WO2016127198A1 - Système gradateur - Google Patents

Système gradateur Download PDF

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Publication number
WO2016127198A1
WO2016127198A1 PCT/AU2016/000033 AU2016000033W WO2016127198A1 WO 2016127198 A1 WO2016127198 A1 WO 2016127198A1 AU 2016000033 W AU2016000033 W AU 2016000033W WO 2016127198 A1 WO2016127198 A1 WO 2016127198A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
circuit
led
pulse
legacy
Prior art date
Application number
PCT/AU2016/000033
Other languages
English (en)
Inventor
Gregory BULL
Warren HERFT
Dean Williams
Original Assignee
Lumitech Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2015900402A external-priority patent/AU2015900402A0/en
Application filed by Lumitech Pty Ltd filed Critical Lumitech Pty Ltd
Priority to AU2016218927A priority Critical patent/AU2016218927A1/en
Priority to EP16748468.2A priority patent/EP3257332A1/fr
Publication of WO2016127198A1 publication Critical patent/WO2016127198A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/10—Controlling the intensity of the light

Definitions

  • This disclosure relates to lighting systems and i particular to dimmer systems for dimming light emitting diode (LED)s i large facil ities.
  • a driver circuit for a light emitting diode including a power supply that derives power from a legacy dimming circuit to produce an output voltage, an input level detector that detects a signal level from the legacy diiniiiing circuit, and a pulse generator that produces a pulse signal having a widt that is dependent on the detected signal level, wherein .the pulse signal is coupled with the output voltage to power the LED,
  • a lighting system for a premises including at least one dimmin control panel at least one legacy dimmin circuit, at least one light emitting diode (LED) element including at least one LED, and at least one driver for the at least one LED element, the at least one driver including a power supply that derives power from the legacy dimming circuit to produce an output voltage, an input level detector that detects a signal level from the legacy dimming circuit, and a pulse generator that produces a pulse signal having a width that is dependent on the detected signal level, wherein the pulse signal is coupled with the output vol tage of the power suppl to power the LED.
  • LED light emitting diode
  • a method o controlling at least one Light Emittin Diode (LED) element includin at least one LED from a legacy dimming circuit of a premises, the method including using a dri ver to:
  • FIG. 2 show's a lighting system in accordance with an embodiment of the present inventi n; ⁇ 0012 ⁇ Figure 3 shows a schemati c of a driver system;
  • Figure 4 shows a specific example of a driver circuit
  • 10015 J Figure 6 shows the power carv e as a function of input control setting
  • FIG. 7 shows a venue lighting system including at least one LED and driver of an embod iment of the present invention:
  • ⁇ 0018 ⁇ Figure shows an alternative circuit diagram for a high power LED embodiment.
  • FIG. 1 shows a prior art dimming arrangement HI
  • a legacy dimmin system 12 for example but not exclusively, the Philips Dynalite system, provides dimming controls to an array of lights 14 dispersed throughout the premises.
  • the lights may he arranged in sets or banks with one di mming control signal going to a subset of the lights of the complete lighting system, i one specific example, the lighting system may be in a theatre with complex lighting system controlled from a main desk or computer.
  • the lighting system might use many high power light dimmers to control the ight levels in the theatre itself and other areas.
  • FIG. 2 shows an embodiment of the present invention in which a translator or driver circuit 20 is installed between the legacy dimming system 12 and an upgraded LED lighting system including LED element 22.
  • the LED element 22 is shown as a single LED b t t e person skilled in the ar will readily understan that an individual LED lighting element may be made up of multiple LCDs within the body of the LED element (as shown in Figures 8 and 9). T e LEDs within an LED element may be all of the same colour or be of multiple colours.
  • the driver 20 translates the power from the existing dimming system 12 into a new form that the LED element 22 can respond to. The driver 20 thus negates the need to re ire the theatre for an LED upgrade.
  • the driver 20 is shown schematically in Figure 3.
  • the driver 20 includes a power supply 21, a power load circuit (input level detector) 24, a Pulse Width Modulation (P W generator 26, a integrator 27 and a current limiter 28 to suit the LED 22,
