Back to Back MOSFET Design

[w.ashcroft]

Hello,
I have a WiFi enabled AC mains light dimmer/switch that uses a back to back MOSFET design. The device sits in series with the load (lightbulb) and therefore does not have its own return/neutral connection.

I'd like to understand how its MOSFET / transistor arrangement works as I'm not fully confident I understand how the control circuitry might be managing the MOSFETs and transistors so that a) it always has power for itself (a tiny amount of current flows through the lightbulb at all times, but not enough to light it); and b) so that a controlled amount of current is allowed to flow through it when any level of light brightness is requested.

Ultimately, what I'd like to do, is convert the device to be a user input device only (with minimal modifications to the circuit), connecting directly to the supply and neutral - by somehow disconnecting the path between the two MOSFETs to prevent shorts. This may seem like a pointless exercise/idea, but actually it would then give me a dimmer that I can use in software as a user input.

Edit: I may have answered my own question.. Could I do this simply by disconnecting the base of each transistor so that there is never a direct path between the two sides (i.e. pin 3).

Many thanks for any help and advice.

[w.ashcroft]

Here is the actual PCB I reversed (the terminals are SUPPLY, NO CONNECTION, LOAD).