CN207083257U - Numerical model analysis dims constant-current controller and drives the device of current source loadses - Google Patents
Numerical model analysis dims constant-current controller and drives the device of current source loadses Download PDFInfo
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- CN207083257U CN207083257U CN201720901899.3U CN201720901899U CN207083257U CN 207083257 U CN207083257 U CN 207083257U CN 201720901899 U CN201720901899 U CN 201720901899U CN 207083257 U CN207083257 U CN 207083257U
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Abstract
The utility model discloses a kind of numerical model analysis to dim constant-current controller integrated circuit; it is internally provided with dimming D/A converting circuit, error amplifying circuit and logic control circuit, wherein a PWM dim signals are converted to steady dc voltage by light modulation D/A converting circuit.The utility model causes intelligent lighting both to meet stroboscopic requirement most harsh in the world, and does not produce the mechanical oscillation sound that any human ear can be heard, while also accomplishes almost to limit without minimum brightness, and Consumer's Experience can obtain significant increase.
Description
Technical field
Constant-current controller is the utility model is related to, is integrated in particular to a kind of numerical model analysis light modulation constant-current controller
Circuit, the current source loadses drive device comprising the integrated circuit, and include the intelligent luminaire of the drive device.
Background technology
As the lighting source of a new generation, light emitting diode (LED) has been used widely.In global illumination market,
LED illumination is estimated to account for more than seventy percent.Occupation rate of market from 1% to 70%, LED illumination have only used the time less than 10 years.
This industry has started to seek transition and upgrade.Compared with traditional lighting, LED illumination has a larger advantage, i.e. realizes lamp
The light modulation (regulation brightness) and toning (color for changing light) of tool are relatively easy.Required for this advantage is exactly intelligent lighting
's.At present, intellectuality is increasingly becoming innovation focus, such as artificial intelligence Al, Internet of Things, smart home etc..In smart home
In, intelligent lighting may realize commercialization at first, and this is substantially industry common recognition.It is following 10 years, will be the big hair of LED intelligent illumination
10 years of exhibition.
The development of LED intelligent illumination can be divided into primary, middle rank, high-grade intelligent stage.In the primary intelligent stage, typically should
With being, remote control (similar TV remote controller) is used to realize the brightness to lamp and the control of color.Present LED intelligent illumination is basic
In this stage.Intermediate stage is the interconnection networking stage, for example, special APP is installed on mobile phone, can be by mobile phone to light fixture
It is controlled, is achieved in a certain degree of long-distance intelligent control, such as scene setting (example：Seabeach dusk setting sun pattern).Mesh
Preceding existing more companies are being explored.Advanced stage is the internet intelligent stage, illuminator is connected into upper internet, using people
Work intelligence and cloud computing technology, realize illumination high-grade intelligent.In this stage, intelligent lighting can realize the voice with owner
It is interactive.It, according to the order of owner, is finely controlled just as illumination house keeper to room illumination scene, brightness and color.It is logical
Voice interface is crossed, this illumination house keeper slowly can have at fingertips the illumination custom and hobby of each owner of family.Along with people
Work intelligent depth learns, and it can just predict the lighting demand of owner, and plan ahead.Substantially, here it is following intelligence
The ultimate aim that can be illuminated.
Fig. 1 is the functional block diagram of prior art intelligent illuminating system.As shown in figure 1, the system divides two large divisions.Part
001 is the intelligent maincenter of whole system, and lighting instruction is sent according to human will.Part 100 is executable portion, and execution comes from portion
Divide 001 instruction.Typically no any physics Hard link between this two parts, but connected by wireless means, such as it is infrared
Line, 433MHz radio frequencies, 2.4G radio frequencies, WIFI, bluetooth, Zigbee etc..
The utility model relates generally to above-mentioned executable portion 100.Part 100 is exactly substantially a traditional lamp
Tool, it has LED light source 120, the constant-current drive circuit 101 of stabling current is provided to light source 120, and the latter is generally termed power supply.
Light fixture is typically made up of three parts, i.e. light source, power supply and physical enclosure.Part 100 is that it is also in place of being different from conventional lamp
With reception of wireless signals and process circuit 102.The circuit specially receives the instruction from part 001, and converts instructions into
PWM dim signals, the duty cycle information that the signal provides can directly control the brightness of light fixture.PWM is English pulse width
Modulation (pulse width modulation) acronym.Reference picture 2, Fig. 2 shows pwm pulse signal.In general, the letter
Number it is the signal cycle fixed and maintain the burst length (namely pulse width) of high level to change.Modulation refers to pair
The adjustment of pulse width changes.The ratio between pulse width and pulse period are dutycycle (Duty Cycle), typically with alphabetical D tables
Show, it is exactly to change dutycycle D to change pulse width.
Fig. 3 shows existing constant current driver circuit for LED.Reference picture 3, rectifier bridge 201, electric capacity 202 are used for 50/60Hz
110/220V AC rectifications filtering.Resistance 203, electric capacity 204 and voltage-regulator diode 215 are light modulation constant-current control circuit 200
Stable operating voltage is provided.Power nmos switch 205, inductance 208, fly-wheel diode 207 are the power devices of Switching Power Supply.
