INDEPENDENT LIGHTING CONTROL

Abstract

Lighting control system (100), comprising: an input configured to be driven with a first polarity and a second polarity reversed from the first polarity, a first light source (108) connected to the input and configured to generate light when driven with the first polarity, a second light source (110) connected to the input and configured to generate light when driven with the second polarity, a control bridge (106) connected to the input and designed to control the polarity of the input, a detection circuit configured to detect a property of the input; and a controller (102) connected to the control bridge (106) and the detection circuit, the controller (102) being configured to: to control the control bridge (106) based on a control drive command (116), to receive a signal indicating the property of the input via the detection circuit, connecting the first light source (108) to the input if the property of the input is less than a threshold value, connecting the second light source (110) to the input if the property of the input is greater than or equal to the threshold value, and To provide lighting control signals to the input to independently control the first light source (108) and the second light source (110).

Description

AREA

[0001] The embodiments described herein relate to a lighting control system having a driver for independently controlling multiple light sources. BACKGROUND OF THE INVENTION

[0002] DE 20 2012 101 221 U discloses an LED controller with a two-core cable. EP 2 761 978 B1 discloses an LED lighting unit with color and dimming control. US 10,136,485 B1 discloses methods for adjusting the light output of lighting systems. US 2013 / 0009560 A1 discloses a lighting control device and an LED lighting system. SUMMARY

[0003] The embodiments described herein provide control of multiple light sources using a single driver output. For example, two or more light sources may share a single input node. A control bridge circuit reverses the polarity of power supplied to the input node. Additionally, a driver circuit generates independent control signals for each light source, which are supplied to the control bridge. This provides independent control of each light source using a single closed electrical connection (e.g., a single pair of wires). In some implementations, a controller further controls whether a light source receives power based on a current value or a voltage value supplied to the input node. The light sources, the control bridge, the driver circuit, and the controller may be located in a common light fixture housing.

[0004] While the invention is disclosed in the independent claims, further embodiments of the invention are disclosed in the subordinate claims, the drawings, and the following description. One embodiment provides a lighting control system comprising an input driveable in a first polarity and a second polarity reversed from the first polarity, a first light source connected to the input and configured to produce light when driven in the first polarity, and a second light source connected to the input and configured to produce light when driven in the second polarity. The lighting control system includes a control bridge connected to the input and configured to control the polarity of the input, and a controller connected to the control bridge.The controller is configured to control the control bridge based on a control drive command and to provide lighting control signals to the input to independently control the first light source and the second light source.

[0005] Another embodiment provides a lighting control system comprising a first light source, a second light source, a driver circuit configured to drive the first light source and the second light source independently, and a detection circuit. The detection circuit is configured to detect a characteristic of the driver circuit, connect the first light source to the driver circuit when the characteristic of the driver circuit is less than a threshold, and connect the second light source to the driver circuit when the characteristic of the driver circuit is greater than or equal to the threshold.

[0006] Another embodiment provides a lighting control system comprising an input driveable in a first polarity and a second polarity reversed from the first polarity, a first light source connected to the input and configured to generate light when driven in the first polarity, and a second light source connected in series with the first light source and configured to generate light when driven in the second polarity. The lighting control system includes a control bridge connected to the input and configured to drive the first light source and the second light source independently, and a sensing circuit configured to sense a characteristic of the input. The lighting control system includes a controller connected to the control bridge, the sensing circuit, and the input.The controller is configured to control a polarity of the input via the control bridge, to receive a signal indicating the characteristic of the control bridge via the control bridge, to connect the first light source to the input when the characteristic of the input is less than a threshold value, and to connect the second light source to the input when the characteristic of the input is greater than or equal to the threshold value.

[0007] Before any implementations of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and arrangement of the components shown in the following description or in the following drawings. The disclosure may have other implementations and may be practiced or practiced otherwise.

[0008] It should also be understood that the phraseology and terminology used herein is for the purpose of description and should not be considered limiting. The use of "having," "comprising," or "with," and variations thereof, herein is intended to include the elements listed thereafter and equivalents thereof, as well as additional elements. The terms "mounted," "connected," and "coupled" are used generally and include both direct and indirect mountings, connections, and couplings. Further, "connected" and "coupled" are not limited to physical or mechanical connections or couplings and can include electrical connections or couplings, whether direct or indirect. Electronic communications and messages can also be conducted using other known means, including direct connections, wireless connections, etc.

[0009] It should be noted that a variety of hardware and software-based devices, as well as a variety of structural components, may be used to implement the disclosure. Furthermore, and as described in the following sections, the specific configurations depicted in the drawings are intended to illustrate implementations of the disclosure. Alternative configurations are possible.

