Adjustable color ambient lighting with 2-wire interface

Abstract

A lighting controller includes an H-bridge circuit having a high side with at least one switch and a low side with at least one switch, wherein the high side is electrically coupled to a first output for a first one or more LEDs of a first color and the low side is electrically coupled to a second output for a second one or more LEDs of a second color, and an electronic controller configured to receive an input color command and, in response, control the at least one high side switch to generate a first pulse-width modulation signal, and control the at least one low side switch to generate a second pulse-width modulation signal, whereby the first output and the second output cause the first one or more LEDs and the second one or more LEDs to produce the input color.

Description

ADJUSTABLE COLOR AMBIENT LIGHTING WITH 2-WIRE INTERFACECROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to provisional application no. 63 / 527,790, filed July 19, 2023, which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] This disclosure generally relates to light color mixing with a 2-wire interface, such as for use in an automobile.BACKGROUND

[0003] Known vehicle lighting systems generally include one of a 4- wire adjustable RGB system, a Local Interconnect Network (LIN)-controlled 3-wire adjustable RGB system, or a 2- wire fixed color system.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] FIG. 1 is a diagrammatic view of an example lighting system.

[0005] FIG. 2A is a schematic view of an example H-bridge circuit that may find use in the example system of FIG. 1.

[0006] FIG. 2B is a block diagram view of a control scheme for switches of the lighting system of FIG. 1.

[0007] FIGS. 3A, 3B, 3C, and 3D are circuit schematics of an example pair of LEDs driven in three different operational states of the circuit of FIG. 2.

[0008] FIGS. 4-10 illustrate various examples of pulse- width modulation signals that may be output by the circuit of FIG. 2 for driving LEDs.

[0009] FIGS. 11-14 are plots illustrating example light output of the system of FIG. 1.

[0010] FIG. 15 is a flow chart illustrating an example method of controlling a set of LEDs.DETAILED DESCRIPTION

[0011] The instant disclosure includes a type of ambient (“atmospheric” I “mood”) lighting system (ambient lamp node(s), associated drive and wiring) that provides the user control over a white light color (e.g., temperature) which may be adjusted from “warm white” at one extreme to “cool white” at the other extreme, or another mix of two color LEDs. This system, whileoffering white light color adjustability (configurability) would have a significantly lower cost compared to fully color adjustable “RGB” systems through a simple lower cost lamp (node) and use of a 2- wire wiring system compared to 3-wire or 4- wire for RGB. In addition to color adjustment, the instant disclosure also provides intensity adjustment independent of the color adjustment (two dimensions of control).

[0012] A lighting system according to the present disclosure improves upon known vehicle lighting systems. Known adjustable systems require 3-wire or 4-wire interfaces, which add significant weight to a vehicle relative to a 2-wire interface. Known 2-wire systems are not adjustable. Accordingly, an adjustable 2-wire system according to the present disclosure provides adjustability at lower weight and less complexity, and without a requirement of microcontrollers on individual LEDs or LED pairs for intensity or color adjustment.

[0013] Referring to the drawings, in which similar numerals are used to refer to the same or similar features in the various views, FIG. 1 is a diagrammatic view of an example lighting system 100 that includes a first signal wire 102 and a second signal wire 104 contained in a 2- wire harness 106, a first one or more LEDs 108, a second one or more LEDs 110, and an electronic lighting controller 112.

[0014] The first LEDs 108 and the second LEDs 110 may be connected to the first signal wire 102 and the second signal wire 104 in reverse parallel with one another. That is, the first LEDs 108 may be connected across the first and second signal wire 108, 110 in a first polarity with the anode of the first LED 108 connected to one of the first signal wire 102 or the second signal wire 104 and the cathode connected to the other, and the second LEDs 110 connected across the first and second signal wires 102, 104 in a second, opposite polarity, with its anode and cathode respectively coupled to the opposite wires as the first LEDs 108. As a result, the first LEDs 108 and second LEDs 110 may receive inverted signals with respect to one another. The LED lamps may be arranged with blocking diodes, as discussed below. The blocking diodes may prevent the LEDs from experiencing reverse voltage. The LEDs 108, 110 may be arranged in pairs, with a single first LED 108 in reverse parallel with a single second LED 110 in each pair. The first LEDs 108 may all be the same color as each other, and the second LEDs 110 may all be the same color as each other. The first LEDs 108 may be a different color from the second LEDs 110.

