CN103857127B - Dimmable LED with the additional constant current drive circuit of constant voltage - Google Patents
Dimmable LED with the additional constant current drive circuit of constant voltage Download PDFInfo
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- CN103857127B CN103857127B CN201210511039.0A CN201210511039A CN103857127B CN 103857127 B CN103857127 B CN 103857127B CN 201210511039 A CN201210511039 A CN 201210511039A CN 103857127 B CN103857127 B CN 103857127B
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- 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
- H05B45/14—Controlling the intensity of the light using electrical feedback from LEDs or from LED modules
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- 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
- H05B45/18—Controlling the intensity of the light using temperature feedback
-
- 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
- H05B45/395—Linear regulators
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- 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]
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Abstract
This disclosure relates to the Dimmable LED with the additional constant current drive circuit of constant voltage.Drive circuit for LED includes the first order, and it is configured to receive AC input electric power and produces the D/C voltage of regulation.Linear current regulators are coupled in the first order and are configured to the lamp current that regulation is supplied to LED.Feedback circuit is coupled in the first order and is configured to the D/C voltage of monitoring regulation and operates the first order so that the D/C voltage of the regulation is maintained at less constant voltage.The drive circuit also includes voltage drop monitoring and the voltage drop observation circuit including being coupled in the feedback circuit.The voltage drop observation circuit is configured to adjust voltage less constant caused by the first order.The voltage drop of the voltage drop monitoring circuit monitors linear current regulators and reduce the less constant voltage in voltage drop increase.
Description
Technical field
LED light source is related generally in terms of the disclosure, and more particularly relates to the drive circuit of LED.
Background technology
Light emitting diode（LED）It is by semi-conducting material（Typically, GaAs）The light source of construction.With other diode-likes
Seemingly, p-n junction is formed by using various impurity doped semiconductors to form LED.When a current is applied, carrier flows into the knot, its
In positively charged hole combined with negatively charged electronics so that electronics falls on lower level and thus released energy to be visible
Or infrared light.As in all diodes, electric current is easily from the p effluents of the positive doping of device to the n sides of negative doping but phase
Anti- direction is not all right.Therefore LED is typically by direct current（DC）Power drives.
In illumination applications using multiple individual LED or LED element come to construct LED lamp component or LED be common.Will
Multiple LED elements are incorporated to single led lamp component and provide many advantages, such as the light output of raising and appropriate fault mode.Should
Appropriate failure typically realizes because Individual components in different time failures, light output due to Individual components failure and
Gradually degrade with the time.By connecting individual LED element series connection or bunchiness, higher voltage and lower electric current water can be used
Flat driving LED lamp component, so as to provide flexibility in driver design and allow have bigger effect in drive circuit
Rate.By being connected with multi-string LED, wherein these connection in series-parallel, sometimes referred to as series-multiple connection group is set, and LED lamp component can become
More can other benefits fault-tolerant while that keep being connected in series component.
In many LED applications, such as in traffic lighting or domestic lighting application, drive circuit is by locally available AC electricity
Mains power supply.These application generally by phase angle light-dimming method provide dimming function, wherein by sine wave not
Same angle trigger current conducts and changes AC input electric power, thus reduces the amount of the electric power included in the input electric power.At this
In a little applications, AC grid power signals（It can be phase angle light-adjustable power signal）, DC electricity is converted into by LED driver circuit
Power and the brightness for being caused LED lamp generation stabilization by LED driver circuit regulation.However, appoint although having in input electric power
What phase control dimming, the electric adjustment included in typical LED driver effectively removes phase control dimming and with
Constant brightness operation LED.Therefore, in order to keep dimming behavior, specific light modulation detection and control circuit power must wrap
Include in LED driver, so as to cause higher driver cost and bigger driver size.
For driving the typical drive circuit of LED to be divided into two classes：Single-stage and multistage, in multistage, twin-stage or two-stage
Driver is most common.Each type has its specific Pros and Cons set.Single-stage drive circuit cost is relatively low, size is smaller
And high drive efficiency can be provided.Weigh however, single-stage driver faces between power factor and LED ripple current.
Single-stage driver also has the dimming behavior than multiple drive power device difference.Twin-stage and other multiple drive power utensils have outstanding light modulation
And it can realize high power factor while still keep low ripple current.However, multistage and twin-stage driver compares single-stage
Driver manufacturing cost is higher, size is bigger and has lower total drive efficiency.
Therefore it provides at least some of LED driver circuit solved in above identified issues will be desirable.
The content of the invention
As described herein, one exemplary embodiment overcome one in other inferior positions above or known in the art or
It is multiple.
