Configuration of a load regulating device for lighting control

Abstract

The present disclosure relates to the configuration of a load regulation device for lighting control. A load regulation device, such as an LED driver, can be configured to control the intensity of a light source based on an analog control signal and a preconfigured dimming curve. The LED driver can sense the amplitude of the analog control signal and determine new low-end and / or high-end control signal amplitudes that fall outside the input signal range of the dimming curve. The LED driver can rescale the preconfigured dimming curve according to the new low-end and / or high-end control signal amplitudes and dim the light source based on the rescaled dimming curve. Multiple LED drivers controlled by the same analog control signal can communicate with each other regarding the amplitude of the analog control signal sensed by each LED driver and match their target intensity levels despite sensing different analog control signals. A controller can be provided to coordinate the operation of the multiple LED drivers.

Description

[0001] This application is a divisional application of the patent application for invention with the application date of July 13, 2018, application number 201880056978.6, and invention title "Configuration of a Load Regulation Device for Lighting Control".

[0002] Cross - reference to related applications

[0003] This application claims the priority of U.S. Provisional Patent Application No. 62 / 532,753, filed on July 14, 2017, the entire disclosure of which is incorporated herein by reference. Background Art

[0004] Newer light sources such as high - efficiency light sources (such as light - emitting diode (LED) light sources and compact fluorescent lamps (CFLs)) require a load regulation device (such as a ballast or a driver) to be properly illuminated. The load regulation device typically receives an AC voltage from an alternating current (AC) power source and regulates at least one of the load voltage generated across the light source or the load current conducted through the light source. The load regulation device can be configured to control the light output of the light source (e.g., to control the intensity or color of the light source). Example dimming methods can include pulse - width modulation (PWM) techniques, constant - current reduction (CCR) techniques, and / or a combination of PWM techniques and CCR techniques. Examples of load regulation devices (e.g., LED drivers) are described in more detail in the commonly assigned U.S. Patent No. 8,492,988, entitled "CONFIGURABLE LOAD CONTROL DEVICE FOR LIGHT - EMITTING DIODE LIGHT SOURCE", issued on July 23, 2010, and U.S. Patent No. 8,680,787, entitled "LOAD CONTROL DEVICE FOR A LIGHT - EMITTING DIODE LIGHT SOURCE", published on March 25, 2014, the entire disclosures of which are incorporated herein by reference.

[0005] The load regulating device can be configured to control the connected light source in response to a control signal (e.g., to adjust the intensity or color of the light source). The control signal can be an analog control signal or a digital control signal. The digital control signal can be, for example, a digital PWM control signal, a digital message sent using a communication protocol (e.g., a standard protocol such as the Digital Addressable Lighting Interface (DALI) protocol or a proprietary protocol such as the ECOSYSTEM protocol), etc. The analog control signal can be, for example, a "zero to ten volts" (0 - 10V) control signal, a "ten to zero volts" (10 - 0V) control signal, an analog pulse width modulation (PWM) control signal, etc. The analog control signal can be sent from a remote control device (e.g., an external 0 - 10V control device). The remote control device can be installed in an electrical wall box and can include an intensity / color adjustment actuator (e.g., a slider control). The remote control device can adjust the amplitude of the control signal (e.g., adjust the direct current (DC) voltage level of the control signal) between a low-end amplitude (e.g., zero to one volt) and a high-end amplitude (e.g., nine to ten volts) in response to the actuation of the intensity / color adjustment actuator. The low-end amplitude can correspond to the minimum light level or color temperature of the light source, while the high-end amplitude can correspond to the maximum light level or color temperature of the light source. As the amplitude of the control signal is adjusted between the low-end amplitude and the high-end amplitude, one or more aspects of the light source can be adjusted accordingly. For example, the intensity level of the light output can be adjusted between the minimum light level and the maximum light level according to a dimming curve, and the color (e.g., color temperature) of the light output can be controlled according to a color tuning curve, etc.

[0006] When the control signal is an analog signal, the amplitude and / or intensity of the control signal can be affected by the interference and / or electromagnetic characteristics of components located between the remote control device and the load regulating device. For example, a long wire extending from the remote control device to the load regulating device can degrade the amplitude of the control signal received by the load regulating device (e.g., a voltage drop in the amplitude of the 0 - 10V control signal due to the resistance in the wire). This voltage drop in the amplitude of the control signal can shift the normal dimming range of the light source. For example, instead of receiving a voltage with an amplitude of 1V as a signal to set the light level of the light source to the minimum level, the light source can receive a voltage with an amplitude of 0.8V. Similarly, instead of receiving a voltage with an amplitude of 9V as a signal to set the light level of the light source to the maximum level, the light source can receive a voltage with an amplitude of 8.8V.

[0007] When multiple lighting fixtures are controlled by the same control device but are installed at different distances from the remote control device, the difference between the originally generated control signal and the amplitude of the actually received control signal can be particularly significant. For example, the control signal received by one lighting fixture can deviate from the original signal amplitude more or less than the control signal received by another lighting fixture. In this way, the same control signal generated by the remote control device can produce different light intensities and / or colors at different lighting fixtures, thereby causing an undesirable visual effect in a multi-light source environment (e.g., the inconsistency of light output can be more easily perceived towards the lower end of the dimming range). Summary of the Invention

[0008] This document describes a load regulating device that can be configured to control the intensity and / or color of a light source based on an analog control signal (e.g., such as a 0 - 10V control signal). The load regulating device can be configured to control the intensity of the light source based on a pre-configured dimming curve and / or control the color of the light source based on a color tuning curve with respect to the analog control signal. If the load regulating device determines that the amplitude of the analog control signal falls outside the input signal range of the dimming curve or the color tuning curve, the load regulating device can determine a new low-end control signal amplitude and / or a new high-end control signal amplitude. For example, the load regulating device can rescale the pre-configured dimming curve or color tuning curve according to the new low-end and / or high-end control signal amplitudes. The load regulating device can adjust the intensity and / or color of the light source based on the rescaled dimming curve or color tuning curve.

[0009] A load control system can include multiple load regulating devices that are controlled by the same control device and are thus controlled by the same analog control signal. The load regulating devices can communicate with each other (e.g., to compensate for variations in the amplitude of the control signal received by each load regulating device) with respect to the amplitude of the analog control signal sensed (e.g., received) by each load regulating device. For example, although there are differences in the amplitude of the analog control signal sensed by the load regulating devices, the multiple load regulating devices can still match their target intensity levels. A controller (e.g., the control device or a separate controller) can coordinate the operation of the multiple load regulating devices to achieve consistent light output among the light sources within the range of the control signal. Brief Description of the Drawings

[0010] Figure 1 An example load control system is shown, where an LED driver is configured to control the operation of an LED light source based on an analog control input signal.

[0011] Figure 2 An example load control system is shown that includes multiple LED drivers controlled by a remote control device.

[0012] Figure 3 Another example load control system is shown that includes a plurality of LED drivers controlled by a remote control device.

[0013] Figure 4 An example technique is shown for adjusting the dimming curve of an LED driver in response to a 0 - 10V control signal during normal operation of the LED driver.

[0014] Figure 5 An example technique is shown for adjusting the dimming curve of an LED driver in response to a 0 - 10V control signal during a special mode.

[0015] Figure 6 An example technique is shown for achieving consistent dimming performance among a plurality of LED drivers controlled by a remote control device.

[0016] Figure 7 An example technique is shown for using a special mode to achieve consistent dimming performance among a plurality of LED drivers controlled by a remote control device.

[0017] Figure 8 Another example technique is shown for using a special mode to achieve consistent dimming performance among a plurality of LED drivers controlled by a remote control device.

