WO2016197263A1 - Power efficient led drivers - Google Patents

Power efficient led drivers Download PDF

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Publication number
WO2016197263A1
WO2016197263A1 PCT/CN2015/000401 CN2015000401W WO2016197263A1 WO 2016197263 A1 WO2016197263 A1 WO 2016197263A1 CN 2015000401 W CN2015000401 W CN 2015000401W WO 2016197263 A1 WO2016197263 A1 WO 2016197263A1
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Prior art keywords
leds
current
voltage
array
led
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PCT/CN2015/000401
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French (fr)
Chinese (zh)
Inventor
Hezhang Chu
Ho Yin LEE
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Abbeydorney Holdings Ltd.
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Priority to PCT/CN2015/000401 priority Critical patent/WO2016197263A1/en
Publication of WO2016197263A1 publication Critical patent/WO2016197263A1/en

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    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B45/00Circuit arrangements for operating light emitting diodes [LED]
    • H05B45/30Driver circuits
    • H05B45/37Converter circuits

Abstract

Method and system for driving LED lighting application (200) provide a driving circuit(202) that can power an array of LEDs(204) in a more efficient manner. The disclosed driving circuit(202) achieves higher power efficiency by maintaining the LED forward voltage and current at or near the minimum level needed to turn on the LED. In some embodiments, this entails providing the LEDs with a forward voltage and current that are within an initial nonlinear region (102) of the LED current-voltage curve (100). A greater number of LEDs may then be deployed to compensate for potentially less lumen output as a result of operating the LEDs at or near their turn-on point. Such an arrangement produces substantially the same lumen output as existing LED lighting application (200) while consuming less power and generating less heat, thereby increasing power efficiency.

Description

POWER EFFICIENT LED DRIVERS

Inventor (s) : Hezhang CHU and Ho Yin LEE

FIELD OF THE INVENTION

The disclosed embodiments relate generally to methods and systems for driving solid-state lighting devices, such as light emitting diodes (LEDs), and particularly to a more power efficient method and system for driving such lighting devices.

BACKGROUND OF THE INVENTION

An LED emits light when a voltage exceeding the LED "turn-on" or forward voltage is applied across the LED to allow current to flow through the LED. The current flowing through the LED, or forward current, must be a constant or DC current Within the LED, a significant portion of the current—as much as 70 percent according to some estimates—is converted to heat while only a The heat must be removed or otherwise dissipated in some way to prevent the LED from becoming too hot, which can lower its efficiency and also shorten the life of the LED. Compounding this heat problem, existing LED drivers are Generally designed to over drive the LED so as to maximize the amount of light The over driving increases the forward current well beyond the LED minimum "turn-on" point, which not only exacerbates the heat dissipation problem, but also results in wasted power, as the amount of light from the LED, typically measured In lumen (Lm), does not increase linearly with increasing current.

Thus, a need exists for an improved driving circuit in LED lighting applications and other similar lighting applications, and particularly for a more power efficient driving circuit in such lighting applications.

SUMMARY OF THE DISCLOSED securities

The disclosed embodiments are directed to a method and system for driving LED lighting applications and other similar lighting applications. The particular driving circuit achieves higher power efficiency by carefullymanaging the forward voltage and current of the LEDs. In particular, rather than over driving the system provides a driving circuit that can drive an array of LEDs in a more power efficient manner compared to existing driving circuits. The LEDs to try and shine the output of the LEDs with a forward voltage and current that are A greater number of LEDs may then be deployed to compensate for the particular lower lumen output resulting from LEDs at or near their turn-on point. The use of a forward voltage and current That LED at the same LED lighting applications and other similar lighting applications to produce substantially the bare oxide output as existing LED lighting applications while consuming less power and generating less heat, Power efficiency.

