DIGITAL SWITCH COMMUNICATION

• US 20100213759A1
• Filed: 08/05/2009
• Published: 08/26/2010
• Est. Priority Date: 02/20/2009
• Status: Active Grant

• Current Assignee: WTEC GmbH
• Original Assignee: Redwood Systems, Inc. (CommScope Holding Company, Inc.)
• Inventors: Covaro, Mark
• Granted Patent: US 8,207,635 B2
• Time in Patent Office: Days
• US Class Current: 307/1
• CPC Class Codes: H04B 2203/547 via DC power distribution
• CPC Class Codes: H04B 3/542 the information being in digital form
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 47/185 via power line carrier transmission

Abstract

In one example, an electric circuit may be provided that is coupled to a line. The electric circuit may include a switch connected in series with a load, where the switch and the load are in series between two conductors of the line. The line may provide power to the load. The electric circuit may also include a resistive element connected in parallel with the switch and in series with the load. The switch may be configured to short circuit the resistive element when closed such that the voltage on the line varies between two voltage levels when the switch is opened and closed. The line provides power to the load when the switch is opened and when the switch is closed.

Claims

1. An electric circuit electrically coupled to and for communicating over a line, the electric circuit comprising:

a switch electrically coupled in series with a load, the switch and the load in series between first and second conductors, the first and second conductors comprising the line, wherein the line provides direct current power to the load; and

a resistive element electrically coupled in parallel with the switch and in series with the load;

wherein the switch is configured to short circuit the resistive element when closed such that a voltage on the line varies between a first voltage level and a second voltage level when the switch is opened and closed;

wherein the voltage on the line is an electric potential difference between the first and second conductors; and

wherein the line provides the direct current power to the load when the switch is opened and when the switch is closed.

2. The electric circuit of claim 1, wherein the load and the resistive element are included in a load device and the switch is included in a separate device.

3. The electric circuit of claim 1, wherein the electric circuit and the load are included in a load device.

4. The electric circuit of claim 1, wherein the resistive element includes a light-emitting diode, and a light-emitting diode fixture includes the light-emitting diode and the load.

5. The electric circuit of claim 1, wherein the switch includes a transistor.

6. The electric circuit of claim 1, wherein a direct current power signal on the line provides the direct current power to the load, the electric circuit is configured to receive information included in the direct current power signal, the direct current power signal has a constant duty cycle but has different ones of a plurality of frequencies over time, and each one of the frequencies corresponds to a respective portion of the information.

7. The electric circuit of claim 1, wherein the first voltage level is less than the second voltage level, and the second voltage level minus the first voltage level is less than ten percent of the first voltage level.

8. A system comprising:

a power device electrically coupled to a line and configured to generate a direct current power signal over the line; and

a power communicator in communication with the power device, the power communicator configured to receive data in a form of a plurality of variations of voltage on the line caused from a variation of resistance on the line during generation of the direct current power signal;

the direct current power signal is operable to power a load device during the plurality of variations of voltage on the line, the load device electrically coupled to the line.

9. The system of claim 8, wherein the power communicator is configured to direct the power device, in response to the data received, to alter the average power of the direct current power signal.

10. The system of claim 8, further comprising the load device and a load communicator:

wherein the load communicator is configured to transmit a switch signal to a switch for transmission of the data, wherein;

the variation of resistance on the line is in response to either a closure of a switch or an opening of the switch;

whether the switch is open or closed is based on the switch signal; and

the switch is configured to control whether current on an electric current path from a first conductor to a second conductor through the load device flows through either the switch or a resistive element based on whether the switch is closed or open, respectively.

11. The system of claim 8, further comprising the load device, wherein the load device is a light-emitting diode fixture.

12. The system of claim 11 further comprising a photosensor electrically coupled to the line, wherein the power communicator is further configured to receive the data from the photosensor, the data including a light level detected at the photosensor, and, in response to receipt of the light level, to direct the power device to alter the power of the direct current power signal.

13. The system of claim 8, wherein the direct current power signal is a pulse-width modulated signal and the power communicator is further configured to:

set a duty cycle of the pulse-width modulated signal to correspond to a determined power level; and

vary a frequency of the pulse-width modulated signal for a transmission of information while the duty cycle of the pulse-width modulated signal is fixed for continued transmission of power at the determined power level, wherein a variation in the frequency of the pulse-width modulated signal represents at least a portion of the information.

14. A method comprising:

receiving a direct current power signal on a line at a load device, the load device powered from the direct current power signal when a voltage on the line is at a first voltage level and a second voltage level, wherein the voltage on the line is an electric potential difference between first and second conductors, the first conductor and the second conductor comprising the line;

transmitting data over the line, wherein transmitting the data includes alternating the voltage on the line between the first voltage level and the second voltage level by switching a resistive element in and out of a current path, the current path passing from the first conductor to the second conductor through the load device.

15. The method of claim 14 further comprising including the resistive element in a device different than the load device.

16. The method of claim 14, wherein powering the load device from the direct current power signal includes converting a pulse-width modulated signal to a regulated constant voltage signal, wherein the direct current power signal includes the pulse-width modulated signal.

17. The method of claim 14, wherein powering the load device includes illuminating at least one light-emitting diode from the direct current power signal, the at least one light-emitting diode included in a light-emitting diode fixture.

18. The method of claim 14, wherein switching the resistive element in and out of the current path includes opening and closing a switch connected in parallel with the resistive element.

19. The method of claim 14 further comprising receiving information from the direct current power signal by detecting which ones of a plurality of determined frequencies the direct current power signal has over time while the direct current power signal maintains a constant duty cycle, wherein each one of the frequencies corresponds to a respective portion of the information and wherein the direct current power signal is a pulse-width modulated signal.

20. The method of claim 14 further comprising adjusting a resistance of the resistive element so that the second voltage minus the first voltage remains at less than twenty percent of the first voltage.

21. A system comprising:

a power device electrically coupled to a line and configured to generate a direct current power signal over the line;

a load device electrically coupled to the line, the load device powered from the direct current power signal;

a load communicator electrically coupled to the line; and

a power communicator in communication with the power device, the power communicator configured to communicate with the load communicator over the line through a pulse-width modulation of the direct current power signal, the load communicator configured to communicate with the power communicator through alteration of impedance on the line during the pulse-width modulation and the powering of the load device.

22. The system of claim 21, wherein the alteration of impedance on the line includes a modification of resistance on the line.