[0018] Figure 9 is Figure 1 A simplified equivalent schematic diagram of the depicted example LED driver. Detailed Description

[0019] Figure 1 FIG. 1 is a simplified block diagram of an example load control system 100 for controlling the amount of power delivered to an electrical load such as a light - emitting diode (LED) light source 102 (e.g., an LED light engine or other suitable lighting load), another type of lighting device, motorized window coverings, an HVAC system, etc. The load control system 100 may include a load - regulating device (e.g., such as an LED driver 104) for controlling the operating characteristics (e.g., the intensity and / or color (e.g., color temperature)) of the LED light source 102. The LED driver 104 may be coupled to a power source capable of generating an AC line voltage, such as an alternating current (AC) power source 108. The LED light source 102 may include a single LED, multiple LEDs connected in series or parallel, or a suitable combination thereof, one or more organic light - emitting diodes (OLEDs), etc. Further, the power source may include a DC power source capable of generating a direct - current (DC) supply voltage (e.g., instead of or in addition to the AC line voltage) for certain electrical loads.

[0020] The load control system 100 may include a load control device 120 (e.g., a 0-10V control device), which may be implemented as a wall-mounted control device or a remotely installed control device (e.g., located in a utility closet and / or in a junction box behind a wall or above a ceiling). The load control device 120 may be configured to control the operating characteristics of the LED light source 102 by generating a control signal V CS and providing it to the LED driver 104 to control the electrical load. The control signal V CS may include, for example, an analog control signal, such as a 0-10V control signal.

[0021] The load control device 120 may receive power from an AC power source 108 (e.g., by being connected to the AC power source) or from a different internal or external power source (e.g., as Figure 1 shown, the load control device 120 may not need to be connected to the AC power source 108). For example, as Figure 1 shown, the load control device 120 may be powered by the LED driver 104.

[0022] The load control device 120 may include control terminals 122, which are adapted to be coupled to the LED driver 104 via control wiring 110. The load control device 120 may include a driver communication circuit for generating a control signal V CS (e.g., a 0-10V control signal or a 10-0V control signal) (e.g., a 0-10V communication circuit not shown in Figure 1 ). The driver communication circuit may include a current sink circuit, which is adapted to sink current through the LED driver 104 via the control wiring 110. The driver communication circuit may also include a current source circuit or a current source / sink circuit for generating the control signal V CS . Thus, the LED driver 104 may be configured to generate a link supply voltage to allow the current sink circuit to generate the control signal V CS on the control wiring 110. The load control device 120 may include a control circuit (not shown), which is used to control the current sink circuit in response to the actuation of an intensity adjustment actuator (e.g., a linear slider or knob) to generate the control signal V CS . The control circuit may adjust the amplitude of the control signal V CS to have a desired DC amplitude V DES , which indicates the target value of the operating characteristics (e.g., the intensity of the LED light source) of the LED light source 102.

[0023] The LED driver 104 may be configured to control the load voltage V LOADthe magnitude and / or the load current I conducted through the LED light source 102 LOAD magnitude. The LED driver 104 can be configured to control the load voltage V CS in response to receiving a control signal V via the control wiring 110 from the load control device 120 LOAD and / or the load current I LOAD magnitude. For example, the LED driver 104 can be configured to control the load voltage V LOAD and / or the load current I LOAD magnitude based on preconfigured settings and / or a preconfigured dimming curve. Such a preconfigured dimming curve can depict the target intensity L of the LED light source 102 TRGT (e.g., which can correspond to a specific output of the LED driver 104) versus the control signal V CS . The relationship can be, for example, a linear relationship or a square-law relationship.

[0024] The LED driver 104 can store data associated with the preconfigured dimming curve in a memory (e.g., one or more look-up tables). Upon receiving the control signal V CS , the LED driver 104 can look up the data stored in its memory in response to the magnitude of the control signal and determine the target intensity L TRGT . For example, according to the preconfigured dimming curve, if the received 0 - 10V control signal has a low-end magnitude V LE (e.g., 1 volt), then the LED driver 104 can be configured to set the target intensity L of the LED light source 102 TRGT to a low-end intensity L LE (e.g., approximately 1%). Similarly, if the received 0 - 10V control signal has a high-end magnitude V HE (e.g., 10 volts), then the LED driver 104 can be configured to set the target intensity L of the LED light source 102 TRGT to a high-end intensity L HE (e.g., approximately 100%). If the received 0 - 10V control signal has a magnitude between the low-end magnitude V LE and the high-end magnitude V HE , then the LED driver 104 can set the target intensity L of the LED light source 102 based on the dimming curve TRGT to a value between the low-end intensity L LE and the high-end intensity L HE .

[0025] The LED driver 104 can be configured, for example, to adjust the intensity of the LED light source 102 between the low-end intensity L LE and the high-end intensity L HEbetween. The LED driver 104 can be configured to adjust the intensity of the LED light source 102 using constant current reduction (CCR) techniques, pulse width modulation (PWM) techniques, and / or pulse frequency modulation (PFM) techniques. Additionally or alternatively, the LED driver 104 can be configured to turn the LED light source 102 on and off to adjust the intensity of the LED light source 102 and / or to adjust the color (e.g., color temperature) of the LED light source 102.

[0026] The control signal V generated by the load control device 120 CS The amplitude and / or intensity of can be affected by the interference and / or electromagnetic characteristics of components located between the control device 120 and the LED driver 104. For example, the control wiring 110 can cause the control signal V received by the LED driver 104 CS to degrade in amplitude (e.g., a voltage drop in the amplitude of the control signal V due to resistance in the wire) CS The voltage drop in the amplitude of the control signal V CS can affect the operation of the LED driver 104. For example, a user can manipulate the load control device 120 to control the amplitude of the control signal V CS to an amplitude of 1V in an attempt to set the light level of the LED light source 102 to a low-end intensity L LE . Due to signal degradation caused by the control wiring 110, the LED driver 104 may misinterpret the control signal V CS , and set the target intensity L of the LED light source 102 TRGT to a value different from the value expected by the user. For example, when the load control device 120 generates a control signal V CS to control the LED light source 102 to a low-end intensity L LE , the control signal V received by the LED driver 104 CS may have an amplitude of 0.8V instead of 1V, which may create a "dead band" during adjustment of the intensity adjustment actuator of the load control device 120 because the LED driver 104 may not respond to the control signal V CS when the amplitude of is less than 1V (e.g., when the amplitude of the control signal V received by the LED driver 104 CS is between 0.8V and 1V) CS .

[0027] The LED driver 104 can be configured to respond to detecting that the amplitude of the control signal V CS is within a stored low-end amplitude V representing an endpoint of a dimming curve LE and a stored high-end amplitude V HEoutside the range and rescale the dimming curve. The LED driver 104 can be configured to adjust the intensity of the LED light source in response to a dimming curve defined by an initially stored low-end amplitude V LE and a high-end amplitude V HE The LED driver 104 can be configured to measure the amplitude of a control signal V CS and compare the measured voltage with the low-end amplitude V LE and the high-end amplitude V HE If the measured amplitude of the control signal V CS is less than the low-end amplitude V LE the LED driver 104 can update the stored low-end amplitude V LE to be equal to the measured amplitude of the control signal V CS and rescale the stored dimming curve based on the updated low-end amplitude. If the measured amplitude of the control signal V CS is greater than the high-end amplitude V HE the LED driver 104 can update the stored high-end amplitude V HE to be equal to the measured amplitude of the control signal V CS and rescale the stored dimming curve based on the updated high-end amplitude.