The one side of one exemplary embodiment is related to the drive circuit for LED.In one embodiment, the driving
Device circuit includes the first order, and it is configured to receive AC input electric power and produces the D/C voltage of regulation.Linear current regulators coupling
Together in the first order and it is configured to adjust the lamp current for being supplied to LED.Feedback circuit is coupled in the first order and configured
Into the D/C voltage for monitoring regulation and the first order is operated so that the D/C voltage of the regulation is maintained at less constant voltage.Should
Drive circuit also includes voltage drop monitoring and the voltage drop observation circuit including being coupled in the feedback circuit.The voltage drop is supervised
Slowdown monitoring circuit is configured to adjust voltage less constant caused by the first order.The voltage drop monitoring circuit monitors linear current is adjusted
Save the voltage drop of device and reduce the less constant voltage in voltage drop increase.
The other side of one exemplary embodiment is related to electric -lighting set.In one embodiment, electric lighting electricity
Road includes：Drive circuit, it is configured to receive AC input electric power and produces lamp current；And LED, it is coupled in lamp electricity
Stream.The drive circuit includes the first order, and it is configured to receive AC input electric power and produces the D/C voltage of regulation.Linear current
Adjuster is coupled in the first order and is configured to the lamp current that regulation is supplied to LED.Feedback circuit is coupled in the first order
And it is configured to the D/C voltage of monitoring regulation and operates the first order so that the D/C voltage of the regulation is maintained at less constant
Voltage.The drive circuit also includes voltage drop monitoring and the voltage drop observation circuit including being coupled in the feedback circuit.
The voltage drop observation circuit is configured to adjust voltage less constant caused by the first order.The voltage drop monitoring circuit monitors
The voltage drop of linear current regulators and reduce the less constant voltage when voltage drop increase.
The other side of one exemplary embodiment is related to the method for operating LED driver circuit, wherein the first power
Level is used to AC input electric power being converted into DC output voltages.In one embodiment, feedback signal is formed from the DC output voltages,
It is used to adjust the DC output voltages in less constant voltage.The DC output voltages are supplied to LED and linear electricity
Stream source is used to adjust lamp current.Monitor the voltage drop of linear current source and adjust feedback signal with electric beyond threshold value in voltage drop
Reduce DC output voltages during pressure.
These and other aspects of one exemplary embodiment will become with advantage from the following detailed description taken into consideration with accompanying drawing
Obtain substantially.However, it is understood that these figures are only designed for the restriction for illustrating purpose and the limitation not as the present invention, the present invention
Limitation should refer to the claim enclosed.The present invention other aspect and advantage will be illustrated in explanation afterwards, and
And part by from explanation it is clear that or can be learned by the practice of the present invention.In addition, the aspect and advantage of the present invention can
Realize and obtain by the instrument that is particularly pointed out in the claim enclosed and combination.
Brief description of the drawings
Accompanying drawing illustrate the disclosure presently preferred embodiment, and with general remark given above and be described below
Describe the principle for, playing a part of explaining the disclosure together in detail.As shown in whole figure, the instruction of similar label is similar
Or corresponding part.
Fig. 1 illustrates the functional block diagram of the exemplary LED driver circuit of one embodiment according to this technology.
The schematic diagram of the exemplary power conversion stage of aspect of Fig. 2 diagrams comprising the disclosure.
The schematic diagram of the exemplary dimming detection circuit of aspect of Fig. 3 diagrams comprising the disclosure.
The exemplary linear constant current regulator of dimming function of Fig. 4 diagrams with the aspect comprising the disclosure is shown
It is intended to.
Fig. 5 illustrates the functional block diagram of the exemplary LED driver circuit of one embodiment according to this technology.
The schematic diagram of the exemplary feedback circuit of aspect of Fig. 6 diagrams comprising the disclosure.
Fig. 7 illustrates the exemplary method using voltage drop monitoring driving LED of one embodiment according to this technology
Flow chart.
The flow chart of the method to LED light modulation of aspect of Fig. 8 diagrams comprising the disclosure.
Embodiment
Referring now to Figure 1, it can be seen that one and half grades of LED driver systems of one embodiment of the with good grounds disclosure
100 functional block diagram.Using the LED driver system 100（It includes one and half grades of drivers in one embodiment）To carry
For power of powering to LED or lamp component 106, it includes one or more light-emitting diodes.LED driver system 100 it is defeated
Enter electric power by input electric power source or signal 102（Such as local power network or other suitable AC electric power sources）Supply.It is suitable for defeated
The typical grid power for entering electric power 102 can be about 110 volts of root mean square at about 50 to 60 hertz（Vrms）To about
250Vrms.The input electric power signal 102 can also be supplied by light adjusting controller, and input electric power signal 102 may include in this case
Such as the phase controlled dimming signal of forward phase control dim signal, reverse phase control light modulation etc., or when it is expected to dim
Other the suitable AC dim signals for reducing input electric power.The first order 104 is coupled in input electric power signal 102 and is configured to
The electric power 114 of output voltage regulation, it can be supplied to LED lamp component 106 via output end 131 and 132.The first order 104 is
Active power change-over circuit, it includes the AC-DC change-over circuits such as bridge diode, for will generally sinusoidal input electric power
Signal 102 is converted into all-wave or halfwave rectifier DC signals.In certain embodiments, the first order 104 also includes dc-dc converter,
It is configured to provide PFC and the electric power of the voltage-regulation is adjusted in the form of the DC output voltages of the first order
114.LED 106 receives electric current from the electric power 114 of voltage-regulation, and it is returned by linear current regulators 108.
