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GB2514380A - LED driver circuit - Google Patents

LED driver circuit Download PDF

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Publication number
GB2514380A
GB2514380A GB1309200.2A GB201309200A GB2514380A GB 2514380 A GB2514380 A GB 2514380A GB 201309200 A GB201309200 A GB 201309200A GB 2514380 A GB2514380 A GB 2514380A
Authority
GB
United Kingdom
Prior art keywords
driver circuit
led driver
generator
rectifier
choke
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.)
Withdrawn
Application number
GB1309200.2A
Other versions
GB201309200D0 (en
Inventor
Bernard Frederick Fellerman
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to GB1309200.2A priority Critical patent/GB2514380A/en
Publication of GB201309200D0 publication Critical patent/GB201309200D0/en
Publication of GB2514380A publication Critical patent/GB2514380A/en
Withdrawn legal-status Critical Current

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
    • 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]
    • H05B45/375—Switched mode power supply [SMPS] using buck topology
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Landscapes

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

Abstract

An LED driver circuit 1 has a rectifier 3 to rectify AC mains 2 to provide a DC output. A waveform generator 5 is driven by the rectifier to create a low duty cycle waveform. An air cored choke 7 is provided in series with a switch 5A, such as a MOSFET, driven by the generator output and LEDs X are connected in series with the choke output. In use the time between pulses from the generator is such as to allow the choke to fully decay between generator pulses.

Description

I
Title: LED Driver Circuit The present invention relates to a LED driver circuit.
It is known to provide arrays of LED lights driven by a low DC voltage often converting a mains voltage to a working DC voltage through a transformer and rectifier circuit. Such array of LEDs may be used in many applications such as lamps, street lights, shops, garages, gardens, car parks and the like, and are less costly to run than incandescent type light bulbs. In the case of lamps, the light output is restrained by the amount of power deliverable by the transformer which has to be quite small in order for it to fit in a casing which is equivalent in size to a conventional light bulb.
The invention seeks to provide an LED driver circuit which can deliver a greater light output to power input ratio than that known hitherto and which can be made compact in size.
According to the present invention there is provided an LED driver circuit comprising: a) a rectifier to rectify AC mains to provide a DC output b) a waveform generator driven by the rectifier to create a low duty cycle waveform, c) an air cored choke in series with the generator output, and d) LEDs connected n series with the choke output, in use the time between pulses from the generator being such as to allow the choke to fUlly decay between generator pulses.
Preferably the rectifier is a (liii wave bridge rectifier.
Preferably the rectifier includes a smoothing capacitor.
Preferably the rectifier has a half wave output to power the waveform generator.
Preferably a resistor is provided between the half wave output and the waveform generator.
Preferably the choke has a diode which feeds back the voltage produced by the decaying magnetic field of the choke to substantially double the current to the LEDs.
Preferably the waveform generator delivers a waveform of around 1:14 duty cycle.
An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a circuit diagram of a driver circuit and Figure 2 shows an optional dimmer circuit for the driver circuit.
Referring to Figure 1 there is shown a LED driver circuit I for an array of LEDs X. Circuit 1 connects to a sinusoidal AC mains input 2.
A full wave bridge rectifier 3 is provided having an AC input 3A,3B and a DC output 3C,3D. The output of rectifier 3 is smoothed by a capacitor 4.
A waveform generator 5 is provided which delivers a special waveform of 1:14 duty cycle. Generator 5 is powered by a half wave output of the rectifier 3 through a resistor 6.
As the generator 5 is powered by a half wave output of the rectifier 3, it is half the voltage which also means quarter power to the resistor 6.
The output of the generator 5 is in series with an air cored choke 7 which cannot saturate and does not cause high frequency noise. Choke 7 is wired in series with LEDs X. In use of circuit 1, the time between pulses from the generator 5 is such as to allow the choke 7 to fully decay between the generator pulses. This prevents the current from steadily increasing until the circuit blows, thus eliminating the so called "Buck Effect".
The average current produced by generator 5 is typically 175ma with a pulse 14 times that value, i.e. 2.45 amps.
The choke 7 has a diode 8 which feeds back the voltage produced by the decaying magnetic field of the choke to substantially double the current to the LEDs X, i.e. doubling the current to 350ma.
Generator 5 includes a Mosfet transistor 5A which has very low on state losses and is fast switching which makes it very suitable for this circuit.
The circuit is simple but effective and is low cost. It only has 18 components so it will fit easily into a housing the size of a domestic lamp. An number LEDs X maybe driven, e.g. LEDs. The circuit is very compact, and whilst it may be used to drive LEDs in a number of different applications (e.g. in street lighting applications), the circuit lends itself to being positioned inside of an LED lamp to replace conventional light bulbs. The LED's could also be in the form a pairs of LEDs.
The circuit shown in Figure 2 may be wired in series with the AC mains input 2 to provide a dimming circuit to dim the LEDs X and so alter their light output.
The invention my take a form different to that specifically described above.
Further modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims (9)