Filter capacitor 209 is the operating current that LED load 120 provides low ripple.The detection stream overpower nmos switch 205 of resistance 206
Electric current.When pwm signal is continuously it is high when, drive circuit is put into oscillation mode, and its work wave is as shown in Figure 4.Work as DRV signal
After low uprise, power nmos switch 205 is opened therewith, and the electric current of inductance 208 is with (VIN-VOUT)/L208Slope rise, examining
Pressure drop IS on measuring resistance 206 can also rise therewith.When pressure drop IS is more than reference voltage VREF1 (such as 400mV), comparator
213 output RST is just height from low upset, and the signal is re-fed into the first reset terminal R1 of rest-set flip-flop 211, and reset terminal will for height
Forced resetting rest-set flip-flop 211 so that its output end becomes low from height.The output DRV of driver 212 also becomes from height therewith
Low, power nmos switch 205 is accordingly turned off.Inductance 208 enters discharge regime therewith, and electric current is with VOUT/L208Slope decline.
When valley point current detection circuit 214 detects that inductive current drops to some value (most commonly 0), a high level can be exported
Signal is to the set S ends of rest-set flip-flop 211 so that it, which is exported from low, becomes high.The output DRV of driver 212 is also therewith from height
Become low, power nmos switch 205 is opened therewith.Drive circuit works again and again like this.It is from fig. 4, it can be seen that electric
The operating current of sense 208 is triangular wave, and its peak value is equal to VREF1/R206, its valley is zero, so inductance average current is peak value
The half of electric current, that is, 0.5*VREF1/R206.The average value of inductive current namely loads 120 current average, i.e., public
Formula 1：
I120=0.5*VREF1/R206 1
Theoretically, R is changed206Resistance, it is possible to change load 120 operating current.
If pwm signal is not high, but low level, situation will be entirely different.PWM low levels become by phase inverter 217
Into high level, be re-fed into second reset terminal R2 of rest-set flip-flop, immediately forced resetting rest-set flip-flop 211, as long as and PWM be
Low level, rest-set flip-flop 211 are at reset state, and output end Q remains low, and DRV signal is also low, power switch always
205 are constantly in disconnection OFF state, that is, drive circuit stops oscillation work completely, and the operating current of inductance 208 is zero, is born
Also no electric current flows through load 120.If pwm signal is periodically pulsing signal, the drive circuit in Fig. 3 will be in pwm signal
The stage of high level is in normal working condition, and is to be in halted state in the low level stage in the signal.It is easy to manage
Solution, if the dutycycle D of pwm signal is in 0.5, that is, PWM a cycles, half the time high level, system work；Half
Time low level, system-down, the half when brightness for so loading 120 just only has most bright (correspond to PWM always when most bright
For high level, drive circuit is working all the time).It is easy to show that, load 120 average operating current (average operating current and its
Brightness is substantially proportional to) between the dutycycle D of pwm pulse signal, following linear math relation be present：
I120=0.5*D*VREF1/R206 2
Therefore, theoretically, as long as being finely controlled the dutycycle D of pwm pulse signal, it is possible to the bright of load 120
Degree is accurately controlled.
In the prior art, the solution of LED color is adjusted as shown in Figure 5,6.Fig. 5 shows existing changes in temperature light intelligence
The structured flowchart of energy illuminator.The system includes separate warm light light source 121 and cold light light source 122, and respectively with
Two sets of constant-current drive circuits 101A and 101B corresponding to light source 121,122.Reception of wireless signals sends out two-way with process circuit 102
Independent dimmer pulse signal PWM1, PMW2, can just be controlled to the colour temperature of light fixture and brightness.Here, it is necessary to illustrate, LED
Light source color temperature represents with absolute temperature K, in below 3300K, it is photochromic it is partially red give warm sensation, this light is generally referred to as
" warm colour light " or " warm light "；Colour temperature is centre in 3000K--6000K, and people is imitated under this tone without particularly apparent visual psychology
Fruit, therefore it is referred to as " neutrality " colour temperature, this light is called " neutral light "；Colour temperature photochromic indigo plant partially, gives chilly sense more than 6000K
Feel, this light is called " cool colour light " or " cold light ".
Fig. 6 shows the structured flowchart of existing full color intelligent illuminating system.The system includes independently of each other red green
Blue (RGB) three groups of light sources, and three set constant-current drive circuit 101C, 101D and 101E corresponding with three groups of light sources difference.Wirelessly
Signal receives dimmer pulse signal PWM1, PMW2 and PWM3 that three tunnel independences are sent out with process circuit 102, and just light fixture can be carried out
Full color and brilliance control.In Fig. 5,6, the complete phase of operation principle of each constant-current drive circuit and constant-current drive circuit in Fig. 1 101
Together.
Constant current driver circuit for LED shown in Fig. 3, it is currently the main flow structure of in the market constant-current drive circuit.Driving electricity
Road uses opened loop control, simple in construction, but following defect be present：
First, PWM light modulating frequencies are relatively low, typically in 200Hz or so, stroboscopic phenomenon can be caused.Stroboscopic refers to LED light source light
Flux (being commonly called as brightness) is with the fluctuation of certain frequency.There is substantial amounts of research to find, light source stroboscopic and antimigraine, headache, self-closing disease,
The neurological disorder such as visual fatigue and discomfort has substantial connection, and serious meeting makes human eye cause illusion, and then triggers accident.2017
The problem of year party of CCTV 315 has just exposed LED lamp stroboscopic, causes concern of the whole society to this problem.Send out within 2015
In the IEEE files of cloth, stroboscopic risk is divided into several grades, as shown in fig. 7, heavy line lower right region for devoid of risk etc.
