Composability of subcircuits

Let’s say that I have a subcircuit for the main part of a buck converter, and I’ve parameterized it to accept an arbitrary inductor, diode, etc:

def buck_converter(
        nmos: Part,
        diode: Part,
        inductor: Part,
        cap_input: Part,
        cap_output: Part,
):
    @subcircuit
    def buck_impl(pwm: Net, v_in: Net, v_out: Net, gnd: Net):
        buck_inner_net = Net('buck_inner')

        nmos_inst = nmos.copy()
        nmos_inst['gate'] = pwm
        nmos_inst['drain'] = v_in
        nmos_inst['source'] = buck_inner_net

        inductor_inst = inductor.copy()
        inductor_inst['+'] = buck_inner_net
        inductor_inst['-'] = v_out

        diode_inst = diode.copy()
        diode_inst['-'] = buck_inner_net
        diode_inst['+'] = gnd

        cap_input_inst = cap_input.copy()
        cap_input_inst['+'] = v_in
        cap_input_inst['-'] = gnd
        cap_output_inst = cap_output.copy()
        cap_output_inst['+'] = v_in
        cap_output_inst['-'] = gnd

    return buck_impl

However, what if I want to replace the diode with synchronous rectification? What I’d like to be able to do is create another subcircuit that provides that functionality, and be able to pass it in as the diode parameter. As long as it has the same pin names, that should work.

However, I can’t do that, as the Circuit interface is nothing like the Part interface, and I can’t create a part with multiple components.

It seems to me that idea of a Circuit isn’t a very nice abstraction. It serves as a bag of parts and nets, a duplicate of the data that is already stored in the part and net graph. Why can’t that bag of parts and nets be built up as it is needed?

[matthuszagh]

Hi @flaviut, I’m curious if you’ve made any progress with this, as I’m also very interested in this functionality/think it’s a great idea.

[xesscorp]

The Circuit object didn’t come along until the latter part of SKiDL development. It was kind of a grab-bag of pieces. Re-thinking it as a type of Part makes sense.

I’m concerned about your mention of “non-backwards compatible”. To me, that means there would be current features of SKiDL that would not be available in a future version that used your ideas. I can’t really see why that would be. Maybe you mean something else.

I think getting the composability feature you want can be done with some tweaking of the Circuit object in the current version of SKiDL. However, a refactoring may lead to simplification and clearing of some of SKiDL’s underbrush. To that end, maybe I could make a branch where you could flesh-out some of your ideas and see where it leads.