In one embodiment, exemplary LED driver system 100 also includes dimming detection circuit 110, and it is configured to supervise
Survey input voltage 122 and generate proportional to the dimming level of the phase angle dimming level instruction of input electric power signal 102
Dim signal 120.The dim signal 120 is received by linear current regulators or control circuit 108, and it correspondingly adjusts lamp current
116 realize the light output of the desired light modulation from LED 106.In order to keep constant light output, lamp current 116 is kept
In steady state value, however, due to environment and other factors, may change across the voltage drop of LED 106.When the electricity across LED 106
During drops, proportionally increase across the voltage drop of linear current regulators 108.In the case of linear regulator, with switch
Adjuster is compared, the power that linear regulator dissipates and the voltage drop across adjuster and the current in proportion by adjuster.From
And when across the voltage drop increase of linear current regulators 108, the power of dissipation proportionally increases.Similarly, when by inputting
When the dimming level for the needs that electric power signal 102 indicates is low, it will increase across the voltage drop of linear current regulators 108, so as to enter
One step makes the power increase that linear current regulators 108 dissipate.Any power to be dissipated in linear current regulators 108 can not be used
In generation light.So as to reduce the power to be dissipated by linear current regulators as much as possible, this is desirable.
In one embodiment, in order to help to reduce the power wasted, linear current regulators 108 are across linear current
The voltage drop of adjuster 108 generates fall voltage signal 118 when exceeding threshold quantity.The fall voltage signal 118 is supplied to the first order
104, herein it be used to reduce the electric power 114 or DC output voltages of voltage-regulation, to reduce by linear current regulators 108
The power of dissipation.
Referring now to Figure 2, it can be seen that there is the diagram of the schematic diagram of exemplary power conversion stage 200, the exemplary power
Switching stage 200 is provided AC input electric power（Such as the AC input electric power signal 102 above with respect to Fig. 1 descriptions）It is converted into adjusting
D/C voltage part.Power conversion stage 200 by fuse F201 input connector CON1 input 1 and 2（Commonly referred to as
For feed end pin and return terminal pin 2）Receive input electric power, fuse F201 be used for protect power conversion stage 200 exempt from surge or
Excessive electric current can be caused to flow into other exceptions of power conversion stage 200.Including input filter 220 come repair input electric power and
The harmonic wave and switching noise for preventing from being formed in power conversion stage 200 are sent back to input electric power by input connector CON1.
The input filter 220 includes a pair of electricity of the capacitor C210 being connected in parallel with connector CON1 input 1 and 2 and heel
Sensor L201 and L202, each of which respectively with input connector CON1 feed end pin 1 and input connector CON1 return terminal
Pin 2 is connected in series.Each inductor L201, L202 are connected in parallel with resistor R201 and R202 respectively.
Bridge diode circuit BD1 is used to AC electrical power conversions being connected in parallel into full-wave rectification DC electric power and across DC electric power
Capacitor C201 provide certain initial filter to contribute to full-wave rectification caused by smooth bridge diode circuit BD1 to believe
Number.Flyback converter（Typically indicated by label 222）Rectification DC electric power caused by bridge diode BD1 is changed and is adjusted to
Less constant voltage V201 at output end V+ and V-.The flyback converter 222 passes through with first winding T201-1
Electric power is delivered to secondary or outlet side from primary side with secondary winding T201-2 transformer T201.Diode D201 is to output
Power rectifier and the filter condenser C208 being connected in parallel with output voltage V201 provide output voltage V201 filtering peace
It is sliding.The resistor R216 and capacitor C207 being connected in series and diode D201 are connected in parallel with transformer T201 outlet side
Other finishing is provided on T201-2.Electric power in primary side T201-1 is controlled by switching device Q201, integral control circuit
U201 is by driving resistor R213 to carry out duty ratio modulation to switching device Q201.One exemplary embodiment shown in figure 2
In, switching device Q201 is illustrated as n- channel metal-oxide field-effect transistors（MOSFET）.Alternatively, it may be advantageous to use
Other kinds of switching device.Switching device Q201 drain electrode connects back to bridge-type two by diode D202 and resistor R212
Pole pipe BD1 positive output carrys out protection switch device Q201 from too high voltages and electricity is provided when switching device Q201 is not turned on
Flow circulating path.Capacitor C206 also with R212 parallel coupleds.
