Diodes (?) AH284 - brushless fan controller with integrated hall sensor : weekend die-shot

We've found this chip inside ThermalRight X-silent 120 fan. Chip has markings 284 9511 which probably means it is Diodes AH284 (or compatible). On the chip there are 2 power FETs and hall-effect sensor.
Die size 1360x1118 µm.