  • the power suppl 21 produces an output voltage while the integrator 27 produces a pulsed output, the width of which is determined by DC level produced by the power load circuit 24 from an incoming waveform 23 of a legacy dimming circuit.
  • the output voltage and pulsed outpiit are coupled, via the current limiter 28 to the LED 2 to power the LED with pulsing current.
  • the overall light output of the LED 22 detectable to a human observer is dependent on the pulse width .
  • the frequency of the pulsing current is sufficiently high to prevent any observable flicker of the LED for a human observer.
  • the frequency may be selected to be above the human fusio flicker rate which is the threshold frequenc above which the average human eye is unable to discern the fluctuation in light intensity and therefore the average human observer will not be able to discern any flicker.
  • the human fusion flicker threshold is often considered to be approximately 60 Hz but is dependent on number of parameters of the light including, without limitation, the frequency of the modulation, the wavelength of the emitted light, the drop in amplitude from the peak level across the cycle (amplitude modulation), the ambient lighting levels, age and fatigue of the observer, etc. Furthermore, the human fusion flicker threshold is a statistical average representing the value at which half the human test population can no longer discern flicker. For audience lighting, it is- not satisfactory to subject half the audience to flickering light sources. Thus, it is preferable if the pulse signal frequency is selected to be well above the human fusion flicker threshold to accommodate a greater number of patrons. In one embodiment, the pulse signal frequency is greate than 500 Hertz (Hz). In one embodiment, the pulse signal frequency is greater than 1000 Hz. n one embodiment the pulse signal frequency is greater than 2000 Hz.
  • the power supply 21 receives an input 23 from the legacy dimmer circuit and creates a circuit voltage from the dimmer signal.
  • the dimmer signal will be a chopped mains waveform produced by a TRIAC, myristor or the like.
  • the mains waveform will be 230V AC, 50 Hz based on the mains supply but this will differ from country to country.
  • the leading edge modulated power 2 of the dimmer circuit first encounters a transformer 41.
  • the transformer is a toroidal iron core transformer. This is to ensure that it responds as necessar to the leading edge signal 23 front the dimme circuit, as well as increasing the reliability of the circuit.
  • the transformer is selected to prov ide a match with the forward voltage of the LED. When at foil power the secondary AC RMS voltage should be the same as or close to the LED forward voltage.
  • the transformer 4 isolates the circuit, particularly the LED, electrically from the mains and presents an inductive loa to the Leading Edge Dimmer reducing the voltage to 50 VAC max. it is rectified 42 and filtered with a large value capacitor 43, e.g. 4700 ⁇ , after which the DC voltage rises to about 70 VDC, depending on the power level applied from the dimmer circuit, The Anode 2 1 of the LED 22 is connected to this 70V positive D power rail 406, The inductor 401 and the high speed diodes 402, 403 give a boost to the DC rail 406 at the lower end of the power range.
  • a large value capacitor 43 e.g. 4700 ⁇
  • the output of the rectifier circuit 42 i s also used to produce a supply vol tage , e.g. 1 V supply voltage 404, which is used to power various components of the driver circuit, such as the one of more integrated circuits, op amps, etc. as will be described in more detail below.
  • a supply vol tage e.g. 1 V supply voltage 404
  • the LED cathode 22 is switched to negative via a powe MOSFET 407 and the current through the LED i controlled by Pulse Width Modulation of the MOSFET 407 as follows.
  • the power load circuit 24 receives the AC output from the transformer and passes it through a separate rectifier 45 to an RC network 46 and an Optocoupler 47. This circuit creates a DC signal which follows the level sent from the dimmer circuit while isolating th potentially high voltages of the dimmer circuit.
  • kHz kilofaertz
  • the Cruos Timer is a 555 Crnos Timer chip, powered by the 12V supply voltage 404 deri ved from the rectifier circuit 42, though other ty es of tinier chips will be apparent to the person skilled in the art
  • the Op Amp 410 using an R/C network 41 1 , creates a stable and adj ustable sawtooth wa veform of around 3 Hz at the output of the Op Amp 410.
  • the signal combiner 27 uses a second Op Amp 415 to compare the 3 hz sawtoot waveform from Op Amp 410 with the DC level from the optically coupled 4? power level detection stage 24.