[0010] Other aspects of the embodiments will become apparent upon consideration of the detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram of a lighting control system according to some embodiments. Fig. 2 is a block diagram of another lighting control system according to some embodiments. Fig. 3 is a circuit diagram of the lighting control system of Fig. 1 according to some embodiments. Fig. 4 is a flowchart of a method used by the lighting control system of Fig. 1 is performed, according to some embodiments. Fig. 5 is a block diagram of a light array with a property detection circuit according to some embodiments. Fig. 6 is a flowchart of a process performed by the property detection circuit of Fig. 5 is performed, according to some embodiments. The Fig. 7A-7B are block diagrams of a lighting control system according to some embodiments. Fig. Figure 8 is a diagram of current commands for the lighting control system of the Fig. 7A-7B according to some embodiments. Fig. Figure 9 is a diagram of pulse width modulated (PWM) control signals for the lighting control system of the Fig. 7A-7B according to some embodiments. Fig. 10 is a flowchart of a method used by the lighting control system of Fig. 7A-7B, according to some embodiments. Fig. 11 is a circuit diagram of a light array according to some embodiments. Fig. 12 is a diagram showing a current flow through a delay current circuit in the light array of Fig. 11 according to some embodiments. Fig. 13 is a diagram illustrating current flow through a first lighting circuit in the light array of Fig. 11 according to some embodiments. Fig. 14 is a diagram illustrating current flow through a second lighting circuit in the light array of Fig. 11 according to some embodiments. Fig. 15 is a diagram of the Fig. 12-14 superimposed on a single chart. Fig. 16 is an illustration of a lamp housing according to some embodiments. Fig. 17 is an illustration of a luminaire housing connected to a driver, according to some embodiments. Fig. 18 is an illustration of a plurality of light housings connected to a driver, according to some embodiments. Fig. 19 is an illustration of a plurality of light housings connected to a multi-channel driver, according to some embodiments. DETAILED DESCRIPTION

[0011] Before any aspects of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and arrangement of the components shown in the following description or in the following drawings. The disclosure may support other aspects and may be practiced or embodied otherwise. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be considered limiting.

[0012] Fig. 1 provides a lighting control system 100 according to one example. The lighting control system 100 may include a controller 102, a driver circuit 104, a control bridge 106, a first light source 108, and a second light source 110. In some cases, the controller 102, the driver circuit 104, the control bridge 106, the first light source 108, and the second light source 110 are located within a luminaire housing 101. In other cases, components of the lighting control system 100 may be located external to the luminaire housing 101. The controller 102 may receive, among other things, a first control plane 112, a second control plane 114, and a control drive command 116. In some embodiments, the first control plane 112, the second control plane 114, and / or the control drive command 116 are received from a user interface included in or otherwise coupled to the lighting control system 100.The first control plane 112, the second control plane 114, and / or the control drive command 116 are received from an external device via a data connection (e.g., a wired connection via Ethernet, a wireless connection, or the like). The external device may be, for example, a wall station, a lighting control console, an architectural control system, or the like. The controller 102 generates commands to control the driver circuit 104 and the control bridge 106 based on the first control plane 112, the second control plane 114, and the control drive command 116, as described in more detail below.

[0013] In some embodiments, the controller 102 includes, among other things, an electronic processor 130, a memory 132, and an input / output interface 134. The electronic processor 130, the memory 132, the input / output interface 134, and the various modules connected to the controller 102 are connected by one or more control and / or data buses (e.g., a common bus). The input / output interface 134 includes routines for transferring information between components in the controller 102 and other components of the lighting control system 100. In some implementations, the controller 102 is partially or entirely implemented on a semiconductor (e.g., a field-programmable gate array ("FPGA")) chip.

[0014] The memory 132 includes, for example, read-only memory (ROM), random access memory (RAM) (e.g., dynamic random access memory [DRAM], synchronous DRAM [SDRAM], etc.), electronically erasable programmable read-only memory (EEPROM), flash memory, a hard drive, an SD card, other non-transitory, computer-readable media, or a combination thereof. The electronic processor 130 is coupled to the memory 132 and executes software instructions that may be stored in a RAM of the memory 132 (e.g., during execution), a ROM of the memory 132 (e.g., on a generally persistent basis), or another non-transitory computer-readable medium such as another memory or disk. Alternatively or additionally, the memory 132 is included in the electronic processor 130. Software included in some implementations of the lighting control system 100 may be stored in the memory of the controller 102.For example, the software includes firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. In other constructions, the controller 102 includes additional, fewer, or different components. For example, the controller 102 may consist entirely of hardware components, such as switches and logic gates.

[0015] The driver circuit 104 may, for example, be a constant current (CC) driver, a constant voltage (CV) driver, an analog voltage driver, an analog current driver, or a combination thereof. The driver circuit 104 is configured to control the first light source 108 and / or the second light source 110 based on commands from the controller 102. For example, the driver circuit 104 may vary the current supplied to the first light source 108 and the second light source 110 by varying the amplitude of the current or the duty cycle of a pulse-width modulated (PWM) voltage. In some embodiments, the controller 102 performs the operation of the driver circuit 104, or the driver circuit 104 is implemented within the controller 102.

