CN103781257B - System and method for adjusting LED current - Google Patents
System and method for adjusting LED current Download PDFInfo
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- CN103781257B CN103781257B CN201410053177.8A CN201410053177A CN103781257B CN 103781257 B CN103781257 B CN 103781257B CN 201410053177 A CN201410053177 A CN 201410053177A CN 103781257 B CN103781257 B CN 103781257B
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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
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- 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
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Abstract
The invention discloses the system and method for adjusting LED current.The system includes system controller, inductor, first resistor device, switch and the first diode.The system controller includes the first controller terminal and ground terminal, and the system controller is configured as the output drive signal at the first controller terminal.The inductor includes the first inductor terminals and the second inductor terminals, and the first inductor terminals are coupled to ground terminal, and the second inductor terminals are coupled to one or more light emitting diodes.The first resistor device includes first resistor device terminal and second resistance device terminal, first resistor device terminal are coupled to ground terminal.The switch is configured as receiving drive signal and is coupled to second resistance device terminal.First diode includes the first diode terminal and the second diode terminal and is coupled to first resistor device.
Description
Divisional application explanation
It is on December 8th, 2011 applying date that the application, which is, entitled " for adjusting system and the side of LED current
Please in the Chinese invention patent application No.201110415842.X of method " division.
Technical field
The present invention relates to integrated circuit.More specifically, the invention provides the system and method for adjusting electric current.Only
As an example, application flows through light emitting diode (LED) electric current to the present invention to adjust.It will be appreciated that the present invention has
Wider application.
Background technology
Light emitting diode (LED) has been widely used in various electronics.LED is had been accepted as relative to such as incandescent lamp
Etc other light sources there is the advantages of prominent.For example, these advantages include high efficiency and long-life.But for low-power consumption
There are still challenge for LED applications, for example, current accuracy is poor, light conversion efficiency is low and the chi of printed circuit board (PCB) (PCB)
It is very little big.The current accuracy of difference would generally shorten LED life-span, and low light conversion efficiency can usually increase heating, its
LED life-span may be shortened.
Fig. 1 is the traditional diagram of simplification for showing the system for driving LED.System 100 includes system controller 102, delayed
Rush device circuit (snubber circuit) 116, transformer 118, commutation diode 132, capacitor 134, one or more
LED136, power switch 138, current-sense resistor 140 and two resistors 142 and 144.System controller 102 includes
Terminal 104,106,108,110,112 and 114.Buffer circuits 116 include resistor 120, capacitor 122 and diode 124.
Transformer 118 includes armature winding 126, secondary windings 128 and assists winding 130.For example, power switch 138 is transistor.
If the closure of switch 138 (for example, conducting), primary current 148 flow through armature winding 126, switch 138 and resistance
Device 140, and the storage energy of transformer 118.Resistor 140 generates current sensing signal 150, and current sensing signal 150 is being held
Sub 114 (for example, CS) places are detected.If switch 138 disconnects (for example, cut-off), the energy quilt being stored in transformer 118
Discharge to drive one or more LED136.The information relevant with the output voltage 152 associated by one or more LED136 is led to
Assists winding 130 is crossed to be extracted.Assists winding 130 generates feedback signal 146, feedback signal together with resistor 142 and 144
146 are detected at terminal 106 (for example, FB) place.At least it is based on current sensing signal 150 and feedback signal 146, system controller
102 export gate drive signal 152 come driving switch 138 by terminal 112 (for example, GATE), so as to adjust flow through one or
Multiple LED136 electric current 154.
But system 100 generally has low efficiency in terms of electric energy transmission, and such poor efficiency is often as
Caused by the poor efficiency of transformer 118 and/or the energy consumption of buffer circuits 116.In addition, many ancillary equipment of system 100 can
Some requirements of PCB sizes can be unsatisfactory for.
Therefore, improve for driving LED technology to become extremely important.
The content of the invention
The present invention relates to integrated circuit.More specifically, the invention provides the system and method for adjusting electric current.Only
As an example, application flows through light emitting diode (LED) electric current to the present invention to adjust.It will be appreciated that the present invention has
Wider application.
According to one embodiment, a kind of system for being used to adjust one or more electric currents includes：System controller, inductance
Device, first resistor device, switch and the first diode.System controller includes the first controller terminal and ground terminal, the system
Controller is configured as the output drive signal at the first controller terminal.Inductor includes the first inductor terminals and the second electricity
Sensor terminal, the first inductor terminals are coupled to ground terminal, and the second inductor terminals are coupled to one or more luminous
Diode.First resistor device includes first resistor device terminal and second resistance device terminal, and first resistor device terminal, which is coupled to, to be connect
Ground terminal.Switch is configured as receiving drive signal and is coupled to second resistance device terminal.In addition, the first diode includes
First diode terminal and the second diode terminal and first resistor device is coupled to, the second diode terminal is coupled to one
Individual or multiple light emitting diodes.
According to another embodiment, it is a kind of be used for adjust one or more electric currents system include system controller, transformer,
First resistor device, switch and the first diode.System controller includes the first controller terminal and ground terminal, system control
Device is configured as the output drive signal at the first controller terminal.Transformer includes armature winding and armature winding, it is primary around
Group includes the first winding terminals and the second winding terminals, and secondary windings includes tertiary winding terminal and the 4th winding terminals, and first
Winding terminals are coupled to ground terminal, and the second winding terminals are coupled to one or more light emitting diodes, tertiary winding end
Son is coupled to ground terminal.First resistor device includes first resistor device terminal and second resistance device terminal, first resistor device end
Son is coupled to ground terminal.Switch is configured as receiving drive signal and is coupled to second resistance device terminal.In addition, the
One diode includes the first diode terminal and the second diode terminal and is coupled to first resistor device, the second diode end
Son is coupled to one or more light emitting diodes.
According to another embodiment, a kind of system for being used to adjust one or more electric currents includes system controller, is configured
To receive sensing signal, resistor and inductor to switch output drive signal and from the resistor for being connected to switch and inductor
Either directly or indirectly it is connected to one or more light emitting diodes.In addition, drive signal and one or more switch periods
Associated, each switch periods of one or more switch periods include the ON time section of switch and the deadline of switch
Section.In addition, each switch periods of one or more switch periods are multiplied by the demagnetization associated with inductor equal to a coefficient
The demagnetization period of journey, the coefficient are more than 1.In addition, flow through the mean size of the first electric current of one or more light emitting diodes with
The peak value size of sensing signal in each switch periods of one or more switch periods is proportional.
According to another embodiment, a kind of system for being used to adjust one or more electric currents includes modulation and drive component, adopted
Sample keeps component, amplifier module, error amplifier and comparator.Modulation and drive component are configured as to switch output driving letter
Number, drive signal is associated with least one switch periods, and at least one switch periods include the ON time section and use of switch
In the demagnetization period of demagnetization process.Sampling keeps component to be configured as receiving the current related sensing signal with flowing through switch,
Sensing signal is sampled at the middle of ON time section, and keeps the sensing signal sampled.Amplifier module is configured
To receive the sensing signal for sampling and keeping during the period of demagnetizing and generating amplified signal.In addition, error amplifier quilt
It is configured to receive amplified signal during the period of demagnetizing and at least generates integrated signal with together with the first capacitor.In addition, than
Compared with device be configured as at least receive integrated signal and at least based on the information associated with integrated signal to modulate and driving group
Part exports comparison signal.
In another embodiment, a kind of system for being used to adjust one or more electric currents includes modulation and drive component, put
Big component, error amplifier and comparator.Modulation and drive component be configured as to switch output drive signal, drive signal with
At least one switch periods are associated, and at least one switch periods include the ON time section of switch and moving back for the process of demagnetizing
The magnetic period.Amplifier module is configured as receiving sensing signal during the period of demagnetizing and generates amplified signal, sensing signal with
Flow through switch first is current related.In addition, error amplifier be configured as during the period of demagnetizing receive amplified signal and
At least integrated signal is generated with together with the first capacitor.In addition, comparator is configured as at least receiving integrated signal and at least
Comparison signal is exported to modulation and drive component based on the information associated with integrated signal.
In another embodiment, a kind of method for being used to adjust one or more electric currents includes：From be connected to switch and electricity
The resistor of sensor receives sensing signal, and handles the information associated with sensing signal.In addition, this method includes：At least
Drive signal for switch is generated based on the information associated with sensing signal；The processing information associated with drive signal；
And the electric current of one or more light emitting diodes is at least flowed through based on the information generation associated with drive signal, one or more
Individual light emitting diode is connected directly or indirectly to resistor and inductor.Moreover, drive signal switchs with one or more
Cycle is associated, when each switch periods of one or more switch periods include ON time section and the cut-off of switch of switch
Between section.Each switch periods of one or more switch periods are multiplied by the demagnetization process associated with inductor equal to a coefficient
Demagnetize the period, the coefficient is more than 1.In addition, electric current and the sensing signal in each switch periods of one or more switch periods
Peak value size it is proportional.