  • the mag itude of the pulse signal output of Op Am 410 is fixed, but the width will depend on the DC level input Figure 5 " shows that as the D level 51 derived from the dimmer waveform 23 increases, the pulse width 52 at the output of O Amp 415 will increase proportionally.
  • the higher the D level input the longer withi the cycle it takes for the waveform input to reach the DC level 54 and cause the comparator to switch from high to low. That is, the higher the DC level input the longer the pulse signal output remains high, i.e. the wider the pulse signal output.
  • a sawtooth profile is used because it has been found by the present inventors to produce more linear response and therefore easier operatio for the user.
  • waveforms e.g. sine
  • the 3 kHz pulse signal output of the op amp 410 is coupled to the LED 22 via the power MOSFET 407. Operating at this frequency, whic is a frequency well above the human tiicke fusion rate, the LED will appear to be a steady state light source with no observable flicker.
  • the intensity of the light output of the LED 22 that is detectable by person will depend on th average time for which the LED is on and is therefore dependent on the width of the pulse signal output supplied from the op amp 410 to the power MOSFET 407. At very short pulse widths (low dut cycle), the LED 22 will be mostly off and the average light output will be very low. At long pulse widths (high duty cycle), the LED will he on for longer periods and the overall light output of the LED 22 will increase, up to 100% duty cycle at which the LED will be on constantly and will produce its maximum output.
  • the MOSFET 407 source has a resistor 48 which allows a voltage to develop across it proportional to the LED current. If the current is above the LED's rating it lowers the voltage at the comparator input and stabtlises the power.
  • a current limiting resistor 409 limits the current of the circuit.
  • FIG. 6 shows the power response curve as a function of the settings from the control desk.
  • the input waveform 23 is little more than a spike. Fortunately the LED is also only just startin to light and does not require much current.
  • the desk setting moves from "0" to above (e.g. on a scale of 1 to 10) and beyond, there is • tmtnedtately generated 12 volts to run the circuit 20 via the supply voltage 404, and a fast rising DC voltage to about 70 volts on the power rail 406.
  • the PWM generator 26 comes to life and attempts to drive the output.
  • the PWM width- is controlled b the input level voltage with the higher the input level the wider the Pulse Width becomes,
  • the circuit is adjusted so that the maximum input level is equal to the point that the current limiter 409 is set to, for the particular LED.
  • the example circuit of Figure 4 is designed to output 700mA at 50 Volts to the LED element 22 and the specific component values indicated, as may he read from Figure 4, reflect this circuit design.
  • the component values ma be adjusted for different circuit characteristics, in particularly the linearity of the output, and that additional components ma be added while other components may be deleted depending on the ultimate circuit requirements, LED to be dri ven, output of the legacy dimmer circuit, etc.
  • the circuit may b modified for suitability with LED elements having a forward voltage drop of 36V, 42V, 50V, etc.
  • the driver circuit derives a DC signal level from the AC signal of the legac dimmer circuit and uses the DC signal to generate output pulses of varying widt from 100% to zero dependent on the DC signal level, thereby enabling the LED lamp to dim evenly and smoothly from 00% to zero and back. Because there is al ays more energy available than the LED could ever need, it is possible to create a linear output to the LED.
  • LED lighting systems are more efficient to operate and have reduced maintenance requirements.
  • the typical life span of a hi gh powered halogen light is 1000 hours compared to 50,000 hours for an equi valent LED.
  • the system herein described in the preferred embodiments enables the venue to tap into the efficiency and maintenance benefits of modem LED li ghting without replacing their current legacy dimming system.
  • FIG. 7 shows a schematic of venue lighting system 70 incorporating the upgraded LED system herein described.
  • the venue includes a legacy dimming system having a plurality of dimmer circuits 72 that are driven from a mains supply 73 and receive control signals from a control panel 74 at a control desk.
  • the venue lighting system 70 may include legac lighting systems, e.g. high powered halogen lamps, as well as LED elements, each LED element having one or more LEDs.