In exemplary flyback adjuster 222, output voltage V201 is adjusted by integrated circuit U201, and integrated circuit U201 exists
The embodiment includes many calibration power factor correctings（PFC）One in controller IC.Integrated circuit U201 or
Pfc controller adjusting switch device Q201 dutycycle causes the power factor of power conversion stage 200 close to one and makes DC electric
Pressure V201 is maintained at less constant value.Pfc controller U201 passes through resistor R203 and R204 and filter condenser
C202 and C205 receives operation power on pin 8.Operation power is also by diode D203 and resistor R211 from transformer
T201 tertiary winding T201-3 is supplied to pfc controller U201.Transformer T201（It is flyback transformation in one embodiment
Device）Tertiary winding T201-3 be used to provide zero crossing by the current-limiting resistor R215 and filter condenser C209 that is connected in parallel
Detection signal（ZCD）Pin 5 to pfc controller U201.Current-sense resistor R208 be coupled in series with switching device Q201 and
Current sensing signal is provided between circuit ground 224 and at pfc controller U201 pin 4.By making to take out from input electric power
The voltage of the electric current taken and input electric power keeps realizing high power factor with phase.In order to realize this, pfc controller U201 leads to
The multiplier crossed at pfc controller U201 pin 4 inputs and senses the voltage of input electric power.In exemplary flyback transformer 222,
Input voltage is sensed at the full-wave rectification D/C voltage exported from bridge diode BD1 by resistor R205 and R206, and
It is filtered with the resistor R207 and capacitor C204 that are connected in parallel defeated to form multiplier at pfc controller U201 pin 4
Enter signal.
Realize voltage V201 regulation with by output voltage V201 by using resistor divider network R208, R209
Feeding is back to the operational amplifier exposed at pfc controller U201 pin 1（op-amp）The summing junction of type compensation circuit.This shape
Into feedback control loop, it, which is played, adjusts output voltage V201 in less constant horizontal effect.The stability of control ring
Realized by integration control, the integration control between summing junction 226 and pfc controller U201 compensation input pin 2 by connecting
Capacitor C203 formed.The feedback control loop allows pfc controller U201 modulator switching devices Q201 dutycycle to cause root
Output voltage V201 is set to be maintained at less constant level according to the feedback signal at node 226.So as to be put on by adjustment
The feedback signal of node 226 and adjust the voltage at output voltage V201.As that will discuss in more detail below, the feature can
For reducing LED driver system according to it is expected to adjust output voltage V201（Such as above-described LED driver system
100）Other parts in the power that dissipates.
Referring now to Figure 3, it can be seen that there is exemplary dimming detection circuit 300, it includes comparator circuit, for generating
Corresponding to the DC dim signals V303 of the dimming level indicated by input voltage signal V302.The dim signal detects circuit 300
Illustrate the example of the DC dim signals V303 of the dimming level for generating instruction phase angle dim signal part.Exemplary
In dimming detection circuit 300, input voltage signal V302 is the input electric power signal of rectification, such as by being retouched above with reference to Fig. 2
Signal caused by the bridge rectifier circuit BD1 stated.In numerous applications, such as LED illumination is transformed into incandescent bulb earlier
In the application of bright lamp tool, input electric power（Such as Fig. 1 input electric power signal 102）It may include phase angle as known in the art
Dim signal.The phase angle dim signal can have any appropriate type, such as the control of forward phase angle or reverse phase
Angle control light modulation.When input electric power is phase angle dim signal, dim signal V303 will be full-wave rectification phase angle light modulation letter
Number.Comparator A301 is used to provide and put to charging capacitor C301 but resistor R306 by resistor R305 offer charging signals
Power path.Working voltage source V301 provides operation power and to comparator A301 and is additionally operable to via by resistor R304 and R303
The resistor divider network of formation and reference voltage is produced to the input of comparator A301 noninvert.Input voltage signal V302
The paraphase that comparator A301 is put on via the second resistance device divider network formed by resistor R301 and R302 inputs.From
And DC dim signals V303 changes on the contrary with the dimming level indicated by input voltage signal V302, i.e. become clear when needs
During light output, DC dim signals V303 is low-voltage and vice versa.
Referring now to Figure 4, it can be seen that the one exemplary embodiment of linear current regulating circuit 400, it can be used for will stream
LED lamp component LA401 current regulation is crossed in the less constant amount controlled by dim signal V303.The linear current is adjusted
Circuit 400 illustrate according to DC dim signals V303 by by LED lamp component LA401 current regulation in less constant amount
One example.Lamp current is supplied by voltage source V201, such as above-described circuit for power conversion 200.Alternatively, other voltages
Regulation circuit may be used to provide voltage source V201, also referred to as adjust voltage.
In one embodiment, current regulating circuit 400（Also referred to as controller）Including a pair of transistor Q401 and Q402,
Wherein transistor Q401 colelctor electrode causes transistor Q402 controls to flow through LED lamp component from LED lamp component LA401 reception electric currents
Electric current.Working voltage V401 supplies current to transistor Q402 base stage by resistor R403.Resistor R405 is coupled in
The increase for the electric current for causing to flow through controlling transistor Q402 between controlling transistor Q402 emitter stage and circuit ground 402 makes hair
Voltage increase at emitter-base bandgap grading 404.Second transistor Q401 is coupled in controlling transistor Q402 base stage 406 and circuit ground 402
Between, and transistor Q401 base stage or control terminal are coupled in controlling transistor Q402 emitter stage by resistor R406.DC
Dim signal V303, such as the DC dim signal V303 generated by above-described exemplary dimming detection circuit 300, pass through electricity
Hinder the diode D401 and D402 that device R402 connects with a pair of series and put on transistor Q401 base stage.
