US 6,646,853 B2Granted

Current control of a power supply for an ionizer

AssigneeIllinois Tool Works Inc.

InventorsMichael A. Jacobs, Ken S. Foo

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Abstract

A control circuit for an ionizer controls an output of at least one of a positive voltage direct current (DC) power supply (PS) and a negative voltage DC PS. Each PS is connected to at least one ionizing pin. The control circuit controls the output of the power supplies so as to cause a flow of positive and negative ions from the ionizer and directed towards a target. The control circuit includes a positive PS return current sense resistor that biases the negative voltage PS to decrease the output of the negative voltage PS when the current detected by the positive sense resistor increases and to increase the output of the negative voltage PS when the current detected by the positive sense resistor decreases. The control circuit includes a similar negative PS return current sense resistor and associated bias circuitry for controlling the negative voltage power supply.

Claims8

Dependent claims

A control circuit for an ionizer which controls an output of at least one of a positive voltage direct current power supply and a negative voltage direct current power supply, each being connected to at least one ionizing pin so as to cause a flow of positive and negative ions to be emitted from the ionizer and directed towards a target, wherein the control circuit comprises at least one of:

(a) a positive power supply return current sense resistor that biases the negative voltage power supply to decrease the output of the negative voltage power supply when a positive ion current detected by the positive power supply return current sense resistor increases and to increase the output of the negative voltage power supply when the positive ion current detected by the positive power supply return current sense resistor decreases, thereby creating a static-free environment at the target;
or
(b) a negative power supply return current sense resistor that biases the positive voltage power supply to decrease the output of the positive voltage power supply when a negative ion current detected by the negative power supply return current sense resistor increases and to increase the output of the positive voltage power supply when the negative ion current detected by the negative power supply return current sense resistor decreases, thereby creating the static-free environment at the target.

A control circuit for an ionizer which controls an output of at least one of a positive voltage direct current power supply and a negative voltage direct current power supply, each being connected to at least one ionizing pin so as to cause a flow of positive and negative ions to be emitted from the ionizer and directed towards a target, the control circuit having a mode selector switch and wherein the control circuit comprises at least one of:

(a) a positive power supply return current sense resistor that biases the positive voltage power supply to increase the output of the positive voltage power supply when a positive ion current detected by the positive power supply return current sense resistor decreases and to decrease the output of the positive voltage power supply when the positive ion current detected by the positive power supply return current sense resistor increases, thereby creating a static-free environment at the target when the mode selector switch is in a first position and that biases the negative voltage power supply to decrease the output of the negative voltage power supply when a positive ion current detected by the positive power supply return current sense resistor increases and to increase the output of the negative voltage power supply when the positive ion current detected by the positive power supply return current sense resistor decreases when the mode selector switch is in a second position;
or
(b) a negative power supply return current sense resistor that biases the negative voltage power supply to increase the output of the negative voltage power supply when a negative ion current detected by the negative power supply return current sense resistor decreases and to decrease the output of the negative voltage power supply when the negative ion current detected by the negative power supply return current sense resistor increases, thereby creating the static-free environment at the target when the mode selector switch is in the first position and that biases the positive voltage power supply to decrease the output of the positive voltage power supply when a negative ion current detected by the negative power supply return current sense resistor increases and to increase the output of the positive voltage power supply when the negative ion current detected by the negative power supply return current sense resistor decreases when the mode selector switch is in the second position.

Dependencies are inferred from the claim text.