In another embodiment, a kind of method for being used to adjust one or more electric currents includes driving of the generation for switch
Signal, drive signal is associated with least one switch periods, at least one switch periods include switch ON time section and
The demagnetization period for the process of demagnetizing.This method also includes：Receive and flow through the current related sensing signal of switch；Processing with
The associated information of sensing signal；And sensing signal is sampled at the middle of ON time section.In addition, this method bag
Include：Keep the sensing signal sampled；The sensing signal for sampling and keeping is received during the period of demagnetizing；And processing is with connecing
The information that the sensing signal for sampling and keeping received is associated.This method also includes：At least based on being adopted with what is received
The information generation amplified signal that sample and the sensing signal kept are associated；Receive amplified signal；And processing and amplified signal phase
The information of association.In addition, this method includes：Integrated signal is at least generated based on the information associated with amplified signal；At least connect
Receive integrated signal；The processing information associated with integrated signal；And at least generated based on the information associated with integrated signal
Comparison signal.
In another embodiment, a kind of method for being used to adjust one or more electric currents includes driving of the generation for switch
Signal, drive signal is associated with least one switch periods, at least one switch periods include switch ON time section and
The demagnetization period for the process of demagnetizing.In addition, this method includes：The current related of switch is received and flows through during the period of demagnetizing
Sensing signal；The processing information associated with the sensing signal received；It is and related based on the sensing signal to being received
The information generation amplified signal of connection.This method also includes：Receive amplified signal, the processing information associated with amplified signal；And
And integrated signal is at least generated based on the information associated with amplified signal.In addition, this method includes：At least receive integration letter
Number；The processing information associated with integrated signal；Comparison signal is at least generated based on the information associated with integrated signal；And
Receive comparison signal.
Depending on embodiment, one or more benefits can be obtained.Can be comprehensive with reference to following detailed description and drawings
Ground understands these benefits of the present invention and each other objects, features and advantages.
Brief description of the drawings
Fig. 1 is the traditional diagram of simplification for showing the system for driving LED.
Fig. 2 is to show the simplification diagram according to an embodiment of the invention for being used to drive LED system.
Fig. 3 (a) is to show some components according to an embodiment of the invention for being used to drive LED system controller
Simplify diagram.
Fig. 3 (b) is the simplified timing diagram of system controller according to an embodiment of the invention.
Fig. 4 (a) is to show some components according to another embodiment of the present invention for being used to drive LED system controller
Simplify diagram.
Fig. 4 (b) is the simplified timing diagram of system controller according to another embodiment of the present invention.
Fig. 5 is to show the simplification diagram according to another embodiment of the present invention for being used to drive LED system.
Fig. 6 is to show the simplification diagram for being used to drive LED system according to further embodiment of this invention.
Fig. 7 is to show the simplification diagram for being used to drive LED system according to further embodiment of this invention.
Embodiment
The present invention relates to integrated circuit.More specifically, the invention provides the system and method for adjusting electric current.Only
As an example, application flows through light emitting diode (LED) electric current to the present invention to adjust.It will be appreciated that the present invention has
Wider application.
Fig. 2 is to show the simplification diagram according to an embodiment of the invention for being used to drive LED system.The diagram is only
It is example, it should not undeservedly limit the scope of claim.It would be recognized by those skilled in the art that many variants, replacement and
Modification.
System 200 includes adjustment circuit 201, rectification and filter circuit 204 and buck (buck-boost) switch electricity
Road 206.Rectification and filter circuit 204 include 212, two fuse (fuse) 208, rheostat 210, common mode filtering inductor X electricity
Container 214 and 216, rectifier bridge 218 and filter condenser 220.Buck on-off circuit 206 include buck inductor 222,
Switch 224, flyback diode 226, filter condenser 228, current-sense resistor 230 and output dummy resistor 232.
Adjustment circuit 201 includes system controller 202, three capacitors, 234,236 and 238, five resistors 240,242,244,246
With 248, two diodes 250 and 252 and Zener diode 254.System controller 202 include six terminals 260,262,
264th, 266,268 and 270.
For example, the different terminals of system controller 202 are for various purposes.As an example, table 1 is shown to system
The description of terminal in controller 202.
Table 1
| Terminal | Terminal names | Description |
| 260 | GND | Controller or chip ground |
| 262 | GATE | Raster data model |
| 264 | CS | Current sense inputs |
| 266 | VDD | Power input |
| 268 | COMP | Control loop compensates |
| 270 | FB | Output voltage feeds back |
In another example, the terminal of the terminal of resistor 230 and inductor 222 with being both coupled to chip 272 (examples
Such as, controller ground).Below, can by chip 272 referred to as.In another example, loop compensation is in system controller 202
Inside performs.In another example, terminal 268 (for example, COMP) is omitted.In another example, switch 224 is transistor.
According to one embodiment, a terminal of inductor 222 (for example, L2) with being couple to chip 272 and the other end
Son is couple to one or more LED280.For example, a terminal of resistor 230 (for example, R7) with being couple to chip 272 and
Another terminal is couple to switch 224.In another example, a terminal of diode 226 (for example, D1) is (for example, cathode terminal
Son) resistor 230 is couple to, and another terminal (for example, anode terminal) is couple to one or more LED280.Show another
In example, terminal 264 (for example, CS) passes through capacitor 238 (for example, C5) with being couple to chip 272, and pass through resistor 248
(for example, R5) is couple to both resistor 230 (for example, R7) and switch 224.In another example, terminal 270 (for example, FB)
Pass through resistor 246 (for example, R4) with being couple to chip 272, and pass through resistor 244 (for example, R3) and diode 252
(for example, D3) is couple to inductor 222 (for example, L2).In another example, terminal 262 (for example, GATE) is couple to switch
224 (for example, being coupled at the gate terminal of switch 224).In another example, terminal 260 (for example, GND) is couple to chip
Ground 272.Resistor 248 (for example, R5) and capacitor 238 (for example, C5) are omitted in certain embodiments.
According to another embodiment, AC input 274 is applied to rectification and filter circuit 204, and it generates input signal 276.
For example, adjustment circuit 201 receives input signal 276, and gate drive signal 288 is exported by terminal 262 (for example, GATE)
With driving switch 224.In another example, buck on-off circuit 206 receives input signal 276 and is used to drive one or more
LED280.In another example, the switch periods of system 200 include the conducting of the closure (for example, conducting) during it of switch 224
Period Ton, and the deadline section T of the disconnection (for example, cut-off) during it of switch 224off。
According to another embodiment, when switching 224 closures (for example, conducting), electric current 278 flows through resistor 230 and inductance
Device 222.For example, the storage energy of inductor 222.In another example, voltage signal 290 is generated by resistor 230.Show another
In example, the size of voltage signal 290 is proportional to the product of electric current 278 and the resistance of resistor 230.In another example, holding
The voltage signal 290 is detected via resistor 248 in sub 264 (for example, CS) places.
According to some embodiments, when switching 224 disconnections (for example, cut-off), deadline section ToffStart, and inductance
The demagnetization process of device 222 starts.For example, at least a portion of electric current 278 flows to one or more LED280 simultaneously from inductor 222
And flow through diode 226.In another example, resistor 232 has big resistance, and flows through one or more LED280 electricity
Stream 284 is in size close to electric current 278.In another example, at (for example, FB) place of terminal 270 via including resistor 244
The output voltage signal 286 associated with one or more LED280 is detected with the resistor divider including resistor 246.
In another example, during the demagnetization process of inductor 222 voltage signal 286 higher than chip 272 voltage.Show another
In example, after the demagnetization process of inductor 222 is completed, the size of voltage signal 286 drops to low value.In another example
In, system 200 works under the input and output loading of wide scope, for example, in AC85V~264V input range and three
Or worked under more (more than three) LED output loading.
In another embodiment, by making the peak of electric current 278 via (for example, CS) monitoring voltage of terminal 264 signal 290
Value is approximate in each switch periods of system 200 to keep constant.For example, by via terminal 270 (for example, FB) monitoring voltage
Signal 286 detects the demagnetization period of inductor 222.In another example, the switch periods of system 200 are inductors 222
The N double-lengths of demagnetization period, wherein N are greater than 1 coefficient.Therefore, according to some embodiments, can determine to flow through based on following formula
The mean size of one or more LED280 electric current 284.