In general, in one aspect, the disclosed embodiments are directed to a driving circuit for driving an array of LEDs. The driving circuit includes, among other things, an AC/DC voltage converter configured to receive an AC voltage and output a DC voltage, And a DC/DC current converter connected to the AC/DC voltage converter and configured to receive the DC voltage from the AC/DC voltage converter and output a DC current. The driving circuit further includes a voltage and current regulator connected to the DC/ DC current converter and configured to receive the DC current from the DC/DC current converter and output a forward voltage and current to the array of LEDs. The voltage and current regulator is further configured to maintain the forward voltage and current to the array of LEDs Within an initial nonlinear region of a current-voltage curve for an LED in the array of LEDs.

In general, in another aspect, the disclosed embodiments are directed to a LED lighting application. The LEDs lighting application includes, among other things, an array of LEDs, and a driving circuit connected to the array of LEDs and configured to provide a forward voltage and Current to the array of LEDs. The driving circuit maintains the forward voltage and current to the array of LEDs within an initial nonlinear region of a current-voltage curve for an LED in the array of LEDs. The LEDs are arranged in one or more strings of LEDs, each string of LEDs composed of one or more LED packages connected in series to one another, each LED package containing a plurality of individual LEDs connected in series to one another.

In general, in yet another aspect, the disclosed embodiments are directed to a method of driving an array of LEDs. The method includes, among other things, receiving an AC voltage, converting the AC voltage to a DC current, using the DC current to The forward voltage and current provided to the array of LEDs are maintained within an initial nonlinear region of a current-voltage curve for an LED in the array Of LEDs.

BRIEF DESCRIPTION OF THE DRAWINGS

The additional and other advantages of the disclosed embodiments will become apparent upon reading the following detailed description and upon reference to the drawings,

1A is a current-voltage curve showing the forward voltage and current used by the power efficient driving circuit disclosed herein to drive an LED according to some embodiments;

1B is a luminosity-current curve showing the forward current used by the power efficient driving circuit disclosed herein to drive an LED and the resulting relative luminous intensity from the LED according to some embodiments;

2 is a block diagram of the power efficient driving circuit disclosed herein to some embodiments;

FIG. 3 is circuit diagram for the power efficient driving circuit

4A-4D illustrating the layers of a printed circuit board for the power efficient driving circuit disclosed herein to some embodiments.

DETAILED DESCRIPTION OF THE DISCLOSED SERVICE

As an initial matter, it will be appreciated that the development of an actual, real commercial application incorporating aspects of the disclosed embodiments will require many implementation specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation specific decisions may include, and Between having a limited to, compliance with system related, business related, government related and other constraints, which may vary by specific implementation, location and from time to time. While a developer's effects might be complex and time consuming in an absolute sense, such Effort would nevertheless be a routine undertaking for those of skill in this art having the benefit of this disclosure.

It should also be understood that the disclosed disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. Thus, the use of a singular term, such as, but not limited to, "a" and the like, is not intended ",", ",", "lower," "down," "up," "side," and the like, used in the written description are for clarity in specific reference to the drawings and are not intended to limit the scope of the invention.

As alluded to above, rather than over driving LEDs to try and shine lumen output, the driving circuit disclosed herein is designed to maintain the LED forward voltage and current at or near (eg, within 10 percent) the minimum level needed to turn on the An example of a current-voltage curve 100 showing the forward voltage and current for a typical LED can be seen in FIG. 1A, although not generally drawn to scale. An example of luminance-current curve 110 showing the forward current and corresponding relative The shape and location of these curves 100 and 110 may of course vary depending on operating temperature, diode size, diode material, manufacturing process, number of diodes Per package, and several other factors. An example of an LED with si 1A and 1B is component number HL-A-2835H431W-S1-08-HR1 from Guangzhou Hongli Opto-Electronic Co., Ltd., of Huadong Town, Huadu Dist. , Guangzhou, China.

In the graph of FIG. 1A, the horizontal axis represents voltage (V) and the vertical axis represents current (I) . As the curve 100 shows, current does not begin to flow, and hence the LED does not turn on or emitlight, After the forward voltage reaches approximately 2.6 V and the LED turns on, current begins flowing through the LED and increases quickly with increasing voltage. The increase in forward current is most linear, but there is a small The region of the curve 100 up to about 60 mA, generally indicated at 102, where the current increase is largely nonlinear for this particular curve. In accordance with the disclosed embodiment, the driving circuit disclosed herein is designed to drive the LED using a forward voltage and Current that are within this initial nonlinear region 102 of the curve 100. Such a forward voltage and current in the nonlinear region 102 are considered to beat or near the minimum level needed to turn on the LED for purposes of the present disclosure. On the other hand, driving the LED with a forward voltage and current that are outside The initial nonlinear region 102 of the curve 100 is considered to be over driving the LED for purposes of the present disclosure.