[0028] The LED driver 104 can be configured to measure the amplitude of a control signal V CS to determine whether the amplitude of the control signal V CS at the first power-on falls outside the stored low-end amplitude V LE and the stored high-end amplitude V HE In addition, the LED driver 104 can be configured to periodically measure the amplitude of the control signal V CS to determine whether the amplitude of the control signal V CS during normal operation of the LED driver 104 falls within the stored low-end amplitude V LE and the stored high-end amplitude V HE Finally, the LED driver 104 can be configured to enter a special calibration mode, in which the LED driver 104 can measure the amplitude of the control signal V CS to determine whether the amplitude of the control signal V CS falls outside the stored low-end amplitude V LE and the stored high-end amplitude V HE

[0029] Figure 2 ​Illustrates an example load control system 200 that includes a plurality of LED light sources 202A - 202C having respective LED drivers 204A - 204C controlled by a remote control device (e.g., a 0 - 10V control device 220). It should be understood that although three LED drivers and corresponding LED light sources are shown in the figure, the load control system 200 can include any number of LED drivers and corresponding LED light sources. Further, although described primarily with reference to 0 - 10V control signals, it should be understood that the load regulating devices described herein (e.g., LED drivers 204A - 204C, etc.) can perform any of the techniques described herein in response to other types of analog control signals.

[0030] Each LED driver 204A - 204C can be adapted to receive line voltage from an AC power source 208. The LED driver can be further adapted to be coupled to the 0 - 10V control device 220 via control wiring 210. The 0 - 10V control device 220 can receive power from the AC power source 208 (e.g., by being connected to the AC power source). Alternatively or additionally, the 0 - 10V control device can receive power from a different internal or external power source (e.g., the 0 - 10V control device 220 may not need to be connected to the AC power source 208). The 0 - 10V control device 220 can be configured to generate an analog control signal V CS (e.g., a 0 - 10V control signal) on the control wiring 210 to the plurality of LED light sources 202A - 202C in response to receiving a user input (e.g., a dimming command).

[0031] Since the LED light sources 202A - 202C can be installed in different locations and / or connected to the 0 - 10V control device 220 through wiring with different characteristics (e.g., the length of the wiring can be different, the electromagnetic characteristics of the wiring can be different, etc.), the control signal V generated by the 0 - 10V control device 220 CS can exhibit different degrees of degradation as received by the respective LED drivers 204A - 204C. For example, the 0 - 10V control device 220 can control the amplitude of the control signal V CS to a pre - configured low - end amplitude (e.g., 1V) in response to a user input to set all the LED light sources to a low - end intensity L LE (e.g., approximately 1%). Due to the different characteristics (e.g., different resistances) of the wiring between the 0 - 10V control device 220 and the LED drivers 204A - 204C and / or other electromagnetic conditions, the first LED driver 204A may sense the control signal V CShas an amplitude of 1.2V, while the second LED driver 204B may sense that the amplitude of the control signal is 1.1V. If both LED drivers 204A, 204B are configured to respond to the control signal V CS in accordance with a pre-configured dimming curve and are not configured to accommodate variations in the amplitude of the control signal V CS received by the two LED drivers 204A, 204B, then even if the user's intention is to set both light sources to the same intensity level (e.g., low-end intensity L LE ), the light outputs of the two LED light sources 202A, 202B may be adjusted to different intensity levels.

[0032] The LED drivers 204A - 204C can be configured to communicate with each other so as to synchronize their dimming curves to ensure that each LED light source 202A - 202C is controlled to the same intensity in response to the 0 - 10V control device 220. The LED drivers 204A - 204C can communicate with each other regarding the measured amplitude of the control signal V CS and / or regarding the pre-configured intensity levels of the LED drivers corresponding to the measured amplitude. Based on the communication, the LED drivers 204A - 204C can adjust their pre-configured intensity levels (e.g., the LED drivers can rescale the corresponding dimming curves) and accordingly (e.g., based on the rescaled dimming curves) control their associated LED light sources 202A - 202C. The LED drivers 204A - 204C can reach an agreement via the communication on a common intensity level corresponding to the current amplitude of the control signal V CS . Then, the LED drivers 204A - 204C can dim their associated LED light sources 202A - 202C to the common intensity level such that, despite variations in the amplitude of the control signal at each LED driver, a consistent light output can be produced at multiple LED light sources. The LED drivers 204A - 204C can be configured to perform one or more of the foregoing operations in a special mode (e.g., during debugging, at startup, and / or when initiated by the user). The LED drivers 204A - 204C can be configured to constantly perform one or more of the foregoing operations (e.g., during normal operation of the electrical load without entering the special mode).

[0033] For example, when the amplitude of the control signal V CS received by one of the LED drivers 204A - 204C is equal to (or less than) the stored low-end amplitude V LE , the LED driver can be configured to send an indication signal (e.g., a simple signal) to indicate that the LED driver is at the low-end intensity L LEFor example, the LED drivers 204A - 204C can send indication signals by sending wireless signals (e.g., radio frequency (RF) signals) and / or generating high - frequency signals and / or pulses on the control wiring 210. The LED drivers 204A - 204C that receive the indication signals can store the current amplitude of the control signal V CS as the low - end amplitude V LE in the dimming curve, and re - scale the dimming curve between the stored high - end amplitude V HE and the updated low - end amplitude V LE . The LED drivers 204A - 204C can also be configured to adjust the high - end voltage V HE in a similar manner. In addition, the LED drivers 204A - 204C can be configured to synchronize multiple points between the low - end amplitude V LE and the high - end amplitude V HE . When one of the LED drivers 204A - 204C generates a high - frequency signal and / or pulse on the control wiring 210 to send an indication signal, the LED driver can be configured to control the corresponding LED light sources 202A - 202C in response to the control signal V CS .

[0034] Additionally, each of the LED drivers 204A - 204C can be configured to update the stored low - end amplitude V Figure 1 and / or the stored high - end amplitude V LE as described above for the LED driver 104 with reference to HE (e.g., without communicating with each other). For example, each of the LED drivers 204A - 204C can be configured to measure the amplitude of the control signal V CS , and if the measured amplitude is outside the range of the stored low - end amplitude V LE and the stored high - end amplitude V HE , then update the stored low - end amplitude V LE and / or the stored high - end amplitude V HE .

[0035] Figure 3Another example load control system 300 is shown, which includes a plurality of LED light sources 302A - 302C having respective LED drivers 304A - 304C controlled by a remote control device (e.g., a 0 - 10V control device 320). The 0 - 10V control device 306 can be connected to an AC power supply 308 (e.g., connected to the hot side of the AC power supply) and can generate a switched hot output SH for controlling the power delivered to the LED drivers 304A - 304C. The 0 - 10V control device 320 can be configured to (e.g., in response to receiving a user input such as a dimming command) additionally generate an analog control signal (e.g., a 0 - 10V control signal V CS ). Each LED driver 304A - 304C can be adapted to receive the line voltage between the switched hot side SH of the 0 - 10V control device and the neutral side N of the AC power supply 308. Each LED driver 304A - 304C can be adapted to receive the 0 - 10V control signal V CS .