[0016] The control bridge 106 may be a circuit that alternatively controls the voltage and current (e.g., alternating current) to the first light source 108 and the second light source 110. For example, in the example of Fig. 1, the first light source 108 includes a first light-emitting diode (LED) D1 and a second LED D2 with a first polarity such that current flows through the first light source 108 only when the current is positive. The second light source 110 includes a third LED D3 and a fourth LED D4 with a second polarity such that current flows through the second light source 110 only when the current is negative. The first light source 108 and the second light source 110 are connected at an input node 120. The control bridge 106 controls the polarity of the current supplied to the input node 120 to drive each light source independently.

[0017] In the example of Fig. 1, the first light source 108 and the second light source 110 are connected in parallel (or more precisely, anti-parallel due to the opposite polarities). However, in other examples, the first light source 108 and the second light source 110 may instead be connected in series (or more precisely, in series with each other due to the opposite polarities). For example, Fig. 2 illustrates the lighting control system 100 with a first light source 108' and a second light source 110'. The first light source 108' includes a first LED D1, a second LED D2, and a first diode D5. The second light source 110' includes a third LED D3, a fourth LED D4, and a sixth diode D6. The fifth diode D5 and the sixth diode D6 provide a path for the current regardless of the polarity of the current. Specifically, when the current supplied to the input node 120 has a positive polarity, the current flows through the first LED D1, the second LED D2, and the sixth diode D6, thus bypassing the third LED D3 and the fourth LED D4. When the current supplied to the input node 120 has a negative polarity, the current flows through the third LED D3, the fourth LED D4, and the fifth diode D5, thus bypassing the first LED D1 and the second LED D2.

[0018] While the first light source 108 and the second light source 110 are illustrated as having two LEDs, in some implementations, the first light source 108 and the second light source 110 may have more or fewer LEDs. Additionally, the lighting control system 100 may include more than two light sources. The light sources included in the lighting control system 100 may be collectively referred to below as a light array or an LED array.

[0019] Fig. 3 illustrates an exemplary circuit diagram for implementing the lighting control system 100. In the example of Fig. 3, the driver circuit 104 is designed as a constant current LED driver. The controller 102 includes a variety of logic hardware, such as a first AND gate 300, a second AND gate 302, and a NAND gate 304. Additionally, in the example of Fig. 3, the first control plane 112 is a 20 kHz PWM signal, the second control plane 114 is a 20 kHz PWM signal, and the control drive command 116 is a 1 kHz PWM signal. The first AND gate 300 receives the first control plane 112 and the control drive command 116 as inputs. The second AND gate 302 receives the second control plane 114 and the output of the NAND gate 304 as inputs. The NAND gate 304 receives the control drive command 116 as both inputs, which ensures that the output of the NAND gate 304 is always opposite the value of the control drive command 116. The outputs of the first AND gate 300 and the second AND gate 302 are provided to the driver circuit 104.

[0020] The controller 102 may also include a first high-side and low-side driver (HL driver) 306 and a second HL driver 308 for driving the control bridge 106. The control bridge 106 may include a first high-side field-effect transistor (FET) 320, a first low-side FET 322, a second high-side FET 324, and a second low-side FET 326. The first HL driver 306 generates a G1 H signal, which is provided to the gate of the first high-side FET 320 for controlling the first high-side FET 320. The first HL driver 306 also generates a G1 L signal, which is provided to the gate of the first low-side FET 322 for controlling the first low-side FET 322. The second HL driver 308 generates a G2H signal, which is provided to the gate of the second high-side FET 324 for controlling the second high-side FET 324. The second HL driver 308 also generates a G2L signal, which is provided to the gate of the second low-side FET 326 for controlling the second low-side FET 326.In some embodiments, instead of FETs, the control bridge 106 is made of another type of suitable switching device, such as a bipolar transistor, a metal-oxide-semiconductor FET (MOSFET), a junction FET (JFET), or the like.

[0021] Controller 102 controls the FETs included in control bridge 106 to control whether first light source 108 or second light source 110 receives power. Additionally, driver circuit 104 generates commands for either first light source 108 or second light source 110 based on signals from controller 102. The commands generated by driver circuit 104 are provided to input node 120. Accordingly, by simultaneously controlling driver circuit 104 and control bridge 106, controller 102 manages independent control of first light source 108 and second light source 110.

[0022] Fig. 4 provides a method 400 for operating the lighting control system 100 according to some embodiments. The method 400 may be performed by the controller 102, the driver circuit 104, the control bridge 106, or a combination thereof. The steps of the method 400 are described in an iterative manner for descriptive purposes. Various steps described herein with respect to the method 400 may be performed concurrently, in parallel, or in an order different from the illustrated serial and iterative manner of execution.

[0023] In block 402, the controller 102 receives lighting control levels. For example, if two light sources are present, the controller 102 receives the first control level 112 and the second control level 114. In block 404, the controller 102 receives the controller drive command 116.

