Three-way switch

This application claims the benefit of U.S. Patent Application No. 61/784,342, filed Mar. 14, 2013.

Embodiments described herein relate generally to systems and methods for power switches.

In building wiring, multiway switching is the interconnection of two or more electrical switches to control an electrical load (often, but not always, lighting) from more than one location. For example, this allows lighting in a hallway, stairwell, or large room to be controlled from multiple locations. While a “normal” light switch needs to be only a Single Pole, Single Throw (SPST) switch, multiway switching requires the use of switches that have one or more additional contacts and two or more wires must be run between the switches. When the load is controlled from only two points, Single Pole, Double Throw (SPDT) switches are used. One example of a multiway switch is a three-way switch. Electrically, a three-way switch is a Single-Pole, Double-Throw (SPDT) switch. By correctly connecting two of these switches together, toggling either switch changes the state of the load from off to on, or on to off. The switches may be arranged so that they are in the same orientation for off, and contrasting orientations for on.

FIG. 4 is a block diagram of a conventional three-way switch. Conventional implementations of a three-way switch require all switches to be replaced in case of a device failure. In addition, it requires the installer to know which end is the load versus the supply (slave or master). With the advent of home automation, it would be beneficial to have more capable three-way switches.

Each patent, patent application, and/or publication mentioned in this specification is herein incorporated by reference in its entirety to the same extent as if each individual patent, patent application, and/or publication was specifically and individually indicated to be incorporated by reference.

FIG. 1 is a block diagram of a RF-based three-way switch, under an embodiment.

FIG. 2 is a block diagram of a low-leakage rectifier, under an embodiment.

FIG. 3 is a state table of the RF three-way switch, under an embodiment.

FIG. 4 is a block diagram of a conventional three-way switch.

Although the detailed description herein contains many specifics for the purposes of illustration, anyone of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the embodiments described herein. Thus, the following illustrative embodiments are set forth without any loss of generality to, and without imposing limitations upon, the claimed invention.

Generally, devices and methods described herein comprise a relay coupled between conductors and rectifier circuits. A converter is coupled between the rectifier circuits and a radio frequency (RF) device. Control signals are coupled to the RF device. A physical switch is coupled to the RF device, and the control outputs of the physical switch form a multi-way switch.

FIG. 1 is a block diagram of a RF-based three-way switch, under an embodiment. The switch of an embodiment comprises a physical switch coupled or connected to an RF device or processor. The RF device is coupled or connected to a converter, which in an embodiment comprises a DC-to-DC converter. The converter is coupled or connected to the local power supply by a relay circuit and numerous rectifier circuits.

The switch of an embodiment simplifies the installation process involving three-way switches by only having to replace one of the three-way switches in a multi-switch installation. Furthermore, the switch of an embodiment is positionally agnostic in that it can function as either the master or the slave (supply or load). In addition the switch is Radio Frequency (RF) controlled (e.g., Zigbee, WiFi, etc.), and is configured to report the status or state of the light (i.e. on or off) as well as the current power consumption.

FIG. 2 is a block diagram of a rectifier circuit, under an embodiment. Each rectifier circuit of an embodiment is a low-leakage rectifier, but the embodiment is not so limited. Power to the RF switch of an embodiment is provided by the combination of the rectifier circuits and the converter. Each rectifier circuit of an embodiment includes a combination of low-leakage diodes. An optional shunt resistor is included in an embodiment to clamp reverse leakage current to direct current (DC) ground. Multiple instances of the circuit are implemented in an embodiment to reduce the reverse leakage current of any particular diode to relatively smaller magnitudes.

The local power supply to the switch is an alternating current (AC) system comprising three circuit conductors. The local power supply therefore includes a first conductor that is a “hot” conductor carrying an electric potential relative to electrical ground or neutral, a second conductor that is a neutral return conductor of the local power supply circuit, and a ground conductor with continuity to earth ground. In an embodiment, each conductor of the local power supply is coupled or connected to the converter using a dedicated rectifier circuit, but the embodiment is not so limited.

As described herein the switch of an embodiment includes at least three instances of the rectifier circuit, one coupled or connected to each of the relay three-way switch connections, i.e. one to the normally closed (NC) contact, one to the common (C), and one to the normally open (NO) contact. The physical conductors of the local power supply are connected to the RF-enabled three-way switch at each of the relay inputs, i.e. NC, C, and NO contacts, instead of the physical switch. The physical switch comprises a low-voltage contact to the RF device that acts as an input to the RF device to indicate user input.

The RF device comprises a processor and is coupled to numerous control signals. In an embodiment, the RF device is coupled to signals VT 1 -VT 3 , CS 1 -CS 3 , relay enable signals, and physical switch contacts NC, NO, COM. The VT 1 -VT 3 signals act as voltage sensors to determine whether or not line voltage is present at each of the AC terminals. The CS 1 -CS 3 signals are current sensors, which could be implemented at current transformers, hall effect devices, or other such means as measuring current.

In operation, the device is indicated to be “ON” when current sensor CS 1 and CS 3 or CS 1 and CS 2 indicate current flowing. If a user activates or presses the physical switch, then the RF device reads the input, and contacts the relay accordingly. If an RF command is indicated to turn off or turn on the device, then the RF device contacts the relay accordingly. FIG. 3 is a state table of the RF three-way switch, under an embodiment.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in a sense of “including, but not limited to.” Words using the singular or plural number also include the plural or singular number respectively. Additionally, the words “herein,” “hereunder,” “above,” “below,” and words of similar import, when used in this application, refer to this application as a whole and not to any particular portions of this application. When the word “or” is used in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list and any combination of the items in the list.

The above description of embodiments and corresponding systems and methods is not intended to be exhaustive or to limit the systems and methods to the precise forms disclosed. While specific embodiments of, and examples for, the systems and methods are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the systems and methods, as those skilled in the relevant art will recognize. The teachings of the systems and methods provided herein can be applied to other systems and methods, not only for the systems and methods described above.

The elements and acts of the various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments and corresponding systems and methods in light of the above detailed description.

In general, in the following claims, the teens used should not be construed to limit the invention and corresponding systems and methods to the specific embodiments disclosed in the specification and the claims, but should be construed to include all systems that operate under the claims. Accordingly, the invention and corresponding systems and methods is not limited by the disclosure, but instead the scope is to be determined entirely by the claims.

While certain aspects of the systems and methods are presented below in certain claim forms, the inventors contemplate the various aspects of the systems and methods in any number of claim forms. Accordingly, the inventors reserve the right to add additional claims after filing the application to pursue such additional claim forms for other aspects of the systems and methods described herein.