[yayitscaroline]

Ah, this makes sense. Do you know how the "chopping it up into AC"works?

[qntty]

This transformer would be a flyback transformer therefore doesn't need to be driven by anything so hard-to-generate as a sine wave. It can be driven by a "switch" (MOSFET) at it's primary which is connected to DC.

https://en.wikipedia.org/wiki/Flyback_transformer#Operation_...

[cnvogel]

All switching power supplies (hence the name) are driven by either full-on or full-off ("switching") transistors. A "flyback" topology is only one of many possible ways to build a switching power supply, but as it's the simplest, it's the most common in low power supplies.

See the Switch−Mode Power Supply Reference Manual from ON Semiconductor for info on all the other possible ways to build a switching power supply.

[paulmlewis]

I'm no expert so may be corrected, but I assume just an inverter https://en.wikipedia.org/wiki/Power_inverter