Apparatus and methods to control an electron beam of an X-ray tube

An x-ray tube assembly comprising:

• an emitter configured to emit an electron beam toward a target;
• at least one of an emitter focusing electrode disposed proximate the emitter or an extraction electrode disposed proximate the emitter focusing electrode;
• and
• a controller configured to control a voltage supplied to at least one of the emitter focusing electrode and the extraction electrode, the controller including at least one of a (i) first switching unit configured to discretely switch between a common voltage and a positive reference voltage, or (ii) a second switching unit configured to discretely switch between a common voltage, a positive reference voltage and a negative reference voltage, the controller further including a third switching unit having an amplitude controllable voltage source with controllable amplitude, wherein output voltages generated by the first, second and third switching units define a voltage profile for controlling the voltage.

A method for controlling an x-ray tube, the method comprising:

• connecting a plurality of switching units to a form a multi-stage controller, wherein the plurality of switching units include at least one discretely switched unit switching between one of a common voltage and at least one of a positive reference voltage or a negative reference voltage, and further including at least one amplitude-controllable unit switching controllable within a voltage range;
• selectively controlling switches of the plurality of switching units to generate a varying voltage output profile including at least one of positive or negative voltage levels;
• and
• applying the varying voltage output profile to one or more electrodes of an x-ray tube.