(equation 1)
Wherein, ILEDExpression flows through the mean size of one or more LED280 electric current 284, and N represents opening for system 200
Close the ratio between cycle and the demagnetization period of inductor 222, VTH_OCThe peak value of voltage signal 290 is represented, and R7 represents resistor 230
Resistance.
Fig. 3 (a) is to show some components according to an embodiment of the invention for being used to drive LED system controller
Simplify diagram.The diagram is only example, and it should not undeservedly limit the scope of claim.Those skilled in the art will recognize
Know many variants, substitutions and modifications.
System controller 300 includes 302, three switches 304,306 and 308 of timing component, gain stage 310 (for example, amplification
Component), amplifier 312, comparator 314, vibration and shake component 316, trigger 318, logic control component 320, grid drive
Dynamic component 322, overcurrent protection (OCP) component 324, lead-edge-blanking (LEB) component 326, reference signal generator 328, voltage letter
Number maker 330, output over-voltage protection (OVP) component 332, demagnetization detector 334 and capacitor 336.In addition, system controls
Device 300 includes terminal 360,362,364,366,368 and 370.For example, system controller 300 is identical with system controller 202.
In another example, terminal 360,362,364,366,368 and 370 respectively with terminal 260,262,264,266,268 and 270 phases
Together.In another example, amplifier 312 includes operation transconductance amplifier.In another example, amplifier 312 and capacitor 392
It is included in integrator.
According to one embodiment, system controller 300 is used to replace the system controller as the part of system 200
202.For example, the current sensing signal associated with flowing through the electric current (for example, electric current 278) of inductor 222 and resistor 230
390 are received at (for example, CS) place of terminal 364.In another example, timing component 302 is in ON time section TonPeriod generates
Timing signal 338 carrys out closure switch 304 and is up to predetermined amount of time, to be sampled to signal 390.In another example, detection
Signal 340 is stored on capacitor 336.In another example, increase with the size of the signal 390 during the predetermined amount of time
Greatly, the size of detection signal 340 also increases.In another example, switch 304 is after this predetermined time period (for example, turning on
Period TonMiddle at) disconnect (for example, cut-off) immediately.Therefore, according to some embodiments, (example of current sensing signal 390
Such as, in ON time section TonMiddle at) be sampled, and the signal sampled is then kept (for example, storage) in electricity
On container 336.
In another embodiment, the component 334 that demagnetizes receives and output voltage signal (example at terminal 370 (for example, FB) place
Such as, signal 286) associated feedback signal 386, the output voltage signal (for example, signal 286) and one or more LED280
It is associated.For example, feedback signal 386 is relevant with the demagnetization process of inductor 222.In another example, as response, demagnetization group
Part 334 exports demagnetization signal 342 and thermal compensation signal 344.In another example, during the demagnetization process of inductor 222, demagnetization
Signal 342 is logic high and thermal compensation signal 344 is logic low.In another example, in the demagnetization of inductor 222
After process terminates, demagnetization signal 342 is logic low and thermal compensation signal 344 is logic high.
According to another embodiment, if demagnetization signal 342 is logic high and thermal compensation signal 344 is logic low electricity
It is flat, then switch 306 closures (for example, conducting) and switch 308 disconnects (for example, cut-off).For example, gain stage 310 passes through switch
306 receive stored detection signal 340 and export amplified signal 346 to amplifier 312.In another example, amplify
Device 312 receives reference signal 348 (for example, V from reference signal generator 328ref).In another example, as response, amplification
Device 312 generates integrated signal 350 together with capacitor 392 based on amplified signal 346 and reference signal 348.In another example,
Comparator 314 receives integrated signal 350 and receives ramp signal 352 from vibrating and shaking component 316, and generates comparison signal
354.In another example, trigger 318 receives comparison signal 354 and receives clock signal from vibrating and shaking component 316
356, and export modulated signal 358 to logic control component 320.In another example, logic control component 320 is also from output
The reception signal 373 of OVP components 332, two signals 374 and 376 are received from voltage signal maker 330, and from OCP components 324
Reception signal 380.In another example, as response, logic control component 320 is to the output signal 378 of gate driver device 322
To influence the ON time section of switch 224.In another example, signal 378 is pulsewidth modulation (PWM) signal.According to some realities
Example is applied, during the demagnetization process of inductor 222, one or more LED280 average current and the average electricity of inductor 222
Flow into estimated rate (for example, the estimated rate is equal to 1).For example, one or more LED280 average current can be according to following formula
To determine.
(equation 2)
Wherein, ILEDExpression flows through one or more LED280 average current, VrefReference signal 348 is represented, R7 is represented
The resistance of resistor 230, and G represents the gain of gain stage 310.In another example, one or more LED280 are averaged
The constant magnitude of electric current.
In another embodiment, if demagnetization signal 342 is logic low and thermal compensation signal 344 is logically high electricity
It is flat, then switch 306 and disconnect (for example, cut-off) and switch 308 closures (for example, conducting).For example, gain stage 310 is from chip
372 reception signals 382 (for example, 0V).
Fig. 3 (b) is the simplified timing diagram of system controller 300 according to an embodiment of the invention.The diagram is only
Example, it should not undeservedly limit the scope of claim.It would be recognized by those skilled in the art that many variants, replacing and repairing
Change.
Waveform 301 is denoted as the feedback signal 386 of the function of time, and waveform 303 is denoted as the stream of the function of time
Electric current through inductor 222, and waveform 305 is denoted as the current sensing signal 390 of the function of time.In addition, waveform 307
The timing signal 338 of the function of time is denoted as, waveform 309 is denoted as the modulated signal 358 of the function of time, and ripple
Shape 311 is denoted as the detection signal 340 of the function of time.In addition, waveform 313 is denoted as the demagnetization signal of the function of time
342, and waveform 315 is denoted as the integrated signal 350 of the function of time.
Five period T are shown in Fig. 3 (b)on1、Thalf、Toff1、Tdemag1And Ts1.Period Ton1Start from the moment
t0And end at moment t2, period ThalfStart from moment t0And end at moment t1, and period Toff1Start from the moment
t2And end at moment t4.Period Tdemag1Start from moment t2And end at moment t3, and period Ts1Start from the moment
t0And end at moment t4.For example, t0≤t1≤t2≤t3≤t4.In another example, t1Positioned at period Ton1Middle at.
In another example, ThalfEqual to Ton1Half (for example,)。
According to one embodiment, period Ton1Represent the ON time section of the closure of switch 224 (for example, conducting).For example,
Period Toff1Represent that switch 224 disconnects the deadline section of (for example, cut-off).In another example, period Tdemag1Represent
The demagnetization period of inductor 222.In another example, period Ts1The switch periods of expression system 200.In another example,
Period Ts1Including period Ton1With period Toff1.In another example, period Ton1Including period Thalf.Another
In example, period Toff1Including period Tdemag1。
According to another embodiment, in period Ton1Beginning (for example, in t0Place), the closure of switch 224 is (for example, lead
It is logical).For example, flow through the size increase (for example, as shown in waveform 303) of the electric current (for example, electric current 278) of inductor 222.Another
In one example, the size increase (for example, as shown in waveform 305) of current sensing signal 390.In another example, timing signal
338 are changed into logic high (for example, as shown in waveform 307) from logic low, and switch 304 closures (for example, conducting).
In another example, the size of detection signal 340 is reduced to low value 327 (for example, 0) from preceding value 325, as shown in waveform 311.
In another example, feedback signal 386 is reduced to low value 335 (for example, 0), as shown in waveform 301.In another example, demagnetization signal
342 be logic low (for example, as shown in waveform 313), and switchs 306 and disconnect (for example, cut-off).In another example,
Modulated signal 358 is changed into logic high (for example, as shown in waveform 309) from logic low.
According to another embodiment, in period ThalfPeriod, the size for flowing through the electric current of inductor 222 persistently increase (example
As shown in waveform 303).For example, the size of current sensing signal 390 persistently increases (for example, as shown in waveform 305).Another
In one example, the holding logic high of timing signal 338 (for example, as shown in waveform 307), and the closure of switch 304 (for example,
Conducting).In another example, the size of detection signal 340 increases to peak value 317 (for example, in t1Place), as shown in waveform 311.
In another example, feedback signal 386 keeps low value 335 (for example, 0), as shown in waveform 301.In another example, demagnetization letter
Numbers 342 keep logic lows (for example, as shown in waveform 313), and switch 306 and disconnect (for example, cut-off).In another example
In, modulated signal 358 is in period ThalfPeriod keeps logic high (for example, as shown in waveform 309).In another example
In, in period ThalfEnd at (for example, t1), timing signal 338 is changed into logic low (for example, such as from logic high
Shown in waveform 307), and switch 304 and disconnect (for example, cut-off).
