The content of the invention
The present invention is in order to overcome existing LED dimmer easily to damage load or threshold value phosphere occur, there is provided onePassing zero trigger is planted, adjuster and adjusting method are cut after two line styles of time delayed turn-off.
To achieve these goals, the present invention cuts adjuster, including alternating current switching circuit, zero passage after providing a kind of two line stylesDetection circuit, drive control circuit and power supply circuit.Alternating current switching circuit is connected with load circuit.Zero cross detection circuit detection is handed overThe input current of stream, zero cross signal is exported when input current zero crossing.Drive control circuit connects alternating current switching circuit respectivelyAnd zero cross detection circuit, within an input current cycle, drive exchange to open when drive control circuit receives zero cross signalCircuit turn-on is closed, is loaded in access circuit, driving control circuit output signal makes alternating current switching circuit after a period of time that is delayedCut-off, for a period of time less than or equal to the half period of input current.Power supply circuit connects alternating current switching circuit, zero passage detection respectivelyCircuit and drive control circuit.
In one embodiment of the invention, alternating current switching circuit is made of two VMOS pipe differential concatenations, two VMOS pipesControl pole is connected with drive control circuit.
In one embodiment of the invention, cut after two line styles adjuster further include be connected to circuit input end and drive control electricityPotentiometer between road, the resistance value on potentiometer determine the length of delay time.
In one embodiment of the invention, drive control circuit includes comparison control circuit, PWM generator circuit and driving electricityRoad, comparison control circuit connection potentiometer and zero cross detection circuit, comparison control circuit are believed according to the output of zero cross detection circuitNumber and potentiometer on resistance value control PWM generator circuit duty cycle.
In one embodiment of the invention, potentiometer is push button switch potentiometer.
In one embodiment of the invention, adjuster is cut after two line styles and further includes minimum spacing adjusting potentiometer, it is minimum spacingAdjust potentiometer connection drive control circuit, the minimum spacing shortest time for adjusting potentiometer and determining delay.
In one embodiment of the invention, alternating current switching circuit and drive control circuit are formed on aluminum base circuit board.
In one embodiment of the invention, power supply circuit is connected in parallel on the both ends of alternating current switching circuit, in alternating current switching circuitIn deadline, power supply circuit obtains input voltage and direct current electricity output is formed after AC-DC is changed.
In one embodiment of the invention, the scope of input voltage is 220V~240V, frequency 50Hz.
Another aspect of the present invention cuts adjusting method after also providing a kind of two line styles, including：The input current of exchange is detected, whenZero cross signal is exported during input current zero crossing；Within an input current cycle, drive control circuit receives zero cross signal simultaneouslyAlternating current switching circuit conducting is driven, is loaded in access circuit；It is delayed after a period of time, drive control circuit output signal makes friendshipOn-off circuit cut-off is flowed, for a period of time less than or equal to the half period of input current.
In conclusion cut adjuster and adjusting method compared with prior art after two line style provided by the invention, have withLower advantage：
AC input current is detected by setting zero cross detection circuit, the drive control when AC input current zero crossingCircuit drives are turned on the alternating current switching circuit that load circuit is connected, and realize passing zero trigger.Conducting drives after delay a period of timeControl circuit driving alternating current switching circuit cut-off, the length of delay time will determine power of the output to load, that is, determines negativeThe luminous flux (or illumination brightness) of load, achievees the purpose that light modulation.Adjuster is cut after two line style provided by the invention compared to traditionalControllable silicon dimmer, it is turned in input current zero crossing, and the current value of output to load is smaller at this time, and load will not be producedRaw larger impact, the performance safety of proof load on startup are stablized, load service life length.Further, compared to traditionControllable silicon dimmer, the cut-off of alternating current switching circuit can be achieved load current and complete switches off, and effectively prevent LED lamp thresholdIt is worth the generation of phosphere.
For above and other objects of the present invention, feature and advantage can be become apparent, preferred embodiment cited below particularly,And coordinate attached drawing, it is described in detail below.
Embodiment
Traditional controllable silicon dimmer is due to its Delayed conducting, the characteristic of zero-crossing switching so that it is in conducting in loadWith larger firing current.For low-voltage devices such as LED lamps, it is silicon-controlled can be to LED in larger current caused by conductingLamps and lanterns cause to impact, and bring it about damage.Further, since complete switching off for electric current can not be realized during silicon-controlled cut-off, the characteristicIt will make to have the LED lamp of low start voltage the problem of threshold value flash of light occur.In view of this, applicant by studying for a long timeA kind of passing zero trigger, time delayed turn-off are provided afterwards, and adjuster is cut after two line styles of load current can be complete switched off when offAnd adjusting method.
Fig. 1 cuts the circuit diagram of adjuster after showing two line styles of one embodiment of the invention offer.Fig. 2 show figureThe sequence diagram of input voltage waveform and output voltage waveforms in adjuster is cut after two line styles shown in 1.Also referring to Fig. 1 and figure2.L-IN is electric power incoming line in Fig. 1, and L-OUT is power outlet, and N is zero-power line.In fig. 2, UL is the alternating current of inputSignal is pressed, Ulout is the output voltage signal after cutter after two line styles.