The operation of linear current regulation circuit 400 can be by assuming initially that resistor R406 short circuits and by removing two
Pole pipe D401 understands to remove DC dim signals.This makes DC light adjusting circuits 400 be reduced to linear circuit, wherein lamp current ILEDCan
To be calculated as ILED=0.7 volt/R405 Ω, wherein 0.7 volt be controlling transistor Q402 base-emitter voltage drop and symbol
Ω indicates each resistor with the resistance value of ohmmeter.Now, full linear current regulating circuit 400 is paid close attention to, it includes diode
D401 and resistor R406, lamp current may be calculated ILED=（0.7v-VR406）/ R405 Ω, wherein VR406It is across resistor R406
Voltage.So as to lamp current ILEDDecline as DC dim signals V303 is raised.In certain embodiments, resistor R405 has
Have low resistance, such as several an ohm, and resistor R406 and resistor R402 be it is relatively large, such as several kilohms.Across electricity
Resistance device R406 voltage can be evaluated whether for：VR406=V303*R406 Ω/（R402Ω+R406Ω）And lamp current can be evaluated whether
For：ILED=（0.7- V303*R406 Ω）/（R406Ω+R402Ω）/ R405 Ω, so as to obtain lamp current, it is DC light modulation letters
Number V303 linear function.In demonstrative circuit 400, two diode D401 and D402 connect coupling with DC dim signals V303
Close to improve dimming curve.Each diode D401 and D402 have about 0.7 volt of voltage drop, therefore DC dim signals V303
Linear current regulation circuit 400 is not influenceed until DC dim signals V303 exceeds about 1.4 volts.For example, using above in Fig. 3
With 4 in the demonstrative circuit that illustrates, lamp current linearly subtracts when AC dim signals V302 has the residual angle less than about 144 degree
It is small.Residual angle refers to part of the phase angle dim signal main story power transmission power to the sinusoidal cycles of load.
Fig. 5 diagrams are reduced power dissipation while are kept LED light output and the dimming function of stabilization using voltage drop monitoring
The functional block diagram of one and half grades of LED driver circuits 500 of property.The exemplary LED driver circuit 500 includes the first step voltage
Adjuster 504, it has input 526 and output 514.The first order 504 is configured to the AC input electric power 502 that will be inputted on 526
The D/C voltage for the regulation being converted into output 514.In certain embodiments, the first order 504 includes pfc controller, and it is configured
Same phase is kept into the voltage from the electric current that input electric power 502 extracts and input electric power 502 is made so that the work(of drive circuit 500
Rate factor remains one or close to one.LED or lamp component 506 receive the DC of the regulation from the first order 504 in output 514
Voltage.Linear current controller 508 is coupled in series between LED lamp component 506 and the return 520 of the first order 504 to make lamp electric
Stream 516（It is the electric current for flowing through LED）It is maintained at less constant amount.D/C voltage in output 514 is adjusted by adjuster 510
Section, adjuster 510 are also referred to as feedback control circuit, and it receives feedback signal 522 and operates the first order via control signal 524
504 cause the D/C voltage in output 514 to be maintained at about constant voltage.The adjuster 510 receives feedback letter from summer 512
Number, the summer 512 will export the D/C voltage on 514 and the electricity by voltage drop sensing circuit 528 from linear current regulators 518
The fall voltage signal 534 that pressure drop is formed combines.Described above, the power that is dissipated by linear current regulators 508 with across tune
The voltage drop 518 for saving device 508 is proportional.Electric voltage observation circuit 528 exceeds threshold value in the voltage drop 518 across current regulator 508
Fall voltage signal 534 is produced during amount.When the fall voltage signal 534 is added to the D/C voltage in output 514 in summer 512
When, it changes feedback signal and to adjust the D/C voltage exported on 514 in lower value.Using which, voltage drop monitoring or
Sensing circuit 528 plays a part of reducing the power dissipation in linear current regulators 508 together with summer 512.In order to suitable
In requisition for the application of dimming function, one and half grades of LED driver circuits 500 include dimming detection circuit 536, and it receives input
Electric power signal 532 and produce the dim signal 530 proportional to the dimming level indicated by input electric power signal 532.The tune
Optical signal 530 is received by linear current regulators 508, and the linear current regulators 508 are used to correspondingly adjust lamp electricity herein
Stream 516.