[0015] The controller 112 may include a H-bridge circuit 114 and may generate two pulsewidth modulation (PWM) signals 116, 118. The controller 112 may output the first PWM signal 116 to the first signal wire 102 and may output the second PWM signal 118 to the second signal wire 104.

[0016] The H-bridge circuit 114 enables the polarity driving the first and second LEDs 108, 110 to be reversed partway through each PWM cycle. The H-bridge circuit 114 may have two high side / low side driver “totem poles” and two outputs to both source and sink load current, so the loads driven are not referred to ground (or battery). The drivers may be protected MOSFETs, as discussed in connection with FIG. 2A below.

[0017] The LEDs 108, 110 may be electrically coupled to the H-Bridge circuit 114 via the first and second signal wires 102, 104 so that, when the H-Bridge circuit 114 is driving a voltage defined as positive, the first LEDs 108 turn on. When the H-bridge circuit 114 drives a voltage defined as negative, the second LEDs 110 turn on. The lighting controller 112 may output a mix of polarity at a sufficiently high frequency (typically 100Hz to 300Hz) in order to create a mixed light color.

[0018] The lighting controller 112 may generate the PWM signals in response to a received color input instruction 120 of a desired color. The desired color may be, for example, a desired color temperature or color and a desired total intensity (brightness). The input 120 may be received from a user, or may be received from a vehicle control system that activates, deactivates, or otherwise alters ambient lighting, for example, in response to doors opening and closing, the vehicle being turned on or off, and the like.

[0019] Color mixing with different color LEDs may function particularly well when mixing different color temperatures of white light (e.g., cool white and warm white) due to the persistence of the human eye somewhere between the warm white and cool white colors. This is because of the relative flatness of the Plankian (Black Body) locus over the color temperature range of interest. Mixing warm white and cool white to obtain, for example, neutral white is possible as the locus is not far from a straight line between the warm white and cool white LEDs.

[0020] FIG. 2A is a schematic view of an example H-bridge circuit 200 that may find use in the example system of FIG. 1 (e.g., as the H-bridge circuit 114). The H-bridge circuit 200 may include two pairs of parallel switches, with one pair in series with the other pair. Accordingly, the H-bridge may include four switches QI, Q2, Q3, Q4. Each switch QI, Q2, Q3, Q4 may be a MOSFET, in some embodiments, that may be switched by applying a voltage to its gate HSD_A, HSD_B, LSD_A, LSD_B. The switch pairs may be referred to herein as a “high” pair and a “low” pair, in some embodiments. The high pair may generate and output a positive- voltage PWM signal POS, and the low pair may generate and output a negative- voltage PWM signal NEG. In some embodiments, the output of the high pair POS may be provided on the first signal wire 102, and the output of the low pair NEG may be provided on the secondsignal wire 104. Accordingly, referring to FIGS. 1 and 2A, the lighting controller 1 12 may include at least one high side switch QI, Q3 that generates the first PWM signal POS and at least one low side switch Q2, Q4 that generates the second PWM signal NEG.

[0021] Referring to FIG. 2B, the lighting controller 112 may include a timing controller 202 that generates and outputs respective switching signals to each of the switches QI, Q2, Q3, Q4. In embodiments in which the switches QI, Q2, Q3, Q4 are MOSFETs, the switching signals may be output to the gates of the MOSFETs. The timing controller 202 may control the four switches QI, Q2, Q3, Q4 separately from each other.

