Patent ID: 7550876

Claim:
A pulse generator that generates a voltage pulse, the pulse generator comprising: a plurality of first voltage cells, each voltage cell having a capacitor in series with a main switch such that all capacitors are connected in series when all main switches are on to generate a voltage pulse that is delivered to a load; a plurality of return switches, each return switch associated with a voltage cell, wherein the return switches enable each capacitor in the plurality of voltage cells to charge while each main switch is in an off state; an isolation diode associated with each return switch, wherein the isolation diode provides a path for the voltage pulse when a corresponding voltage cell is inoperative, and a second voltage cell connected in series with the plurality of voltage cells, the second voltage cell including: a pair of capacitors in series with a second main switch; at least one diode arranged with the pair of capacitors such that the pair of capacitors charge in series when the second main switch is off and discharge in parallel when the second main switch is on; and a ringing circuit that includes: an inductor in series with the pair of capacitors; and a ringing capacitor in parallel with the inductor, wherein the ringing capacitor charges to twice a value of the pair of capacitors and provides droop compensation to the voltage pulse.