High voltage power supplies for fast voltage changes

An electron beam assembly comprising:

• an electron beam tool;
• one or more cables having an effective capacitance to ground, CC;
• a primary DC source;
• one or more secondary regulated sources configured to provide regulated outputs to the electron beam tool via the one or more cables;
• and
• a fast power control coupled between the primary DC source and the one or more secondary regulated sources, the fast power control comprising:
• a transfer capacitor coupled to ground;
• a first variable power source arranged between the primary DC source and the one or more secondary regulated sources;
• a second variable power source arranged between the primary DC source and the transfer capacitor;
• and
• a non-transitory tangible computer readable medium with computer readable instructions configured to:
• cause the first variable power source to adjust a first output to the one or more secondary regulated sources;
• and
• cause the second variable power source to adjust a second output to the transfer capacitor.

A method of driving a tool comprising:

• providing, via a primary DC supply, a primary DC signal to a secondary regulated source;
• filtering an output of the primary DC supply to reduce output ripple;
• capacitively coupling the output of the primary DC supply to ground via a transfer capacitor having a capacitance, C1 and a voltage, V1;
• providing an output to the tool via a cable between the secondary regulated source and the tool, the cable having a capacitance, C2 and a voltage, V2;
• modifying the primary DC signal before it reaches the secondary regulated source to fine tune the output to the tool;
• and
• modifying a charge stored on the transfer capacitor such that C1*ΔV1=C2*ΔV2.