[0022] For a PWM system with Period T, and the first LED color (e.g., warm white) on- time defined as P and the second LED color (e.g., cool white) on-time defined as N, and with the color parameter K (range 0 - 1) defined as being 100% warm white light when K = 1, and with dimming factor D (range 0 - 1) defined as being 100% intensity when D = 1 then the warm white and cool white on times may be calculated according to equations (1) and (2) below:P = (K)(D)(T) (Eq. 1)N = (1-K)(D)(T) (Eq. 2)

[0023] In some embodiments, the lighting controller may calculate K and D in response to a desired color instruction. T may be an existing system setting determined according to the input parameters of the LEDs, for example. Based on K, D, and T, the timing controller may create the timing signals, and the timing signals may be level shifted to drive the MOSFET gates. MOSFET control phasing details may prevent shoot through (Q1=>Q2 / Q3=>Q4).

[0024] FIGS. 3A, 3B, 3C, and 3D are schematic views of three example paired LED circuits that may find use with the system of FIG. 1. The LED pair includes a first LED, LED1, of a first color, a second LED, LED2, of a second color, a first blocking diode DI in series with the first LED, and a second blocking diode, D2, in series with the second LED.

[0025] FIG. 3A illustrates a first LED circuit that additionally includes a current-limiting resistor R1 coupled between the LEDs and the second signal wire. During the warm white on time (P), i.e., on time of the first LED. During the LED1 on time (i.e., positive pulses on the first signal wire), DI and LED1 would conduct, while D2 would prevent reverse voltage on LED2. During the cool white on time (N), D2 and LED2 would conduct while DI would prevent reverse voltage on LED1. In both cases resistor R1 limits current (current direction change does not affect R1 a simple Ohmic device).

[0026] FTG. 3B illustrates a second LED circuit that additionally includes a simple resistive, PTC resistive, bi-directional constant current regulator (CCR) coupled between the cathodes of the two LEDs LED1, LED2, and across to a parallel set of diodes D3, D4. During the warm white on time (P), DI, D3 and LED1 would conduct while D2 and D4 would prevent reverse voltage on LED2. During the cool white on time (N), D2, D4 and LED2 would conduct while DI and D3 would prevent reverse voltage on LEDL In both cases, the CCR circuit controls current from within the diode bridge that is formed.

[0027] FIG. 3C illustrates a third LED circuit that additionally includes a bi-directional CCR coupled between the LEDs and the second signal wire. During the warm on time (P), DI and LED1 conduct while D2 prevents reverse voltage on LED2. During the cool white on time (N), D2 and LED2 conduct while DI prevents reverse voltage on LEDL In both cases the bidirectional CCR circuit controls the LED current.

[0028] FIG. 3D illustrates a fourth LED circuit that additionally includes a first current regulating transistor QI (which may be, for example, an NPN BJT) having a terminal in series with LED1 and DI, a second current regulating transistor Q2 (which may be, for example, a PNP BJT) having a terminal in series with LED2 and D2, a biasing resistor R1 connected between the first signal wire and the gates of the current regulating transistors, and both a resistor R2 and a pair of oppositely-biased Zener diodes Zl, Z2 connected in series with one another. The resistor R2 and the Zener diode pair Zl, Z2 may be in parallel with each other between a terminal of the regulating transistors QI, Q2 and the second signal wire.