Level, region is then low-risk class between thick, fine line, and fine line upper left side region be can not be received.According to this mark
Standard, more than 3KHz light modulating frequencies just safety, and 200Hz light modulating frequency apparently pertains to unacceptable category.
Second, light modulation has minimum brightness limitation.The minimum brightness that existing light modulation mechanism can accomplish is 7% or so, then past downward
If, brightness is with regard to unstable.For example, for 100W Intelligent LED lamp, minimum brightness can adjust 7W, Fig. 3 circuit
Framework can not meet lower brightness demand.
Third, the mechanical oscillation audio sound of inductance be present.In Fig. 3 drive circuit, because inductance 208 is operated in interval
Unanimously, this results in inductance and produces the 200Hz that human ear can be heard the frequency (200Hz or so) of pattern, frequency and pwm pulse signal
Mechanical oscillation audio sound.
In addition, in changes in temperature light and full color intelligent lighting controls, due in a system using multiple mutually different
The switch dimming constant-current control circuit of step, cause system will be by related EMC (the Electro Magnetic of electromagnetism
Compatibility) certification can be difficult many.Moreover, the corresponding independent constant-current drive circuit of each light source, so first device
Number of packages amount is more, and PCB surface product is also very big, and along with EMC correlation component numbers volume is not small, totle drilling cost is not quite cheap.
The content of the invention
The purpose of this utility model is, proposes the brand-new circuit framework of an AC/DC light modulation constant-current controller, overcomes existing
There is the drawbacks described above of constant current driver circuit for LED, improve Consumer's Experience comprehensively.
According to first aspect of the present utility model, there is provided a kind of numerical model analysis dims constant-current controller integrated circuit, in it
Portion is provided with light modulation D/A converting circuit, error amplifying circuit and logic control circuit, wherein, D/A converting circuit is dimmed, will
First PWM dim signals are converted to steady dc voltage (EAREF), and the DC voltage (EAREF) dims equal to the first PWM
The dutycycle of signal and the product of the first reference voltage；Error amplifying circuit, by the DC voltage (EAREF) with coming from outside
Difference between the average value of the inductive current detection signal of power conversion stage is amplified, and produces an error signal；Logic control
Circuit includes：Peak comparator, by the inductive current detection signal compared with the error signal, produce the first output
Signal；Valley comparator, by the inductive current detection signal compared with the second reference voltage, produce the second output letter
Number；And trigger, the disconnection of power switch in the power conversion stage is controlled based on first output signal, based on described
Second output signal controls the closure of the power switch.
In the first aspect, it is preferred that it is described light modulation D/A converting circuit include first and second NMOS tube, phase inverter with
And filter circuit, wherein, the first NMOS tube, its grid receives the first PWM dim signals, drain electrode connection first reference
Voltage；Second NMOS tube, its grid receive the first PWM dim signals through the phase inverter, and source electrode connects the integrated circuit
Reference ground (GNDIC), drain electrode and the source electrode of first NMOS tube are commonly connected to node (SD)；Filter circuit, by resistance and
Electric capacity is formed, and the signal of the node (SD) is filtered, exports the DC voltage (EAREF).
Preferably, the RC time constants of the filter circuit are bigger than the cycle of the first PWM dim signals more than 10 times.
According to second aspect, there is provided a kind of device for driving current source loadses, including the collection described in above-mentioned first aspect
Into circuit and power conversion stage, the power conversion stage includes power switch, detection resistance, fly-wheel diode and by inductance
The wave filter that element is formed with capacity cell, is converted into low output DC voltage, there is provided to described by high input direct voltage
Current source loadses, wherein, power switch, its drain electrode is connected with input voltage source, and source electrode is through the detection resistance and the inductance
Element connects；Fly-wheel diode, its negative pole are connected between the source electrode of the power switch and the detection resistance.
In second aspect, it is preferred that described device also includes an optocoupler, from reception of wireless signals and process circuit
The first PWM dim signals light modulation D/A converting circuit is transferred to by the optocoupler.
Preferably, described device also includes two current-limiting resistances, is serially connected in input and the output of the optocoupler respectively
End.
Preferably, the current source loadses are by the different colours of parallel connection or the first light source, the secondary light source group of colour temperature
Into described device also includes：3rd NMOS tube, its grid receives to be adjusted from the 2nd PWM of reception of wireless signals and process circuit
Optical signal, drain electrode connect first light source, source electrode and the reception of wireless signals and process circuit common ground connection；4th NMOS
Pipe, its grid receive the 3rd PWM dim signals from reception of wireless signals and process circuit, and drain electrode connects second light
Source, source electrode and the reception of wireless signals and process circuit common ground connection, wherein, the dutycycle of the first PWM dim signals,
Equal to the half of second and third PWM dim signal dutycycle sum.