According to another embodiment, in period Ton1Remaining time during (for example, in t1Afterwards), it is stored in capacitor
Detection signal 340 on 336 keeps peak value 317 (for example, VCs_1/2Ton).For example, the holding of feedback signal 386 low value 335 (for example,
0), as shown in waveform 301.In another example, demagnetization signal 342 keeps logic low (for example, as shown in waveform 313),
And switch 306 to remain open (for example, cut-off).In another example, modulated signal 358 keeps logic high (for example, such as
Shown in waveform 309).In another example, flow through the electric current of inductor 222 size continue to increase to peak value 331 (for example,
t2Place), as shown in waveform 303.In another example, the size of current sensing signal 390 continue to increase to value 333 (for example,
t2Place), as shown in waveform 305.In another example, the peak value 317 of detection signal 340 is equal to the peak of current sensing signal 390
The half of value 333.
According to another embodiment, in period Toff1Beginning (for example, in t2Place), switch 224 is disconnected (for example, cutting
Only).For example, at least a portion of electric current (for example, electric current 278) flows to one or more LED280 from inductor 222.Another
In example, feedback signal 386 is changed into high level 329 (for example, t from low value 335 (for example, 0)2Place), as shown in waveform 301.Again
In one example, demagnetization signal 342 is changed into logic high (for example, as shown in waveform 313) from logic low, and it indicates inductance
The demagnetization process of device 222 starts.In another example, the closure of switch 306 (for example, conducting).In another example, gain stage
310 receive stored detection signal 340, and export amplified signal 346, the output integration letter of amplifier 312 to amplifier 312
Numbers 350.In another example, modulated signal 358 is changed into logic low (for example, as shown in waveform 309) from logic high.
According to another embodiment, in period Tdemag1Period, inductor 222 demagnetize.For example, the size of feedback signal 386
Low value 335 is kept above, as shown in waveform 301.In another example, the electric current (example of inductor 222 and resistor 230 is flowed through
Such as, electric current 278) size be reduced to low value 321 (for example, as shown in waveform 303).In another example, current sensing signal
390 size is reduced to low value 323 (for example, as shown in waveform 305).In another example, timing signal 338 keeps logic low
Level, and switch 304 and remain open (for example, cut-off).In another example, the holding of detection signal 340 peak value 317 (for example,
As shown in waveform 311).In another example, demagnetization signal 342 keeps logic high (for example, as shown in waveform 313), and
And switch 306 remains closed (for example, conducting).In another example, integrated signal 350 remains greatly in small fluctuation lower aprons
Small by 319 (for example, as shown in waveform 315).In another example, modulated signal 358 is in period Tdemag1Period keeps logic low
Level (for example, as shown in waveform 309).According to some embodiments, in period Tdemag1End at, feedback signal 386 it is big
It is small drastically to decline, as shown in waveform 301.For example, the demagnetization period of inductor 222 is by monitoring terminal 270 (for example, FB) place
Feedback signal 386 and detect.
In another embodiment, in period Toff1Remaining time during (for example, in the demagnetization process of inductor 222
In t3After end), the electric current for flowing through inductor 222 keeps low value 321 (for example, as shown in waveform 303).For example, electric current sense
Survey signal 390 and keep low value 323 (for example, as shown in waveform 305).In another example, timing signal 338 keeps logic low electricity
Flat (for example, as shown in waveform 307), and switch 304 and remain open (for example, cut-off).In another example, detection signal
340 keep peak value 317 (for example, as shown in waveform 311).In another example, demagnetization signal 342 keeps logic high (example
Such as, as shown in waveform 313).In another example, integrated signal 350 keeps size 319 (for example, such as in small fluctuation lower aprons
Shown in waveform 315).In another example, modulated signal 358 keeps logic low (for example, as shown in waveform 309).
According to some embodiments, at the beginning of next switch periods (for example, in t4Place), the new cycle starts.For example,
The size increase (for example, as shown in waveform 303) of the electric current of inductor 222 is flowed through, and the size of current sensing signal 390 is again
Secondary increase is (for example, in t4Place, as shown in waveform 305).In another example, timing signal 338 is changed into patrolling from logic low
High level is collected (for example, in t4Place, as shown in waveform 307), and 304 closures (for example, conducting) are switched with again to electric current sense
Signal 390 is surveyed to sample.In another example, integrated signal 350 (for example, due to very limited amount of loop bandwidth) is in next switch
During cycle size 319 (for example, as shown in waveform 315) is kept in small fluctuation lower aprons.
Fig. 4 (a) is to show some components according to another embodiment of the present invention for being used to drive LED system controller
Simplify diagram.The diagram is only example, and it should not undeservedly limit the scope of claim.Those skilled in the art will recognize
Know many variants, substitutions and modifications.
System controller 400 include two switch 406 and 408, gain stage 410 (for example, amplifier module), amplifier 412,
Comparator 414, vibration and shake component 416, trigger 418, logic control component 420, gate driver device 422, OCP components
424th, LEB components 426, reference signal generator 428, voltage signal maker 430, output OVP components 432, demagnetization detector
434 and capacitor 436.In addition, system controller 400 includes terminal 460,462,464,466,468 and 470.For example, system
Controller 400 is identical with system controller 202.In another example, terminal 460,462,464,466,468 and 470 respectively with
Terminal 260,262,264,266,268 and 270 are identical.In another example, amplifier 412 includes operation transconductance amplifier.
In another example, amplifier 412 and capacitor 492 are included in integrator.
According to one embodiment, system controller 400 is used to replace the system controller as the part of system 200
202.For example, the current sensing signal associated with flowing through the electric current (for example, electric current 278) of inductor 222 and resistor 230
490 are received at (for example, CS) place of terminal 464.In another example, signal 490 is stored on capacitor 436.Demagnetization group
Part 434 receives the feedback signal 486 associated with output voltage signal (for example, signal 286) at terminal 470 (for example, FB) place,
The output voltage signal (for example, signal 286) is associated with one or more LED280.In another example, feedback signal 486
It is relevant with the demagnetization process of inductor 222.In another example, as response, demagnetization component 434 exports the He of demagnetization signal 442
Thermal compensation signal 444.In another example, during the demagnetization process of inductor 222, demagnetization signal 442 be logic high simultaneously
And thermal compensation signal 444 is logic low.In another example, after the demagnetization process of inductor 222 terminates, demagnetization signal
442 be logic low and thermal compensation signal 444 is logic high.In certain embodiments, capacitor 436 is removed.
According to another embodiment, if demagnetization signal 442 is logic high and thermal compensation signal 444 is logic low electricity
It is flat, then switch 406 closures (for example, conducting) and switch 408 disconnects (for example, cut-off).For example, gain stage 410 passes through switch
406 reception signals 490 (or stored signal 490) and export amplified signal 446.In another example, amplifier 412 connects
Amplified signal 446 is received, and reference signal 448 is received (for example, V from reference signal generator 428ref).In another example, make
For response, amplifier 412 generates integrated signal 450 together with capacitor 492 based on amplified signal 446 and reference signal 448.
In another example, comparator 414 receives integrated signal 450 and receives ramp signal 452 from vibrating and shaking component 416.Again
In one example, comparator 414 exports comparison signal 454.In another example, trigger 418 receives comparison signal 454 and from shaking
Swing and shake component 416 and receive clock signal 456, and modulated signal 458 is exported to logic control component 420.Show another
In example, from the output reception signal 473 of OVP components 432, two also are received from voltage signal maker 430 for logic control component 420
Signal 474 and 476, and from the reception signal 480 of OCP components 424.In another example, as response, logic control component 420
To the output signal 478 of gate driver device 422 with the ON time section of influence switch 224.In another example, signal 478 is
Pwm signal.According to some embodiments, during the demagnetization process of inductor 222, one or more LED280 average current with
The average current of inductor 222 is into estimated rate (for example, the estimated rate be equal to 1).For example, one or more LED280's is flat
Equal electric current can determine according to following formula.
(equation 3)
Wherein, ILEDRepresent one or more LED280 average current, VrefReference signal 448 is represented, R7 represents resistance
The resistance of device 230, and G represents the gain of gain stage 410.In another example, one or more LED280 average current
Constant magnitude.In another example, if G is equal to 1, gain stage 410 is omitted.
In another embodiment, if thermal compensation signal 444 is logic high and demagnetization signal 442 is logic low electricity
It is flat, then switch 408 closures (for example, conducting) and switch 406 disconnects (for example, cut-off).For example, gain stage 410 is from chip
472 reception signals 482 (for example, 0V).