[0029] During the warm on time (P), DI and LED1 conduct with QI regulating current, and D2 protects LED2 from reverse voltage. QI has a regulated (fixed) emitter current due to a fixed voltage being impressed across current setting resistor R2. As QI is in its active region, the LED current in Qi’s collector circuit is linearly related to the fixed current in Qi’s emitter circuit by IC = 13 / (13 + 1) * IE, where 13 is the transistor’s “Beta” (current gain factor). So, for 13 > 100 (which is typical), the LED current is almost identical to the current in R2. The fixed voltage being impressed across R2 is approximately 4.3V, in some embodiments, coming from two 4.3V Zener diodes Zl and Z2 on Qi’s base (Zl reverse biased and Z2 forward biased).Z2’s forward voltage is cancelled by Qi’s base to emitter voltage. A 4.3V Zener may be provided, because a Zener diode with that breakdown voltage has a temperature coefficient that almost equals zero. The forward biased Zener (essentially acting as an ordinary silicon diode) exhibits approximately the same dV / dT (voltage vs. temperature dependencies) as the base emitter junction of QI, so overall the current regulation is very stable over temperature without the need for advanced circuits like band gap references, etc. Resistor R3 provides bias to thedual Zener I transistor base circuits. The base and emitter terminals for QI and Q2 are wired in parallel so when one is active the other sees no more than a negative base emitter voltage (-0.5V to -0.8V) which is compatible with most BJT devices that possess a base emitter reverse breakdown voltage of about 5V.

[0030] During the cool on time (N), D2 and LED2 conduct with Q2 regulating current, and DI protects LED1 from reverse voltage. Regulation is achieved in the same manner as for warm white circuit, but with reversed polarities allowed by Q2 being a PNP compared to QI being an NPN. The current direction in the Zener “stack” reverses with Z2 being reverse biased and Z1 being forward biased. Current directions in resistors R2 and R3 reverse as well.

[0031] FIGS. 4-10 illustrate various examples of pulse- width modulation signals that may be output by the circuit of FIG. 2 for driving LEDs.

[0032] FIG. 4 illustrates a first signal example, in which the first LEDs are driven at 100% intensity and the second LEDs are driven at 0% intensity. The first PWM signal is a DC signal at maximum value, and the second PWM signal is a DC signal at zero. In the example of FIG. 4, the color of the first LEDs are output at maximum brightness.

[0033] FIG. 5 illustrates a second signal example, in which the second LEDs are driven at 100% intensity and the first LEDs are driven at 0% intensity. The second PWM signal is a DC signal at maximum negative value, and the first PWM signal is a DC signal at zero. In the example of FIG. 5, the color of the second LEDs are output at maximum brightness.

[0034] FIG. 6 illustrates a third signal example, in which the first LEDs are driven at 50% intensity and the second LEDs are driven at 0% intensity. The first PWM signal is a pulse signal in which the pulse width is half of the pulse period, and the second PWM signal is a DC signal at zero. In the example of FIG. 6, the color of the first LEDs are output at 50% brightness.

[0035] FIG. 7 illustrates a fourth signal example, in which the second LEDs are driven at 50% intensity and the first LEDs are driven at 0% intensity. The second PWM signal is a pulse signal in which the pulse width is half of the pulse period, and the first PWM signal is a DC signal at zero. In the example of FIG. 7, the color of the second LEDs are output at 50% brightness.

[0036] FIG. 8 illustrates a fifth signal example, in which the first LEDs are driven at 75% intensity and the second LEDs are driven at 25% intensity. The first PWM signal is a pulse signal in which the pulse width is 75% of the pulse period, and the second PWM signal is a pulse signal in which the pulse width is 25% of the pulse period. In the example of FIG. 9, there is no temporal gap between adjacent pulses of the first PWM signal and the second PWMsignal, and the pulses of the first PWM signal do not overlap with the pulses of the second PWM signal. In the example of FIG. 8, the output color is a mix of the first and second LEDs, 75% of the first LED color and 25% of the second LED color, at 100% brightness.

[0037] FIG. 9 illustrates a sixth signal example, in which the first LEDs are driven at 25% intensity and the second LEDs are driven at 25% intensity. The first PWM signal is a pulse signal in which the pulse width is 25% of the pulse period, and the second PWM signal is a pulse signal in which the pulse width is 25% of the pulse period. In the example of FIG. 10, there is a temporal gap between adjacent pulses of the first PWM signal and the second PWM signal, and the pulses of the first PWM signal do not overlap with the pulses of the second PWM signal. In the example of FIG. 9, the output color is a mix of the first and second LEDs, 50% of the first LED color and 50% of the second LED color, at 50% brightness.

