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WO2008136685A1 - Electronique de commande pour des del à puissance élevée - Google Patents

Electronique de commande pour des del à puissance élevée Download PDF

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Publication number
WO2008136685A1
WO2008136685A1 PCT/NO2008/000158 NO2008000158W WO2008136685A1 WO 2008136685 A1 WO2008136685 A1 WO 2008136685A1 NO 2008000158 W NO2008000158 W NO 2008000158W WO 2008136685 A1 WO2008136685 A1 WO 2008136685A1
Authority
WO
WIPO (PCT)
Prior art keywords
led driver
current
high power
voltage
noise
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/NO2008/000158
Other languages
English (en)
Inventor
Atle Gran
Willy Kronborg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LEDLIGHT GROUP AS
Original Assignee
LEDLIGHT GROUP AS
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
Application filed by LEDLIGHT GROUP AS filed Critical LEDLIGHT GROUP AS
Publication of WO2008136685A1 publication Critical patent/WO2008136685A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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]
    • H05B45/30—Driver circuits
    • H05B45/355—Power factor correction [PFC]; Reactive power compensation
    • 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]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]

Definitions

  • the present invention relates to a driver device for high power LEDs. More specifically, an optimal solution is described for driving a large number of LEDs with a stable and adapted high-voltage power supply.
  • LED light-emitting diode
  • None of them are designed to supply an output voltage that exceeds 48 volts and they have typically a maximum power output of about 22 watts. Therefore, they cannot drive more than about 14 high power LEDs with a supply voltage of about 3.2 volts which is what is required per LED in order to reach 50 to 80 lumens, a necessity if the LED as a light source is to be competitive in relation to conventional lighting, for example, halogen/sodium vapour lamps etc.
  • US-7116294 describes a LED driver, the main object of which is to deliver constant current strength to series-connected LEDs. This is an important feature of an LED driver and will help to increase the lifetime of the LED lamps.
  • High power LED lighting is now in the process of taking over from traditional lighting in, for example, streets and tunnels.
  • the use of LEDs can result in a power saving of as much as 70%.
  • LED drivers are low voltage devices. To be able to drive, for example, street lighting, six such drivers are required, and when they are to be connected a great deal of work with wiring etc. is called for, and, moreover, a lot of heat will be generated (when heat is measured for six LED drivers, the temperature is just above 100 C°, which means that the lifetime is greatly reduced in that semiconductors dry out).
  • the problem is transferred from the actual light bulb, which today is typically a halogen light bulb with a lifetime of up to 16 000 light burning hours, to LED drivers which today have a light burning time of 150 000 light burning hours, i.e., that drivers must perhaps be changed more often than every 20 000 hours.
  • LED drivers which today have a light burning time of 150 000 light burning hours, i.e., that drivers must perhaps be changed more often than every 20 000 hours.
  • the present invention is a high voltage driver for LEDs.
  • high voltage By using high voltage, it will be possible to drive at least 100 LEDs on one driver, which is very many more than has previously been possible. But the use of high voltage also introduces a number of challenges which, inter alia, are associated with the generation of noise. These problems are solved in the inventive high power LED driver which will be described in more detail below.
  • the object of the present invention is to provide a high power LED driver with rectified high voltage and constant current at the output, low inherent noise generation and a soft start-up.
  • a driver which at least comprises an input, a rectifying circuit, a PFC (Power Factor Correction) circuit comprising means to provide a soft start- up, a current regulator for providing constant current to LEDs, and where the voltage is regulated according to the number of LEDs, and an output that delivers constant current and high voltage to LEDs.
  • PFC Power Factor Correction
  • the driver further comprises excess voltage protection at the said input, an input noise filter, a power bank comprising capacitors to smooth out ripple currents exiting the said PFC circuit, and to provide smooth voltage to the current regulator, and an output noise filter in the form of a L/C filter which removes ripple and noise spikes at the output of the LED driver.
  • the object of the LED driver is to supply rectified high voltage and constant current at the output, and where the LED driver has low inherent noise generation and soft start-up.
  • the input 10 of the driver is connected to excess voltage protection 20 which in turn is connected to an input noise filter 30 ahead of a rectifier 40.
  • the last-mentioned is further connected to a PFC 50 which in turn is connected to a power bank 60.
  • a current regulator 70 and output noise filter 80 ensure that constant current with a minimum of noise is given out to an output 90 to which LEDs are connected. All the modules mentioned above comprise components that are connected to each other via a dedicated printed circuit board.
  • the input 10 of the driver is connected to a terminal that has intakes for large cables having a cross-section designed for high voltage from the supply mains, which is 220V alternating current.
  • the terminal is soldered directly onto the circuit board to which the driver components are also soldered. Cables can be connected on both sides of the terminal so that several LED drivers can thus be connected in parallel without having to mount an extra connection box to reduce the cross-section of the supply cable to the driver.
  • the excess voltage protection 20 comprises fuses in both phases to improve safety. This protects against short circuits to earth on both phases, and short-circuiting between the phases. Usually, there is protection on only one phase in known drivers.
  • transient protection there is also excess voltage protection at the input that consists of transient protection. It is known that transients from the supply mains can damage components if they are allowed to penetrate into sensitive electronics.
  • the transient protection consists of three voltage-dependent resistors, i.e., varistors. Two of them are coupled between each phase and earth, and one is coupled between the phases. The components begin to conduct current when the voltage over them exceeds a set limit. This means that transients are short-circuited between the phases or to earth. These components will efficiently protect against transients from the supply mains.
  • the input noise filter 30 has two functions. First, it is to prevent inherently generated noise from the LED driver from getting into the power supply network. There are special stringent requirements with regard to how much noise is allowed from an electronic product. Secondly, the filter is to prevent noise from the power supply network from passing into the LED driver.