  • the LEDA single dimmer circuit, e.g. dimmer 76 may control a bank of halogen lamps 77.
  • a second dimmer 78 may control a bank of lights that includes non-LEDs, e-.g» halogen lamp 79 as well as LEDs 80.
  • Each LED 80 will include a driver circuit 20 of the type described above that is able to effectively control and dim the respective LED using the signal from the dimmer circuit,
  • Figure 7 demonstrates the flexibility and adaptability of the presently described driver circuit. Because the driver circuits herein described integrate with the legacy dimmer circuits of the venue, the venu operator may partiall upgrade the venue lighting system without having to do an entire- upgrade at once. Furthermore, a single dimmer circuit may include LEDs as well as non-LBD lights allowing halogens to remain in use where such lights remain beneficial while using LEDs wherever suitable.
  • FIG 8 shows an alternative embodiment for a driver circuit 800 for an LED element 820 of one or more LEDs 822 having a forward voltage of 50 Volts. It has been discovered by the present inventors that certain high power LED's can make a tiny noise when driven by PWM systems * While the phenomenon is largely unresearched and unexplained, one possible explanation is that the LED junction may warp as the power mshes in enough to create the noise. Square edged pulses can be faintly heard (if within the audio range) up close to some LED's. Wit many such lamps together in a large installation such as a theatre or auditorium, the noise can become quite audible and noticeable to the audience.
  • the circuit 800 of Figure 8 is similar to the driver circuit of Figure 4 but includes the addition of an anti-ringing filter 810.
  • the anti-ringing filter 810 includes an RC filter that performs a dual role. First, it turns the squar edged pulse int a more rounded pulse which stops the ringing noise. Secondly, it creates a lower depth of modulation on output further reducing the risk of flicker or strobing.
  • the circuit 800 of Figure 8 further includes valle filling circuitry 830 that improves the power factor and increases the efficiency of the circuit
  • the drive level adjustment is shown- located after the rectifier 45 which has also been found to improve the efficiency of the circuit
  • the circuit 800 uses an LM3 I I comparator 815 to achieve a narrow pu!sewidth which provides a better response time at a operatin frequency greater titan 2kHz than the circuit of Figure 4 which shows an L .3-58 comparator.
  • FIG. 9 shows an embodiment of a driver circuit 900 for a higher powered LED element 920 with a forward voltage of 212V.
  • the circuit 900 operates using the same pulse width modulation circuit principles of the previous embodiments but the specific devices and components may differ in power ratings and transformer type and arrangement
  • the transformer 941 outputs first voltage from a first secondary 942 at the higher level e.g.. 195VRMS, for powering the highe powered LED element 920.
  • the transformer 941 also outputs a lower voltage through an additional secondary 943, e.g. at 50VRMS that ca be further reduced to 12 V DC for powering the remainder of the dri ver circuit, including the PWM and input level detector components.
  • the circuit 900 may operate at similar frequencies, e.g. 2200 Hz, as for the previousl described embodiments.
  • the circuit 900 includes the additio of LED temperature limiting.
  • the high power LED e.g. operating at 200 Watts
  • the temperature .uniting circuit 950 includes a temperature sensor 951 that produces an output that couples with the drive input to the optoeoupler 947 of the input level detection circuit. Once the temperature sensor 951 reaches a threshold temperature, it will begin to reduce the output of the signal level detector, thereby reducing the average power of the LEDs and thus their operating temperature.
  • Adj stment components 952 may be used to adjust the threshold temperature at which the temperature limiting circuit begins operating as well as the linearity of the temperature adjustment 3 ⁇ 4 e threshold temperature will be dependent on the LED manufacturers recommendation and etnironmentai factors, e.g. amount o cooling available, fire risk, etc. and thus no specific example of the threshold temperature is provided herein, jOOSOj Although embodiments of the present invention have been illustrated in the accompanied drawings and described in the foregoing description, it will be ' understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit o the invention as set forth and defined b any claims that follow.