[0038] FIG. 10 illustrates a seventh signal example, in which the first LEDs are driven at 3 / 8 intensity and the second LEDs are driven at 1 / 8 intensity. The first PWM signal is a pulse signal in which the pulse width is 3 / 8 of the pulse period, and the second PWM signal is a pulse signal in which the pulse width is 1 / 8 of the pulse period. In the example of FIG. 11 , there is a temporal gap between adjacent pulses of the first PWM signal and the second PWM signal, and the pulses of the first PWM signal do not overlap with the pulses of the second PWM signal. In the example of FIG. 10, the output color is a mix of the first and second LEDs, 75% of the first LED color and 25% of the second LED color, at 50% brightness.

[0039] As can be seen from the examples above, the brightness of the combined LEDs may be set by the percentage of the pulse period occupied by the combined first and second PWM signals. In turn, the output color, i.e., percentage mix of the first and second colors, may be set by the relative pulse lengths of the first and second PWM signals, irrespective of the total amount of the pulse period occupied.

[0040] FIGS. 11-14 are plots illustrating example light output of the system of FIG. 1.

[0041] FIG. 11 and 12 show typical white and warm white LED binning diagrams that demonstrate the feasibility of the green bias technique to minimize mixed color error over an interval on the Plankian Locus. At the 3000K end of that spectrum (FIG. 13), LEDs from the sw309m bin would be of interest, while at the 6000K end of the spectrum (FIG. 12), LEDs from the GOO and H00 bins would be of interest.

[0042] FIGS. 13 and 14 illustrate the Planckian Locus for white LEDs and green-biased LEDs, respectively. Referring to FIG. 13, if the LEDs that define the endpoints of the light spectrum to be controlled were selected to fall on or very near to the Plankian Locus, then the locus of mixed colors would deviate towards purple from the Plankian Locus due to that curvebeing a parabola that opens downward. See error el on Figure 13.

[0043] Referring to FIG. 14, to minimize overall color error (departure from the Plankian Locus or Black Body Locus), the two LEDs that define the endpoints of the white light spectrum to be controlled could be selected to be slightly above the Plankian Locus (i.e.: biased towards green). With the shape of the Plankian locus being a parabola that opens downward, this would put the locus of mixed light color on average closer to the Plankian Locus. See error e2 on Figure 14.

[0044] FIG. 15 is a flow chart illustrating an example method 1500 of controlling a set of LEDs. The method 1500, or one or more aspects of the method 1500, may be performed by the lighting controller, in some embodiments, or another controller coupled to a two- wire interface to which first and second groups of LEDs are connected as described herein. The method 1500 may involve controlling two sets of LEDs — a first set of a first color, and a second set of a second color, in some embodiments.

[0045] The method 1500 may include, at block 1502, receiving a desired color command. The desired color command may include a light intensity (e.g., brightness) and / or a light color, in some embodiments.

[0046] The method 1500 may further include, at block 1504, determining a portion of a PWM period to occupy based on a desired brightness. For example, where the desired color command indicates maximum brightness, the pulses of the PWM signals may collectively occupy 100% of the PWM period. Where the desired color command indicates 50% brightness, the pulses of the PWM signals may collectively occupy 50% of the PWM period. Where the desired color command indicates 25% brightness, the pulses of the PWM signals may collectively occupy 25% of the PWM period, and so on.

[0047] The method 1500 may further include, at block 1506, determining relative pulse widths of first and second PWM signals based on the desired color. Where the desired color is 100% of one of the two colors, block 1506 may include assigning the entirety of the PWM period portion of block 1504 to that color.

