The arrangement looks like a MOSFET half-bridge, Q17 high side, pin 1 = gate drive, pin 2 = output, pin 3 = VIN,; Q22 low side, pin 1 = gate drive, pin 2 = GND plane, pin 3 = output. Q17 will be bootstrapped, and both will be N-CH. Not sure why C51 and C59, but if they're DNP that's fine. R65 seems like it's pulling up, maybe? Not sure why the one trace snaking around. Q17 gate seems to go to via and nothing else, Q22 gate through R77 to via. Guessing a switching controller on the other side (or maybe just a gate driver and MCU. Doesn't look like there's current sensing, which is a bit disturbing. But maybe the load has a low-side shunt and they're doing it the slow way. Which might be good enough for a battery charger. I take it this is the output stage, then?
Anything of comparable rating would probably do, i.e., a couple amperes and 20V, and you might want to trace the gate signals to see what Vgs(on) is and make sure they won't be driven beyond ratings, nor insufficient for current flow. But an exact replacement will need identification.
Tim