[0024] In block 406, the controller 102 controls the control bridge 106 using the control drive command 116. For example, the controller 102 controls the control bridge 106 to reverse the polarity at the input node 120 according to the control drive command 116. In block 408, the controller 102 provides lighting control to the input node 120. For example, the controller 102 provides the first control plane 112 and the second control plane 114 to the driver circuit 104. The driver circuit 104 generates commands to control the first light source 108 and / or the second light source 110, which are provided to the input node 120.

[0025] In some cases, the lighting control system 100 includes a drive splitter circuit for connecting or disconnecting the first light source 108 and the second light source 110 to or from the input node 120. Fig. 5 illustrates an exemplary drive divider circuit 500. As illustrated, the drive divider circuit 500 may include a current sensing circuit 502, a first comparator 505, a second comparator 510, a first switch Q1, and a second switch Q2. A current flowing from the driver circuit 104 through the light array flows through a current sensing resistor R1. The current sensing circuit 502 detects a voltage value of the current sensing resistor R1, which is indicative of a value of the current flowing through the light array. The voltage value is provided to the first comparator 505 and the second comparator 510. The first comparator 505 compares the voltage value to a first threshold value (for example, a voltage value indicative of a current of 750 mA). When the voltage value is less than the first threshold, the first comparator 505 controls the first switch Q1 to an ON state, allowing current to flow through the first light source 108.If the voltage value is greater than the first threshold, the first comparator 505 controls the first switch Q1 to an OFF state, which stops the current flow through the first light source 108.

[0026] Additionally, the second comparator 510 compares the voltage value with the first threshold. If the voltage value is greater than the first threshold, the second comparator 510 controls the second switch Q2 to an ON state, allowing current to flow through the second light source 110. If the voltage value is less than the first threshold, the second comparator 510 controls the second switch Q2 to an OFF state, stopping the current flow through the second light source 110.

[0027] Accordingly, in the example of Fig. 5, the drive divider circuit 500 connects either the first light source 108 or the second light source 110 to the input node 120 based on a characteristic of the driver circuit 104 (e.g., a current supplied by the driver circuit 104, a voltage supplied by the driver circuit 104, etc.). In other embodiments, the first comparator 505 and the second comparator 510 may compare the output of the current measurement circuit 502 with different thresholds. Additionally, if more than two light sources are provided, multiple comparators with unique thresholds may be provided to independently connect each light source to the input node 120. In some cases, the thresholds of the first comparator 505 and the second comparator 510 may overlap, so that current is supplied to both the first light source 108 and the second light source 110.For example, the first comparator 505 may control the first switch Q1 to an ON position when the current is less than about 800 mA, while the second comparator 510 may control the second switch Q2 to an ON position when the current is greater than about 600 mA. Accordingly, both the first switch Q1 and the second switch Q2 are turned ON when the current across the current sense resistor R1 is about 700 mA and both the first light source 108 and the second light source 110 are receiving current.

[0028] Fig. Figure 8 illustrates a method 600 performed by drive divider circuit 500, according to some embodiments. The steps of method 400 are described in an iterative manner for descriptive purposes. Various steps described herein with respect to method 600 may be performed concurrently, in parallel, or in an order different from the illustrated serial and iterative manner of execution.

[0029] In block 602, the drive divider circuit 500 senses a characteristic of the driver circuit 104. For example, the current sense circuit 502 senses a current supplied by the driver circuit 104. In some embodiments, the current sense circuit 502 senses the current at the input node 120. In block 604, the drive divider circuit 500 compares the characteristic of the driver circuit to a threshold. If the characteristic of the driver circuit is less than the threshold, the drive divider circuit 500 proceeds to block 606. If the characteristic of the driver circuit is greater than the threshold, the drive divider circuit 500 proceeds to block 608.

[0030] In block 606, if the characteristic of driver circuit 104 is less than the threshold, drive divider circuit 500 connects first light source 108 to driver circuit 104. For example, first comparator 505 controls first switch Q1 to an ON state to connect first light source 108 to input node 120. Second comparator 510 controls second switch Q2 to an OFF state to disconnect second light source 110 from input node 120. In block 608, if the characteristic of driver circuit 104 is greater than the threshold, drive divider circuit 500 connects second light source 110 to driver circuit 104. For example, first comparator 505 controls first switch Q1 to an OFF state to disconnect first light source 108 from input node 120.The second comparator 510 controls the second switch Q2 to an ON state to connect the second light source 110 to the input node 120. In some embodiments, once the driver circuit 104 is connected to the first light source (block 606) or the second light source (block 608), the method 600 may return to block 602.