Preferably, first light source is cold light source, and the secondary light source is warm light source.
According to the third aspect, there is provided a kind of intelligent luminaire, including reception of wireless signals and process circuit, above-mentioned second
Device and current source loadses described in aspect, wherein, the reception of wireless signals receives what is be wirelessly transferred with process circuit
Lighting instruction, and the lighting instruction is converted into PWM dim signals.
In a third aspect, it is preferred that the current source loadses are LED load.
Constant-current controller integrated circuit is dimmed using numerical model analysis of the present utility model so that intelligent lighting both meets the world
On most harsh stroboscopic requirement, and do not produce the mechanical oscillation sound that any human ear can be heard, while also accomplish almost without most
Small brightness limitation, Consumer's Experience can obtain significant increase.Intelligent illuminating system is additionally, since only comprising a constant current driving electricity
Road, easily by EMC Electro Magnetic Compatibility certifications, simultaneity factor cost is also reduced.For LED illumination industrial upgrades to intelligence
Illumination epoch, the utility model provide solid technology and ensured.
Brief description of the drawings
To more fully understand the utility model, hereafter with embodiment combination accompanying drawing, the utility model is described in further detail.
In accompanying drawing：
Fig. 1 is the functional block diagram of prior art intelligent illuminating system；
Fig. 2 shows pwm pulse signal；
Fig. 3 shows existing constant current driver circuit for LED；
Fig. 4 is the working waveform figure of drive circuit shown in Fig. 3；
Fig. 5 shows the structured flowchart of existing changes in temperature light intelligent illuminating system；
Fig. 6 shows the structured flowchart of existing full color intelligent illuminating system；
Fig. 7 is IEEE stroboscopic risk stratification schematic diagrames；
Fig. 8 shows numeral, the LED operation current waveform of two kinds of light modulations of simulation；
Fig. 9 is the functional block diagram of the utility model intelligent illuminating system；
Figure 10 shows the main working signal waveform of system shown in Figure 9；
Figure 11 shows the constant current driver circuit for LED of the embodiment of the utility model one；
Figure 12 shows the light modulation D/A converting circuit of the embodiment of the utility model one；
Figure 13 shows the operating voltage waveform of circuit shown in Figure 12；
Figure 14 shows the constant current driver circuit for LED of another embodiment of the utility model.
Embodiment
, can be by greatly improving PWM dimmer pulses frequency according to the requirement of IEEE shown in Fig. 7 for above-mentioned stroboscopic problem
Rate solves, for example frequency brings up to more than 3KHz.
For minimum brightness problem, can be solved in theory by the way that PWM dimmer pulses frequency is greatly reduced, such as frequency drop
It is low to below 20Hz, so, minimum brightness can just drop to 1% or so.
For the mechanical oscillation audio sound problem of inductance, in theory can by greatly improve PWM dimmer pulses frequency come
Solve, for example frequency brings up to more than 20KHz.Because 20KHz is the limit of common human ear frequency response, frequency is up named super again
Sound wave, human ear can't hear.
It can be seen that three of the above solution is all relevant with pwm pulse frequency.Stroboscopic, mechanical oscillation acoustic problem are all
Can be solved by improving PWM frequency, but minimum brightness problem but needs to reduce PWM frequency, both run in the opposite direction.So
Apparently, PWM frequency rise nor, drop nor, can not move.Applicant it has been investigated that, in fact, this have behind one it is total
Root, that is, the normal working frequency FSW of general lighting AC/DC light modulation constant-current controllers is not high enough, and only 50KHz is left
The right side, typically between 30KHz to 100KHz.Less than 30KHz, human ear may hear mechanical oscillation sound；Higher than 100KHz, power
The switch efficiency of switch can be decreased obviously.This point is applicable all city's ionizing radiation AC/DC Switching Power Supplies.Maximum PWM light modulations frequency
Rate is relevant with system switching frequency, is limited by following empirical equation：
FPWM＜ FSW/200 3
As the working frequency F of AC/DC light modulation constant-current controllersSWDuring only 50KHz, maximum PWM light modulating frequencies just only have
250Hz；Minimum PWM light modulating frequencies cannot be below 100Hz, and otherwise human eye will experience 100Hz light flash.So intelligence
PWM light modulating frequencies can be illuminated typically to take between 100Hz to 300Hz.And minimum brightness (corresponding PWM dimmer pulse minimum duties
Than) limited by following empirical equation：
DMIN(PWM) ＞ 20*FPWM/FSW 4
This explanation, the minimum pulse width of pwm pulse cannot be less than the switch periods of 20 AC/DC light modulation constant-current controllers
(1/FSW).If FSWFor 50KHz, minimum PWM pulse width is exactly 400uS.If FPWMFor 200Hz, minimum duty cycle DMINJust
It is 8%.This explains the reason for minimum brightness limitation.