The relative luminous intensity resulting from driving the LED using the above-referenced forward voltage and current is indicated by the region 112 on the curve 110 in FIG. 1B, where the horizontal axis represents current and the vertical axis represents the luminous luminous intensity. As can Be seen, the relative luminous intensity increases relatively linearly with increasing forward current up to about 60 mA or about 1.0 candela (cd) for this particular curve 110. This linear region of the curve 110 is generally indicated at 112in FIG. 1B. Beyond this Linear region 112, the luminous intensity does not increase increase linearly with forward current such that each subsequent increase in forward current may result in a progressively small increase in luminous intensity, potentially due to the greater heat generated as a result of the higher current Affecting the LED. The nonlinear increase generally holds true whether for luminous intensity, luminous flux, luminous power, lumen output, or other measures of light from the LEDs. On the other hand, the amount of light from the LEDs does increase generally linearly with Each additional LED. Thus, by leveraging the linear region 112 of the curve 110, the disclosed driving circuit can produce substantially the same number of lumens (eg, within 10 percent) as existing applications, but using less Power and generating less heat than existing applications, by driving a greater number of LEDs using a smaller forward voltage and current.

The LED lighting application 200 may be any lighting application in which the driving circuit 200 is used to drive or otherwise provide power to an array Of LEDs 204. Examples of such lighting applications may include standard A-style omnidirectional LED lights, LED flood lights, LED tube lights, and similar lighting applications having various wattage ratings for both indoor and outdoor uses.

In the example of FIG. 2, the driving circuit 202 drives the array of LEDs 204 by converting an AC input voltage into a relatively constant DC output current and providing that current to the LEDs. The driving circuit 202 may incorporate a number of functional components that 2, including an AC/DC voltage converter 212 and a DC/DC current converter 214 connected downstream to the AC/DC voltage converter 212. An AC power source, typically a 120 V AC mains, provides Power to the driving circuit 202. When connected to the driving circuit 202, AC voltage from the 120 V AC mains is converted by the AC/DC voltage converter 212 into a DC voltage that is provided to the DC/DC current converter 214. DC voltage is then converted by DC/DC current converter 214 to a relatively constant DC current that is fed t o the array of LEDs 204.

In accordance with the disclosed embodiment, the driving circuit 202 is configured to provide a forward voltage and current that are at or near the minimum level needed to drive or otherwise cause the array of LEDs 204 to turn on and emit light. The driving circuit 202 may further incorporate a voltage and current regulator 216 designed to control or otherwise limit the forward voltage and current provided to the array of LEDs 204. specific, the voltage and current regulator 216 may be configured to ensure that the driving circuit 202 Providing only the minimum forward voltage and current needed, as discussed above, to drive the array of LEDs 204. A greater number of LEDs may then be deployed with the driving circuit 202 to make up for any deficiency in lumens outputted by the LEDs as a Result of the voltage and current reg Ator 216 limiting the voltage and current to the LEDs.

In other embodiments, the voltage and current regulator 216 may instead be operationally internal to the 2, and other figures described as that a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a May may shown, those having ordinary skill in the art will understand that any block may be divided into two more constituent blocks, and any two or more blocks may be combined into a single block, without departing from the scope of the disclosed embodiments.

As can be seen in FIG. 2, the array of LEDs 204 may be arranged in one or more strings of LEDs 206, each string 206 being composed of one or more LED packages 208, labeled ED1, ED2, ...EDn, connected in series In addition, each LED package 208 may contain one or more individual LEDs 210 that may also be connected in series to one another. The number of individual LEDs 210 in each LED package 208 may vary and may be selected based on, Among other things, the lumen output needed for the lighting application, number of LED packages the lighting application can feasibly physical house, heat dissipation capacity, acceptable power consumption level, and other factors. The voltage and current regulator 216 may then be adjusted or otherwise Fine-tuned as needed based on the total number of individual LEDs 210 to ensure the driving circuit 202 provides only the minimum forward voltage and current needed to drive the LEDs, as discussed above.