The LED with constant current is driven to keep stable lamp output, this is desirable.However, across LED forward direction
Voltage drop changes due to environment and manufacture factor.For example, LED forward drop reduces as temperature increases.Description
Linear current regulators 508 change its voltage drop to operate on the contrary by the voltage drop with LED.This means raised when temperature
When, LED voltage general who has surrendered declines and linear current regulators 508 will increase its voltage drop to keep constant current.Use electricity
Pressure drop monitors, and electric voltage observation circuit 528 is used to fall voltage signal 534 feeding back to voltage regulator 510, and which in turn reduces electricity
The amount of the power to be dissipated in throttle regulator 508.The increased voltage drop causes increased dissipation on linear current regulators 508
Power.Table 1 below provides some typical values and does not use voltage drop monitoring to reduce electric current like that as described herein to illustrate
The power to be dissipated in the drive circuit of power dissipation in adjuster.Reference table 1, in this example, the D/C voltage in output 514
It it is approximately 14 volts and desired LED current is approximately 0.5 ampere.As seen in table 1, when LED voltage drop is 11 volts,
Linear current regulators 508 have dissipated 1.5 watts.When LED voltage rises, under the power dissipated by linear current regulators 508
Drop.So as to which when LED voltage is approximately 13 volts, the power to be dissipated in linear current regulators 508 is 0.5 watt.
Table 2 provides the typical value for the LED driver circuit 500 for including above-described novel voltage drop monitoring method.
As seen in table 2, when LED voltage is approximate 12 volts or is approximate more than 12 volts, the voltage drop of current regulator 508 is in threshold
Below threshold voltage and electric voltage observation circuit 528 does not generate any fall voltage signal.When LED voltage drops to less than 12 volts of approximation
When, such as 11 volts are dropped to, the voltage drop of current regulator 508 starts to generate beyond threshold voltage and electric voltage observation circuit 528
Fall voltage signal, it promotes the first step voltage with lower value, in such as about 13 volts regulation outputs 514.Reduce in output 514
The first step voltage power for causing to dissipate in linear current regulators 508 proportionally decline, it is about 1 in this example
Watt.
Referring now to Figure 6, it can be seen that have for producing as can be used for operation first order voltage regulator（Such as retouch above
The first order 504 stated）Control signal 524 exemplary feedback control circuit 510 and summer 512.LED D600 receives DC
Voltage 612, it produces the electric current by lamp, and it is by current-regulating transistor Q402（Such as the control above with reference to Fig. 4 descriptions
Transistor Q402）Regulation.Resistor divider network（It is included in what is be connected in series between DC electric power 612 and circuit ground 614
Resistor R603 and R604）Voltage Feedback 616 is formed, it is coupled in feedback control circuit 510 by resistor R602.Zener two
Pole pipe Z601, which is coupled between current regulator transistor Q402 and summer 512, to be caused as across current regulator transistor Q402
Voltage drop exceed Zener diode D601 breakdown voltage when, fall voltage signal puts on circuit node 616, herein it
Voltage Feedback is added to by resistor R602.Operation amplifier type A601 receives reference voltage V601 and produces regulation or control
Signal 524.By the resistor R601 with being connected in series and capacitor C602 parallel coupleds in exemplary feedback control circuit 510
Capacitor C601 stable and optimization is provided.
The exemplary method for being used to drive LED of aspect of Fig. 7 diagrams comprising voltage drop monitoring technology described herein
Flow chart.In one embodiment, this method uses one and half grades of drive circuits, and it includes the first order, for AC is defeated
Enter electrical power conversion 702 into DC output powers.704 feedback signals are formed from the DC output voltages, and the feedback signal is used to incite somebody to action
The voltage-regulation 706 of DC output voltages is in the less constant voltage corresponding to feedback signal.In certain embodiments, first
Level includes PFC, for will be kept by the voltage of the electric current that the first order extracts and input electric power with mutually so that LED drives
The power factor of dynamic device is one or close to one.To LED（Such as LED）708 DC output powers are provided.In one embodiment
In, the LED can include the multiple LED elements or other suitable LEDs set using series-multiple connection group.LED electric current
（That is, the electric current of LED is flowed through）By linear current source（Referred to herein as linear current regulators）710 are kept generally
Constant amount.The power to be dissipated in the linear current source is proportional to lamp current and across the voltage drop of the linear current source.Because
The power is not used for producing light, the energy that it is substantially wasted.Therefore reduce and dissipated by linear current source as much as possible
Power, this is desirable.Linear current source power reduce can by monitoring 712 across linear current source voltage drop and reality
It is existing.When voltage drop exceeds 714 threshold voltage, fall voltage signal is used to adjust 716 feedback signals for forming 704 above.Such as
Voltage above-described, that reduction DC output voltages are adjusted to by increase feedback signal.The feedback signal of adjustment is subsequently used for
By the regulation 706 of DC output voltages in substantially relatively low voltage.
Fig. 8 shows that the exemplary LED driving methods 700 for illustrating in the figure 7 include the side of dimming function
The flow chart of method 800.In certain embodiments, AC input electric power includes dim signal, such as phase controlling is adjusted forward or backwards
Optical signal.In order to realize dimming function, the dim signal in 802 AC input electric powers is monitored.The dim signal is changed with shape
Into 806 dimmer voltages, it is typically DC dimmer voltages, and wherein the voltage of dim signal corresponds to input dim signal.DC is dimmed
Voltage is used for the amount for adjusting the lamp current provided by linear current source.