[0031] The Fig. 7A-7B illustrate an exemplary lighting control system 200 implementing drive splitter circuits. The lighting control system 200 includes the driver circuit 104, the control bridge 106, a first drive splitter circuit 700, a second drive splitter circuit 712, a first light source 708, a second light source 710, a third light source 720, and a fourth light source 722. The first drive splitter circuit 700, the first light source 708, and the second light source 710 may hereinafter be collectively referred to as a first light array. The second drive splitter circuit 712, the third light source 720, and the fourth light source 722 may hereinafter be collectively referred to as a second light array. The first light array and the second light array are connected between a positive input drive+ and a negative input drive-.A first input node 120A is connected to the positive input drive+ and a second input node 120B is connected to the negative input drive. The first input node 120A serves as the input node for the lighting control system 200 when the lighting control system 200 is driven with a first polarity (e.g., a positive polarity). The second input node 120B serves as the input node for the lighting control system 200 when the lighting control system 200 is driven with a second polarity (e.g., a negative polarity). Although not shown, the driver circuit 104 and the control bridge 106 are controlled by the controller 102. The driver circuit 104 and the control bridge 106 shown in FIG. Fig. 7A are substantially similar to the control bridge 106 described above with reference to Fig. 3 is described.

[0032] The first drive divider circuit 700 may include a first current measuring circuit 702, a first comparator 704, a second comparator 706, a first switch Q1, and a second switch Q2. The first drive divider circuit 700 may operate substantially similarly to the drive divider circuit 500 described above with reference to Fig. 5. A current flowing through either the first light source 708 or the second light source 710 flows through a first current sensing resistor R1. The first current sensing circuit 702 detects a voltage value of the first current sensing resistor R1, which is indicative of a value of the current flowing through the first light source 708 or the second light source 710.

[0033] The first light source 708 may include a first LED D1, a second LED D2, a third LED D3, and a fourth LED D4 connected in series and configured to allow the flow of current having a first polarity (e.g., a positive polarity). The second light source 710 may include a fifth LED D5, a sixth LED D6, a seventh LED D7, and an eighth LED D8 connected in series and also configured to allow the flow of current having the first polarity. Accordingly, controlling the first switch Q1 and the second switch Q2 determines whether current flows through the first light source 708 or the second light source 710. In some cases, the first switch Q1 and the second switch Q2 may be controlled based on the values ​​of the first comparator 704 and the second comparator 706 to allow current to flow through both the first light source 708 and the second light source 710 in parallel.A first blocking diode D9 is provided in parallel with the first light source 708 and the second light source 710. The current bypasses the first light source 708 and the second light source 710 through the first blocking diode D9 when the current has a second polarity opposite to the first polarity (e.g., flows from the negative input drive+ to the positive input drive+).

[0034] In the illustrated embodiment, the second light array is connected in series with the first light array. The second drive divider circuit 712 may include a current measuring circuit 714, a third comparator 716, a fourth comparator 718, a third switch Q3, and a fourth switch Q4. The second drive divider circuit 712 may operate substantially similarly to the drive divider circuit 500 described above with reference to Fig. 5. A current flowing through either the third light source 720 or the fourth light source 722 flows through a second current sensing resistor R1. The second current sensing circuit 714 detects a voltage value of the second current sensing resistor R2, which is indicative of a value of the current flowing through the third light source 720 or the fourth light source 722.

[0035] The third light source 720 may include a tenth LED D10, an eleventh LED D11, a twelfth LED D12, and a thirteenth LED D13 connected in series and configured to allow the flow of current having a second polarity (e.g., a positive polarity). The second light source 710 may include a fourteenth LED D14, a fifteenth LED D15, a sixteenth LED D16, and a seventeenth LED D17 connected in series and also configured to allow the flow of current having the second polarity. Control of the third switch Q3 and the fourth switch Q4 determines whether current flows through the third light source 720 or the fourth light source 722.In some cases, the third switch Q3 and the fourth switch Q4 may be controlled based on the values ​​of the third comparator 716 and the fourth comparator 718 to allow current to flow in parallel through both the third light source 720 and the fourth light source 722. A second blocking diode D18 is provided in parallel with the third light source 720 and the fourth light source 722. The current bypasses the third light source 720 and the fourth light source 722 when the current is in a first polarity opposite to the second polarity (e.g., flows from the positive input drive + to the negative input drive -).

[0036] The driver circuit 104 provides drive signals for each light source via the input node 120. Fig. Figure 8 provides a diagram 800 illustrating signals provided to the first light source 708, the second light source 710, the third light source 720, and the fourth light source 722. Additionally, Fig. 9 provides a diagram 900 showing controls of the control bridge 106 and the detection circuits 702, 714 over the same period of Fig. 8. In particular, diagram 900 represents a basic PWM signal used by the lighting control system 200, a current selection PWM signal used by the sensing circuit 702, 714, and the control bridge command used to control the control bridge 106.

[0037] From the time period T0 to T1, the driver circuit 104 provides a drive signal with a first magnitude C1. Additionally, from the time period T0 to T1, the controller 102 controls the control bridge 106 so that the polarity of the current is positive (e.g., a positive magnitude). Since the polarity of the current is positive, current flows through the first light array and bypasses the second light array. In the example of Fig. 8-9, the first quantity C1 is smaller than the threshold value of the first comparator 704 and the second comparator 706. Accordingly, the first switch Q1 is controlled to an ON position and the second switch Q2 is controlled to an OFF position. From time T0 to T1, current flows only through the first light source 708.