As one example of the above LED driving strategy, it has been found that a 4 W A-style lightbulb application requires a field output output near 450 Lm may need around 90 individual LEDs 210 to achieve the pixel output. These 90 individual LEDs 210 May be arranged in any manner known to those having ordinary skill in the art that is feasible for the specific requirements of the LED lighting application. Thus, for example, one string of 30 series-connected LED packages 208 may be used, each LED package 208 Three series-connected individual LEDs 210. In another example, one string of 45 series-connected LED packages 208 may be used, each LED package 208 containing two individual LEDs 210. It is also possible to use LED packages 208 with only a single individual LED 210 and then select the number of LED packages 208 And/or the number of strings of LEDs 206 as needed. For example, a single string of 90 series-connected LED packages 208, each package containing a single LED 210 may be used. Fine-tuning the voltage and current regulator 216to ensure that the driving circuit 202 provides only theminimumforward voltage and currentneeded, as discussed above, which may be about 249 V and about 12 mA, respectively, for this particular example.

As another example, it has been observed that a 7 W A-style lightbulb application requiring a field output output near 850 Lm may need roughly 140 individual LEDs to achieve the target lumen output. As before, these 140 individual LEDs 210 may be arranged in Any manner known to those having ordinary skill in the art that is feasible for the specific requirements of the LED lighting application. There may be, for example, two parallel strings of 35 series-connected LED packages 208, each LED package 208 containing two series- Connected individual LEDs 210. alternatively, there may be four parallel strings of 35 series-connected LED packages 208, each LED package 208 containing one individual LED 210. The target lumen output may then be achieved by adjusting or fine-tuning the voltage and current Regulator 216so the driving circuit 202 provides only the Minimum forward voltage and current needed, as discussed above, which may be about 188 V and about 30 mA, respectively, for this particular example.

In the previous examples, it is also possible for the voltage and current regulator 216 to be adjusted such that the driving circuit 202 drives the LEDs well beyond the minimum forward voltage and current in the event such over driving should ever be needed.

2 insofar as an LED lighting application 300, the specific implementation of the 7 W A-style lightbulb application discussed above is depicted in FIG. 2 insofar as an LED lighting application 300 The array of LEDs 304 is composed of two parallel strings of LEDs 306, each string 306 having 35 series-connected LED packages 308, labeled ED1, ED2, ... ED35, each LED Package containing two series-connected individual LEDs310 for a total of 140 LEDs. Connection of the array of LEDs 304 to the driving circuit 302 may be enhanced via terminals or similar connection 3. The driving circuit 302 itself is composed of a combination of discrete and integrated circuit components connected as shown and having the values listed in Table 1 below. An AC/DC voltage converter is indicated generally at 312 and a The DC/DC current converter is generally indicated at 314. As before, an AC power source, typically a 120 V AC mains, provides power to the driving circuit.

Component Description F1 Fuse 1A 125VAC DB1 Diode Bridge Rectifier RV1 Varistor 275VAC R1/R2 Resistor 10K R3 Resistor 220K R4 Resistor 750K R5 Resistor 3.3K R6/R8/R10 Resistor 510K R7 Resistor 10K R9 Resistor 10ohms L/N Line Wire #26AWG 150°C 3KV LED- Wire #26AWG 150°C 3KV LED+ Wire #26AWG 150°C 3KV C1 Capacitor 47nF 500V C4/C5 Capacitor 1uF 50V C2 Capacitor 10nF 1000V C3 Capacitor 0.1 uF 250VDC C6 Capacitor 2.2uF 400V D3 Diode Schottky 60V 1A