[0048] The method 1500 may further include, at block 1508, generating and outputting a positive pulse-width modulation (PWM) signal along the first wire and, at block 1510, generating and outputting a negative PWM signal along the second wire. The positive PWM signal may have the pulse width of the first signal determined above. The negative PWM signal may have the pulse width of the second signal determined above. The method may include controlling the respective period and pulse duration of the positive and negative PWM signals to cause the first one or more LEDs and the second one or more LEDs to produce the desiredcolor. For example, the method may include controlling the pulse duration of the positive PWM signal to effect a desired intensity of the first color, and controlling the pulse duration of the negative PWM signal to effect a desired intensity of the second color. In some embodiments, controlling the first and second PWM signals may include controlling the respective period and pulse duration of the positive and negative PWM signals so that the pulses of the positive PWM signal do not overlap with the pulses of the negative PWM signal.

[0049] In some embodiments, controlling the PWM signals may include creating a temporal gap between the pulses of the positive PWM signal and the pulses of the negative PWM signal to create a reduced-intensity light output, e.g., to occupy less than the entirety of the pulse period.

[0050] The instant disclosure may be used to vary ambient lighting color between white and some other non-white color. In this manner control could adjust to white for near functional lighting and to the other color for pure ambient lighting.

[0051] The instant disclosure may also be used to vary ambient lighting color between two primary colors. Varying between red and green would allow hues of orange and yellow to be created. Varying between red and blue would allow shades of purple and violet to be created. Varying between green and blue would provide aqua and turquoise hues.

[0052] In a first aspect of the present disclosure, a lighting controller includes an H-bridge circuit having a high side with at least one switch and a low side with at least one switch, wherein the high side is electrically coupled to a first output for a first one or more LEDs of a first color and the low side is electrically coupled to a second output for a second one or more LEDs of a second color, and an electronic controller configured to receive an input color command and, in response, control the at least one high side switch to generate a first pulsewidth modulation signal, and control the at least one low side switch to generate a second pulsewidth modulation signal, whereby the first output and the second output cause the first one or more LEDs and the second one or more LEDs to produce the input color.

[0053] In an embodiment of the first aspect, the H-bridge circuit includes a high side having two switches, and a low side having two switches. In a further embodiment of the first aspect, the electronic controller is configured to control the two high side switches separately to generate the first pulse- width modulation signal, and control the two low side switches separately to generate the second pulse- width modulation signal. In a further embodiment of the first aspect, each of the two high side switches and the two low side switches is a respective MOSFET. In a further embodiment of the first aspect, the electronic controller is configured to control each MOSFET by applying a respective gate voltage.

[0054] Tn an embodiment of the first aspect, the first pulse-width modulation signal is a positive voltage signal and the second pulse-width modulation signal is a negative voltage signal.

[0055] In a second aspect of the present disclosure, a lighting system is provided that includes a first signal wire, a second signal wire, a first one or more LEDs connected to the first and second signal wires along a first polarity, a second one or more LEDs connected to the first and second signal wires along a second polarity that is opposite the first polarity, and an electronic lighting controller configured to receive an input color command and, in response, generate a positive pulse- width modulation (PWM) signal along one of the first or second signal wires, generate a negative PWM signal along the other of the first or second signal wires, and control a respective period and pulse duration of the positive and negative PWM signals to cause the first one or more LEDs and the second one or more LEDs to produce the input color.

[0056] In an embodiment of the second aspect, the lighting system further includes a signal harness containing the first and second signal wires.

[0057] In an embodiment of the second aspect, each LED of the first one or more LEDs and the second one or more LEDs is electrically coupled to a blocking diode to prevent a negative voltage across the LED.

[0058] In an embodiment of the second aspect, the electronic lighting controller includes an H-bridge circuit having a high side with at least one switch and a low side with at least one switch, wherein an output of the high side is electrically coupled to the first signal wire and an output of the low side is electrically coupled to the second signal wire. In a further embodiment of the second aspect, the H-bridge circuit includes a high side having two switches, and a low side having two switches. In a further embodiment of the second aspect, the electronic lighting controller is configured to control the two high side switches separately to generate the first pulse-width modulation signal, and control the two low side switches separately to generate the second pulse-width modulation signal. In a further embodiment of the second aspect, each of the two high side switches and the two low side switches is a respective MOSFET.