[0036] Since the LED light sources 302A - 302C can be installed in different locations and / or connected to the 0 - 10V control device 320 through wiring with different characteristics (e.g., the length of the wiring can be different, the electromagnetic characteristics of the wiring can be different, etc.), the control signal V CS generated by the 0 - 10V control device 320 can exhibit different degrees of degradation as received by the respective LED drivers 304A - 304C. For example, the 0 - 10V control device 320 can send a control signal V LE with a pre - configured low - end amplitude V CS (e.g., 1 volt) in response to a user input to set all the LED light sources to a low - end intensity L LE (e.g., approximately 1%). Due to the varying characteristics (e.g., different resistances) of the wiring between the 0 - 10V control device 320 and the LED drivers 304A - 304C and / or other electromagnetic conditions, the first LED driver 304A may sense the amplitude of the control signal V CS as 1.2V, while the second LED driver 304B may sense the amplitude of the control signal as 1.1V. If both LED drivers are configured to react to the control signal V CS according to a pre - configured dimming curve and are not configured to accommodate the variation in the amplitude of the control signal V CS received by the two LED drivers 304A, 304B, then even though the user's intention is to set the two light sources to the same intensity level (e.g., the low - end intensity L LE) The light outputs of the two LED light sources 302A and 302B may also be dimmed to different intensity levels.

[0037] The 0-10V control device 320 can communicate with the LED drivers 304A-304C to cause the LED drivers to adjust their pre-configured intensity levels (e.g., the LED drivers can rescale the corresponding dimming curves), and accordingly (e.g., based on the rescaled dimming curves) control their associated LED light sources. The 0-10V control device 320 can be configured to initiate a calibration procedure to synchronize the dimming curves of the LED drivers 304A-304C to ensure that in response to the control signal V generated by the 0-10V control device 320 CS , each of the LED light sources 202A-202C is controlled to the same intensity. For example, the 0-10V control device 320 can step through multiple amplitudes of the control signal V between a low-end amplitude V LE and a high-end amplitude V HE , and the LED drivers 304A-304C can measure and store the amplitude of the control signal V at the respective LED drivers for each step. The LED drivers 304A-304C can generate a dimming curve from the stored amplitudes of the control signal V CS for use during normal operation. Then, the LED drivers 304A-304C can control their associated LED light sources according to the dimming curve determined from the stored amplitudes of the control signal V CS . CS CS

[0038] Additionally, the LED drivers 304A-304C can each be configured to communicate with each other to synchronize their dimming curves as described above for the LED drivers 204A-204C with reference to Figure 2 . Further, as described above for the LED driver 104 with reference to Figure 1 , the LED drivers 304A-304C can each be configured such that if the measured amplitude is outside the range of the stored low-end amplitude V LE and the stored high-end amplitude V HE , then by measuring the amplitude of the control signal V CS and updating the stored low-end amplitude V LE and / or the stored high-end amplitude V HE to update the stored low-end amplitude V LE and / or the stored high-end amplitude V HE .

[0039] Although the LED drivers are described herein as being able to communicate directly with each other, it will be understood that the LED drivers may also be able to communicate with each other via an intermediate device. For example, an LED driver may communicate wirelessly (e.g., via an RF signal) with a system controller or a smart personal device (e.g., a smart phone), and may then relay the communication message(s) to other LED drivers.

[0040] Figure 4 An example technique 400 is shown for adjusting a target intensity of a load regulating device (e.g., an LED driver) in response to an analog control signal (e.g., a 0-10V control signal) during normal operation of an LED driver (e.g., LED driver 104, LED drivers 204A - 204C, and / or LED drivers 304A - 304C). The LED driver may be pre-configured with a dimming curve that defines a relationship between the target intensity and the amplitude of the 0-10V control signal. According to the pre-configured dimming curve, the amplitude of the 0-10V control signal may be in a range from a low-end amplitude V LE to a high-end amplitude V HE . The low-end amplitude V LE , the high-end amplitude V HE and each of a plurality of intermediate amplitudes may correspond to a target intensity of the LED driver. The amplitude of the 0-10V control signal (e.g., the control input voltage) and / or their associated target intensities may be stored in the memory of the LED driver.

[0041] The LED driver may be powered on at 410 and read (e.g., measure) the 0-10V control signal at 412. At 414, the LED driver may compare the 0-10V control signal with the pre-configured high-end amplitude V HE stored in the memory. If the LED driver determines that the 0-10V control signal is greater than the pre-configured high-end amplitude V HE , then at 416, the LED driver may replace the pre-configured high-end amplitude V HE with the sensed 0-10V control signal. If the 0-10V control signal is not greater than the pre-configured high-end amplitude V HE , then at 418, the LED driver may compare the 0-10V control signal with the pre-configured low-end amplitude V LE . If the LED driver determines that the 0-10V control signal is less than the pre-configured low-end amplitude V LE , then at 420, the LED driver may replace the pre-configured low-end amplitude V LE with the sensed 0-10V control signal. If the LED driver determines that the 0-10V control signal falls within the pre-configured low-end amplitude V LEand a preconfigured high-end amplitude V HE then the LED driver can keep the preconfigured low-end and high-end control input voltages unchanged.

[0042] Upon determining that the low-end amplitude V LE and / or the high-end amplitude V HE has changed, the LED driver can, at 422, rescale the preconfigured dimming curve based on the new low-end amplitude V LE and / or the high-end amplitude V HE The LED driver can perform the rescaling in various ways. The LED driver can be configured to rescale the light intensity level to the control input voltage actually received by the LED driver. For example, if the LED driver receives a low-end amplitude of 0.8V instead of the preconfigured 1V amplitude, the LED driver can remap the preconfigured low-end intensity level L LE (e.g., an intensity level of 1%) to 0.8V (e.g., 0.8V can become the new low-end amplitude). The LED driver can be configured to rescale the amplitude of the control signal actually measured by the LED driver to the voltage on the preconfigured dimming curve (e.g., such that the preconfigured mapping between the light intensity level and the control input voltage need not be changed). For example, if the LED driver receives a low-end amplitude of 0.8V instead of the preconfigured 1V amplitude, the LED driver can rescale 0.8V to 1V such that the preconfigured low-end intensity level L LE (e.g., 1%) can be set to the target intensity level of the light source in response to the LED driver sensing a 0.8V control input. The LED driver can save the rescaled dimming curve (e.g., update the mapping between the light intensity level and the control input voltage in memory). Alternatively, the LED driver can determine the rescaled light intensity levels without saving them in memory.

[0043] At 424, the LED driver can dim the LED light source (e.g., whether the dimming curve has been rescaled). If the amplitudes of the low-end and high-end amplitudes are the same as their preconfigured values, the LED driver can dim the LED light source based on the preconfigured dimming curve. If either or both of the low-end and high-end amplitudes have changed from their preconfigured values, the LED driver can set the intensity of the LED light source based on the rescaled version of the preconfigured dimming curve.

[0044] Figure 5Illustrates an example technique 500 for adjusting the dimming curve of an LED driver (e.g., LED driver 104, LED drivers 204A - 204C, and / or LED drivers 304A - 304C) in response to a 0 - 10V control signal using a special mode. The LED driver can be pre - configured with a dimming curve for the 0 - 10V control signal. The pre - configured range of the control signal can be between a low - end amplitude V LE and a high - end amplitude V HE . The low - end amplitude V LE , the high - end amplitude V HE , and each of the multiple intermediate amplitudes can correspond to a target intensity level of the LED light source. The amplitudes and / or their associated target intensity levels can be stored in the memory of the LED driver.

[0045] The LED driver can be powered on at 510. After power - on, the LED driver can receive (e.g., measure) the 0 - 10V control signal at 512. At 514, the LED driver can determine whether it should enter a special mode in which the LED driver can adjust its pre - configured dimming curve with respect to the 0 - 10V control signal received by the LED driver. The LED driver can be configured to automatically enter the special mode or wait for a user command to enter the special mode. The LED driver can decide not to enter the special mode, in which case the LED driver can maintain the pre - configured dimming curve and continue normal operation. During normal operation, the LED driver can enter the special mode in response to a user command, for example.

