is very useful. I have already found that the actuator has large asymmetrical latencies that was caused by the clamping diodes capacitance.