Ground/voltage open input
AssigneeHamilton Sundstrand Corporation
InventorsLon R. Hoegberg, Brennan Fox
Life of this patent
Estimating the term…
Abstract
An input circuit includes an input line for providing input regarding state of a load. A first impedance is connected to the input line at a first node for connecting a voltage source to the input line. A second impedance is connected to the input line at a second node for connecting the input line to ground. A Zener diode is connected in the input line in series between the first and second nodes to impede current flowing through the Zener diode below the Zener voltage thereof in a direction from the first node to the second node, and to allow current above the Zener voltage thereof in the direction from the first node to the second node.
Claims13
An input circuit comprising:
- an input line for providing input regarding state of a load;
- a first impedance connected to the input line at a first node for connecting a voltage source to the input line;
- a second impedance connected to the input line at a second node for connecting the input line to ground;
- a Zener diode connected in the input line in series between the first and second nodes to impede current flowing through the Zener diode below the Zener voltage thereof in a direction from the first node to the second node, and to allow current above the Zener voltage thereof in the direction from the first node to the second node;
- a load line connected to the input line at an input node on a side of the first node opposite the second node for connecting a load to the input line;
- and
- a third impedance connected to the input line at the input node for providing voltage open input from the input line to a logic device connected to the second node of the input line.
A method of providing input from a load to a logic device comprising:
- impeding current through an input line to a logic device with a Zener diode to ensure a logic low is input to the logic device when voltage across the Zener diode is below the Zener voltage of the Zener diode;
- and
- allowing current through the input line to ensure a logic high is input to the logic device when voltage across the Zener diode exceeds the Zener voltage of the Zener diode, wherein impeding the current and allowing current include providing voltage open input to the logic device to determine whether a voltage source is powered on or not.
Dependencies are inferred from the claim text.