As shown in Figure 1, adjuster is cut after two line style provided in this embodiment includes alternating current switching circuit 1, zero passage detection electricityRoad 2, drive control circuit 3 and power supply circuit 4.Alternating current switching circuit 1 is connected with load circuit.The detection of zero cross detection circuit 2 is handed overThe input current of stream, zero cross signal is exported when input current zero crossing.Drive control circuit 3 connects alternating current switching circuit respectively1 and zero cross detection circuit 2, within an input current cycle, exchange is driven when drive control circuit 3 receives zero cross signalOn-off circuit 1 turns on, and loads in R access circuits, and drive control circuit 3, which exports signal, after a period of time that is delayed makes alternating-current switchCircuit 1 ends, for a period of time less than or equal to the half period of input current.Power supply circuit 4 connect respectively alternating current switching circuit 1,Zero cross detection circuit 2 and drive control circuit 3.
The present invention is not limited in any way the concrete structure of zero cross detection circuit 2.As long as it can realize zero crossing detection functionAny available circuit is used equally for the present invention.In this present embodiment, the scope of input voltage is 220V~240V, and frequency is50Hz.However, the present invention is not limited in any way this.
Cut after two line style provided in this embodiment in adjuster, input current is detected by zero cross detection circuit 2, defeatedWhen entering current zero-crossing point, alternating current switching circuit 1 turns on.Input current value is smaller at this time, that is, flow through load R electric current it is smaller, noCan to load R cause to impact, load can clean boot, there is good security performance.One section of the conducting of alternating current switching circuit 1 delayIt will end after time, in actual use, user can set different delay times according to the different use environments of load R.In this present embodiment, it is LED lamp to load R.However, the present invention is not limited in any way this.In other embodiments, the present inventionIt adjuster be provided after two line styles provided can be equally used for adjusting the product such as electric fan and (need to configure corresponding component, do not existDescribed in this example).
Specifically, energy saving to achieve the purpose that when ambient light is brighter, the brightness of LED lamp can be relatively at this timeIt is low, the shorter time that is delayed is set at this time, i.e., the power exported in one cycle to LED lamp is relatively low.And in ambient lightWhen line is dark, due to needing preferable illuminance, need output larger to the power in LED lamp at this time, it is corresponding to setThe time for putting delay is longer.
In this present embodiment, adjuster is cut after two line styles to be included being connected between circuit input end and drive control circuit 2Potentiometer 5, the resistance value on potentiometer 5 determines the length of delay time.Drive control circuit 3 include comparison control circuit 31,PWM generator circuit 32 and drive circuit 33.Comparison control circuit 31 connects potentiometer 5 and zero cross detection circuit 2, compares controlCircuit 31 controls the duty of PWM generator circuit 32 according to the resistance value exported on signal and potentiometer 5 of zero cross detection circuit 2Than.In actual use, user only need to can be real by adjusting the gear (different gears corresponds to different resistance values) of potentiometer 5The control of existing delay time, that is, realize the light modulation of LED lamp.
Describe in detail below with reference to Fig. 1 to the principle dimmed using potentiometer 5 and zero cross detection circuit 2.When input current signal zero crossing, zero cross detection circuit 2 exports zero cross signal.Due to being influenced by load characteristic, such as when negativeCarry for inductive load when, can there are phase difference, zero cross detection circuit 2 between the zero signal on the voltage and electric current of input circuitThe zero crossing of the automatic detecting circuit electric current of meeting, comparison control circuit 31 output signal to PWM generator circuit 32, PWM generatorCircuit 32 exports Continuity signal to drive circuit 33, drive circuit 33 and drives alternating current switching circuit 1 to turn on.When load is resistive negativeDuring load, the zero cross signal that zero cross detection circuit 2 detects is input voltage zero-acrross ing moment, and there is no phase difference between the two.
After alternating current switching circuit 1 turns on, comparison control circuit 31 judges the resistance value of potentiometer 5, specifically judgesThe resistance value of the access circuit part of potentiometer 5 accounts for the percentage of potentiometer resistance, and comparison control circuit 31 is defeated according to this percentageGo out pick-off signal to PWM generator circuit 32, realize the control of pwm signal duty cycle, that is, when realizing that alternating current switching circuit 1 is delayedBetween control.Implementation can be：One charging capacitor connected with potentiometer 5 is set in comparison control circuit 31, compares controlCircuit 31 processed obtains the magnitude of voltage on charging capacitor, when the magnitude of voltage reaches the voltage threshold of setting, comparison control circuit 31Output pick-off signal to PWM generator circuit 32, alternating current switching circuit 1 ends, charging capacitor electric discharge.However, the present invention is to thisIt is not limited in any way.Specifically, when potentiometer 5 10 accesses circuit, charging capacitor reaches voltage threshold at this timeTime is R1*C*10%, and wherein R1 is the resistance value of locator 5, and C is the capacitance of charging capacitor, i.e. alternating current switching circuit 1 is ledTurned off after logical R1*C*10%.And when potentiometer 5 absolutely accesses circuit, at this time charging capacitor reach voltage threshold whenBetween be R1*C, i.e., alternating current switching circuit conducting R1*C after turn off.When carrying out circuit design, the half of input current signal can be setCycle is equal to R1*C, i.e., when all access circuits of potentiometer 5, LED lamp is up to high-high brightness.
