Dimming control for LED-based luminaires

Patent metadata

Field	Value
Publication number	US-9967944-B2
Application number	US-201715628975-A
Country	US
Kind code	B2
Filing date	Jun 21, 2017
Priority date	Jun 22, 2016
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A PWM dimmer includes a source terminal, a load terminal, a power stage, an interface, and control circuitry. The power stage is coupled between the source terminal and the load terminal and is configured to receive from the source terminal an AC supply signal and provide a pulsed AC load signal to the load terminal in response to a control signal. The AC supply signal has a sinusoidal envelope with a positive half-cycle and a negative half-cycle for each cycle. The pulsed AC load signal tracks the envelope and includes a plurality of pulses in the positive half-cycle and the negative half-cycle for each cycle. The interface is configured to receive dimming control information bearing on a dimming level from a user or remote terminal. The control circuitry is configured to receive the dimming control information from the interface and generate the control signal based on the dimming control information.

First claim

What is claimed is:

1. A pulse width modulated (PWM) dimmer comprising:
a source terminal;
a load terminal;
a power stage coupled between the source terminal and the load terminal and configured to receive from the source terminal an AC supply signal having an envelope with a positive half-cycle and a negative half-cycle for each cycle and provide to the load terminal a pulsed AC load signal that tracks the envelope and comprises a plurality of pulses in each of the positive half-cycle and the negative half-cycle for each cycle based on a control signal;
an interface configured to receive dimming control information bearing on a dimming level; and
control circuitry configured to receive the dimming control information from the interface and generate the control signal based on the dimming control information, wherein an RMS value of the pulsed AC load signal varies as the dimming level varies and corresponds to the dimming level.

2. The PWM dimmer of claim 1 wherein a duty cycle of the pulsed AC load signal varies as the dimming level varies.

3. The PWM dimmer of claim 2 wherein the control signal is a PWM signal that corresponds with the pulsed AC load signal.

4. The PWM dimmer of claim 1 wherein when the AC supply signal is at a magnitude less than a defined threshold, the pulsed AC load signal corresponds directly with the AC supply signal.

5. The PWM dimmer of claim 1 wherein the interface comprises a wireless communication interface configured to:
wirelessly receive information indicative of the dimming level and transmitted from a terminal device; and
provide the dimming control information bearing on the dimming level to the control circuitry.

6. The PWM dimmer of claim 1 wherein the interface comprises a user input interface configured to directly receive human input indicative of the dimming level and provide the dimming control information bearing on the dimming level to the control circuitry.

7. The PWM dimmer of claim 6 wherein the interface further comprises a communication interface configured to transmit fixture control information indicative of the dimming level and intended for at least one remote lighting fixture, wherein:
in a first mode, the control circuitry causes the power stage to provide the pulsed AC load signal to the load terminal, such that the RMS value of the pulsed AC load signal varies as the dimming level varies and corresponds to the dimming level; and
in a second mode, the control circuitry causes the power stage to pass the AC supply signal substantially unaltered to the load terminal and causes the communication interface to transmit the fixture control information indicative of the dimming level to the at least one remote lighting fixture, wherein the at least one remote lighting fixture outputs light at the dimming level.

8. The PWM dimmer of claim 7 wherein the communication interface is a wireless communication interface and the fixture control information is transmitted wirelessly.

9. The PWM dimmer of claim 7 wherein the user input interface is further configured to directly receive human input indicative of a correlated color temperature, CCT, and provide color control information bearing on the CCT to the control circuitry, and in the second mode, the control circuitry causes the communication interface to transmit fixture control information indicative of the CCT to the at least one remote lighting fixture, wherein the at least one remote lighting fixture outputs light at the CCT.

10. The PWM dimmer of claim 7 wherein the communication interface is a wireless communication interface and the fixture control information is transmitted wirelessly.

11. The PWM dimmer of claim 7 wherein the user input interface is further configured to directly receive human input indicative of a value for a variable lighting parameter and provide parameter control information bearing on the value for the variable lighting parameter to the control circuitry, and in the second mode, the control circuitry causes the communication interface to transmit fixture control information indicative of the value of the variable lighting parameter to the at least one remote lighting fixture, wherein the at least one remote lighting fixture outputs light according to the value for the variable lighting parameter.

12. The PWM dimmer of claim 6 wherein the user input interface comprises at least one of a mechanical switch, mechanical rotary dial, and a mechanical slider for receiving the human input.

13. The PWM dimmer of claim 6 wherein the user input interface comprises at least one of a capacitive touch interface and a touch screen for receiving the human input.

14. The PWM dimmer of claim 1 wherein the interface comprises:
a user input interface configured to directly receive human input indicative of a correlated color temperature, CCT, and provide color control information bearing on the CCT to the control circuitry; and
a communication interface configured to transmit fixture control information indicative of the CCT and intended for at least one remote lighting fixture, wherein:
in a first mode, the control circuitry causes the power stage to provide the pulsed AC load signal to the load terminal, such that the RMS value of the pulsed AC load signal varies as the dimming level varies and corresponds to the dimming level; and
in a second mode, the control circuitry causes the power stage to pass the AC supply signal substantially unaltered to the load terminal and causes the communication interface to transmit the color control information indicative of the CCT to the at least one remote lighting fixture, wherein the at least one remote lighting fixture outputs light at the CCT based on the fixture control information indicative of the CCT.

15. The PWM dimmer of claim 1 further comprising a sensor associated with the control circuitry, which is further configured to provide the control signal based on a sensor signal received from the sensor.

16. The PWM dimmer of claim 1 wherein when the dimming level corresponds to a maximum light output level, the control circuitry causes the power stage to pass the AC supply signal substantially unaltered to the load terminal.

17. The PWM dimmer of claim 1 further comprising a power supply configured to convert the AC supply signal to a DC supply signal, which is used to power the control circuitry.

18. The PWM dimmer of claim 1 further comprising:
a housing in which the power stage, the interface, and the control circuitry reside; and
a pair of mounting tabs, wherein the housing is physically configured to be received by a wall-mounted, electrical junction box, and openings through mounting tabs align with respective mounting holes associated with the junction box.

19. A pulse width modulated (PWM) dimmer comprising:
a source terminal;
a load terminal;
a power stage coupled between the source terminal and the load terminal and configured to receive from the source terminal an AC supply signal having an envelope with a positive half-cycle and a negative half-cycle for each cycle and provide to the load terminal a pulsed AC load signal that tracks the envelope and comprises a plurality of pulses in each of the positive half-cycle and the negative half-cycle for each cycle based on a control signal;
an interface configured to receive dimming control information bearing on a dimming level; and
control circuitry configured to receive the dimming control information from the interface and generate the control signal based on the dimming control information

Assignees

• Cree Inc

Inventors

• Fang Yuan
• Power David

Classifications

• H05B45/37

  Converter circuits · CPC title

• H05B45/46

  having LEDs disposed in parallel lines · CPC title

• H05B47/19

  via wireless transmission · CPC title

• H05B33/0815

  Electricity · mapped topic

• H05B33/0845

  Electricity · mapped topic