Component Description D4 Diode General Purpose 85V 200MA VR2 Diode Zener 100V 310MW VR3 Diode Zener 13V 150MW Q1 Transistor General Purpose PNP 80V 0.5A Q2 Transistor MOSFET P-Channel 300V 210MA D1/D2 Diode General Purpose 400V 1A PCB 29.0mm x 17.5mm x1.6mm Copper 2-layer IC1 Constant Current LED Driver L2 Inductor 3.3mH 140mA L3 Inductor 680uH 250mA T1 Transformer 880uH

TABLE 1

In general operation, AC voltage from the AC main, typically 120 V at 60 Hz, is converted to DC voltage by a full-wave rectifier composed of diode bridge DB1, varistor RV1, and an inductive network made of resistors R1, R2, inductors L2, L3, and capacitors C1, C2, C3, connected as shown. A fuse F1 provides overcurrent protection for the LED lighting application 300. The rectified and filtered input voltage is applied to one end of the primary winding of transformer T1. Diode D3 Is used to protect the integrated circuit IC1 from negative ringing (drain voltage below source voltage) when the power MOSFET Q2 is off and the input voltage is below the reflected output voltage. Transistor Q1, Zener diode VR3, and resistors R7, R8 help improve The efficiency of the driving circuit. A constant current driver IC1, which may bepart number LNK457DG from P Ower Integrations, Inc., of San Jose, California, USA, provides the forward voltage and current that drive the array of LEDs 304. The constant current driver IC1 is powered from its BYPASS pin (Pin 2) via a decoupling capacitor C5. Resistors R4, R6 and Zener diode VR2 regulate the voltage across IC1.

In accordance with the disclosed embodiment, a voltage and current regulator 316 is connected to the feedback pin of the constant current driver IC1 to control the forward voltage and current to the array of LEDs 304. This voltage and current regulator 316 may then be adjusted or Otherwise, the fine and current regulator 316 is composed of resistors R5, R9, capacity C4, and diode D4, connected as shown and having The values listed in Table 1. It has been observed that these particular components R5, R9, C4, and D4 having the values listed in Table 1, when connected as shown in the 7 W A-style lightbulb application of FIG. 3, mayproduceperformance Measures similar to those shown below in Table 2:

Figure PCTCN2015000401-appb-000001

TABLE 2

As can be seen in the third row of Table 2, the driver efficiencyis about 90.08 percent and 90.81 percent, respectively, before and after the LED thermal has stabilized when a voltage and current regulator 316 as described above is connected to the 7 W A- 3. In contrast, for existing 7 W A-style lightbulb applicationsthat over drive the LEDs rather than minimize the forward voltage and current to the LEDs, the driver efficiency is significantly higher.

In addition, the particular design of the voltage and current regulator 316 shown here allows the driving circuit 302 to be used with another lighting application Having a different array of LEDs 304 simply by adjusting or otherwise fine-tuning the voltage and current regulator 316 for the other lighting application without having to alter other components in the driving circuit 302. For example, resistor R9, by virtue of being connected between a feedback pin and a ground pin of the constant current driver IC1, acts as a limiting resistor that restricts the amount of forward current provided to the array of LEDs 304. Changing the value of limiting resistor R9 therefore changes the amount forward current that may be Provided to the array of LEDs 304. By changing R9 from the 10 ohms listed in Table 1 to 23 ohms, the driving circuit 302 may be dropped in as a driving circuit for the 4 W A-style lightbulb application discussed earlier. Table 3 below shows Performance measures similar to those that may be o Btained for the referenced 4 W A-style lightbulb application when driven by the driving circuit 302 in which resistor R9 has a value of 23 ohms:

Figure PCTCN2015000401-appb-000002

TABLE 3

As the third row of Table 3 shows, the lamp efficiency is about 89.35% and 91.85%, respectively, before and after the LED thermal has stabilized when R9 is replaced in the voltage and current regulator 316 as described above for the 4 W A-style On the other hand, for existing 4 W A-style lightbulb lighting applications that over drive the LEDs, the lamp efficiency is substantially higher.