[0046] If the LED driver decides to enter the special mode at 514, the LED driver can compare the 0 - 10V control signal with the pre - configured high - end control input voltage V HE at 516. If the LED driver determines that the 0 - 10V control signal is greater than the pre - configured high - end amplitude V HE , then at 518, the LED driver can replace the pre - configured high - end amplitude V HE with the sensed 0 - 10V control signal. If the 0 - 10V control signal is not greater than the pre - configured high - end control input voltage V HE , then at 520, the LED driver can further compare the 0 - 10V control signal with the pre - configured low - end amplitude V LE . If the LED driver determines that the received 0 - 10V control signal is less than the pre - configured low - end amplitude V LE , then at 522 the LED driver can replace the pre - configured low - end control input voltage V LE with the 0 - 10V control signal.

[0047] If the pre - configured low - end amplitude VLE and the high-end amplitude V HE If either or both are updated, the LED driver can use the new value at 524 to adjust a pre-configured dimming curve (e.g., using the rescaling techniques described herein). Then, before exiting the special mode, at 526, the LED driver can select a target intensity for the LED light source based on the received 0-10V control signal and the rescaled dimming curve. If the LED driver determines, after making the comparisons at 516 and 520, that the received 0-10V control signal falls within the pre-configured low-end amplitude V LE and the pre-configured high-end amplitude V HE then the LED driver can maintain the low-end amplitude V LE and the high-end amplitude V HE and the pre-configured dimming curve unchanged. Then, at 526, the LED driver can dim the LED light source according to the pre-configured dimming curve.

[0048] Multiple LED drivers controlled by a remote control device (e.g., a 0-10V control device) can be configured to communicate with each other (e.g., as described herein, via a wired or wireless communication scheme). The information transmitted can include the status of the LED driver (e.g., reporting an operating fault), the output current / power of the LED driver, the intensity of the LED light source, the color temperature of the LED light source, the color of the LED light source, a power failure condition occurring at the LED light source, etc. This communication can be received by other LED drivers, which can adjust their own operations based on the information included in the communication (e.g., such that multiple LED drivers can have a matching target intensity level in response to a control signal sent by the remote control device despite differences in the amplitudes received by the LED drivers).

[0049] Figure 6 Example technique 600 for achieving consistent dimming performance among multiple LED drivers (e.g., LED drivers 204A-204C and / or LED drivers 304A-304C) controlled by a remote control device (e.g., a 0-10V control device) is shown. Each LED driver can be pre-configured with a dimming curve for a control signal generated by the 0-10V control device. The pre-configured range of the control signal can be between a low-end amplitude V LE and a high-end amplitude V HE The low-end amplitude V LE the high-end amplitude V HE and each of the multiple intermediate amplitudes can correspond to a target intensity level of the LED light source. The amplitudes and / or their associated target intensity levels can be stored in the memory of the LED driver.

[0050] Multiple LED drivers can be powered on at 610 and measure the 0 - 10V control signal sent by the 0 - 10V control device at 620. At 630, each LED driver can determine the target intensity level of its associated LED light source based on the measured 0 - 10V control signal. At 640, one or more of the LED drivers (e.g., all LED drivers) can attempt to communicate with other LED drivers regarding the measured magnitude of the control signal and / or the pre - configured intensity level of the LED driver corresponding to the measured magnitude. This communication can indicate the actual pre - configured intensity level (e.g., 1%, 5%, 50%, etc.) of the LED driver corresponding to the measured magnitude of the 0 - 10V control signal (e.g., based on the pre - configured dimming curve of the LED driver). Alternatively or additionally, this communication can indicate where the corresponding intensity level lies along the dimming curve of the transmitting LED driver. For example, an LED driver can indicate that its intensity level corresponding to the measured magnitude of the control signal is at the low end of the dimming range without specifying the actual value of the target intensity level.

[0051] For example, as described herein, communication can be performed via a wired (e.g., via DALI, EcoSystem link, power line communication (PLC) technology, etc.) or wireless (e.g., via RF signal) communication scheme. Communication can be performed on the 0 - 10V control line during a selected time period, during which the participating LED drivers can temporarily stop measuring the 0 - 10V control signal on the control line (e.g., the receiving LED driver can avoid measuring the magnitude of the 0 - 10V control signal while the transmitting LED driver is using the control line to send a communication signal). For example, an LED driver can be configured to short - circuit the 0 - 10V control line to transmit a "0" or "1", an LED driver can be configured to perform another type of PLC on the control line, and / or an LED driver can be configured to communicate wirelessly with each other.

[0052] At 650, other LED drivers in the system may receive one of the communications. At 660, the recipients of the communications may check if their own target intensity levels are lower than the level indicated in the communication in response to measuring the 0-10V control signal. At 670, LED drivers with lower target intensity levels may transmit their respective levels, and the operations described in conjunction with 650-670 may be repeated until the lowest target intensity level is identified. At 680, the LED driver reporting the lowest target intensity level may be designated as the leader for future communications (e.g., all other LED drivers may then listen to communications from the leader and adapt their respective dimming operations based on the actions taken by the leader). In an alternative implementation, one of the LED drivers may be preconfigured (e.g., preprogrammed) as the leader of LED drivers, and a common intensity level may be specified for all LED drivers in response to the measured control signal. In yet another alternative implementation, the actions taken at 680 may be omitted and no leader may be designated (e.g., the LED drivers may adapt their respective dimming operations based on the lowest intensity level transmitted between drivers without designating a leader for future operations).

[0053] At 690, the LED drivers may store the lowest target intensity level identified by the foregoing process as a common intensity level corresponding to the respective amplitudes of the control signals measured by the LED drivers. For example, where the LED drivers are configured to only indicate whether their light intensity is at the low end rather than reporting the actual light intensity, one of the LED drivers may report that its target light intensity is the low end intensity L in response to the measured 0-10V control signal. LE , while other LED drivers may report their target light intensity higher than the low-end intensity L LE In this way, the LED drivers can determine that the light intensity of the measured amplitude mapped to their corresponding 0-10V control signal should be the low-end intensity L LE , and the LED drivers may adjust their respective preconfigured dimming curves accordingly (eg, may be adjusted using the rescaling techniques described herein). At 695, the LED drivers may tune the respective intensities of their associated LED light sources based on the adjusted dimming curves.

[0054] As another example (e.g., in the case where LED drivers are configured to report their actual light intensity corresponding to a measured 0-10V control signal), the LED drivers can synchronize their dimming behavior at multiple points along the dimming range. For example, in response to a common 0-10V control signal, a first LED driver may report a 49% target light intensity, a second LED driver may report a 50% target light intensity, and a third LED driver may report a 51% target light intensity. In this way, the LED drivers can determine that the common target intensity level corresponding to the 0-10V control signal should be the lowest level (e.g., 49%), and the LED drivers can map that level to the measured magnitude of their respective 0-10V control signals. Other schemes can also be used to determine the common intensity level. For example, the average of the reported target intensity levels can be taken as the common intensity level (e.g., if the reported light intensity levels are 49%, 50%, and 51%, the common intensity level can be determined to be 50%). As another example, a leader of the LED drivers (e.g., specified via the techniques described herein) can determine the common intensity level in response to the 0-10V control signal and instruct the other drivers to tune their respective target intensities to the common intensity level.