So as to although having been shown, being described and pointed out such as applied to the of the invention of one exemplary embodiment of the invention
Basic novel feature, it will be understood that those skilled in that art can be in the form and details of the device of diagram and their operation
On make it is various omission and replacement and change without departing from the spirit and scope of the present invention.In addition, it is manifestly intended that using big
Identical mode performs the function that is substantially the same to obtain all combinations of those elements of identical result in the present invention in cause
In the range of.Moreover, it should be appreciated that the structure for exemplifying and/or describing together with any disclosed form of the present invention or implementation
And/or element can be included in any other disclosed or description or suggestion form or reality as the general content of design alternative
Apply in example.It is therefore intended that only limited such as the scope instruction for the claim enclosed herein.
Claims (20)
1. a kind of drive circuit for LED, the drive circuit includes：
The first order, it is configured to receive AC input electric power and produces the D/C voltage of regulation；
Linear current regulators, it is coupled in the first order and is configured to adjust lamp current；
Feedback circuit, it is coupled in the first order, wherein the feedback circuit is configured to monitor the D/C voltage of the regulation simultaneously
And the operation first order is so that the D/C voltage of the regulation is maintained at the voltage of substantial constant；And
Voltage drop observation circuit, its voltage for being coupled in the feedback circuit and being configured to adjust the substantial constant, its
Described in the voltage drop of linear current regulators described in voltage drop monitoring circuit monitors and make institute in the voltage drop increase
The voltage for stating substantial constant reduces.
2. drive circuit as claimed in claim 1, wherein the voltage drop observation circuit is configured to surpass in the voltage drop
Reduce the voltage of the substantial constant when going out threshold voltage, and when the voltage drop is below the threshold voltage not
Reduce the voltage of the substantial constant.
3. drive circuit as claimed in claim 2, wherein the voltage drop observation circuit includes Zener diode.
4. drive circuit as claimed in claim 1, wherein the first order includes bridge diode circuit.
5. drive circuit as claimed in claim 1, wherein the first order is configured to the power for making the drive circuit
Factor remains one or less than one.
6. drive circuit as claimed in claim 1, wherein the linear current regulators include the first and second transistors,
And wherein described the first transistor controls the lamp current, the second transistor controls the base stage electricity of the first transistor
Stream, and the lamp current is coupled in the base stage of the second transistor via resistor.
7. drive circuit as claimed in claim 1, wherein the AC input electric power includes dim signal, and the driving
Device circuit includes light adjusting controller, wherein the light adjusting controller is coupled in the AC input electric power and is adapted to described in operation
Linear current regulators cause the lamp current to correspond to the dim signal.
8. drive circuit as claimed in claim 7, wherein the control output coupling of the light adjusting controller is in described linear
Current regulator, and wherein described light adjusting controller monitors the dim signal and the control output includes D/C voltage,
It is inversely proportional with the dimming level that the dim signal indicates.
9. drive circuit as claimed in claim 8, wherein what the light adjusting controller was connected in series by one or more
Diode-coupled is in the linear current regulators.
10. a kind of electric -lighting set, including：
Drive circuit, it is configured to receive AC input electric power and produces lamp current；And
LED, it is coupled in the lamp current, wherein the drive circuit includes：
The first order, its D/C voltage for being coupled in the AC input electric power and being configured to produce regulation；
Linear current regulators, it is coupled between the first order and the LED, and the linear current regulators are configured to
The lamp current is adjusted to the amount of substantial constant；
Feedback circuit, it is coupled in the first order, wherein the feedback circuit is configured to monitor the D/C voltage of the regulation simultaneously
And the operation first order causes the D/C voltage of the regulation to be maintained at the voltage of substantial constant；And
Voltage drop observation circuit, its voltage for being coupled in the feedback circuit and being configured to adjust the substantial constant,
The voltage drop of linear current regulators described in wherein described voltage drop monitoring circuit monitors and when the voltage drop increase
When reduce the voltage of the substantial constant.
11. electric -lighting set as claimed in claim 10, wherein the LED includes setting and coupling using series-multiple connection group
One or more LED diodes of conjunction.
12. electric -lighting set as claimed in claim 10, wherein the voltage drop observation circuit is adapted in the voltage
Drop reduces the voltage of the substantial constant when exceeding threshold voltage.
13. electric -lighting set as claimed in claim 12, wherein the voltage drop observation circuit includes Zener diode.
14. electric -lighting set as claimed in claim 10, wherein the first order is configured to make the drive circuit
Power factor remains one or less than one.
15. electric -lighting set as claimed in claim 10, wherein the first order includes flyback power converter.
16. electric -lighting set as claimed in claim 10, wherein the AC input electric power includes dim signal, the driving
Device circuit includes light adjusting controller, and
Wherein described light adjusting controller be coupled in the AC input electric power and be adapted to the operation linear current regulators with
The lamp current is adjusted relevantly with the dim signal.
