Nanosecond pulse generator using a fast recovery diode

Design and operation of a fast recovery diode based pulse generator is presented. The generator produces 3 ns wide, 600 V amplitude pulses into a 50 ohm load at the maximum repetition rate of 100 kHz. Pulses shorter than 10 ns are essential for the studies of biological cell response to high electric fields while avoiding ordinary electroporation effects dominant at long pulses. The use of a mass-produced fast recovery surface-mount rectifier diode in this circuit substantially simplifies the generator and results in low cost and very small footprint. Similar diode switched pulse generators have been described in the literature using mostly custom fabricated snap-recovery diodes. Here we give an example of an ordinary low cost diode performing similarly to the custom fabricated counterpart. The diode switched circuit relaxes the requirement on the speed of the main closing switch, in our case a low cost power MOSFET-saturable core transformer combination.