High power pulse generator
Use Power MOSFETs with very low Rdson. Look into an N-channel as well, to reduce Rdson. Don't forget to manage heat dissipation. Even at 90% efficient, you still need to dissipate 80W! Since your microcontroller probably can't drive the FET quickly enough, you probably need a preamp/level shifter stage as well.

See http://www.onsemi.com/PowerSolutions/product.do?id=NVD5890NL as an example. 

You don't mention your application, but if you are trying to build an audio amplifer, open loop Class D amplifiers are limited in their THD.