[0055] The communication and / or coordination described herein can be performed in a special mode (e.g., a calibration mode). Figure 7 An example technique 700 is shown for using such a special mode to achieve consistent dimming performance among multiple LED drivers (e.g., LED drivers 304A - 304C) controlled by a remote control device (e.g., a 0-10V control device 320). Each LED driver can be pre-configured with a dimming curve regarding an analog control signal (e.g., control signal V CS ) generated by the 0-10V control device. The pre-configured range of the control signal can be between a low-end magnitude V LE (e.g., 1 volt) and a high-end magnitude V HE (e.g., 10 volts). The low-end magnitude V LE , the high-end magnitude V HE , and each of the multiple intermediate control input voltages can correspond to a target intensity level of the LED light source. The magnitudes and / or their associated target intensity levels can be stored in the memory of the LED driver.

[0056] The LED driver can be powered on at 710 and receive a signal (e.g., the signal can include a command and / or announcement to enter a special mode such as a calibration mode). The command or announcement can be sent from a remote control device to the LED driver, which can be configured to communicate with the LED driver and initiate the special mode (e.g., to coordinate the calibration of multiple LED drivers). The LED driver that receives the command or announcement can enter the special mode at 720 and can send an acknowledgement message to the remote control device. Once in the calibration mode, the LED driver can receive and measure multiple amplitudes of the control signal V CS where the multiple amplitudes can include a low-end amplitude V LE , a high-end amplitude V HE and / or an amplitude between the low-end amplitude V LE and the high-end amplitude V HE . For example, the LED driver can receive and measure multiple amplitudes of the control signal V CS intended to synchronize the dimming operation of the LED driver at multiple intensity levels (e.g., 10%, 20%, 30%, etc.). The remote control device can be configured to send the amplitudes in response to receiving a user input or command from a central controller. At 740, each LED driver can determine the target intensity level of its associated LED light source in response to the measured amplitudes (e.g., based on a predetermined dimming curve of the LED driver).

[0057] At 750, one or more of the LED drivers (e.g., all LED drivers) can attempt to communicate information about their respective target intensity levels (e.g., in response to receiving and measuring the control signal V CS ) to other LED drivers. The information can indicate the actual target intensity level of the transmitting LED driver in response to receiving and measuring the control signal V CS . Alternatively or additionally, the information can include an indication of where the target intensity level is located along the dimming range of the LED driver (e.g., the information can indicate whether the target intensity level is at the low-end intensity L LE or the high-end intensity L HE without specifying the actual value of the target intensity level). For example, as described herein, communication can be performed via a wired (e.g., via DALI, EcoSystem link, PLC technology, etc.) or wireless (e.g., via RF signal) communication scheme. Communication can be performed on the 0-10V control line during a selected time period, during which the participating LED drivers can temporarily stop reading the analog control signal from the control line (e.g., the receiving LED driver can avoid measuring the control signal V CSThe magnitude). For example, the LED driver can be configured to short the 0 - 10V control line to transmit "0" or "1", the LED driver can be configured to perform another PLC on the control line, and / or the LED drivers can be configured to communicate wirelessly with each other.

[0058] At 760, other LED drivers in the system can receive one of the communications. At 770, each receiver of the communication can check whether its own target intensity level is lower than the transmitted level. At 780, LED drivers with a target intensity level lower than the transmitted level can transmit their corresponding levels to other drivers, and the operations described in conjunction with 760 - 780 can be repeated until the lowest target intensity level is identified. For example, one of the LED drivers may report its target light intensity corresponding to the measured magnitude of the 0 - 10V control signal as the low - end intensity L LE , while other LED drivers may report target light intensities higher than the low - end intensity L LE . In this way, the LED drivers can determine that the intensity level mapped to the measured magnitude of the control signal V CS should be the low - end intensity L LE .

[0059] At 790, the LED driver with the lowest target intensity level can be designated as the leader for future communications (e.g., all other LED drivers can subsequently listen to the communications from the leader and can adapt their corresponding dimming operations based on the actions taken by the leader). In an alternative implementation, one of the LED drivers can be pre - configured (e.g., pre - programmed) as the leader of the LED drivers, and a common intensity level can be prescribed for all LED drivers in response to the measured control signal. In yet another alternative implementation, the action taken at 790 can be omitted and no leader can be designated (e.g., the LED drivers can adapt their corresponding dimming operations based on the lowest intensity level transmitted between the drivers without designating a leader for future operations). At 795, the LED drivers can re - scale their corresponding pre - configured dimming curves (e.g., using the re - scaling techniques described herein) based on the lowest target intensity level reported among the LED drivers, such that the dimming behavior of the LED drivers can be synchronized. Once the synchronization is complete, the drivers can exit the calibration mode.

[0060] In the examples described herein, a designated controller (e.g., a control device such as a 0 - 10V control device, a system controller, etc.) can coordinate the operation of multiple load regulating devices (e.g., LED drivers). Alternatively, one of the multiple load regulating devices can be used as a controller. The load regulating devices can be controlled by a common load control device (e.g., a 0 - 10V control device) and can be capable of communicating with each other (e.g., via a 0 - 10V control line connecting the LED driver and the load control device, using a wireless communication scheme, etc.). The controller can communicate with the load regulating devices using one or more of the communication techniques described herein (e.g., via a 0 - 10V control line) and can send control signals / messages (e.g., an announcement such as entering a calibration mode) to the load regulating devices. In an example implementation of this feature, the controller can announce the start of a special mode for calibration, and each LED driver that receives the announcement can enter the special mode and send a confirmation message to the controller after completing the calibration.

[0061] The calibration procedure can also be performed in cases where communication between a remote control device (e.g., Figure 3 the 0 - 10V control device 320 shown) and the LED drivers (e.g., LED drivers 304A - 304C) is limited or non - existent. The LED drivers can be configured to enter a special mode (e.g., a calibration mode) in response to a signal received from the remote control device. The remote control device can adjust the magnitude of the control signal V CS in steps (e.g., steps) to multiple different magnitudes between a high - end magnitude V HE and a low - end magnitude V LE , and the LED drivers can measure and store the magnitude of the control signal V CS for each step. The remote control device can first control the magnitude of the control signal V CS to the high - end magnitude V HE (e.g., 10 volts), and then decrease the magnitude of the control signal V CS by a step voltage V STEP (e.g., 1 volt) until the magnitude of the control signal V CS reaches the low - end magnitude V LE (e.g., 1 volt). The remote control device can hold the magnitude of the control signal V CS at each step for a step time period T STEP (e.g., 10 seconds) to allow the LED drivers to measure the magnitude of the control signal V CS at each step. The LED drivers can each generate a dimming curve from the stored magnitudes of the control signal V CS at each step for use during normal operation. Then, the LED drivers can operate according to the control signal V CSto control their associated LED light sources according to the stored dimming curves of the amplitudes.

[0062] Figure 8 An example technique 800 is shown for achieving consistent dimming performance among one or more LED drivers (e.g., LED drivers 304A - 304C) controlled by a remote control device (e.g., a 0 - 10V control device 320) using a special mode. Each LED driver can be pre - configured with a dimming curve regarding the control signal generated by the 0 - 10V control device. The pre - configured range of the control signal can be between a low - end amplitude V LE (e.g., 1 volt) and a high - end amplitude V HE (e.g., 10 volts). The low - end amplitude V LE , the high - end amplitude V HE and each of the multiple intermediate amplitudes can correspond to a target intensity level of the LED light source. The amplitudes and / or their associated target intensity levels can be stored in the memory of each LED driver.

[0063] The LED driver can receive a signal (e.g., the signal can include a command and / or an announcement to enter a special mode such as a calibration mode), and enter the special mode at 810. The command or announcement can be sent from the remote control device (e.g., the 0 - 10V control device 320) to the LED driver, which can be configured to communicate with the LED driver and initiate the special mode (e.g., to coordinate the calibration of multiple LED drivers). For example, the remote control device can send a digital message including a command to enter the special mode to the LED driver via one or more wireless signals (e.g., RF signals) and / or via one or more signals conducted on the 0 - 10V control line. Additionally, the remote control device can be configured to cause the LED driver to enter the special mode by power - cycling (e.g., turning off and on) the LED driver a predetermined number of times (e.g., three times within ten seconds) within a certain time period.

