# US 2014/0197337 A1 · Low power self-limiting input circuit

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2014/0197337 A1
- Document ID: US20140197337A1
- Status: Published application
- Kind: A1
- Application number: 13/743,394
- Filed: 2013-01-17
- Published: 2014-07-17
- Earliest claimed: 2013-01-17
- Assignees: Rockwell Automation Technologies, Inc.
- Applicants: Rockwell Automation Technologies, Inc.
- Inventors: Joseph Vazach; Terry L. Deloria
- Web page: https://patentgrep.com/patent/US20140197337A1

## CPC

- H04B 10/802: {for isolation, e.g. using optocouplers}
- H03K 19/01806: {Interface arrangements}
- H04B: TRANSMISSION
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## Abstract

An input circuit for an input module having a plurality of inputs is disclosed. Each input circuit has a reduced number of components, providing for an increased number of inputs within an input module of comparable size to prior art input modules. Alternately, the input module may have a like number of inputs in a reduced size in comparison to prior art input modules. The reduced number of components similarly reduces the power dissipated by each input circuit.

## Claims

### Claim 1

An input circuit for an industrial controller, comprising:
a first terminal and a second terminal configured to receive a voltage potential, wherein the first terminal is configured to be a positive terminal for the voltage potential with respect to the second terminal;
a zener diode having a cathode and an anode, the cathode electrically connected to the first terminal;
a current limit diode having a cathode and an anode, the anode of the current limit diode electrically connected to the anode of the zener diode; and
an opto-coupler having a light emitter and a photosensor, the light emitter electrically connected in series between the cathode of the current limit diode and the second terminal.

### Claim 2

An input circuit for an input module in an industrial controller, comprising:
an input configured to receive a range of direct current (DC) voltages;
a zener diode electrically connected to the input to operate in a breakdown region when the DC voltage is applied to the input;
a current limit diode electrically connected in series with the zener diode to operate in a current limiting mode when the DC voltage is applied to the input; and
an opto-coupler having an input and an optically isolated output wherein the input is electrically connected to the series-connected zener diode and current limit diode and the optically isolated output generates a signal that corresponds to a logical true when the DC voltage is applied to the input and a logical false when the DC voltage is removed from the input.

### Claim 3 (depends on 2)

The input circuit of claim 2 wherein the range of DC voltages is between 10 volts and 32 volts.

### Claim 4 (depends on 3)

The input circuit of claim 3 wherein an amplitude of current at the input is greater than or equal to 2 milliamps.

### Claim 5 (depends on 2)

The input circuit of claim 2 wherein the input includes a first terminal and a second terminal.

### Claim 6 (depends on 5)

The input circuit of claim 5 wherein the first terminal is configured to receive a voltage potential within the range of DC voltages and the second terminal is configured to be connected to one of a common and a ground.

### Claim 7 (depends on 6)

The input circuit of claim 6 wherein the second terminal is a shared connection between the input circuit and at least one other input circuit on the input module.

### Claim 8 (depends on 6)

The input circuit of claim 6 wherein each of the first and second terminals are configured to receive an electrical conductor external to the input module.

### Claim 9 (depends on 6)

The input circuit of claim 6 wherein the first terminal is configured to receive an electrical conductor external to the input module and the second terminal is configured to be connected internal to the input module.