  PandaX-II experiment is a dark matter direct detection experiment using about
half-ton of liquid xenon as the sensitive target. The electrical pulses
detected by photomultiplier tubes from scintillation photons of xenon are
recorded by waveform digitizers. The data acquisition of Pandax-II relies on a
trigger system that generates common trigger signals for all waveform
digitizers. Previously an analog device-based trigger system was used for the
data acquisition system. In this paper we present a new FPGA-based trigger
system. The design of this system and trigger algorithms are described. The
performance of this system on real data is presented.