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  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

Selon la présente invention, un local comprenant un système de gradation d'intensité pour l'éclairage de grandes surfaces peut être mis à niveau pour utiliser des diodes électroluminescentes (DEL) comprenant un circuit d'attaque sans mettre à niveau le système de gradation existant. Le circuit d'attaque reçoit un signal de commande provenant du système de gradation existant, par exemple une forme d'onde de secteur hachée, et détermine un niveau de signal à partir du signal de commande. Le niveau de signal est utilisé comme entrée pour moduler une durée d'impulsion d'un signal à modulation de largeur d'impulsion (MLI) ayant une fréquence supérieure à la fréquence de fusion de papillotement des humains. Le signal à modulation de largeur d'impulsion est fourni aux DEL. La durée de l'impulsion détermine le courant moyen fourni à l'élément DEL, et donc le niveau de lumière émis par les DEL.
PCT/AU2016/000033 2015-02-09 2016-02-09 Système gradateur WO2016127198A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU2016218927A AU2016218927A1 (en) 2015-02-09 2016-02-09 Dimmer system
EP16748468.2A EP3257332A1 (fr) 2015-02-09 2016-02-09 Système gradateur

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2015900402 2015-02-09
AU2015900402A AU2015900402A0 (en) 2015-02-09 Dimmer system

Publications (1)

Publication Number Publication Date
WO2016127198A1 true WO2016127198A1 (fr) 2016-08-18

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PCT/AU2016/000033 WO2016127198A1 (fr) 2015-02-09 2016-02-09 Système gradateur

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AU (1) AU2016218927A1 (fr)
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020107171A1 (fr) * 2018-11-26 2020-06-04 上海晶丰明源半导体股份有限公司 Circuit de commande, système de pilotage, puce, procédé de commande et procédé de pilotage

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080150450A1 (en) * 2006-12-21 2008-06-26 Texas Instruments Inc Systems and methods for led based lighting
US20110109249A1 (en) * 2009-11-10 2011-05-12 Green Mark Technology Inc. Dimmable led lamp and dimmable led lighting apparatus
US20120043909A1 (en) * 2010-08-17 2012-02-23 Keystone L.E.D. Holdings Llc LED Luminaires Power Supply
US20120161665A1 (en) * 2010-12-23 2012-06-28 Tom William Thornton Precision light control apparatus and methods
US20130249431A1 (en) * 2012-03-05 2013-09-26 Luxera, Inc. Dimmable Hybrid Adapter for a Solid State Lighting System, Apparatus and Method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080150450A1 (en) * 2006-12-21 2008-06-26 Texas Instruments Inc Systems and methods for led based lighting
US20110109249A1 (en) * 2009-11-10 2011-05-12 Green Mark Technology Inc. Dimmable led lamp and dimmable led lighting apparatus
US20120043909A1 (en) * 2010-08-17 2012-02-23 Keystone L.E.D. Holdings Llc LED Luminaires Power Supply
US20120161665A1 (en) * 2010-12-23 2012-06-28 Tom William Thornton Precision light control apparatus and methods
US20130249431A1 (en) * 2012-03-05 2013-09-26 Luxera, Inc. Dimmable Hybrid Adapter for a Solid State Lighting System, Apparatus and Method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020107171A1 (fr) * 2018-11-26 2020-06-04 上海晶丰明源半导体股份有限公司 Circuit de commande, système de pilotage, puce, procédé de commande et procédé de pilotage
US11737180B2 (en) 2018-11-26 2023-08-22 Shanghai Bright Power Semiconductor Co., Ltd. Control circuit, chip and control method

Also Published As

Publication number Publication date
AU2016218927A1 (en) 2017-09-28
EP3257332A1 (fr) 2017-12-20

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