In this present embodiment, potentiometer 5 is push button switch potentiometer.The potentiometer 5 of this kind of structure is being closed or openedThe position of lamplight brightness will not change during LED lamp.However, the present invention is not limited in any way the structure of potentiometer 5.
In actual use, when delay time very in short-term, LED lamp in dimming process it is possible that low-light level glistenPhenomenon.To avoid the problem, in this present embodiment, adjuster is cut after two line styles and further includes minimum spacing adjusting potentiometer 6, it is minimumSpacing adjusting potentiometer 6 connects drive control circuit 3, and in this present embodiment, control is compared in minimum spacing adjusting potentiometer 6 connectionCircuit 31.The minimum spacing shortest time for adjusting potentiometer 6 and determining delay.Specifically, when potentiometer 5 accesses circuit partWhen resistance value is less than minimum spacing adjusting potentiometer 6, comparison control circuit 31 sends out output pick-off signal during delay R2*C to PWMRaw device circuit 32, alternating current switching circuit 1 ends after R2*C is turned on, and wherein R2 is the minimum spacing resistance value for adjusting potentiometer.MostThe small spacing effect for adjusting potentiometer 6 is to adjust the minimum brightness of LED lamp, avoids LED lamp from being dodged in dimming scopeLight.In other embodiments, when load is the inductive loads such as electric fan, minimum delay time R2*C cannot be below35%, no person will cause motor step-out phenomenon, produce high pressure self-induction pulse voltage and puncture alternating current switching circuit 1.
In this present embodiment, alternating current switching circuit 1 is made of two VMOS pipe differential concatenations, the control pole of two VMOS pipesIt is connected with drive control circuit 3.The alternating current switching circuit of this kind of structure can complete switch off electric current in cut-off, and LED is bornLoad is not in phosphere.In addition, this kind of alternating current switching circuit not only minimizes switching damage, and improve loadOutput waveform, reduces the dash current to load, has more preferable dimming effect.In practical applications, tune is cut after two line stylesSection device power is larger, and when such as reaching more than 400W, the power of two VMOS pipes also will be larger at this time, needs to solve to dissipate in designThe problem of hot.With more preferable heat dissipation effect, in this present embodiment, to set 3 shape of alternating current switching circuit 1 and drive control circuitInto be both circuit board and the aluminum base circuit board of heat sink on.The design cuts adjuster after can reducing two line styles to greatest extentVolume.However, the present invention is not limited in any way this.It can be dissipated in other embodiments using extra increase heat sinkHeat.
In this present embodiment, power supply circuit 4 is connected in parallel on the both ends of alternating current switching circuit 1, in the cut-off of alternating current switching circuitIn time, power supply circuit 4 obtains input voltage and direct current electricity output is formed after AC-DC is changed.Due to alternating current switching circuit 1Turn on the voltage range that delay time is variable, which will cause power supply circuit 4 provided in this embodiment to have ultra-wide.However,The present invention is not limited in any way the concrete structure of power supply circuit 4.In other embodiments, the DC power supply that can connect outside comesPower for alternating current switching circuit 1, zero cross detection circuit 2 and drive control circuit 3.
Corresponding with cutting adjuster after above-mentioned two line style, the present embodiment cuts adjusting method after also providing a kind of two line styles,Including：
The input current of exchange is detected, zero cross signal is exported when input current zero crossing；
Within an input current cycle, drive control circuit receives zero cross signal and drives alternating current switching circuit to turn on,Load in access circuit；
Be delayed a period of time after, drive control circuit output signal end alternating-current switch, described a period of time be less than orEqual to the half period of input current.
In conclusion cut after two line style provided by the invention adjuster and adjusting method by set zero cross detection circuit comeAC input current is detected, drive control circuit drives when AC input current zero crossing exchanges out with what load circuit was connectedCircuit turn-on is closed, realizes passing zero trigger.Drive control circuit driving alternating current switching circuit cut-off, prolongs after conducting delay a period of timeWhen the time length by determine output to load on power, that is, determine load luminous flux (or illumination brightness), reach light modulationPurpose.Adjuster is cut after two line style provided by the invention and compares traditional controllable silicon dimmer, it is in input current zero crossingWhen turn on, the current value of output to load is smaller at this time, will not produce larger impact to load, and proof load is on startupPerformance safety is stablized, load service life length.Further, cut compared to traditional controllable silicon dimmer, alternating current switching circuitComplete switching off for load current only can be achieved, effectively prevent the generation of LED lamp threshold value phosphere.
Although the present invention is disclosed above by preferred embodiment, but is not limited to the present invention, this any known skillSkill person, without departing from the spirit and scope of the present invention, can make a little change and retouch, therefore protection scope of the present invention is worked asSubject to claims scope claimed.