The output stage is fed by a uPC1246 commutator.
The datasheet for this chip can be found here:
The commutator takes the hall sensor signals and a PWM signal to generate the drive for the power stage.
The PWM comes from a KA3525A. The datasheet for that is here:
The datasheet for the IR2101 gate driver chip is here:
http://www.irf.com/product-info/datashe ... ir2101.pdf
About the only other circuits on the board are a ramp-up delay and throttle conditioning amplifier and a couple of voltage regulators.
There's a locked rotor safety circuit that will kill the PWM output after a few seconds if it doesn't see the halls changing.