As it was noted above, three above problem has a common ground existing for prior art, exactly all dimmed with pwm pulse
Frequency is relevant.Here, in order to work out solution, applicant considers to change a kind of new thinking.In fact, dimming mode except
Outside pwm pulse digital dimming, also simulation light modulation.Fig. 8 shows that numeral, two kinds of simulation dim (by taking 50% light modulation as an example)
LED operation current waveform.As can be seen that digital dimming is intermittent illumination mode；And simulate the hair that light modulation is continuous-stable
Light mode.Dimmed according to simulation, theoretically, can solve the problems, such as three above completely.First, LED continuous and stables light,
So stroboscopic phenomenon not be present.Similarly, inductance is also continuous non-stop run, so will not also produce human ear can hear
Mechanical oscillation sound.Compared with it is difficult to minimum brightness restricted problem, but it is not without method solution.
In history, what is be applied at first is simulation light regulating technology.But as the rise of digital technology, digital dimming are fast
Speed achieves overwhelming advantage.Compared to simulation light regulating technology, digital light-adjusting circuit is simple in construction, reliable, design debugging production
All it is easier, while cost is also cheap.In intelligent lighting, if abandoning digital dimming technology comprehensively, also imply that and abandon
All advantages of the technology.Wise way is to create a kind of digital analog mixed light regulating technology, can encumbrance simultaneously
The shortcomings that both the advantages of word light regulating technology are with light regulating technology is simulated, and can avoidance.Reference picture 9,10, Fig. 9 are the utility model
The functional block diagram of intelligent illuminating system, Figure 10 show its main working signal waveform.Because data signal easily produces, pass
It is defeated anti-interference strong, so reception of wireless signals is fully retained with process circuit 102.In reception of wireless signals and process circuit 102
Between LED load 120, using the utility model original creation comprising numerical model analysis light modulation constant-current controller drive circuit 111,
It receives digital PWM dim signal, but exports the operating current of continuous-stable.
Reference picture 11, Figure 11 show the constant current driver circuit for LED of the embodiment of the utility model one.In the drive circuit,
Provided with numerical model analysis light modulation constant-current controller integrated circuit 300 and power conversion stage.Wherein, power conversion stage is opened including power
205, detection resistance 206, fly-wheel diode 207, the wave filter being made up of inductance 208 and electric capacity 209 are closed, to height input is straight
Stream voltage VIN is converted into low output DC voltage VOUT, there is provided to LED load 120.The drain electrode of power switch 205 and input electricity
VIN connections are pressed, resistance 206 is connected its source electrode with inductance 208 after testing.The negative pole of fly-wheel diode 207 is connected to power switch
Between 205 source electrode and detection resistance 206.
In the inside of numerical model analysis light modulation constant-current controller integrated circuit 300, provided with light modulation D/A converting circuit 330, by mistake
Poor amplifying circuit 320 and logic control circuit 310.Wherein, D/A converting circuit 330 is dimmed by the PWM dim signals of outside
Steady dc voltage EAREF is converted to, DC voltage EAREF is equal to the dutycycle and reference electricity of above-mentioned PWM dim signals
Press VREF3 (such as 200mV) product.Error amplifying circuit 320 is integral error amplifying circuit, and error amplifier 321 will be straight
The difference amplification of voltage EAREF and inductive current detection signal IS average value is flowed, produces error signal；Electric capacity 322 and resistance 323
It is frequency compensation element.In logic control circuit 310, peak comparator 213 is by inductive current detection signal IS and above-mentioned error
Signal is compared, and produces output signal RST；Valley comparator 314 is by inductive current detection signal IS and reference voltage VREF2
It is compared, produces output signal SET.Here, reference voltage VREF2 is, for example, 10mV, it means that, under inductive current valley
When dropping near zero, power switch 205 can just close to charge to inductance 208, and now circuit is operated in critical conduction mode；Trigger
211 disconnections based on output signal RST control power switch 205, the closure based on output signal SET control power switch 205.
As it was noted above, Fig. 3 circuit employs open loop constant current control structure, its LED load operating current is determined by formula 1
It is fixed.Although seeming from formula 1, load current is only relevant with the internal reference voltage VREF1 of controller 200 size, actual
On due to not being closed loop configuration, formula 1 is an approximation, and real load current size is also relevant with a lot of other factors,
For example the height of the height of the height of working frequency, the quality of the magnetic core of inductance 208, environment temperature, line voltage, output are negative
Carry the high low of voltage.Result caused by these factors is exactly, and (for example is reduced to reference voltage VREF1 reduction from 400mV
40mV, corresponding 10% simulation light modulation), the error of formula 1 will be very big, can not receive at all.Want to reach high-precision
It is required that, it is necessary to using the current constant control structure of closed-loop.The advantage of closed-loop system is to correct error automatically, and above-mentioned factor is not
The output accuracy of Closed-loop Constant-current system can be influenceed.
According to the utility model, Figure 11 circuit use is exactly closed-loop current constant control framework.Compared with Fig. 3, Figure 11
In the relative positions of three power components turn upside down, this allows for the electric current of inductance 208, and no matter in the charging stage, (power is opened
Close 205 close stages) or discharge regime (disconnected phase of power switch 205) all flow through detection resistance 206, be achieved in pair
The real-time uninterrupted monitoring of output current, this is the precondition of full closed loop control.
Because using open loop technique, the inside of control circuit 200 is provided with error compensation circuit 216 in Fig. 3, to output electricity
The precision of stream carries out necessary amendment.Figure 11 circuits use technology of closed loop, so above-mentioned compensation circuit need not be set, but its
Error amplifying circuit 320 is provided with inside control circuit.
