I have been trying for over 1 week to get an ALL N-CHANNEL FET h-bridge working. I have tried the MC33883 chip and the HIP4082 chip, and neither seem to work as advertised. I built the circuits exactly like the examples shown in the application notes, and they do not seem to work. I am trying to drive large MOSFET's the IRFS3004-7PPbF, which has a gate capacitance of 9130 pf. I have scaled up the charge pump capacitors accordingly, yet nothing seems to work. I either get no gate drive, or wildly oscillating gate drive at about 1.6Khz. I have read hundreds of pages of application notes, and dozens of group postings, and many people are having trouble getting these things to work. I even wen to the trouble of making sure that the pulse width modulator input to the low side drivers is always running, because some of the h-bridge controller chips don't have a full charge pump included within them, and rely on the operation of the low size driver PWM current pulses to keep the high side gate driver capacitors charging. I have provided everything I can think of that these chips think they want to operate properly, and they still will not work.