[0038] From the time period T1 to T2, the driver circuit 104 provides a drive signal with a second magnitude C2. Additionally, from the time period T1 to T2, the controller 102 controls the control bridge 106 such that the polarity of the current is positive. In the example of Fig. 8-9, the second quantity C2 is greater than the threshold value of the first comparator 704 and the second comparator 706. Accordingly, the first switch Q1 is controlled to an OFF position and the second switch Q2 is controlled to an ON position. From T1 to T2, current flows only through the second light source 710.

[0039] From time period T2 to T3, driver circuit 104 provides a drive signal with a third magnitude -C1. Additionally, from time period T2 to T3, controller 102 controls control bridge 106 such that the polarity of the current is negative (e.g., a negative magnitude). Since the polarity of the current is negative, current flows through the second light array and bypasses the first light array. In the example of Fig. 8-9, the first value -C1 is smaller than the threshold value of the third comparator 716 and the fourth comparator 718. Accordingly, the third switch Q3 is controlled to an ON position and the fourth switch Q4 is controlled to an OFF position. From T2 to T3, current flows only through the third light source 720.

[0040] From the time period T3 to T4, the driver circuit 104 provides a drive signal with a fourth magnitude -C2. Additionally, from the time period T3 to T4, the controller 102 controls the control bridge 106 such that the polarity of the current is negative. In the example of Fig. 8-9, the second quantity -C2 is greater than the threshold value of the third comparator 716 and the fourth comparator 718. Accordingly, the third switch Q3 is controlled to an OFF position and the fourth switch Q4 is controlled to an ON position. From T3 to T4, current flows only through the fourth light source 722.

[0041] Fig. 10 provides an example method 1000 for operating the lighting control system 200 according to some embodiments. The steps of the method 1000 are described in an iterative manner for descriptive purposes. Various steps described herein with respect to the method 1000 may be performed concurrently, in parallel, or in an order different from the illustrated serial and iterative manner of execution.

[0042] In block 1002, the controller 102 receives lighting control levels for each of the light sources. For example, the controller 102 receives a first control level for the first light source 708, a second control level for the second light source 710, a third control level for the third light source 720, and a fourth light source 722. In some cases, the controller 102 provides the lighting control levels to the driver circuit 104.

[0043] In block 1004, the controller 102 receives the control drive command to drive the control bridge 106. In block 1006, the controller 102 controls the control bridge 106 using the control drive command.

[0044] In block 1008, the driver circuit 104 provides a lighting control signal to the input node 120. For example, the driver circuit 104 provides the current signals illustrated in diagram 800 to the input node 120. In block 1010, the drive divider circuit senses a current of the input node 120. For example, the first current measuring circuit 702 measures the current of the input node 120, the second current measuring circuit 714 measures the current of the input node 120, or both the first current measuring circuit 702 and the second current measuring circuit 714 measure the current of the input node 120.

[0045] In block 1012, the drive divider circuit compares the current of input node 120 to a threshold. For example, the first comparator 704, the second comparator 706, the third comparator 716, and the fourth comparator 718 each compare the current of input node 120 to their respective thresholds. If the current of input node 120 is less than the threshold, the drive divider circuit proceeds to block 1014. If the current of input node 120 is greater than the threshold, the drive divider circuit proceeds to block 1016.

[0046] In block 1014, the drive splitter circuit connects the first light source to the driver circuit 104. For example, the first comparator 704 controls the first switch Q1 to an ON position to connect the first light source 708 to the input node 120. In some cases, the third comparator 716 controls the third switch Q3 to an ON position to connect the third light source 720 to the input node 120. In block 1016, the drive splitter circuit connects the second light source to the driver circuit 104. For example, the second comparator 706 controls the second switch Q2 to an ON position to connect the second light source 710 to the input node 120. In some cases, the fourth comparator 718 controls the fourth switch Q4 to an ON position to connect the fourth light source 722 to the input node 120.In some embodiments, once the driver circuit 104 is connected to the first light source (block 1014) or the second light source (block 1016), the method 1000 may return to block 1002.

[0047] In some embodiments, the lighting control system further includes a delay circuit to delay the flow of current in the light array. Fig. 11 illustrates a circuit diagram for an exemplary lighting control system 1100. The lighting control system 1100 includes a delay circuit 1105, a first lighting circuit 1110, and a second lighting circuit 1115. The delay circuit 1105 includes a delay transistor Q7 connected in series with a resistor R5. When the driver circuit 104 begins providing drive signals, the driver circuit 1105 provides an initial path for current until the current level reaches a desired value. For example, when the driver circuit 104 begins providing drive signals, current flows through the delay circuit 1105 for a predetermined period of time (e.g., a delay period). Fig. Figure 12 illustrates an example diagram of the current flow through the delay circuit 1105 at the start of each drive cycle.

