Load control device for controlling a driver for a lighting load

• US 10,236,789 B2
• Filed: 07/29/2015
• Issued: 03/19/2019
• Est. Priority Date: 08/01/2014
• Status: Active Grant

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Inventors: Steiner, James P., Cooper, Daniel G., Bedell, Ryan S.
• Primary Examiner(s): Kim, Seokjin
• Application Number:
  US14/813,006
• Publication Number:
  US 20160036349A1
• Time in Patent Office: 1,329 Days
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/50 responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
• CPC Class Codes: H05B 45/59 for reducing or suppressing flicker or glow effects
• CPC Class Codes: H05B 47/10 Controlling the light source
• CPC Class Codes: H05B 47/115 by determining the presence or movement of objects or living beings
• CPC Class Codes: H05B 47/17 Operational modes, e.g. switching from manual to automatic mode or prohibiting specific operations
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A load control device is configured to generate a control signal having a desired magnitude for controlling a load regulation device adapted to control the power delivered to an electrical load. The load control device may comprise a control terminal arranged to provide the control signal to the load regulation device, a communication circuit for generating the control signal, and a control circuit configured to generate an output signal that is provided to the communication circuit. The communication circuit may be characterized by non-linear operation. The control circuit may adjust the magnitude of the output signal in response to the difference between the magnitude of the control signal and the desired magnitude to adjust the magnitude of the control signal towards the desired magnitude. The control circuit may also be configured to determine if an incompatible load regulation device is coupled to the load control device.

Claims

1. A load control device for controlling a load regulation device adapted to control power delivered from a power source to an electrical load, the load control device comprising:

first and second control terminals adapted to be coupled to the load regulation device for providing a control signal to the load regulation device;

a control circuit configured to generate an output signal for controlling a magnitude of the control signal to a desired magnitude, the desired magnitude indicating a target amount of power to be delivered to the electrical load; and

a communication circuit coupled to the control circuit for receiving the output signal and to the first and second control terminals for generating the control signal, the communication circuit comprising a current sink circuit that is adapted to receive a link supply voltage across the first and second control terminals from the load regulation device, and the current sink circuit configured to sink current through the load regulation device to generate the control signal;

wherein the control circuit is further configured to;

receive a feedback signal indicating the magnitude of the control signal;

determine a difference between the magnitude of the control signal and the desired magnitude; and

adjust the magnitude of the output signal in response to the difference between the magnitude of the control signal and the desired magnitude, so as to adjust the magnitude of the control signal towards the desired magnitude.

2. The load control device of claim 1, further comprising:

a controllably conductive device adapted to be coupled in series electrical connection between the power source and the load regulation device;

wherein the control circuit is configured to render the controllably conductive device conductive and non-conductive to turn the electrical load on and off, respectively.

3. The load control device of claim 2, wherein the control circuit comprises a microprocessor including a digital-to-analog converter (DAC) for generating the output signal.

4. The load control device of claim 3, wherein, when the control circuit is turning on the electrical load, the control circuit is configured to override adjustment of the magnitude of the output signal in response to the difference between the magnitude of the control signal and the desired magnitude, and to feed a predetermined value into the DAC for a period of time.

5. The load control device of claim 4, wherein the electrical load is a light-emitting diode (LED) light source, and the predetermined value comprises a low-end value corresponding to a low-end intensity of the LED light source.

6. The load control device of claim 5, wherein the control circuit is configured to measure an input value of the DAC when an intensity of the LED light source is at the low-end intensity and to store the input value of the DAC in memory as the low-end value for use when turning on the LED light source.

7. The load control device of claim 4, wherein, when the control circuit is turning on the electrical load, the control circuit is configured to override adjustment of the magnitude of the output signal in response to the difference between the magnitude of the control signal and the desired magnitude, and to feed the predetermined value into the DAC until the load regulation device has started to generate a link supply voltage at the control terminals.

8. The load control device of claim 3, wherein the microprocessor is configured to determine an adjustment value from the difference between the magnitude of the control signal and the desired magnitude, and to adjust the magnitude of the output signal by the adjustment value.

9. The load control device of claim 1, wherein the communication circuit comprises a 0-10V communication circuit for generating a 0-10V control signal.

10. The load control device of claim 9, wherein the communication circuit is configured to control the magnitude of the 0-10V control signal to the desired magnitude according to at least one of a linear mode or a square-law mode.