  1. CLAIMS1. An LED driver circuit comprising: e) a rectifier to rectify AC mains to provide a DC output 1) a waveform generator driven by the rectifier to create a low duty cycle waveform, g) an air cored choke in series with the generator output, and h) LEDs connected n series with the choke output, in use the time between pulses from the generator being such as to allow the choke to fully decay between generator pulses.
  2. 2. An LED driver circuit according to claim I, wherein the rectifier is a full wave bridge rectifier.
  3. 3. An LED driver circuit according to claim 1 or 2, wherein the rectifier includes a smoothing capacitor.
  4. 4. An LED driver circuit according to claim 1, 2, or 3, wherein the rectifier has a half wave output to power the waveform generator.
  5. 5. An LED driver circuit according to claim 4, wherein a resistor is provided between the half wave output and the waveform generator.
  6. 6. An LED driver circuit according to any preceding claim, wherein the choke has a diode which feeds back the voltage produced by the decaying magnetic field of the choke to substantially double the current to the LEDs.
  7. 7. An LED driver circuit according to any preceding claim, wherein the waveform generator delivers a waveform of around 1:14 duty cycle.
  8. 8. An LED driver circuit substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
  9. 9. An LED lamp having an LED driver circuit according to any preceding claim.
GB1309200.2A 2013-05-22 2013-05-22 LED driver circuit Withdrawn GB2514380A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1309200.2A GB2514380A (en) 2013-05-22 2013-05-22 LED driver circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1309200.2A GB2514380A (en) 2013-05-22 2013-05-22 LED driver circuit

Publications (2)

Publication Number Publication Date
GB201309200D0 GB201309200D0 (en) 2013-07-03
GB2514380A true GB2514380A (en) 2014-11-26

Family

ID=48747145

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1309200.2A Withdrawn GB2514380A (en) 2013-05-22 2013-05-22 LED driver circuit

Country Status (1)

Country Link
GB (1) GB2514380A (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100079124A1 (en) * 2008-09-30 2010-04-01 John Laurence Melanson Adjustable Constant Current Source with Continuous Conduction Mode ("CCM") and Discontinuous Conduction Mode ("DCM") Operation
GB2475146A (en) * 2009-11-03 2011-05-11 Intersil Inc An LED driver with open loop dimming
EP2389046A2 (en) * 2010-05-19 2011-11-23 Monolithic Power Systems, Inc. Triac dimmer compatible switching mode power supply and the method thereof
EP2503847A2 (en) * 2011-03-23 2012-09-26 Panasonic Corporation Lighting device and illumination apparatus
EP2515614A2 (en) * 2011-04-18 2012-10-24 Panasonic Corporation Lighting device for semiconductor light-emitting element and illumination fixture using the same
US20130119881A1 (en) * 2011-11-15 2013-05-16 On-Bright Electronics (Shanghai) Co., Ltd. Led lighting systems and methods for constant current control in various operation modes
EP2603059A1 (en) * 2011-12-05 2013-06-12 Panasonic Corporation Lighting apparatus and illuminating fixture with the same

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100079124A1 (en) * 2008-09-30 2010-04-01 John Laurence Melanson Adjustable Constant Current Source with Continuous Conduction Mode ("CCM") and Discontinuous Conduction Mode ("DCM") Operation
GB2475146A (en) * 2009-11-03 2011-05-11 Intersil Inc An LED driver with open loop dimming
EP2389046A2 (en) * 2010-05-19 2011-11-23 Monolithic Power Systems, Inc. Triac dimmer compatible switching mode power supply and the method thereof
EP2503847A2 (en) * 2011-03-23 2012-09-26 Panasonic Corporation Lighting device and illumination apparatus
EP2515614A2 (en) * 2011-04-18 2012-10-24 Panasonic Corporation Lighting device for semiconductor light-emitting element and illumination fixture using the same
US20130119881A1 (en) * 2011-11-15 2013-05-16 On-Bright Electronics (Shanghai) Co., Ltd. Led lighting systems and methods for constant current control in various operation modes
EP2603059A1 (en) * 2011-12-05 2013-06-12 Panasonic Corporation Lighting apparatus and illuminating fixture with the same

Also Published As

Publication number Publication date
GB201309200D0 (en) 2013-07-03

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)