[0048] The first lighting circuit 1110 includes a first switch Q1 for controlling whether the first lighting circuit 1110 receives power. For example, at the end of the delay period, when the current flow through the delay circuit 1105 is below the current threshold (e.g., 750 mA), the first switch Q1 is controlled to supply power to the first lighting circuit 1110. Fig. 13 illustrates an example diagram of the current flow through the first lighting circuit 1110 at the end of the delay period.

[0049] The second lighting circuit 1115 includes a second switch Q2 for controlling whether the second lighting circuit 1115 receives power. For example, at the end of the delay period, if the current flow through the delay circuit 1115 is above the current threshold, the second switch Q3 is controlled to supply power to the second lighting circuit 1115. Fig. 14 illustrates an example diagram of the current flow through the second lighting circuit 1115 at the end of the delay period. Fig. 15 represents Fig. 12, Fig. 13 and Fig. 14 superimposed in a single diagram. As in Fig. 15, at the end of each delay period, either the first lighting circuit 1110 or the second lighting circuit 1115 is controlled based on the magnitude of the current.

[0050] While the embodiments described herein primarily relate to sensing the current of input node 120 (e.g., the current supplied by driver circuit 104), in some cases, other characteristics of input node 120 are monitored to determine whether to connect light sources to driver circuit 104. For example, a voltage value supplied by driver circuit 104 to input node 120 may be detected by a characteristic detection circuit. The voltage value is then compared to a threshold value. The light sources are connected to input node 120 based on the voltage value. As another example, a duty cycle of the current supplied by driver circuit 104 to input node 120 may be varied. The voltage value is then compared to a threshold value. The light sources are connected to input node 120 based on the duty cycle.

[0051] The light sources described herein can be controlled to provide various shades of white light (e.g., tunable light), color mixing, color fading, and similar lighting operations. Each connected light source can have any desired light color, such as a combination of red light, green light, blue light, and white light of various shades and warmth. While each light source is controlled independently and at a different time, the light sources can be controlled at a frequency high enough that, to a viewer of the luminaire, each light source remains on. Lights

[0052] The lighting control systems described herein can be implemented in several different types of luminaires. For example, Fig. 16 illustrates a luminaire 1600 according to an implementation. In Fig. 16, all components (or substantially all components) of the lighting control system 100 are located within the housing 1604 of the luminaire 1600. However, in some cases, certain components of the lighting control system 100 may instead be located outside the housing 1604. For example, Fig. 17 illustrates a lighting system 1700 having a driver 1704 located outside a lamp housing 1701. In some cases, only the light sources (such as the first light source 108 and the second light source 110) are located inside the lamp housing 1701, while the control elements (such as the controller 102, the driver circuit 104, and the control bridge 106) are located outside the lamp housing 1701.

[0053] Additionally, in some implementations, multiple luminaire housings are connected in series with the control elements. For example, Fig. 18 illustrates a lighting system 1800 including a driver 1804 and a plurality of light housings 1801. In some embodiments, each of the light housings 1801 houses a single light source (such as only the first light source 108 or the second light source 110). In other cases, each of the light housings 1801 may be identical, such that they output the same light based on the controls from the driver 1804. The control elements (such as the controller 102, the driver circuit 104, and the control bridge 106) may be located within the driver 1804.

[0054] In some implementations, driver 104 is a multi-channel driver. For example, Fig.19 illustrates a lighting system 1900 having a multi-channel driver 1904 for controlling a first light 1901 and a second light 1902. However, the multi-channel driver 1904 may control more than two lights based on the number of lights included in the lighting system 1900. The multi-channel driver 1904 may include the controller 102, the driver 104, and the control bridge 106. However, instead of controlling all lights using a single input, the first light 1901 and the second light 1902 are connected to different inputs of the multi-channel driver 1904.

[0055] Thus, the embodiments described herein provide, among other things, a lighting control system with a driver for independently controlling multiple light sources. Various features and advantages are set forth in the following claims.

