US 7,843,138 B2 · Power supply for a hot-filament cathode

Abstract

In accordance with one embodiment of the present invention, there is provided a switch-mode power supply to generate the heating current for a hot-filament electron-emitting cathode. The power supply directly couples, without an output power transformer, the output from a full-bridge converter that operates at an output frequency in the range from ten Hz to tens of Khz to the output terminals of the power supply. A connection to a reference potential that minimizes the potential fluctuation of the cathode is provided by the center tap on an autotransformer connected across the output terminals, where the conductors in the autotransformer are sized for half of the emission current from the cathode rather than the much larger heating current.

Claims8

Dependent claims

A power-supply apparatus for generating an alternating heating current for an electron-emitting hot-filament cathode comprising:

an internal differential alternating-current (ac) source of electrical power, wherein said source has sufficient current and voltage capacity to heat an electron-emitting cathode to electron-emitting temperature;
an autotransformer comprising a single winding having two ends and a center tap;
two power output terminals;
one reference output terminal connected to a reference potential;
wherein said internal differential ac source of electrical power is connected to said two ends of said autotransformer winding, with said two ends connected respectively to the said two power output terminals;
and
wherein said center tap is connected to said reference output terminal.

4 more elements

Dependencies are inferred from the claim text.

Power supply for a hot-filament cathode

Life of this patent

Power supply for a hot-filament cathode

Life of this patent

Abstract

Claims8