[0064] During the special mode, the LED driver can use a variable n to store the measured amplitude of the control signal V CS , while the remote control device steps through multiple amplitudes of the control signal V CS . Since the low - end amplitude V CS and the high - end amplitude V LE of the control signal V HE can be 1 volt and 10 volts, the variable n can be between a minimum number N MIN and a maximum number N MAXwithin the range between (the minimum number and the maximum number can be equal to 1 and 10 respectively). After entering the special mode at 810, the LED driver can initialize the variable n to the maximum number N at 820 MAX (e.g., 10).

[0065] At 830, the LED driver can measure the amplitude of the control signal V CS to generate the measured amplitude sample V[n]. At 840, the LED driver can store the measured amplitude sample V[n] in the memory corresponding to the intensity L[n]. For example, when n is within the range between 1 and 10 and the corresponding intensity range of the LED driver is between 10% and 100%, the intensity L[n] can be derived using the example formula shown below:

[0066] L[n] = n·10%.

[0067] For example, for an LED driver with a low-end intensity L MIN of 10% and a high-end intensity L MAX of 100%, when the variable n is equal to 10, the intensity L[n] can be 100%, when the variable n is equal to 9, the intensity L[n] can be 90%, when the variable n is equal to 8, the intensity L[n] can be 80%, and so on. If at 850 the variable n is not equal to the minimum number N MIN , then before measuring the amplitude of the control signal V CS again at 830, the LED driver can decrement the variable n by 1 at 860 and wait at 870. Before measuring the amplitude of the control signal V CS at 830, the LED driver can wait for the length of the step time period T STEP (e.g., 10 seconds). Additionally, before measuring the amplitude of the control signal V CS at 830, the LED driver can wait at 870 until the remote control device steps down the amplitude of the control signal V CS to the next level. Thus, the LED driver can measure multiple amplitudes of the control signal V CS so as to synchronize the dimming operation of the LED driver at multiple intensity levels (e.g., 100%, 90%, 80%, etc.).

[0068] When at 850 the variable n is equal to the minimum number N MIN , at 880, for the range from the minimum number N MIN to the maximum number N MAXFor a variable n, the LED drivers can each generate a relationship (e.g., a dimming curve) defined by the measured amplitude samples V[n] at each intensity L[n]. At 890, all LED drivers can exit the special mode, and technology 800 can exit.

[0069] In addition to using the calibration and / or communication techniques described herein, the 0-10V control device can also be configured to adjust its control signal using closed-loop control. For example, the 0-10V control device can be configured to increase or decrease the amplitude of the 0-10V control signal based on feedback from one or more load regulation devices (e.g., LED drivers). This feedback can indicate, for example, the amplitude of the output voltage applied across the light source or the amplitude of the load current conducted through the light source. Using this feedback, the 0-10V control device can automatically account for signal degradation on long wires to ensure that a uniform and consistent light output can be produced at multiple light sources.

[0070] Figure 9 is a simplified block diagram of a load regulation device (e.g., LED driver 900) that can be deployed as Figure 1 a load regulation device (e.g., LED driver 104) in the load control system 100 shown, one or more of the LED drivers 204A - 204C in the load control system 200, one or more of the LED drivers 304A - 304C in the load control system 300, etc. The LED driver 900 can be configured to implement one or more of the techniques described herein. For example, the LED driver 900 can be configured to control the amount of power delivered to the LED light source 902 and thus control certain functional aspects of the LED light source (such as the intensity of the LED light source). The LED driver 900 can be powered by an AC or DC power source. When configured to use AC power, the LED driver 900 can include a switched hot terminal SH and a neutral terminal N that are respectively adapted to be coupled to a load control device (e.g., load control device 120) and an alternating current (AC) power source (e.g., AC power source 108). The LED driver 900 can include a control terminal C configured to receive an analog control signal V CS (e.g., a 0-10V signal).

[0071] The LED driver 900 can include a load regulation circuit 910 that can control the amount of power delivered to the LED light source 902. For example, the load regulation circuit 910 can control the intensity of the LED light source 902 at a low-end (i.e., minimum) intensity L OUT by performing pulse-width modulation and / or pulse-frequency modulation on the output voltage V LE (e.g., approximately 1 - 5%) and a high-end (e.g., maximum) intensity LHE (e.g., about 100%). The load regulation circuit 910 can include, for example, a forward converter, a boost converter, a buck converter, a flyback converter, a linear regulator, or any suitable LED driver circuit for adjusting the intensity of the LED light source. Examples of load regulation circuits for LED drivers are described in more detail in commonly assigned U.S. Patent No. 8,492,987, issued July 23, 2010, and U.S. Patent Application Publication No. 2014 / 0009085, filed January 9, 2014 (both titled LOAD CONTROL DEVICE FOR A LIGHT-EMITTING DIODE LIGHT SOURCE), the entire disclosures of which are incorporated herein by reference.

[0072] The LED driver 900 can include a control circuit 920 (e.g., a controller) for controlling the operation of the load regulation circuit 910. The control circuit 920 can include, for example, a digital controller or any other suitable processing device, such as, for example, a microcontroller, a programmable logic device (PLD), a microprocessor, an application specific integrated circuit (ASIC), or a field programmable gate array (FPGA). The control circuit 920 can generate a drive control signal V DRIVE , which is provided to the load regulation circuit 910 for adjusting the amplitude of the output voltage V OUT (e.g., thereby adjusting the load voltage V LOAD generated across the LED light source 902) and / or the amplitude of the load current I LOAD conducted through the LED light source 902 (e.g., thereby controlling the intensity of the LED light source).

[0073] The LED driver 900 can further include a voltage sensing circuit 922 (which can be configured to generate an output voltage feedback signal V OUT that can indicate the amplitude of the output voltage V FB-VOLT ) and a current sensing circuit 924 (which can be configured to generate a load current feedback signal V LOAD that can indicate the amplitude of the load current I FB-CRNT ). The control circuit 920 can receive the voltage feedback signal V FB-VOLT and the load current feedback signal V FB-CRNT , and use a control loop to control the drive control signal V DRIVE to adjust the amplitude of the output voltage V OUT and / or the amplitude of the load current I LOAD (e.g., thus controlling the intensity of the LED light source to a target intensity L TRGT ).

[0074] The control circuit 920 can be coupled to a storage device (e.g., memory 926) configured to store the operating parameters of the LED driver 900 (e.g., the target intensity L of the LED light source TRGT , the low-end intensity L LE , the high-end intensity L HE , etc.). The LED driver 900 can further include a power supply 928 that can generate a direct current (DC) supply voltage V for powering the circuits of the LED driver 900 CC .

[0075] The LED driver 900 can include a communication circuit 930 that can be coupled to, for example, a wired communication link or a wireless communication link, such as a radio frequency (RF) communication link or an infrared (IR) communication link. The LED driver 900 can be configured to receive digital messages via the communication circuit 930 and update the data stored in the memory 926 in response to receiving the digital messages. The LED driver 900 can be configured to communicate with other devices (e.g., other LED drivers) using the communication circuit 930 (e.g., using a wired or wireless communication scheme). Alternatively or additionally, the LED driver 900 can not include the communication circuit 230 and can communicate with other devices (e.g., other LED drivers) via a 0-10V control line (e.g., via a Digital Addressable Lighting Interface (DALI) or using Power Line Communication (PLC) technology). The techniques for providing communication via existing power wiring are described in more detail in the co-assigned U.S. Patent No. 9,392,675, entitled "DIGITAL LOAD CONTROL SYSTEM PROVIDING POWER AND COMMUNICATION VIA EXISTING POWER WIRING," issued on July 12, 2016, and U.S. Patent No. 8,068,814, entitled "SYSTEM FOR CONTROL OF LIGHTS AND MOTORS," issued on November 29, 2011, the entire disclosures of which are incorporated herein by reference.