[0059] In an embodiment of the second aspect, the first one or more LEDs are a first color and the second one or more LEDs are a second color that is different from the first color. In a further embodiment of the second aspect, the first one or more LEDs are a cool white color and the second one or more LEDs are a warm white color.

[0060] In a third aspect of the present disclosure, a method for controlling a lighting system including a first one or more LEDs of a first color and a second one or more LEDs of a second color electrically coupled to a two-wire interface comprising a first wire and a second wire isprovided. The method includes receiving a desired color command, generating and outputting a positive pulse-width modulation (PWM) signal along the first wire, generating and outputting a negative PWM signal along the second wire, and controlling a respective period and pulse duration of the positive and negative PWM signals to cause the first one or more LEDs and the second one or more LEDs to produce the desired color.

[0061] In an embodiment of the third aspect, the controlling includes controlling the pulse duration of the positive PWM signal to effect a desired intensity of the first color, and controlling the pulse duration of the negative PWM signal to effect a desired intensity of the second color.

[0062] In an embodiment of the third aspect, the controlling includes controlling the respective period and pulse duration of the positive and negative PWM signals so that the pulses of the positive PWM signal do not overlap with the pulses of the negative PWM signal.

[0063] In an embodiment of the third aspect, the controlling includes creating a temporal gap between the pulses of the positive PWM signal and the pulses of the negative PWM signal to create a reduced-intensity light output.

[0064] In an embodiment of the third aspect, the desired color command includes a light intensity and a light color.

[0065] While this disclosure has described certain embodiments, it will be understood that the claims are not intended to be limited to these embodiments except as explicitly recited in the claims. On the contrary, the instant disclosure is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the disclosure.Furthermore, in the detailed description of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it will be obvious to one of ordinary skill in the art that systems and methods consistent with this disclosure may be practiced without these specific details. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure various aspects of the present disclosure,

[0066] Some portions of the detailed descriptions of this disclosure have been presented in terms of procedures, logic blocks, processing, and other symbolic representations of operations on data bits within a computer or digital system memory. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. A procedure, logic block, process, etc., is herein, and generally, conceived to be a self-consistent sequence of steps or instructions leading to a desired result. The steps are those requiring physical manipulationsof physical quantities. Usually, though not necessarily, these physical manipulations take the form of electrical or magnetic data capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer system or similar electronic computing device. For reasons of convenience, and with reference to common usage, such data is referred to as bits, values, elements, symbols, characters, terms, numbers, or the like, with reference to various presently disclosed embodiments.

[0067] It should be borne in mind, however, that these terms are to be interpreted as referencing physical manipulations and quantities and are merely convenient labels that should be interpreted further in view of terms commonly used in the art. Unless specifically stated otherwise, as apparent from the discussion herein, it is understood that throughout discussions of the present embodiment, discussions utilizing terms such as “determining” or “outputting” or “transmitting” or “recording” or “locating” or “storing” or “displaying” or “receiving” or “recognizing” or “utilizing” or “generating” or “providing” or “accessing” or “checking” or “notifying” or “delivering” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data. The data is represented as physical (electronic) quantities within the computer system’s registers and memories and is transformed into other data similarly represented as physical quantities within the computer system memories or registers, or other such information storage, transmission, or display devices as described herein or otherwise understood to one of ordinary skill in the art.

Claims

CLAIMSWhat is claimed is:

1. A lighting controller comprising: an H-bridge circuit having a high side with at least one switch and a low side with at least one switch, wherein the high side is electrically coupled to a first output for a first one or more LEDs of a first color and the low side is electrically coupled to a second output for a second one or more LEDs of a second color; and an electronic controller configured to receive an input color command and, in response: control the at least one high side switch to generate a first pulse- width modulation signal; and control the at least one low side switch to generate a second pulse-width modulation signal; whereby the first output and the second output cause the first one or more LEDs and the second one or more LEDs to produce the input color.

