Dimmer adaptable to either two or three active wires

• US 8,547,035 B2
• Filed: 04/15/2011
• Issued: 10/01/2013
• Est. Priority Date: 07/15/2009
• Status: Active Grant

• Current Assignee: Crestron Electronics Incorporated
• Original Assignee: Crestron Electronics Incorporated
• Inventors: Kumar, Russikesh
• Primary Examiner(s): Ismail, Shawki
• Assistant Examiner(s): WHITE, DYLAN C
• Application Number:
  US13/088,084
• Publication Number:
  US 20110193490A1
• Time in Patent Office: 900 Days
• Field of Search: 315/291, 315/171, 315/200, 323/285
• US Class Current: 315/291
• CPC Class Codes: H05B 39/044 continuously H05B39/042 takes precedence
• CPC Class Codes: H05B 39/08 by shifting phase of trigger voltage applied to gas-filled controlling tubes also in controlled semiconductor devices in converters H02M5/00; with regulation G05F1/44
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A dimmer adaptable to either two (H, DH) or three (H, N, DH) active wires includes a first full-wave rectifier (D1, D2, D3, D4) across an AC power hot (H) terminal and a dimmer hot (DH) terminal and a second full-wave rectifier (D1, D4, D5, D6) across the AC power hot (H) terminal and an AC power neutral (N) terminal. The dimmer operates in a two-wire configuration by drawing power through a load when a control circuit is not conducting or in a three-wire configuration, when the AC power neutral (N) terminal is connected, by drawing power from AC power hot (H) and AC power neutral (N) terminals. The dimmer operates according to a first set of preset dim levels when current is flowing through the first rectifier and according to a second set of preset dim levels when current is flowing through the second rectifier.

Claims

1. A lighting dimmer adaptable to either two or three active wires, said dimmer comprising:

(a) an AC line hot connection;

(b) an AC line neutral connection;

(c) a dimmer hot connection;

(d) an internal power supply;

(e) an energy storage device associated with, and providing power to, said power supply;

(f) a control circuit powered by said power supply wherein said control circuit is switchably operable to provide either a conductive or a nonconductive electrical path between the AC line hot connection and the dimmer hot connection;

(g) a first full-wave rectifier configured for rectifying an alternating current input voltage present between the AC line hot connection and the dimmer hot connection and to provide a direct current output voltage across the energy storage device, wherein said alternating current input voltage between the AC line hot connection and the dimmer hot connection is present when

(i) the control circuit is providing a nonconductive electrical path between the AC line hot connection and the dimmer hot connection and

(ii) an external load is connected between the dimmer hot connection and an AC line neutral return

(h) a second full-wave rectifier configured for rectifying an alternating current input voltage present between the AC line hot connection and the AC line neutral connection and to provide a direct current output voltage across the energy storage device, wherein said alternating current input voltage between the AC line hot connection and the AC line neutral connection is present only when the dimmer is connected to three active wires; and

(i) wherein said control circuit switchably operates to provide either a conductive or a nonconductive electrical path between the AC line hot connection and the dimmer hot connection

(i) according to a first set of preset dimming levels when current is flowing through the first full-wave rectifier, and

(ii) according to a second set of preset dimming levels when current is flowing through the second full-wave rectifier.

2. The lighting dimmer of claim 1 further comprising a zero cross detector between the AC line hot connection and bus common of the lighting dimmer, wherein the zero cross detector provides an input signal to the control circuit, said input signal comprising zero cross information and information indicating whether current is flowing through the first or second full-wave rectifier.

3. The lighting dimmer of claim 2 wherein the input signal varies in duty cycle according to the duty cycle of AC supplied to the external load when current is flowing through the first full-wave rectifier.

4. The lighting dimmer of claim 2 wherein the input signal is a square wave and a polarity reversal of the signal after the control circuit switches from providing a non-conductive electrical path to a conductive electrical path in one of the half cycles of the alternating current input voltage indicates a current flow through the first full-wave rectifier.

5. The lighting dimmer of claim 2 wherein the input signal is a square wave and wherein a logic high in the positive half cycle of the alternating current input voltage indicates a current flow through the first full-wave rectifier.

6. The lighting dimmer of claim 1 further comprising a current detector in series with either the first or second full-wave rectifier and providing an input signal to the control circuit.

7. The lighting dimmer of claim 6 further comprising a current detector in series with the first full-wave rectifier and providing an input signal to the control circuit.

8. The lighting dimmer of claim 7 wherein the current detector is a shunt resistor ammeter connected in series with the first full-wave rectifier.

9. The lighting dimmer of claim 1 wherein the control circuit comprises a triac and the first and second set of preset dimming levels each correspond to a set of firing angles of the triac.

10. The lighting dimmer of claim 1 wherein the second set of preset dimming levels comprises a dimming level corresponding to full power.

11. A method for operating a lighting dimmer according to either a first set of preset dimming levels or a second set of preset dimming levels, said method comprising the steps of:

(a) providing the lighting dimmer, said lighting dimmer comprising

(i) a control circuit switchably operable to provide either a conductive or a nonconductive electrical path between an AC line hot connection and a dimmer hot connection of the lighting dimmer

(ii) a first full-wave rectifier configured for rectifying an alternating current input voltage present between the AC line hot connection and the dimmer hot connection, wherein said alternating current input voltage between the AC line hot connection and dimmer hot connection is present when the control circuit is providing a nonconductive electrical path between the AC line hot connection and the dimmer hot connection and an external load is connected between the dimmer hot connection and an AC line neutral return, and

(ii) a second full-wave rectifier configured for rectifying an alternating current input voltage present between the AC line hot connection and an AC line neutral connection wherein said alternating current input voltage between the AC line hot connection and the AC line neutral connection is present only when the dimmer is connected to three active wires;

(b) switchably providing a conductive or nonconductive electrical path between the AC line hot connection and the dimmer hot connection according to a first set of preset dimming levels when current is flowing through the first full-wave rectifier; and

(c) switchably providing a conductive or nonconductive electrical path between the AC line hot connection and the dimmer hot connection according to a second set of preset dimming levels when current is flowing through the second full-wave rectifier.

12. The method of claim 11 further comprising the step of determining whether current is flowing through either the first of second full-wave rectifier.

13. The method of claim 12 wherein the step of determining whether current is flowing through the first or second full-wave rectifier further comprises the step of receiving at the control circuit an input signal from a zero cross detector between the AC line hot connection and common ground, said signal comprising information regarding current flow in the lighting dimmer.

14. The method of claim 13 wherein the input signal is a square wave and further comprising the step of recognizing a logic high in the positive half cycle of the input signal to indicate current flow in the first full-wave rectifier.

15. The method of claim 12 wherein the step of determining whether current is flowing through either a first or a second full-wave rectifier further comprises the step of receiving at the control circuit a signal from a current detector in series with either the first or second full-wave rectifier.

16. The method of claim 15 wherein the current detector is in series with first full-wave rectifier.