In the last embodiment, although a particular design has been shown for the AC/DC voltage converter 312, the DC/DC current converter 314, and the voltage and current regulator 316, numerous equivalent alternative designs may be used without departing from the scope of For example, instead of a single resistor R9in the voltage and current regulator 316, two resistors having roughly the same value as R9 may be used, and the like. Voltage converter 312, the DC/DC current converter 314, and the voltage and current regulator 316 for illustrative purposes only, and one or more components may be added to or removed from the absence of the scope of the disclosed embodiments. Design for the AC/DC voltage converter 312, the DC / DC current converter 314, and the voltage and current regulator 316 shown above should be viewed as exemplary only and not exhaustive.

4A to 4D, an exemplary printed circuit board (PCB) is shown that may be used for implementing the driving circuit disclosed herein to some embodiments. The PCB shown here may be a copper based PCB having at least a top overlay 400 (FIG. 4A), a top trace layer 402 (FIG. 4B) , a bottom overlay 404 (FIG. 4C), and a bottom trace layer 406 (FIG. 4B) . The operation and interaction of the various layers is self- Suffice it to say, it is important that the impedance of the PCB be analyzed and factored into any design of the voltage and current regulator 316 and The derivation of the value of limiting resistor R9. Other PCB layouts besides the one shown here may of course be used without Detached from the scope of the disclosed embodiments.

Of particular aspects, implementations, and applications of the present disclosure have illustrated and described, it is to understood that the present disclosure is not limited to the precise construction and compositions disclosed herein and that various modifications, and variations may be apparent From the insufficient descriptions without departing from the scope of the disclosed embodiments as defined in the appended claims.

Claims (21)

  1. A driving circuit for driving an array of LEDs, comprising:
    An AC/DC voltage converter configured to receive an AC voltage and output a DC voltage;
    a DC/DC current converter connected to the AC/DC voltage converter and configured to receive the DC voltage from the AC/DC voltage converter and output a DC current; and
    a voltage and current regulator connected to the DC/DC current converter and configured to receive the DC current from the DC/DC current converter and output a forward voltage and current to the array of LEDs,
    The voltage and current regulator is further configured to maintain the forward voltage and current to the array of LEDs within an initial nonlinear region of a current-voltage curvefor an LED in the array of LEDs.
  2. The driving circuit of claim 1, wherein the DC/DC current converter is a constant current driver and the voltage and current regulator includes a limiting resistor connected between a feedback pin and a ground pin of the constant current driver.
  3. The driving circuit of claim 1, wherein the limiting resistor has a resistance value that is specifically selected to restrict the forward current to the array of LEDs to within the initial nonlinear region of the current-voltage curve of the array of LEDs.
  4. The driving circuit of claim 3, wherein the array of LEDs is configured for a 4 W lighting application and the limiting resistor is a 23 ohm resistor.
  5. The driving circuit of claim 3, wherein the array of LEDs is configured for a 7 W lighting application and the limiting resistor is a 10 ohm resistor.
  6. An LED lighting application, including:
    An array of LEDs; and
    A driving circuit connected to the array of LEDs and configured to provide a forward voltage and current to the array of LEDs, the driving circuit maintaining the forward voltage and current to the array of LEDs within an initial nonlinear region of a current-voltage curve for An LED in the array of LEDs;
    The array of LEDs is arranged in one or more strings of LEDs, each string of LEDs composed of one or more LED packages connected in series to one another, each LED package containing a plurality of individual LEDs connected in series to one another.
  7. The LED lighting application of claim 6, wherein the LED lighting application is a 4 W lightbulb application and the array of LEDs is arranged in one string of 30 series-connected LED packages.
  8. The LED lighting application of claim 7, each LED package contains three series-connected individual LEDs.
  9. The LED lighting application of claim 6, wherein the LED lighting application is a 7 W lightbulb application and the array of LEDs is arranged in two parallel strings of 35 series-connected LED packages.
  10. The LED lighting application of claim 9, each LED package contains two series-connected individual LEDs.
  11. The LED lighting application of claim 6, wherein the LED lighting application isone of: an A-style omnidirectional LED lightbulb, an LED flood light lightbulb, an LED tube light lightbulb.
  12. A method of driving an array of LEDs, comprising:
    Receiving an AC voltage;
    Converting the AC voltage to a DC current;
    Using the DC current to generate a forward voltage and current; and
    Providing the forward voltage and current to the array of LEDs;
    The forward voltage and current provided to the array of LEDs are maintained within an initial nonlinear region of a current-voltage curve for an LED in the array of LEDs.
  13. The method of claim 12, wherein the forward voltage and current are generated using a constant current driver, the constant current driverhaving a limiting resistor connected between a feedback pin and a ground pin of the constant current driver.
  14. The method of claim 13, wherein the limiting resistor has a resistance value that is specifically selected to restrict the forward current to the array of LEDs to within the initial nonlinear region of the current-voltage curve of the array of LEDs.
  15. The method of claim 14, wherein the array of LEDs is configured for a 4 W lighting application and the limiting resistor is a 23 ohm resistor.
  16. The method of claim 14, wherein the array of LEDs is configured for a 7 W lighting application and the limiting resistor is a 10 ohm resistor.
  17. The method of claim 12, wherein the array of LEDs is arranged in one or more strings of LEDs, each string of LEDs composed of one or more LED packages connected in series to one another, each LED package containing a plurality of individual LEDs connected in Series to one another.
  18. The method of claim 15, wherein the array of LEDs is arranged in one string of 30 series-connected LED packages.
  19. The method of claim 18, where each LED package contains three series-connected individual LEDs.
  20. The method of claim 16, wherein the array of LEDs is arranged in two parallel strings of 35 series-connected LED packages.
  21. The method of claim 20, where each LED package contains two series-connected individual LEDs.
PCT/CN2015/000401 2015-06-12 2015-06-12 Power efficient led drivers WO2016197263A1 (en)