Fig. 4 (b) is the simplified timing diagram of system controller 400 according to another embodiment of the present invention.The diagram is only
Example, it should not undeservedly limit the scope of claim.It would be recognized by those skilled in the art that many variants, replacing and repairing
Change.
Waveform 401 is denoted as the feedback signal 486 of the function of time, and waveform 403 is denoted as the stream of the function of time
Electric current through inductor 222, and waveform 405 is denoted as the current sensing signal 490 of the function of time.In addition, waveform 407
The modulated signal 458 of the function of time is denoted as, and waveform 409 is denoted as the demagnetization signal 442 of the function of time, and
And waveform 411 is denoted as the integrated signal 450 of the function of time.
Four period T are shown in Fig. 4 (b)on2、Toff2、Tdemag2And Ts2.Period Ton2Start from moment t5And
End at moment t6, period Toff2Start from moment t6And end at moment t8, and period Tdemag2Start from moment t6And
End at moment t7, and period Ts2Start from moment t5And end at moment t8.For example, t5＜ t6＜ t7＜ t8。
According to one embodiment, period Ton2Represent the ON time section of the closure of switch 224 (for example, conducting).For example,
Period Toff2Represent that switch 224 disconnects the deadline section of (for example, cut-off).In another example, period Tdemag2Represent
The demagnetization period of inductor 222.In another example, period Ts2The switch periods of expression system 200.In another example,
Period Ts2Including period Ton2With period Toff2.In another example, period Toff2Including period Tdemag2。
According to another embodiment, in period Ton2Beginning (for example, in t5Place), the closure of switch 224 is (for example, lead
It is logical).For example, flow through the size increase (for example, as shown in waveform 403) of the electric current (for example, electric current 278) of inductor 222.Another
In one example, the size increase (for example, as shown in waveform 405) of current sensing signal 490.In another example, feedback signal
486 are reduced to low value 419 (for example, t5Place 0), as shown in waveform 40l.In another example, demagnetization signal 442 is logic low electricity
Flat (for example, as shown in waveform 409), and switch 406 and disconnect (for example, cut-off).In another example, modulated signal 458 from
Logic low is changed into logic high (for example, as shown in waveform 407).
According to another embodiment, in period Ton2Period, flow through inductor 222 electric current (for example, electric current 278) it is big
The small peak value 415 that persistently increases to is (for example, t6Place), as shown in waveform 403.For example, the size of current sensing signal 490 persistently increases
Greatly to peak value 417 (for example, t6Place), as shown in waveform 405.In another example, feedback signal 486 keeps the (example of low value 419
Such as, 0), as shown in waveform 401.In another example, demagnetization signal 442 keeps logic low (for example, such as the institute of waveform 409
Show), and switch 406 and remain open (for example, cut-off).In another example, modulated signal 458 keeps logic high (example
Such as, as shown in waveform 407).
According to another embodiment, in period Toff2Beginning (for example, in t6Place), switch 224 is disconnected (for example, cutting
Only).For example, at least a portion of electric current (for example, electric current 278) flows to one or more LED280 from inductor 222.Another
In example, feedback signal 486 is changed into high level 413 (for example, t from low value 419 (for example, 0)6Place), as shown in waveform 401.Again
In one example, demagnetization signal 442 is changed into logic high (for example, as shown in waveform 409) from logic low, and it indicates inductance
The demagnetization process of device 222 starts.In another example, the closure of switch 406 (for example, conducting).In another example, gain stage
410 receive stored current sensing signal 490, and export amplified signal 446, the output product of amplifier 412 to amplifier 412
Sub-signal 450.In another example, modulated signal 458 is changed into logic low (for example, such as the institute of waveform 407 from logic high
Show).
According to another embodiment, in period Tdemag2Period, inductor 222 demagnetize.For example, the size of feedback signal 486
It is kept above low value 419 (as shown in waveform 401).In another example, the electric current (example of inductor 222 and resistor 230 is flowed through
Such as, electric current 278) size be reduced to low value 421 (for example, in t7Place), as shown in waveform 403.In another example, current sense
The size of signal 490 is reduced to low value 423 (for example, in t7Place), as shown in waveform 405.In another example, demagnetization signal 442
Logic high (for example, as shown in waveform 409) is kept, and switchs 406 and remains closed (for example, conducting).In another example
In, integrated signal 450 remains size 425 (for example, as shown in waveform 411) in small fluctuation lower aprons.In another example,
Modulated signal 458 is in period Tdemag2Period keeps logic low (for example, as shown in waveform 407).According to some implementations
Example, in period Tdemag2End at, the size of feedback signal 486 drastically declines, as shown in waveform 401.For example, inductor
222 demagnetization period is detected by monitoring the feedback signal 486 at terminal 270 (for example, FB) place.
In another embodiment, in period Toff2Remaining time during (for example, in the demagnetization process of inductor 222
In t7After end), the electric current for flowing through inductor 222 keeps low value 421 (for example, as shown in waveform 403).For example, electric current sense
Survey signal 490 and keep low value 423 (for example, as shown in waveform 405).In another example, demagnetization signal 442 keeps logically high electricity
Flat (for example, as shown in waveform 409) and switch 406 remain closed (for example, conducting).In another example, integrated signal 450
Size 425 (for example, as shown in waveform 411) is kept in small fluctuation lower aprons.In another example, modulated signal 458 is kept
Logic low (for example, as shown in waveform 407).
According to some embodiments, at the beginning of next switch periods (for example, in t8Place), the new cycle starts.For example,
The size for flowing through the electric current of inductor 222 increases (for example, as shown in waveform 403) again, and current sensing signal 490 is big
It is small to increase (for example, as shown in waveform 405) again.In another example, integrated signal 450 is (for example, due to very limited amount of ring
Road bandwidth) during next switch periods keep size 425 (for example, as shown in waveform 411) in small fluctuation lower aprons.
Fig. 5 is to show the simplification diagram according to another embodiment of the present invention for being used to drive LED system.The diagram is only
It is example, it should not undeservedly limit the scope of claim.It would be recognized by those skilled in the art that many variants, replacement and
Modification.
System 500 includes adjustment circuit 501, rectification and filter circuit 504 and buck on-off circuit 506.Rectification and
Filter circuit 504 includes fuse 508, rheostat 510, common mode filtering inductor 512, two X capacitors 514 and 516, rectifier bridges
518 and filter condenser 520.Buck on-off circuit 506 includes armature winding 522, secondary windings 552, switchs 524, be anti-
Swash formula diode 526, filter condenser 528, current-sense resistor 530 and output dummy resistor 532.Adjustment circuit
501 include 534,536 and 538, six, the capacitor He of resistor 540,542,544,546,548 of system controller 502, three
554 and diode 550.System controller 502 includes six terminals 560,562,564,566,568 and 570.
For example, the terminal of resistor 530 and the terminal with being both coupled to chip 572 of armature winding 522.In another example
In, system controller 502 is identical with system controller 202.In another example, terminal 560,562,564,566,568 and 570
It is identical with terminal 260,262,264,266,268 and 270 respectively.In another example, loop compensation is in system controller 502
Portion is performed, and terminal 568 (for example, COMP) is omitted.In another example, switch 524 is transistor.
According to one embodiment, a terminal of armature winding 522 with being couple to chip 572 and another terminal be couple to
One or more LED580.For example, a terminal of secondary windings 552 with being couple to chip 572 and another terminal pass through electricity
Resistance device 544 is couple to terminal 570 (for example, FB).In another example, a terminal of resistor 530 (for example, R7) is couple to
Chip 572, and another terminal is couple to switch 524.In another example, a terminal of diode 526 (for example, D1)
(for example, cathode terminal) is couple to resistor 530, and another terminal (for example, anode terminal) is couple to one or more
LED580.In another example, terminal 564 (for example, CS) by capacitor 538 (for example, C5) with being couple to chip 572, and
And both resistor 530 (for example, R7) and switch 524 are couple to by resistor 548 (for example, R5).In another example, end
570 (for example, FB) of son pass through resistor 546 (for example, R4) with being couple to chip 572.In another example, (the example of terminal 562
Such as, GATE) it is couple to switch 524 (for example, being coupled at the gate terminal of switch 524).In another example, (the example of terminal 560
Such as, GND) with being couple to chip 572.Resistor 548 (for example, R5) and capacitor 538 (for example, C5) in certain embodiments by
Omit.
According to another embodiment, AC input 574 is applied to rectification and filter circuit 504, and it generates input signal 576.
