Unrecognized circuit symbols in datasheet

[Rusttree]

In Linear's datasheet for the LTC3115-1, the block diagram has two symbols I don't recognize. See the attached image. I've drawn red arrows pointing to the symbols.

The top one is a loop at pin SW1. Is that supposed to represent an ammeter?

The other one is what looks like an op-amp with 3 inputs (one inverting and two non-inverting). How does that work?

Thanks!

 

[alec_t]

The top one is a loop at pin SW1

That's a current-sensor. The sensed current is compared with 3A to control current-limiting.

The other one is what looks like an op-amp with 3 inputs

Two input signals are summed at the non-inverting inputs.

 

[Rusttree]

Perfect. Thank you!