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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090261748A1 (en) * 2008-04-15 2009-10-22 Mckinney Steven Modified dimming LED driver
CN102056378A (en) * 2009-11-03 2011-05-11 英特赛尔美国股份有限公司 Led driver with open loop dimming control
KR20110132188A (en) * 2010-05-31 2011-12-07 주식회사 파워넷 Led driving device having high efficiency
CN202488840U (en) * 2012-03-14 2012-10-10 杨卫民 Light-emitting diode (LED) constant-current power supply
CN202873122U (en) * 2012-07-20 2013-04-10 张志军 LED control unit and constant current-type unit voltage stabilization LED control circuit
TWI448191B (en) * 2012-01-10 2014-08-01 Univ Nat Taipei Technology Feedback control to reduce power consumption light-emitting diode driving device
CN104244492A (en) * 2012-04-07 2014-12-24 吴槐 LED working mode control apparatus
WO2015036551A1 (en) * 2013-09-13 2015-03-19 Koninklijke Philips N.V. Controller for controlling a current regulating element of a lighting load
CN104470100A (en) * 2014-11-17 2015-03-25 苏州蓝特照明科技有限公司 Switching power supply of LED floodlight

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090261748A1 (en) * 2008-04-15 2009-10-22 Mckinney Steven Modified dimming LED driver
CN102056378A (en) * 2009-11-03 2011-05-11 英特赛尔美国股份有限公司 Led driver with open loop dimming control
KR20110132188A (en) * 2010-05-31 2011-12-07 주식회사 파워넷 Led driving device having high efficiency
TWI448191B (en) * 2012-01-10 2014-08-01 Univ Nat Taipei Technology Feedback control to reduce power consumption light-emitting diode driving device
CN202488840U (en) * 2012-03-14 2012-10-10 杨卫民 Light-emitting diode (LED) constant-current power supply
CN104244492A (en) * 2012-04-07 2014-12-24 吴槐 LED working mode control apparatus
CN202873122U (en) * 2012-07-20 2013-04-10 张志军 LED control unit and constant current-type unit voltage stabilization LED control circuit
WO2015036551A1 (en) * 2013-09-13 2015-03-19 Koninklijke Philips N.V. Controller for controlling a current regulating element of a lighting load
CN104470100A (en) * 2014-11-17 2015-03-25 苏州蓝特照明科技有限公司 Switching power supply of LED floodlight

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