2. The lighting controller of claim 1, wherein the H-bridge circuit comprises: a high side having two switches; and a low side having two switches.

3. The lighting controller of claim 2, wherein the electronic controller is configured to: control the two high side switches separately to generate the first pulse-width modulation signal; and control the two low side switches separately to generate the second pulse- width modulation signal.

4. The lighting controller of claim 2, wherein each of the two high side switches and the two low side switches is a respective MOSFET.

5. The lighting controller of claim 4, wherein the electronic controller is configured to control each MOSFET by applying a respective gate voltage.

6. The lighting controller of claim 1 , wherein the first pulse-width modulation signal is a positive voltage signal and the second pulse-width modulation signal is a negative voltage signal.

7. A lighting system comprising: a first signal wire; a second signal wire; a first one or more LEDs connected to the first and second signal wires along a first polarity; a second one or more LEDs connected to the first and second signal wires along a second polarity that is opposite the first polarity; and an electronic lighting controller configured to receive an input color command and, in response: generate a positive pulse- width modulation (PWM) signal along one of the first or second signal wires; generate a negative PWM signal along the other of the first or second signal wires; and control a respective period and pulse duration of the positive and negative PWM signals to cause the first one or more LEDs and the second one or more LEDs to produce the input color.

8. The lighting system of claim 7, further comprising a signal harness containing the first and second signal wires.

9. The lighting system of claim 7, wherein each LED of the first one or more LEDs and the second one or more LEDs is electrically coupled to a blocking diode to prevent a negative voltage across the LED.

10. The lighting system of claim 7, wherein the electronic lighting controller comprises: an H-bridge circuit having a high side with at least one switch and a low side with at least one switch, wherein an output of the high side is electrically coupled to the first signal wire and an output of the low side is electrically coupled to the second signal wire.1 1 . The lighting system of claim 10, wherein the H-bridge circuit comprises: a high side having two switches; and a low side having two switches.

12. The lighting system of claim 11, wherein the electronic lighting controller is configured to: control the two high side switches separately to generate the first pulse- width modulation signal; and control the two low side switches separately to generate the second pulse- width modulation signal.

13. The lighting system of claim 1 1 , wherein each of the two high side switches and the two low side switches is a respective MOSFET.

14. The lighting system of claim 7, wherein the first one or more LEDs are a first color and the second one or more LEDs are a second color that is different from the first color.

15. The lighting system of claim 14, wherein the first one or more LEDs are a cool white color and the second one or more LEDs are a warm white color.

16. A method for controlling a lighting system comprising a first one or more LEDs of a first color and a second one or more LEDs of a second color electrically coupled to a two- wire interface comprising a first wire and a second wire, the method comprising: receiving a desired color command; generating and outputting a positive pulse-width modulation (PWM) signal along the first wire; generating and outputting a negative PWM signal along the second wire; and controlling a respective period and pulse duration of the positive and negative PWM signals to cause the first one or more LEDs and the second one or more LEDs to produce the desired color.

17. The method of claim 16, wherein the controlling comprises: controlling the pulse duration of the positive PWM signal to effect a desired intensity of the first color; and controlling the pulse duration of the negative PWM signal to effect a desired intensity ofthe second color.

18. The method of claim 16, wherein the controlling comprises controlling the respective period and pulse duration of the positive and negative PWM signals so that the pulses of the positive PWM signal do not overlap with the pulses of the negative PWM signal.

19. The method of claim 16, wherein the controlling comprises creating a temporal gap between the pulses of the positive PWM signal and the pulses of the negative PWM signal to create a reduced-intensity light output.

20. The method of claim 16, wherein the desired color command comprises a light intensity and a light color.

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