11. The load control device of claim 10, wherein the control circuit is configured to switch between the linear mode and the square-law mode in response to an advanced programming mode of the load control device.

12. The load control device of claim 1, wherein the communication circuit comprises a current sink circuit arranged to sink current through the control terminals.

13. The load control device of claim 1, further comprising a photodetector configured to detect a light level in the vicinity of the load control device, the control circuit configured to determine a dimming curve model for the load regulation device and electrical load using the detected light level.

14. The load control device of claim 13, wherein the control circuit is configured to determine the dimming curve model by:

adjusting the magnitude of the output signal through a plurality of values, determining a light level at each of the plurality of values of the output signal using the photodetector, and correlating the light levels and the plurality of values of the output signal to determine a dimming curve model for the load regulation device and electrical load.

15. The load control device of claim 14, wherein the control circuit is configured to determine the dimming curve model by selecting between a plurality of preconfigured dimming curve models or by creating a dimming curve model using the correlation of the light levels and the plurality of values of the output signal.

16. The load control device of claim 14, wherein the control circuit is further configured to determine the dimming curve model by:

determining an ambient light level when the electrical load is off using the photodetector, subtracting the ambient light level from the light level at each of the plurality of values of the output signal to determine an intensity level of the electrical load at each of the plurality of values of the output signal, and correlating the intensity levels of the electrical load and the plurality of values of the output signal to determine the dimming curve model for the load regulation device and electrical load.

17. The load control device of claim 16, wherein the control circuit is further configured to determine the dimming curve model by:

receiving feedback from a daylight sensor, subtracting the feedback from the intensity level at each of the plurality of values of the output signal to determine a refined intensity level of the electrical load at each of the plurality of values of the output signal, and correlating the refined intensity levels of the electrical load and the plurality of values of the output signal to determine the dimming curve model for the load regulation device and electrical load.

18. The load control device of claim 13, wherein the control circuit is configured to detect flickering of the electrical load using the photodetector, and upon detecting flickering of the electrical load, increase the output signal.

19. A load control device for controlling a load regulation device adapted to control power delivered from an AC power source to an electrical load, the load control device comprising:

first and second control terminals adapted to be coupled to the load regulation device for providing a control signal to the load regulation device;

a control circuit configured to generate an output signal for controlling a magnitude of the control signal to a desired magnitude, the desired magnitude indicating a target amount of power to be delivered to the electrical load; and

a communication circuit coupled to the control circuit for receiving the output signal and to the first and second control terminals for generating the control signal, the communication circuit comprising a current sink circuit that is adapted to receive a link supply voltage across the first and second control terminals from the load regulation device, and the current sink circuit configured to sink current through the load regulation device to generate the control signal;

a photodetector configured to detect a light level in the vicinity of the load control device; and

wherein the control circuit is further configured to;

adjust the magnitude of the output signal through a plurality of values;

determine a light level at each of the plurality of values of the output signal using the photodetector; and

correlate the light levels and the plurality of values of the output signal to determine a dimming curve model for the load regulation device and electrical load.

20. The load control device of claim 19, wherein the control circuit is configured to determine the dimming curve model by selecting between a plurality of preconfigured dimming curve models or by creating a dimming curve model using the correlation of the intensity levels of the electrical load and the plurality of values of the output signal.

21. The load control device of claim 19, wherein the control circuit is further configured to determine the dimming curve model by:

determining an ambient light level when the electrical load is off using the photodetector, subtracting the ambient light level from the light level at each of the plurality of values of the output signal to determine an intensity level of the electrical load at each of the plurality of values of the output signal, and correlating the intensity levels of the electrical load and the plurality of values of the output signal to determine the dimming curve model for the load regulation device and electrical load.

22. The load control device of claim 21, wherein the control circuit is further configured to determine the dimming curve model by:

receiving feedback from a daylight sensor, subtracting the feedback from the intensity level at each of the plurality of values of the output signal to determine a refined intensity level of the electrical load at each of the plurality of values of the output signal, and correlating the refined intensity levels of the electrical load and the plurality of values of the output signal to determine the dimming curve model for the load regulation device and electrical load.

23. The load control device of claim 19, wherein the control circuit is configured to detect flickering of the electrical load using the photodetector, and upon detecting flickering of the electrical load, increase the output signal.