For example, adjustment circuit 501 receives input signal 576, and gate drive signal 588 is exported by terminal 562 (for example, GATE)
With driving switch 524.In another example, buck on-off circuit 506 receives input signal 576 and is used to drive one or more
LED580.In another example, the switch periods of system 500 include the conducting of the closure (for example, conducting) during it of switch 524
Period Ton, and the deadline section T of the disconnection (for example, cut-off) during it of switch 524off。
According to another embodiment, when switching 524 closures (for example, conducting), electric current 578 flows through resistor 530 and bag
Include the transformer of armature winding 522 and secondary windings 552.E.g., including transformation of armature winding 522 and secondary windings 552
Device storage energy.In another example, voltage signal 590 is generated by resistor 530.In another example, voltage signal 590
Size is proportional to the product of electric current 578 and the resistance of resistor 530.In another example, passed through at terminal 564 (for example, CS) place
The voltage signal 590 is detected by resistor 548.
According to some embodiments, when switching 524 disconnections (for example, cut-off), deadline section ToffStart, and it is primary
The demagnetization process of winding 522 starts.For example, at least a portion of electric current 578 flows to one or more LED580 from resistor 530
And flow through diode 526.In another example, resistor 532 has big resistance, and flows through one or more LED580's
Electric current 584 is in size close to electric current 578.In another example, at terminal 570 (for example, FB) place via including resistor
Resistor divider including 544 and 546 detects the voltage signal 586 associated with secondary windings 552.In another example
In, during the demagnetization process of armature winding 522 voltage signal 586 higher than chip 572 voltage.In another example,
After the demagnetization process of armature winding 522 is completed, the size of voltage signal 586 drops to low value.In another example, system
500 under the input load of wide scope and output loading (for example, one or more LED (for example, a LED) output loading)
Work.
In another embodiment, the peak of electric current 578 is made by monitoring the voltage signal 590 at terminal 564 (for example, CS) place
Value is approximate in each switch periods of system 500 to keep constant.For example, the voltage by monitoring terminal 570 (for example, FB) place
Signal 586 detects the demagnetization period of armature winding 522.In another example, the switch periods of system 500 are armature windings
The N double-lengths of 522 demagnetization period, wherein N are greater than 1 coefficient.Therefore, according to some embodiments, following formula can be based on come really
The mean size of electric current 584 of the constant current through one or more LED580.
(equation 4)
Wherein, ILEDExpression flows through the mean size of one or more LED580 electric current 584, and N represents opening for system 500
Close the ratio between cycle and the demagnetization period of armature winding 522, VTH_OCThe peak value of voltage signal 590 is represented, and R7 represents resistor
530 resistance.For example, system controller 502 is identical with system controller 300, and system controller 300 is used to replace system
The system controller 502 of system 500.In another example, system controller 502 is identical with system controller 400, and system control
Device 400 processed is used to replace the system controller 502 as the part of system 500.
Fig. 6 is to show the simplification diagram for being used to drive LED system according to further embodiment of this invention.The diagram is only
It is example, it should not undeservedly limit the scope of claim.It would be recognized by those skilled in the art that many variants, replacement and
Modification.
System 600 includes adjustment circuit 601, rectification and filter circuit 604 and buck on-off circuit 606.Rectification and
Filter circuit 604 includes fuse 608, rheostat 610, common mode filtering inductor 612, two X capacitors 614 and 616, rectifier bridges
618 and filter condenser 620.Buck on-off circuit 606 includes buck inductor 622, switch 624, the pole of inverse-excitation type two
Pipe 626, filter condenser 628, current-sense resistor 630 and output dummy resistor 632.Adjustment circuit 601 includes
System 634,636 and 638, five, capacitor, 640,642,644,646 and 648, two diodes of resistor of controller 602, three
650 and 652 and Zener diode 654.System controller 602 includes six terminals 660,662,664,666,668 and 670.
For example, resistor 630 terminal and inductor 622 terminal with being both coupled to chip 672 in another example,
System controller 602 is identical with system controller 202.In another example, terminal 660,662,664,666,668 and 670 points
It is not identical with terminal 260,262,264,266,268 and 270.In another example, loop compensation is inside system controller 602
Perform.In another example, terminal 668 (for example, COMP) is omitted.In another example, switch 624 is transistor.
According to one embodiment, a terminal of inductor 622 (for example, L2) with being couple to chip 672 and the other end
Son is couple to one or more LED680.For example, a terminal of resistor 630 (for example, R7) with being couple to chip 672 and
Another terminal is couple to switch 624.In another example, a terminal of diode 626 (for example, D1) is (for example, cathode terminal
Son) with being couple to chip 672, and another terminal (for example, anode terminal) is couple to one or more LED680.Show another
In example, terminal 664 (for example, CS) passes through capacitor 638 (for example, C5) with being couple to chip 672, and pass through resistor 648
(for example, R5) is couple to both resistor 630 (for example, R7) and switch 624.In another example, terminal 670 (for example, FB)
Pass through resistor 646 (for example, R4) with being couple to chip 672, and pass through resistor 644 (for example, R3) and diode 652
(for example, D3) is couple to inductor 622 (for example, L2).In another example, terminal 662 (for example, GATE) is couple to switch
624 (for example, being coupled at the gate terminal of switch 624).In another example, terminal 660 (for example, GND) is couple to chip
Ground 672.Resistor 648 (for example, R5) and capacitor 638 (for example, C5) are omitted in certain embodiments.
According to another embodiment, AC input 674 is applied to rectification and filter circuit 604, and it generates input signal 676.
For example, adjustment circuit 601 receives input signal 676, and gate drive signal 688 is exported by terminal 662 (for example, GATE)
With driving switch 624.In another example, buck on-off circuit 606 receives input signal 676 for driving one or more
Individual LED680.In another example, the switch periods of system 600 include switch 624 and leading for (for example, conducting) are closed during it
Logical period Ton, and the deadline section T of the disconnection (for example, cut-off) during it of switch 624off。
According to another embodiment, when switching 624 closures (for example, conducting), electric current 678 flows through resistor 630 and inductance
Device 622.For example, the storage energy of inductor 622.In another example, voltage signal 690 is generated by resistor 630.Show another
In example, the size of voltage signal 690 is proportional to the product of electric current 678 and the resistance of resistor 630.In another example, holding
The voltage signal 690 is detected via resistor 648 in sub 664 (for example, CS) places.
According to another embodiment, when switching 624 disconnections (for example, cut-off), deadline section ToffStart, and inductance
The demagnetization process of device 622 starts.For example, at least a portion of electric current 678 flows to one or more LED680 simultaneously from inductor 622
And flow through diode 626.In another example, resistor 632 has big resistance, and flows through one or more LED680 electricity
Stream 684 is in size close to electric current 678.In another example, at (for example, FB) place of terminal 670 via including resistor 644
The output voltage signal 686 associated with one or more LED680 is detected with the resistor divider including resistor 646.
In another example, during the demagnetization process of inductor 622 voltage signal 686 higher than chip 672 voltage.Show another
In example, after the demagnetization process of inductor 622 is completed, the size of voltage signal 686 drops to low value.In another example,
System 600 works under the input and output loading of wide scope, for example, AC85V~264V input range and three with
Worked under upper LED output loading.
According to another embodiment, by making the peak of electric current 678 via (for example, CS) monitoring voltage of terminal 664 signal 690
Value is approximate in each switch periods of system 600 to keep constant.For example, by via terminal 670 (for example, FB) monitoring voltage
Signal 686 detects the demagnetization period of inductor 622.In another example, the switch periods of system 600 are inductors 622
The N double-lengths of demagnetization period, wherein N are greater than 1 coefficient.Therefore, according to some embodiments, can determine to flow through based on following formula
The mean size of one or more LED680 electric current 684.
(equation 5)
Wherein, ILEDExpression flows through the mean size of one or more LED680 electric current 684, and N represents opening for system 600
Close the ratio between cycle and the demagnetization period of inductor 622, VTH_OCThe peak value of voltage signal 690 is represented, and R7 represents resistor 630
Resistance.For example, system controller 602 is identical with system controller 300, and system controller 300 is used to replacement system
600 system controller 602.
Fig. 7 is to show the simplification diagram for being used to drive LED system according to further embodiment of this invention.The diagram is only
It is example, it should not undeservedly limit the scope of claim.It would be recognized by those skilled in the art that many variants, replacement and
Modification.