  • the filter is of the second order with characteristics which mean that noise over a certain frequency is short- circuited between the phases (differential mode noise), or to earth (common mode noise).
  • the filter has components on both the alternating current side and the direct current side of the rectifier 40. The rectifier 40 must be present in the LED driver since light-emitting diodes are driven by direct current (DC).
  • the power supply found on the supply mains is alternating current (AC) which enters on one side of the rectifying bridge, and direct current exits on the other side. Therefore there is DC high voltage on the output of the rectifier 40.
  • AC alternating current
  • All components of the LED driver are fastened to a printed circuit board in a layout that is optimised to cool down the heat-generating components.
  • Components which generate heat are soldered to points on the circuit board which have heat-conducting surfaces on one or both sides of the circuit board, and where the surfaces on each side may be connected to each other. This provides an efficient heat distribution and cooling thereby eliminating the need for separate cooling jackets for components that produce a lot of heat.
  • the rectifying circuit 40 also has means for giving the LED driver a soft start-up by limiting the current in the start-up phase. This is done by using a resistor with negative temperature coefficient (NTC) that is coupled to the DC side of the rectifying circuit.
  • NTC negative temperature coefficient
  • An NTC resistor has a relatively high resistance before it becomes hot. Therefore, in a brief start-up phase not as much current will pass through such a resistor as when it becomes hot. Limitation of current in the start-up phase (inrush-current) is important for dimensioning cables, fuses and other components. Giving the driver electronics a so-called soft start-up will prolong the lifetime of sensitive components.
  • the PFC circuit 50 is considered to be the core of the present invention.
  • a PFC Power Factor Correction
  • the object of a PFC is to force the current to take the form of a smooth sine in phase with the voltage. It lessens the inductive and capacitive load on the power grid, which results in a gain by giving smaller losses in wiring, thereby reducing the energy consumption of the LED driver.
  • the PFC circuit 50 also provides a boost in that it gives out 390-395V DC, which is an important function to be able to drive many LEDs on one driver.
  • a typical set-up of components around a PFC circuit 50 comprises a MOSFET which switches on and off extremely quickly, coupled to an inductance (hereafter called primary coil) and a capacitor which counters the said inductive and capacitive load of the LED driver. The load then becomes apparently resistive.
  • the PFC circuit 50 is driven at the start-up by a start-up current via components that supply this current, and during operation the PFC circuit 50 is driven by an operating current which takes over once the PFC circuit 50 has started up. This solution has been chosen to reduce power consumption during operation. This will be explained in more detail below.
  • the start-up current is taken out before the previously mentioned resistor with negative temperature coefficient (NTC), i.e., on the DC side of the rectifier 40 which has high voltage.
  • NTC negative temperature coefficient
  • the operating current is taken out after the NTC resistor from a circuit comprising a secondary coil wound on the same core as the said primary coil that constitutes a part of a typical set-up around the PFC circuit 50. Since the said MOSFET that is coupled to the primary coil switches on and off quickly, a voltage will be induced in said secondary coil on the same core as the primary coil of the PFC circuit 50.
  • a PFC circuit is driven by a low voltage and since the start-up current that is taken out is high voltage, the voltage must be reduced over resistors. This means a heat loss which results in increased power consumption.
  • the operating current is, as mentioned, taken out of the induced voltage on the secondary coil where the number of windings helps to determine what voltage is taken out. The heat loss here is then insignificant on taking out low voltage.
  • a power bank 60 is also connected to the output of the PFC circuit 50. This comprises capacitors that are large enough to absorb and thus smooth out ripple currents exiting the PFC circuit 50, and to provide direct voltage to the current regulator 70 that comes after the PFC circuit 50, which is a precondition for the current regulator 70 to function in a stable and optimal manner.
  • the current regulator 70 ensures a constant current out to the LEDs, and delivers a voltage that is dependent on the number of connected LEDs. It is well known that light-emitting diodes are dependent upon a constant and correct current in order to maintain the right light intensity and lifetime. Unduly high current will give excessively high temperature in the light-emitting diode and shorter lifetime, and unduly low current will result in excessively low light intensity. There is thus a balance between lifetime and light intensity of a light-emitting diode. It is therefore important to have good cooling where the light-emitting diodes are mounted, i.e., in connection with the actual printed circuit board on which they are mounted and/or the holder inside which they are mounted.
  • the current regulator 70 measures the current which at any given time goes out to the LEDs that are coupled to the LED driver, and will from this regulate a MOSFET so that the voltage out to the LEDs at all times is such that the right current is put out.
  • the current regulator will ensure correct supply current even though the number of connected LEDs varies.
  • the output noise filter 80 is an L/C filter which removes ripple and noise spikes at the output of the LED driver. Since the light-emitting diodes need stable voltage in order not to be overloaded by high ripple voltages, this filter will ensure that the wire-bound and radiated noise on the cable to the lamp is dampened.
  • the output 90 of the LED driver will supply constant current and a voltage that is in accordance with the number of connected LEDs.
  • the connection points on the LED driver are a terminal block that is coupled so that both one and two LED lamps, each consisting of a plurality of LEDs and each having its cable, can be connected without having to have two wires in the same terminal, which ensures better contact and less danger of waver and contact breaks.
  • the present invention is capable of driving many more high power LEDs than has to date been possible. With the present LED driver it is possible to drive more than 100 LEDs. This is possible inasmuch as the LED driver uses high voltage, which introduces problems of noise that are solved in the different modules mentioned above.
  • the LED driver produces less noise than the European standards as defined in:

Landscapes

  • Rectifiers (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Power Conversion In General (AREA)
  • Dc-Dc Converters (AREA)

Abstract

L'invention concerne un circuit de commande de DEL à puissance élevée ayant une tension élevée redressée au niveau de la sortie, une génération de bruit inhérente faible et un démarrage doux, dans lequel l'utilisation d'une correction de facteur de puissance (PFC) constitue une partie essentielle de l'invention.
PCT/NO2008/000158 2007-05-04 2008-05-02 Electronique de commande pour des del à puissance élevée Ceased WO2008136685A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO20072329 2007-05-04
NO20072329A NO326331B1 (no) 2007-05-04 2007-05-04 Styringselektronikk for høyeffekt LED

Publications (1)

Publication Number Publication Date
WO2008136685A1 true WO2008136685A1 (fr) 2008-11-13

Family

ID=39943710

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NO2008/000158 Ceased WO2008136685A1 (fr) 2007-05-04 2008-05-02 Electronique de commande pour des del à puissance élevée

Country Status (2)

Country Link
NO (1) NO326331B1 (fr)
WO (1) WO2008136685A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2466790A (en) * 2009-01-05 2010-07-14 Greengage Lighting Ltd A soft start mains LED lamp with LED chain and capacitor

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050128751A1 (en) * 2003-05-05 2005-06-16 Color Kinetics, Incorporated Lighting methods and systems
US20060071614A1 (en) * 2002-12-19 2006-04-06 Koninklijke Philips Electronics N.V. Leds driver
US20070182347A1 (en) * 2006-01-20 2007-08-09 Exclara Inc. Impedance matching circuit for current regulation of solid state lighting
US20080018261A1 (en) * 2006-05-01 2008-01-24 Kastner Mark A LED power supply with options for dimming

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4177022B2 (ja) * 2002-05-07 2008-11-05 ローム株式会社 発光素子駆動装置、及び発光素子を備えた電子機器
JP2004045488A (ja) * 2002-07-09 2004-02-12 Casio Comput Co Ltd 表示駆動装置及びその駆動制御方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060071614A1 (en) * 2002-12-19 2006-04-06 Koninklijke Philips Electronics N.V. Leds driver
US20050128751A1 (en) * 2003-05-05 2005-06-16 Color Kinetics, Incorporated Lighting methods and systems
US20070182347A1 (en) * 2006-01-20 2007-08-09 Exclara Inc. Impedance matching circuit for current regulation of solid state lighting
US20080018261A1 (en) * 2006-05-01 2008-01-24 Kastner Mark A LED power supply with options for dimming

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2466790A (en) * 2009-01-05 2010-07-14 Greengage Lighting Ltd A soft start mains LED lamp with LED chain and capacitor

Also Published As

Publication number Publication date
NO326331B1 (no) 2008-11-10
NO20072329L (no) 2008-11-05

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