Apparatus and method for fast FET switching in a digital output device
AssigneeRockwell Automation Technologies, Inc.
InventorsGeorge D. Maskovyak, Nedyalko V. Ivanov
Life of this patent
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Abstract
An industrial control output device is provided which provides electrical isolation between device power and field power. The device includes two isolation devices, one of which is adapted to energize a power switching device, and the other is adapted to de-energize the switching device. The output device thus minimizes or reduces EMI/RFI emissions and provides fast switching times in selectively providing power to a load. In addition, the invention includes a method of providing power to a load in an industrial control system, which allows fast switching of a digital output with minimal or reduced EMI/RFI emissions.
Claims16
An industrial control device comprising:
- a switching component deriving a threshold switching voltage from a power source and operative to be energized on and de-energized off to selectively provide electrical power from the power source to a load;
- a logic component that generates a first signal and a second signal independent of the first signal and operative to be non-complementary with respect to the first signal, further comprising a pulse generator that generates a low pulse of the second signal for a fixed duration causing the switching component to de-energized by actively removing voltage;
- a first optical component in electrical communication with the switching component and adapted to selectively energize the switching component in response to the first signal, the first optical component comprising a first opto-coupler, the first opto-coupler comprising a first transistor, the first optical component operative to electrically isolate the logic component;
- and
- a second optical component in electrical communication with the switching component and adapted to selectively de-energize the switching component in response to the second signal, the second optical component comprising a second opto-coupler, the second opto-coupler comprising a second transistor, the second optical component operative to electrically isolate the logic component.
A method of providing power to a load in an industrial control system, comprising:
- providing a switching component in electrical communication with a power source and a load, and having a first state and a second state;
- providing electrical power from the power source to the load when the switching component is in the first state;
- discontinuing power from the power source to the load when the switching component is in the second state;
- providing a first isolation component comprising a first opto-coupler having a first transistor in electrical communication with the switching component and adapted to selectively energize the switching component;
- providing a second isolation component comprising a second opto-coupler having a second transistor in electrical communication with the switching component and adapted to selectively de-energize the switching component;
- selectively placing the switching component in the first state by energizing the switching component using the first isolation component, wherein energizing the switching component comprises providing a first signal to the first isolation component;
- and
- selectively placing the switching component in the second state, independent of the first state by de-energizing the switching component using the second isolation component, wherein de-energizing the second isolation component comprises asserting a second signal via a pulse for a fixed duration, whereby the second isolation component actively removes voltage from the switching component.
A method of providing power to a load comprising:
- turning a first optical transistor on in response to a first signal being asserted high;
- deriving a threshold voltage from a power source to facilitate energizing a switching component in response to the first optical transistor being on;
- providing power from the power source to a load via the switching component;
- turning a second optical transistor on in response to a second signal being asserted low via a pulse of a fixed duration;
- de-energizing the switch component in response to the second optical transistor being on by actively removing the voltage on the switching component;
- and
- isolating the load from the power as a result of the switching component being de-energized.
Dependencies are inferred from the claim text.