System 700 includes adjustment circuit 701, rectification and filter circuit 704 and buck on-off circuit 706.Rectification and
Filter circuit 704 includes fuse 708, rheostat 710, common mode filtering inductor 712, two X capacitors 714 and 716, rectifier bridges
718 and filter condenser 720.Buck on-off circuit 706 includes armature winding 722, secondary windings 752, switchs 724, be anti-
Swash formula diode 726, filter condenser 728, current-sense resistor 730 and output dummy resistor 732.Adjustment circuit
701 include 734,736 and 738, six, the capacitor He of resistor 740,742,744,746,748 of system controller 702, three
754 and diode 750.System controller 702 includes six terminals 760,762,764,766,768 and 770.
For example, the terminal of resistor 730 and the terminal with being both coupled to chip 772 of armature winding 722.In another example
In, system controller 702 is identical with system controller 202.In another example, terminal 760,762,764,766,768 and 770
It is identical with terminal 260,262,264,266,268 and 270 respectively.In another example, loop compensation is in system controller 702
Portion is performed, and terminal 768 (for example, COMP) is omitted.In another example, switch 724 is transistor.
According to one embodiment, a terminal of armature winding 722 with being couple to chip 772 and another terminal be couple to
One or more LED780.A for example, terminal with being couple to chip 772, and another terminal passes through electricity for secondary windings 752
Resistance device 744 is couple to terminal 770 (for example, FB).In another example, a terminal of resistor 730 (for example, R7) is couple to
Chip 772, and another terminal is couple to switch 724.In another example, a terminal of diode 726 (for example, D1)
(for example, cathode terminal) with being couple to chip 772, and another terminal (for example, anode terminal) is couple to one or more
LED780.In another example, terminal 764 (for example, CS) by capacitor 738 (for example, C5) with being couple to chip 772, and
And both resistor 730 (for example, R7) and switch 724 are couple to by resistor 748 (for example, R5).In another example, end
770 (for example, FB) of son pass through resistor 746 (for example, R4) with being couple to chip 772.In another example, (the example of terminal 762
Such as, GATE) it is couple to switch 724 (for example, being coupled at the gate terminal of switch 724).In another example, (the example of terminal 760
Such as, GND) with being couple to chip 772.In certain embodiments, resistor 748 (for example, R5) and capacitor 738 (for example, C5)
It is omitted.
According to another embodiment, AC input 774 is applied to rectification and filter circuit 704, and it generates input signal 776.
For example, adjustment circuit 701 receives input signal 776, and gate drive signal 788 is exported by terminal 762 (for example, GATE)
With driving switch 724.In another example, buck on-off circuit 706 receives input signal 776 for driving one or more
Individual LED780.In another example, the switch periods of system 700 include switch 724 and leading for (for example, conducting) are closed during it
Logical period Ton, and the deadline section T of the disconnection (for example, cut-off) during it of switch 724off。
According to another embodiment, when switching 724 closures (for example, conducting), electric current 778 flows through resistor 730 and bag
Include the transformer of armature winding 722 and secondary windings 752.E.g., including transformation of armature winding 722 and secondary windings 752
Device storage energy.In another example, voltage signal 790 is generated by resistor 730.In another example, voltage signal 790
Size is proportional to the product of electric current 778 and the resistance of resistor 730.In another example, passed through at terminal 764 (for example, CS) place
By resistor 748 come detectable voltage signals 790.
According to another embodiment, when switching 724 disconnections (for example, cut-off), deadline section ToffStart, and it is primary
The demagnetization process of winding 722 starts.For example, at least a portion of electric current 778 flows to one or more LED780 from resistor 730
And flow through diode 726.In another example, resistor 732 has big resistance, and flows through one or more LED780's
Electric current 784 is in size close to electric current 778.In another example, at terminal 770 (for example, FB) place via including resistor
Resistor divider including 744 and 746 detects the voltage signal 786 associated with secondary windings 752.In another example
In, during the demagnetization process of armature winding 722 voltage signal 786 higher than chip 772 voltage.In another example,
After the demagnetization process of armature winding 722 is completed, the size of voltage signal 786 drops to low value.In another example, system
700 under the input load of wide scope and output loading (for example, one or more LED (for example, a LED) output loading)
Work.
According to another embodiment, make the peak of electric current 778 by monitoring the voltage signal 790 at terminal 764 (for example, CS) place
Value is approximate in each switch periods of system 700 to keep constant.For example, the voltage by monitoring terminal 770 (for example, FB) place
Signal 786 detects the demagnetization period of armature winding 722.In another example, the switch periods of system 700 are armature windings
The N double-lengths of 722 demagnetization period, wherein N are greater than 1 coefficient.Therefore, according to some embodiments, following formula can be based on come really
The mean size of electric current 784 of the constant current through one or more LED780.
(equation 6)
Wherein, ILEDExpression flows through the mean size of one or more LED780 electric current 784, and N represents opening for system 700
Close the ratio between cycle and the demagnetization period of armature winding 722, VTH_OCThe peak value of voltage signal 790 is represented, and R7 represents resistor
730 resistance.For example, system controller 702 is identical with system controller 300, and system controller 300 is used to replace and made
For the system controller 702 of the part of system 700.
According to another embodiment, a kind of system for being used to adjust one or more electric currents includes：System controller, inductance
Device, first resistor device, switch and the first diode.System controller includes the first controller terminal and ground terminal, the system
Controller is configured as the output drive signal at the first controller terminal.Inductor includes the first inductor terminals and the second electricity
Sensor terminal, the first inductor terminals are coupled to ground terminal, and the second inductor terminals are coupled to one or more luminous
Diode.First resistor device includes first resistor device terminal and second resistance device terminal, and first resistor device terminal, which is coupled to, to be connect
Ground terminal.Switch is configured as receiving drive signal and is coupled to second resistance device terminal.In addition, the first diode includes
First diode terminal and the second diode terminal and first resistor device is coupled to, the second diode terminal is coupled to one
Individual or multiple light emitting diodes.For example, the system is according at least to Fig. 2, Fig. 3 (a), Fig. 3 (b), Fig. 4 (a), Fig. 4 (b) and/or Fig. 6
To realize.
According to another embodiment, it is a kind of be used for adjust one or more electric currents system include system controller, transformer,
First resistor device, switch and the first diode.System controller includes the first controller terminal and ground terminal, system control
Device is configured as the output drive signal at the first controller terminal.Transformer includes armature winding and armature winding, it is primary around
Group includes the first winding terminals and the second winding terminals, and secondary windings includes tertiary winding terminal and the 4th winding terminals, and first
Winding terminals are coupled to ground terminal, and the second winding terminals are coupled to one or more light emitting diodes, tertiary winding end
Son is coupled to ground terminal.First resistor device includes first resistor device terminal and second resistance device terminal, first resistor device end
Son is coupled to ground terminal.Switch is configured as receiving drive signal and is coupled to second resistance device terminal.In addition, the
One diode includes the first diode terminal and the second diode terminal and is coupled to first resistor device, the second diode end
Son is coupled to one or more light emitting diodes.For example, the system is according at least to Fig. 3 (a), Fig. 3 (b), Fig. 4 (a), Fig. 4
(b), Fig. 5 and/or Fig. 7 is realized.
According to another embodiment, a kind of system for being used to adjust one or more electric currents includes system controller, is configured
To receive sensing signal, resistor and inductor to switch output drive signal and from the resistor for being connected to switch and inductor
Either directly or indirectly it is connected to one or more light emitting diodes.In addition, drive signal and one or more switch periods
Associated, each switch periods of one or more switch periods include the ON time section of switch and the deadline of switch
Section.In addition, each switch periods of one or more switch periods are multiplied by the demagnetization associated with inductor equal to a coefficient
The demagnetization period of journey, the coefficient are more than 1.In addition, flow through the mean size of the first electric current of one or more light emitting diodes with
The peak value size of sensing signal in each switch periods of one or more switch periods is proportional.For example, the system is at least
Realized according to Fig. 2, Fig. 5, Fig. 6 and/or Fig. 7.
According to another embodiment, a kind of system for being used to adjust one or more electric currents includes modulation and drive component, adopted
Sample keeps component, amplifier module, error amplifier and comparator.Modulation and drive component are configured as to switch output driving letter
Number, drive signal is associated with least one switch periods, and at least one switch periods include the ON time section and use of switch
In the demagnetization period of demagnetization process.Sampling keeps component to be configured as receiving the first current related sensing letter with flowing through switch
Number, sensing signal is sampled at the middle of ON time section, and keep the sensing signal sampled.Amplifier module by with
It is set to the sensing signal that reception is sampled and kept during the period of demagnetizing and generates amplified signal.In addition, error amplifier
It is configured as receiving amplified signal during the period of demagnetizing and at least generates integrated signal with together with the first capacitor.In addition,
Comparator be configured as at least receive integrated signal and at least based on the information associated with integrated signal to modulation and drive
Component exports comparison signal.For example, the system is realized according at least to Fig. 2, Fig. 3 (a), Fig. 3 (b), Fig. 5, Fig. 6 and/or Fig. 7.