[0076] The LED driver 900 can further include a load controller (e.g., Load control device), the load controller allows the LED driver 900 to be integrated with a wireless control device (e.g., a wireless occupancy sensor, a wireless daylight sensor, and / or other wireless controls). Thus, the LED driver 900 can be configured to receive wireless control signals from a control device (e.g., a sensor) and be configured to control the LED light source 902 accordingly (e.g., turn on / off the LED light source 902, adjust one or more characteristics such as the color, color temperature, and / or intensity of the LED light source 902, etc.).

[0077] The LED driver 900 can be configured to respond to receiving an analog control signal V Figure 1 from a load control device (e.g., the load control device 120 depicted in CS and control the amount of power delivered to the LED light source 902. The control circuit 920 of the LED driver 900 can be configured to generate a link supply voltage at the control terminal C, for example, via the link voltage communication circuit 932. The link supply voltage can have an amplitude of, for example, approximately 10V and can allow the current sink circuit of the load control device to generate a control signal V CS on the control wiring 908. The control circuit 920 of the LED driver 900 can be configured to sense the control signal V CS and adjust the operating characteristics of the LED light source 902 based on the control signal and the relationship between the control signal V CS and the operating characteristics of the LED light source. For example, the control circuit 920 can be configured to adjust the target intensity of the LED light source 902 between a low-end (minimum) intensity L CS and a high-end (maximum) intensity L CS based on the control signal V LE and a dimming curve (e.g., a predetermined dimming curve) representing the relationship between the target light intensity and the control signal V HE .

[0078] Although the examples provided herein are described with reference to one or more light sources, the examples can be applied to other electrical loads. For example, one or more of the embodiments described herein can be used to control various types of electrical loads, such as, for example, motorized curtains or projection screens, motorized interior or exterior blinds, heating, ventilation, and air conditioning (HVAC) systems, air conditioners, compressors, humidity control units, dehumidifiers, water heaters, pool pumps, refrigerators, freezers, televisions or computer monitors, power supplies, audio systems or amplifiers, generators, chargers (such as electric vehicle chargers), and alternative energy controllers (e.g., solar, wind, or thermal energy controllers). A single control circuit can be coupled to and / or adapted to control multiple types of electrical loads in a load control system.

Claims

1. An illumination control system for controlling a first light source and a second light source, the illumination control system comprises: a first load regulating device configured to receive an analog control signal and control the intensity of the first light source based on the amplitude of the analog control signal and a first pre-configured dimming curve; a second load regulating device configured to receive the analog control signal and control the intensity of the second light source based on the amplitude of the analog control signal and a second pre-configured dimming curve; wherein the first load regulating device is configured to: measure a first amplitude of the analog control signal received at the first load regulating device; send an indication signal to the second load regulating device in response to the measured first amplitude of the analog control signal; and wherein the second load regulating device is configured to: receive the indication signal from the first load regulating device; measure a second amplitude of the analog control signal received at the second load regulating device; and adjust the second pre-configured dimming curve based on the measured second amplitude of the analog control signal in response to receiving the indication signal.

2. The illumination control system according to claim 1, wherein the first load regulating device is configured to receive the analog control signal via an analog control link and send the indication signal via the analog control link.

3. The illumination control system according to claim 2, wherein the second load regulating device is configured to avoid measuring the amplitude of the analog control signal when the first load regulating device is sending the indication signal.

4. The illumination control system according to claim 1, wherein the first load regulating device is configured to send the indication signal via a radio frequency communication link.

5. The illumination control system according to claim 1, wherein the first load regulating device is configured to send the indication signal to the second load regulating device if the measured first amplitude of the analog control signal is less than a low-end amplitude of the first pre-configured dimming curve.

6. The illumination control system according to claim 1, wherein the first load regulating device is configured to determine a controlled intensity of the first light source based on the first pre-configured dimming curve and the measured first amplitude of the analog control signal, and wherein the indication signal sent by the first load regulating device includes the controlled intensity.

7. The illumination control system according to claim 1, wherein the indication signal sent by the first load regulating device includes the measured first amplitude of the analog control signal.

8. The illumination control system according to claim 1, wherein the first load regulating device is further configured to adjust the first pre-configured dimming curve based on the measured first amplitude of the analog control signal.

9. An illumination control system for controlling a first light source and a second light source, the illumination control system comprises: A first load regulating device configured to receive an analog control signal and control the intensity of the first light source based on the amplitude of the analog control signal and a first pre-configured dimming curve; A second load regulating device configured to receive the analog control signal and control the intensity of the second light source based on the amplitude of the analog control signal and a second pre-configured dimming curve; wherein the first load regulating device is configured to: Measure a first amplitude of the analog control signal received by the first load regulating device; Determine a first target intensity of the first light source based on the measured first amplitude of the analog control signal and the first pre-configured dimming curve; and Transmit the first target intensity to the second load regulating device; and wherein the second load regulating device is configured to: Measure a second amplitude of the analog control signal received by the second load regulating device; Determine a second target intensity of the second light source based on the measured second amplitude of the analog control signal and the second pre-configured dimming curve; Receive the first target intensity from the first load regulating device; and Adjust the second target intensity based on the first target intensity.

10. An illumination control system for controlling a first light source and a second light source, the illumination control system comprising: A first load regulating device configured to receive an analog control signal and control the intensity of the first light source based on the amplitude of the analog control signal and a first pre-configured dimming curve; A second load regulating device configured to receive the analog control signal and control the intensity of the second light source based on the amplitude of the analog control signal and a second pre-configured dimming curve; and A controller configured to communicate with both the first load regulating device and the second load regulating device and send signals to the first load regulating device and the second load regulating device to place the first load regulating device and the second load regulating device in a calibration mode, wherein during the calibration mode: The first load regulating device is configured to: Measure a first amplitude of the analog control signal; Determine a target intensity of the first light source based on the measured first amplitude of the analog control signal and the first pre-configured dimming curve; and In response to determining the target intensity of the first light source, send a signal to the second load regulating device; and The second load regulating device is configured to: Receive the signal from the first load regulating device; Measure a second amplitude of the analog control signal; and In response to receiving the signal from the first load regulating device, adjust the second pre-configured dimming curve based on the measured second amplitude of the analog control signal.

11. A method of configuring one or more load regulating devices for controlling one or more light sources, the method comprising: Receiving an analog control signal at a first load regulating device; Controlling the intensity of a first light source through the first load regulating device based on the amplitude of the analog control signal and a first pre-configured dimming curve; Receive the analog control signal at the second load regulating device; Control the intensity of the second light source by the second load regulating device based on the amplitude of the analog control signal and a second pre-configured dimming curve; Measure a first amplitude of the analog control signal received at the first load regulating device; In response to the measured first amplitude of the analog control signal, send an indication signal from the first load regulating device to the second load regulating device; And Receive the indication signal at the second load regulating device from the first load regulating device; Measure a second amplitude of the analog control signal received at the second load regulating device; And In response to receiving the indication signal, adjust the second pre-configured dimming curve by the second load regulating device based on the measured second amplitude of the analog control signal.

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