In drive circuit shown in Figure 11, output current is strictly determined by relationship below：
I120=EAREF/R206 5
So-called " strict ", refer to output current only with dimming the output voltage EAREF of D/A converting circuit 330, detecting electricity
The resistance of resistance 206 is relevant, unrelated with other specification, it is not necessary to any compensation circuit.Here it is the characteristics of full closed loop control, and
The utility model can be greatly reduced where the reason for light fixture minimum brightness.
Reference picture 12, Figure 12 show the light modulation D/A converting circuit of the embodiment of the utility model one.As it was noted above, should
The mathematical relationship that change-over circuit is exported between DC voltage EAREF and PWM dim signal dutycycle D is as follows：
EAREF=DPWM*VREF3 6
This is a simple linear relationship, and circuit shown in Figure 12 is one of its implementation.Dim D/A converting circuit
Including NMOS tube 333,334, phase inverter 332 and filter circuit.Wherein, the grid of NMOS tube 333 receives PWM dim signals,
Its connection reference voltage VREF3 that drains；The inverted device 332 of grid of NMOS tube 334 receives the PWM dim signals, and its source electrode connects
The reference ground GNDIC of integrated circuit 300 is met, it drains is commonly connected to node SD with the source electrode of NMOS tube 333；Filter circuit by
Resistance 335 and electric capacity 336 are formed, and node SD signal is filtered, output DC voltage EAREF.
When PWM dim signals are high level so that NMOS tube 334 is closed, and opens NMOS tube 333, node SD voltages
Equal to reference voltage VREF3.When PWM dim signals are low level, accordingly NMOS tube 333 is closed, and open NMOS tube
334, node SD voltage are equal to zero.Figure 13 shows the operating voltage waveform of the change-over circuit.As can be seen that node SD waveforms frequency
Rate and duty cycle information are as PWM, and simply node SD high level is no longer coarse digital voltage, and become stable essence
Really clean analog reference voltage VREF3 (such as 200mV).Pass through the filter circuit being made up of resistance 335, electric capacity 336 again, just
Smooth analog voltage EAREF can be obtained stablizing, the voltage is mathematically exactly equal to the average value of node SD voltages, also
It is product of the dutycycle with reference voltage VREF3 of node SD waveforms, mathematical expression is above-mentioned formula 6.It is in general, above-mentioned
The RC time constants of filter circuit, it is bigger than the cycle of PWM dim signal more than 10 times, i.e.,
R335*C336＞ 10/FPWM 7
Because the frequency of PWM dim signals generally only has 200Hz or so, the cycle is 5 milliseconds or so, above-mentioned filter circuit
RC time constants need to be more than 50 milliseconds.If resistance R335100 megohms of value, electric capacity C336Capacitance then cannot be below 500pF.
Reference picture 14, Figure 14 show the constant current driver circuit for LED of another embodiment of the utility model.In the embodiment,
LED load is made up of light source 121, the light source 122 of parallel connection；Light source 121,122 can have different color or colour temperature, for example,
Light source 121 is warm light source, and light source 122 is cold light source.Here, constant-current controller collection is dimmed using numerical model analysis of the present utility model
Into circuit 300, a set of drive circuit is shared in cold light source and warm light source, so that it may realizes that changes in temperature light is adjusted.It may be noted that integrated circuit
In 300, reference ground is GNDIC, not with rectifier bridge 201 and the common ground connection of filter capacitor 202.Generally, the utility model
Integrated circuit 300 using floating connection (control circuit 200 is then to connect on the spot in Fig. 3).This can connect to PWM dim signals
Receipts impact, because in general, reception of wireless signals and process circuit 102 can all select and rectifier bridge 201 and filtered electrical
Hold 202 common ground connections, so, the transmitting terminal 102 of PWM dim signals is different from the reference ground of receiving terminal 300, needs between them
Signal is transmitted by Phototube Coupling.Therefore, an optocoupler 303 is provided with the drive circuit, by the optocoupler, from wireless signal
Receive and be transferred to integrated circuit 300 with the PWM1 dim signals of process circuit 102., can in the input and output end of optocoupler 303
Current-limiting resistance 301,302 is concatenated respectively, to limit the input and output electric current of optocoupler.
As shown in figure 14, in the drive circuit, it is additionally provided with NMOS tube 304,305.Wherein, the grid of NMOS tube 305 receives
PWM2 dim signals from reception of wireless signals Yu process circuit 102, drain electrode connection cold light source 122, source electrode and wireless signal
Receive and the common ground connection of process circuit 102.The grid of NMOS tube 304 is received from reception of wireless signals and process circuit 102
PWM3 dim signals, drain electrode connection warm light source 121, source electrode and reception of wireless signals and the common ground connection of process circuit 102.NMOS tube
304th, 305 effect is, directly carries out PWM light modulations to warm light source 121, cold light source 122, light modulating frequency can easily reach
More than 3KHz, it is sufficient to avoid injury of the light low frequency stroboscopic to people.