In another embodiment, a kind of system for being used to adjust one or more electric currents includes modulation and drive component, put
Big component, error amplifier and comparator.Modulation and drive component be configured as to switch output drive signal, drive signal with
At least one switch periods are associated, and at least one switch periods include the ON time section of switch and moving back for the process of demagnetizing
The magnetic period.Amplifier module is configured as receiving sensing signal during the period of demagnetizing and generates amplified signal, sensing signal with
Flow through switch first is current related.In addition, error amplifier be configured as during the period of demagnetizing receive amplified signal and
At least integrated signal is generated with together with the first capacitor.In addition, comparator is configured as at least receiving integrated signal and at least
Comparison signal is exported to modulation and drive component based on the information associated with integrated signal.For example, the system is according at least to figure
2nd, Fig. 4 (a), Fig. 4 (b) and/or Fig. 5 are realized.
In another embodiment, a kind of method for being used to adjust one or more electric currents includes：From be connected to switch and electricity
The resistor of sensor receives sensing signal, and handles the information associated with sensing signal.In addition, this method includes：At least
Drive signal for switch is generated based on the information associated with sensing signal；The processing information associated with drive signal；
And the electric current of one or more light emitting diodes is at least flowed through based on the information generation associated with drive signal, one or more
Individual light emitting diode is connected directly or indirectly to resistor and inductor.Moreover, drive signal switchs with one or more
Cycle is associated, when each switch periods of one or more switch periods include ON time section and the cut-off of switch of switch
Between section.Each switch periods of one or more switch periods are multiplied by the demagnetization process associated with inductor equal to a coefficient
Demagnetize the period, the coefficient is more than 1.In addition, electric current and the sensing signal in each switch periods of one or more switch periods
Peak value size it is proportional.For example, the system is realized according at least to Fig. 2, Fig. 5, Fig. 6 and/or Fig. 7.
In another embodiment, a kind of method for being used to adjust one or more electric currents includes driving of the generation for switch
Signal, drive signal is associated with least one switch periods, at least one switch periods include switch ON time section and
The demagnetization period for the process of demagnetizing.This method also includes：Receive and flow through the current related sensing signal of switch；Processing with
The associated information of sensing signal；And sensing signal is sampled at the middle of ON time section.In addition, this method bag
Include：Keep the sensing signal sampled；The sensing signal for sampling and keeping is received during the period of demagnetizing；And processing is with connecing
The information that the sensing signal for sampling and keeping received is associated.This method also includes：At least based on being adopted with what is received
The information generation amplified signal that sample and the sensing signal kept are associated；Receive amplified signal；And processing and amplified signal phase
The information of association.In addition, this method includes：Integrated signal is at least generated based on the information associated with amplified signal；At least connect
Receive integrated signal；The processing information associated with integrated signal；And at least generated based on the information associated with integrated signal
Comparison signal.For example, the system is realized according at least to Fig. 2, Fig. 3 (a), Fig. 3 (b), Fig. 5, Fig. 6 and/or Fig. 7.
In another embodiment, a kind of method for being used to adjust one or more electric currents includes driving of the generation for switch
Signal, drive signal is associated with least one switch periods, at least one switch periods include switch ON time section and
The demagnetization period for the process of demagnetizing.In addition, this method includes：The current related of switch is received and flows through during the period of demagnetizing
Sensing signal；The processing information associated with the sensing signal received；It is and related based on the sensing signal to being received
The information generation amplified signal of connection.This method also includes：Receive amplified signal, the processing information associated with amplified signal；And
And integrated signal is at least generated based on the information associated with amplified signal.In addition, this method includes：At least receive integration letter
Number；The processing information associated with integrated signal；Comparison signal is at least generated based on the information associated with integrated signal；And
Receive comparison signal.For example, the system is realized according at least to Fig. 2, Fig. 4 (a), Fig. 4 (b) and/or Fig. 5.
For example, some or all of components in each embodiment of the present invention individually and/or with least another component phase group
It is one kind or more using one or more component softwares, one or more nextport hardware component NextPorts and/or software and nextport hardware component NextPort to close ground
Kind combines to realize.In another example, some or all of components in each embodiment of the present invention individually and/or with extremely
Few another component realizes in one or more circuits combinedly, for example, in one or more analog circuits and/or one or
Realized in multiple digital circuits.In another example, each embodiment and/or example of the invention can be with combined.
Although having been described for the specific embodiment of the present invention, but it will be apparent to one skilled in the art that it is also present in described
The equivalent other embodiments of embodiment.It will, therefore, be evident that the present invention is not limited by shown specific embodiment, but only by weighing
The scope that profit requires limits.
Claims (5)
1. a kind of system for adjusting one or more electric currents, the system includes：
Modulation and drive component, it is configured as to switch output drive signal, the drive signal and at least one switch periods
Associated, at least one switch periods include the ON time section of the switch and the demagnetization period for the process of demagnetizing；
Sampling keeps component, is configured as receiving the first current related sensing signal with flowing through the switch, is led described
The sensing signal is sampled at the middle of logical period, and keeps the sensing signal sampled；
Amplifier module, it is configured as receiving the sensing signal for sampling and keeping during the demagnetization period and generates amplification
Signal；
Error amplifier, be configured as it is described demagnetization the period during receive the amplified signal and at least with the first capacitor
Integrated signal is generated together；And
Comparator, it is configured as at least receiving the integrated signal and at least based on the information associated with the integrated signal
Comparison signal is exported to the modulation and drive component,
Wherein：
The modulation and drive component include modulation component and gate drivers；
Wherein：
The modulation component is configured as at least receiving the comparison signal and at least based on associated with the comparison signal
Information generation modulated signal, the modulated signal is during the ON time section for the first logic level and at least in institute
It is the second logic level during stating the demagnetization period；And
The gate drivers are configured as at least receiving the modulated signal and at least based on related to the modulated signal
The information of connection generates the drive signal,
Wherein, the modulation component also includes trigger assembly, and the trigger assembly is configured as receiving the comparison signal
And clock signal, and export the modulated signal.
2. the system as claimed in claim 1, wherein：
The sampling keeps component to include timing component and the second capacitor；
Wherein：
The timing component is configurable to generate timing signal；And
Second capacitor is configured to respond to the timing signal, and the sensing signal is received during predetermined amount of time
And it is maintained at the sensing signal sampled at the ending of the predetermined amount of time.
3. system as claimed in claim 2, wherein, the predetermined amount of time starts simultaneously at the beginning of the ON time section
And terminate at the middle of the ON time section.
4. the system as claimed in claim 1, wherein, the error amplifier is additionally configured to receive reference signal, and extremely
It is few that the integrated signal is generated based on the information associated with the reference signal and the amplified signal.
5. a kind of method for adjusting one or more electric currents, this method includes：
The drive signal for switch is generated, the drive signal is associated with least one switch periods, described at least one
Switch periods include the ON time section of the switch and the demagnetization period for the process of demagnetizing；
Receive and flow through the current related sensing signal of the switch；
The processing information associated with the sensing signal；
The sensing signal is sampled at the middle of the ON time section；
Keep the sensing signal sampled；
The sensing signal for sampling and keeping is received during the demagnetization period；
Handle the information associated with the sensing signal for sampling and keeping received；
Amplified signal is at least generated based on the associated information of the sensing signal for sampling and keeping with receiving；
Receive the amplified signal；
The processing information associated with the amplified signal；
Integrated signal is at least generated based on the information associated with the amplified signal；
At least receive the integrated signal；
The processing information associated with the integrated signal；
Comparison signal is at least generated based on the information associated with the integrated signal；
Receive the comparison signal and clock signal and modulation is at least generated based on the information associated with the comparison signal
Signal, the modulated signal is during the ON time section for the first logic level and at least during the demagnetization period
For the second logic level；And
Receive the modulated signal and the drive signal is at least generated based on the information associated with the modulated signal.
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| CN201410053177.8A CN103781257B (en) | 2011-12-08 | 2011-12-08 | System and method for adjusting LED current |
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| CN201110415842.XA CN103167665B (en) | 2011-12-08 | 2011-12-08 | System and method for adjusting current of luminous diode |
| CN201410053177.8A CN103781257B (en) | 2011-12-08 | 2011-12-08 | System and method for adjusting LED current |
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| CN201110415842.XA Division CN103167665B (en) | 2011-12-08 | 2011-12-08 | System and method for adjusting current of luminous diode |
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