17. a kind of method for operating LED driver circuit, methods described includes：
AC input electric power is converted into DC output voltages using the first power stage；
Feedback signal is formed from the DC output voltages；
The DC output voltages are adjusted using the feedback signal；
The DC output voltages are supplied to LED；
Lamp current is adjusted using linear current source；
Monitor the voltage drop of the linear current source；And
The feedback signal is adjusted when the voltage drop exceeds threshold voltage so that the DC output voltages reduce.
18. method as claimed in claim 17, including：
Monitor the dim signal in the AC input electric power；And
It is at least partially based on the dim signal and adjusts the lamp current.
19. method as claimed in claim 18, further comprises：
DC dimmer voltages are formed, it corresponds to the dimming level of dim signal instruction；And
Adjust the lamp current relevantly with the DC dimmer voltages.
20. method as claimed in claim 19, wherein the amplitude of the DC dimmer voltages and the lamp current are inversely proportional.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210511039.0A CN103857127B (en) | 2012-12-04 | 2012-12-04 | Dimmable LED with the additional constant current drive circuit of constant voltage |
| TW102142724A TWI607667B (en) | 2012-12-04 | 2013-11-22 | Dimmable led with constant voltage plus constant current drive circuitry |
| PCT/US2013/072616 WO2014088947A1 (en) | 2012-12-04 | 2013-12-02 | Dimmable led having constant voltage and linear current control using headroom control |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210511039.0A CN103857127B (en) | 2012-12-04 | 2012-12-04 | Dimmable LED with the additional constant current drive circuit of constant voltage |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103857127A CN103857127A (en) | 2014-06-11 |
| CN103857127B true CN103857127B (en) | 2018-01-09 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210511039.0A Active CN103857127B (en) | 2012-12-04 | 2012-12-04 | Dimmable LED with the additional constant current drive circuit of constant voltage |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN103857127B (en) |
| TW (1) | TWI607667B (en) |
| WO (1) | WO2014088947A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9320090B2 (en) | 2014-06-19 | 2016-04-19 | Phoseon Technology, Inc. | LED output response dampening for irradiance step response output |
| CN107787605B (en) * | 2015-06-25 | 2020-04-03 | 飞利浦照明控股有限公司 | LED lighting module |
| CN105682282B (en) * | 2015-12-29 | 2017-07-18 | 科博达技术有限公司 | LED two-way flow equalizing circuit |
| EP3666041B1 (en) * | 2017-08-09 | 2022-01-05 | HELLA GmbH & Co. KGaA | System for operating an electronic light arrangement |
| US10542593B1 (en) * | 2019-01-18 | 2020-01-21 | Infineon Technologies Ag | Power offloading for linear current source |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201690655U (en) * | 2010-05-28 | 2010-12-29 | 电子科技大学 | Flyback road lamp illuminating LED constant-current driving power supply with intelligent dimming function |
| WO2011102799A1 (en) * | 2010-02-19 | 2011-08-25 | Nordic Light Ab | Controlling output current from an electronic drive system of fly-back type |
| CN202050563U (en) * | 2011-02-17 | 2011-11-23 | 昂宝电子（上海）有限公司 | Flyback dimming LED (light-emitting diode) drive circuit |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI383292B (en) * | 2005-12-30 | 2013-01-21 | Hon Hai Prec Ind Co Ltd | Voltage testing apparatus |
| US8390214B2 (en) * | 2009-08-19 | 2013-03-05 | Albeo Technologies, Inc. | LED-based lighting power supplies with power factor correction and dimming control |
| KR20110051062A (en) * | 2009-11-09 | 2011-05-17 | 삼성전자주식회사 | Circuit and method of driving light emitting diodes, and light emitting diode system having the same |
-
2012
- 2012-12-04 CN CN201210511039.0A patent/CN103857127B/en active Active
-
2013
- 2013-11-22 TW TW102142724A patent/TWI607667B/en not_active IP Right Cessation
- 2013-12-02 WO PCT/US2013/072616 patent/WO2014088947A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011102799A1 (en) * | 2010-02-19 | 2011-08-25 | Nordic Light Ab | Controlling output current from an electronic drive system of fly-back type |
| CN201690655U (en) * | 2010-05-28 | 2010-12-29 | 电子科技大学 | Flyback road lamp illuminating LED constant-current driving power supply with intelligent dimming function |
| CN202050563U (en) * | 2011-02-17 | 2011-11-23 | 昂宝电子（上海）有限公司 | Flyback dimming LED (light-emitting diode) drive circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2014088947A1 (en) | 2014-06-12 |
| TWI607667B (en) | 2017-12-01 |
| TW201431435A (en) | 2014-08-01 |
| CN103857127A (en) | 2014-06-11 |
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Effective date of registration: 20200927 Address after: Ohio, USA Patentee after: Karent lighting solutions Co.,Ltd. Address before: New York State, USA Patentee before: General Electric Co. |