Claims

[1] Lighting control system (100) comprising: an input configured to be driven with a first polarity and a second polarity reversed from the first polarity, a first light source (108) connected to the input and configured to generate light when driven with the first polarity, a second light source (110) connected to the input and configured to generate light when driven with the second polarity, a control bridge (106) connected to the input and designed to control the polarity of the input, a detection circuit configured to detect a property of the input; and a controller (102) connected to the control bridge (106) and the detection circuit, the controller (102) being configured to: to control the control bridge (106) based on a control drive command (116), to receive a signal indicating the property of the input via the detection circuit, connecting the first light source (108) to the input if the property of the input is less than a threshold value, connecting the second light source (110) to the input if the property of the input is greater than or equal to the threshold value, and To provide lighting control signals to the input to independently control the first light source (108) and the second light source (110). [2] The lighting control system (100) of claim 1, wherein the controller (102) is configured to: to receive a first control plane (112) associated with the first light source (108), to receive a second control plane associated with the second light source (110), and to generate the lighting control signals based on the first control level (112) and the second control level (114). [3] Lighting control system (100) according to claim 2, wherein the controller (102) is configured to: to control the control bridge (106) based on the control drive command (116) for a first period of time, wherein, during the first period of time, the input is driven in the first polarity, and to control the control bridge (106) based on the control drive command (116) for a second period of time, wherein, during the second period of time, the input is driven in the second polarity. [4] Lighting control system (100) according to any one of the preceding claims, further comprising: a constant current driver circuit connected between the controller and the control bridge, the controller being configured to supply the lighting control signals to the constant current driver circuit. [5] The lighting control system (100) of any preceding claim, wherein the first light source (108) and the second light source (110) are connected in anti-parallel. [6] Lighting control system (100) according to one of the preceding claims, wherein the first light source (108) and the second light source (110) are connected in series with each other. [7] The lighting control system (100) of any preceding claim, wherein the first light source (108) has a first plurality of light-emitting diodes and wherein the second light source (110) has a second plurality of light-emitting diodes. [8] Lighting control system (100) comprising: a first light source (108), a second light source (110), a driver circuit (104) configured to drive the first light source (108) and the second light source (110) independently, a control bridge (106) configured to control a polarity of current provided to the first light source (108) and the second light source (110); and a detection circuit designed to: detect a property of the driver circuit (104), to connect the first light source (108) to the driver circuit (104) when the characteristic of the driver circuit (104) is less than a threshold value, and to connect the second light source (110) to the driver circuit (104) when the characteristic of the driver circuit (104) is greater than or equal to the threshold value. [9] The lighting control system (100) of claim 8, wherein the characteristic of the driver circuit (104) is a current value provided by the driver circuit (104). [10] The lighting control system (100) of claim 8 or 9, wherein the characteristic of the driver circuit (104) is a voltage value provided by the driver circuit (104). [11] The lighting control system (100) of any one of claims 8 to 10, further comprising a third light source, and wherein the detection circuit is further configured to: to connect the third light source to the driver circuit (104) if the characteristic of the driver circuit (104) is greater than a second threshold value, and to disconnect the second light source from the driver circuit (104) when the characteristic of the driver circuit (104) is greater than the second threshold value. [12] Lighting control system (100) comprising: an input configured to be driven with a first polarity and a second polarity reversed from the first polarity, a first light source (108) connected to the input and configured to generate light when driven with the first polarity, a second light source (110) connected in series with the first light source (108) and adapted to generate light when driven with the second polarity, a control bridge connected to the input and configured to drive the first light source (108) and the second light source (110) independently, a detection circuit configured to detect a property of the input, and a controller (102) connected to the control bridge and the input, the controller (102) being configured to: to control the polarity of the input via the control bridge (106), to receive a signal indicating the property of the input via the detection circuit, connecting the first light source (108) to the input if the property of the input is less than a threshold value, and connecting the second light source (110) to the input when the property of the input is greater than or equal to the threshold value. [13] The lighting control system (100) of claim 12, wherein the controller (102) is configured to switch a polarity of the input by providing a pulse width modulated (PWM) signal to the input. [14] A lighting control system (100) according to claim 12 or claim 13, wherein the controller (102) is configured to: to receive a first control plane (112) associated with the first light source (108), to receive a second control plane (114) associated with the second light source (110), and to control the control bridge (106) based on the first control level (112) and the second control level (114). [15] The lighting control system (100) of claim 14, wherein the controller (102) is configured to control the control bridge (106) based on the first control level (112) by providing a first current value less than the threshold value to the input, and wherein the controller (102) is configured to control the control bridge (106) based on the second control level by providing a second current value greater than the threshold value to the input. [16] The lighting control system (100) of any one of claims 12 to 15, wherein the first light source (108) has a first plurality of light-emitting diodes, and wherein the second light source (110) has a second plurality of light-emitting diodes. [17] The lighting control system (100) of any one of claims 12 to 16, wherein the characteristic of the driver circuit is a current value provided by the driver circuit (104). [18] The lighting control system (100) of any one of claims 12 to 17, wherein the characteristic of the driver circuit is a voltage value provided by the driver circuit (104). [19] The lighting control system (100) of any one of claims 12 to 17, wherein the first light source (108) and the second light source (110) are connected at a node, and wherein the lighting control system (100) further comprises: a third light source connected to the input and connected in parallel with the first light source (108), the third light source being adapted to generate light when driven with the second polarity, and a fourth light source connected to the node and connected in parallel with the second light source (110), the fourth light source being configured to generate light when driven at the first polarity. [20] Lighting control system (100) according to claim 19, wherein the controller (102) is configured to: connecting the third light source to the control bridge (106) when the characteristic of the control bridge (106) is greater than or equal to a second threshold value, and to connect the fourth light source to the control bridge (106) if the property of the control bridge (106) is less than a second threshold value.

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