In the drive circuit, three road dimmer pulse signals are shared：PWM1, PWM2 and PWM3.Wherein PWM2 and PWM3 are straight
Driving NMOS tube 305,304 is connect, because their common ground connections；And integrated circuit 300 can by the reception signal PWM1 of optocoupler 303,
Because transmitting terminal and receiving terminal are not altogether.
Signal PWM2 and PWM3 are mutually completely independent, and signal PWM1 is not independent, is constrained by PWM2 and PWM3.Below will
Illustrate, it is assumed that cold light source and the maximum current in warm light source are 300mA, and the operating voltage of two light sources is same.
In the case that PWM2 dutycycles and PWM3 dutycycles are all " 1 ", the operating current sum in cold light source and warm light source is 600mA, this
The maximum output current exactly required.At this time require that the maximum output current that drive circuit is provided is also 600mA just.
So-called maximum, when to be exactly corresponding PWM1 dutycycles be " 1 ".
In the case where signal PWM2 dutycycles are " 1 ", PWM3 dutycycles only have " 1/2 ", cold light source average current is still
300mA, and the average operating current in warm light source only has 150mA, both sums are 450mA.At this time require that drive circuit is carried
The output current of confession is also 450mA just.Corresponding PWM1 dutycycles should be 450/600, i.e., 0.75.
And in the case where PWM2 dutycycles and PWM3 dutycycles are all " 1/2 ", the average operation in cold light source and warm light source
Electric current sum only has 300mA.Now require that the output current that drive circuit is provided is also 300mA just.Corresponding PWM1 is accounted for
Empty ratio should be 300/600, i.e., 0.5.
It can be seen that signal PWM1 dutycycle is determined by PWM2 and PWM3 dutycycle completely, the mathematical relationship between them
It is as follows：
DPWM1=(DPWM2+DPMW3)/2 8
The minimum brightness restricted problem of light fixture is discussed below.According to formula 5 and formula 6, drive circuit provides in Figure 14
Total output current is strictly determined by following formula：
I121+I122=DPWM1*VREF3/R206 9
It means that dutycycle, reference voltage VREF3 and detection resistance of total output current with PWM1 dim signals
206 resistance is relevant, unrelated with other specification, and this is due to the current constant control framework that the utility model employs closed-loop.One
As, reference voltage VREF3, the resistance of detection resistance 206 are fixed, and total output can be changed by changing signal PWM1 dutycycle
Electric current, so as to reach the purpose of regulation brightness.The size of minimum brightness, determined completely by signal PWM1 minimum duty cycle.And
The minimum duty cycle of the signal, limited by the working clock frequency of reception of wireless signals and process circuit 102.In wireless communication
Number receive with process circuit 102 in, all can built in a MCU, at present the 8 of least significant end MCU clock frequencies arrived in 12MHz
Between 50MHz.It is assumed that MCU clock frequencies are 12MHz, a machine cycle is about 12 clock cycle, that is, 1uS.Again
It is assumed that signal PWM1 minimum pulse width is 10 machine cycles, that is, 10uS；Consider that PWM1 frequencies are generally 200Hz,
Cycle is 5000uS, such PWM1 minimum duty cycle DMIN0.2% is equal to, minimum brightness is also 0.2% in theory, very
It is small.Therefore, the experience of user's minimum brightness is greatly improved.
According to full color intelligent lighting, it is necessary to which three independent rgb light sources, they share a drive circuit.Drive
It is corresponding in the presence of three separate PWM toning signals in dynamic circuit, it is also big in the presence of the total output current of regulation of a dependent
Small pwm pulse signal.Its operation principle, circuit structure are similar with Figure 14, will not be repeated here.
In description above, although the utility model is exemplified by driving LED load, those skilled in the art
It can be readily appreciated that the utility model can be used for driving any current source loadses.Though moreover, above with LED light source with handing over
There is no the non-isolated constant current of electrical isolation to be driven to illustrate basis between stream power network, but Spirit Essence of the present utility model is equally suitable
Constant current of isolating for electrical isolation between LED light source and AC network drives.
It is clear that the utility model described here can have many changes, this change, which must not believe that, deviates this reality
With new spirit and scope.Therefore, all changes that will be apparent to those skilled in the art, being included in appended right will
Ask within the covering scope of book.
Claims (10)
1. a kind of numerical model analysis dims constant-current controller integrated circuit, it is internally provided with dimming D/A converting circuit, error amplification
Circuit and logic control circuit, wherein,
D/A converting circuit is dimmed, the first PWM dim signals are converted into steady dc voltage EAREF, the DC voltage
EAREF is equal to the dutycycle of the first PWM dim signals and the product of the first reference voltage；
Error amplifying circuit, by the DC voltage EAREF and the inductive current detection signal from external power switching stage
Difference between average value is amplified, and produces an error signal；
Logic control circuit, including：
Peak comparator, by the inductive current detection signal compared with the error signal, produce the first output signal；
Valley comparator, by the inductive current detection signal compared with the second reference voltage, produce the second output signal；
And
Trigger, the disconnection of power switch in the power conversion stage is controlled based on first output signal, based on described the
Two output signals control the closure of the power switch.
2. integrated circuit as claimed in claim 1, it is characterised in that the light modulation D/A converting circuit includes first and second
NMOS tube, phase inverter and filter circuit, wherein,
First NMOS tube, its grid receive the first PWM dim signals, and drain electrode connects first reference voltage；
Second NMOS tube, its grid receive the first PWM dim signals through the phase inverter, and source electrode connects the ginseng of the integrated circuit
Ground GNDIC is examined, drain electrode and the source electrode of first NMOS tube are commonly connected to node SD；
Filter circuit, it is made up of resistance and electric capacity, the signal of the node SD is filtered, exports the DC voltage EAREF.
3. integrated circuit as claimed in claim 2, it is characterised in that the RC time constants of the filter circuit, than the first PWM
The cycle of dim signal is big more than 10 times.
4. a kind of device for driving current source loadses, including integrated circuit and power any one of claims 1 to 3
Switching stage, the power conversion stage include power switch, detection resistance, fly-wheel diode and by inductance element and capacity cell
The wave filter of composition, high input direct voltage is converted into low output DC voltage, there is provided to the current source loadses, its
In,
Power switch, its drain electrode are connected with input voltage source, and source electrode is connected through the detection resistance with the inductance element；
Fly-wheel diode, its negative pole are connected between the source electrode of the power switch and the detection resistance.
5. device as claimed in claim 4, it is characterised in that described device also includes an optocoupler, from reception of wireless signals
Light modulation D/A converting circuit is transferred to by the optocoupler with the first PWM dim signals of process circuit.
6. device as claimed in claim 5, it is characterised in that described device also includes two current-limiting resistances, is serially connected in respectively
The input and output end of the optocoupler.
7. device as claimed in claim 6, it is characterised in that the current source loadses are by different colours or colour temperature in parallel
The first light source, secondary light source composition, described device also includes：
3rd NMOS tube, its grid receive the 2nd PWM dim signals from reception of wireless signals and process circuit, drain electrode connection
First light source, source electrode and the reception of wireless signals and process circuit common ground connection；
4th NMOS tube, its grid receive the 3rd PWM dim signals from reception of wireless signals and process circuit, drain electrode connection
The secondary light source, source electrode and the reception of wireless signals and process circuit common ground connection,
Wherein, the dutycycle of the first PWM dim signals, equal to the two of second and third PWM dim signal dutycycle sum
/ mono-.
8. device as claimed in claim 7, it is characterised in that first light source is cold light source, and the secondary light source is warm
Light source.
9. a kind of intelligent luminaire, it is characterised in that including appointing in reception of wireless signals and process circuit, claim 4 to 8
Device and current source loadses described in one, wherein, the reception of wireless signals receives the photograph being wirelessly transferred with process circuit
Bright instruction, and the lighting instruction is converted into PWM dim signals.
10. intelligent luminaire as claimed in claim 9, it is characterised in that the current source loadses are LED load.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720901899.3U CN207083257U (en) | 2017-07-25 | 2017-07-25 | Numerical model analysis dims constant-current controller and drives the device of current source loadses |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720901899.3U CN207083257U (en) | 2017-07-25 | 2017-07-25 | Numerical model analysis dims constant-current controller and drives the device of current source loadses |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107222953A (en) * | 2017-07-25 | 2017-09-29 | 许瑞清 | Numerical model analysis dims constant-current controller integrated circuit |
| CN109982489A (en) * | 2019-04-30 | 2019-07-05 | 北京模电半导体有限公司 | Linear constant current stepless dimming controller IC |
| CN110831285A (en) * | 2019-12-06 | 2020-02-21 | 北京模电半导体有限公司 | Constant current source load driving device and lighting lamp |
| CN112788815A (en) * | 2019-11-04 | 2021-05-11 | 海信视像科技股份有限公司 | Display device and power supply circuit |
| CN117528858A (en) * | 2024-01-08 | 2024-02-06 | 杭州罗莱迪思科技股份有限公司 | Hidden-lighting controllable dimming lamp control method |
-
2017
- 2017-07-25 CN CN201720901899.3U patent/CN207083257U/en not_active Withdrawn - After Issue
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107222953A (en) * | 2017-07-25 | 2017-09-29 | 许瑞清 | Numerical model analysis dims constant-current controller integrated circuit |
| CN107222953B (en) * | 2017-07-25 | 2019-03-19 | 许瑞清 | Numerical model analysis dims constant-current controller integrated circuit |
| CN109982489A (en) * | 2019-04-30 | 2019-07-05 | 北京模电半导体有限公司 | Linear constant current stepless dimming controller IC |
| CN112788815A (en) * | 2019-11-04 | 2021-05-11 | 海信视像科技股份有限公司 | Display device and power supply circuit |
| CN112788815B (en) * | 2019-11-04 | 2022-11-08 | 海信视像科技股份有限公司 | Display device and power supply circuit |
| CN110831285A (en) * | 2019-12-06 | 2020-02-21 | 北京模电半导体有限公司 | Constant current source load driving device and lighting lamp |
| CN117528858A (en) * | 2024-01-08 | 2024-02-06 | 杭州罗莱迪思科技股份有限公司 | Hidden-lighting controllable dimming lamp control method |
| CN117528858B (en) * | 2024-01-08 | 2024-04-09 | 杭州罗莱迪思科技股份有限公司 | Hidden-lighting controllable dimming lamp control method |
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