Summary of the invention
In view of this, the purpose of the present invention is to provide a kind of small power consumption, high-efficient leadage circuit and vent discharge flow controlsMethod and LED control circuit processed, to solve technical problem of the existing technology.
The technical solution of the invention is as follows, provides a kind of leadage circuit with flowering structure, comprising:
Current regulating circuit, including adjustment manage and manage concatenated current source or/resistance with the adjustment；Exchange input warp canControl silicon light modulator and rectifier bridge obtain input voltage to load supplying, the both ends of the current regulating circuit respectively with input voltageHigh cold end connection；
It releases control circuit, is connect with the control terminal of the adjustment pipe；When the input voltage is lower than the threshold voltageWhen, then make current regulating circuit generate leakage current by adjusting the control terminal of adjustment pipe, until input current or load electricityStream is greater than threshold current, then makes leakage current be zero by adjusting the control terminal of adjustment pipe.
Preferably, the control circuit of releasing includes input voltage detection circuit, load current detection circuit and patrolsCircuit is collected, the logic circuit is connect with the control terminal of adjustment pipe, the input voltage detection circuit sampled input voltage,And be compared with threshold voltage, comparison result is exported to logic circuit, and the load current detection circuit samples loadElectric current, and be compared with threshold current, comparison result is exported to logic circuit, and the logic circuit receives the input electricityPress the comparison result of detection circuit and the comparison result of load current detection circuit.
Preferably, the control circuit of releasing includes load current detection circuit, leakage current detection circuit and patrolsCircuit is collected, the logic circuit is connect with the control terminal of adjustment pipe, and the load current detection circuit samples load current,And be compared with threshold current, comparison result is exported to logic circuit, described in the leakage current detection circuit samplingLeakage current, and be compared with threshold value of releasing, comparison result is exported to logic circuit, and the logic circuit receives described negativeCarry the comparison result of current detection circuit and the comparison result of leakage current detection circuit.
Preferably, judgement of the input voltage lower than the threshold voltage refers to, the load current detection circuitIt detects that the load current is less than the threshold current, after the first time, determines the input voltage lower than the thresholdThreshold voltage；The first time is the enabled current regulating circuit when load current is 0, the input electric cur- rent measure circuit inspectionThe input current is measured less than the threshold current, and starts timing, when the leakage current detection circuit detect it is describedLeakage current be less than it is described release threshold value when, timing terminates, as at the first time between institute's timing.
Preferably, after the second time, then generating vent discharge when the input voltage is lower than the threshold voltageStream.
Another technical solution of the invention is to provide a kind of leakage current control method of following steps, comprising:
Exchange input obtains input voltage to load supplying, by current regulating circuit through controllable silicon dimmer and rectifier bridgeBoth ends are connect with the high cold end of input voltage respectively, including adjustment manages and manages concatenated current source or/electricity with the adjustmentResistance；
Control circuit of releasing is connected in the control terminal of the adjustment pipe；When the input voltage is lower than the threshold voltageWhen, then make current regulating circuit generate leakage current by adjusting the control terminal of adjustment pipe, until load current is greater than threshold valueElectric current then makes leakage current be zero by adjusting the control terminal of adjustment pipe.
Preferably, judgement of the input voltage lower than the threshold voltage refers to, the load current detection circuitIt detects that the load current is less than the threshold current, after the first time, determines the input voltage lower than the thresholdThreshold voltage；The first time is the enabled current regulating circuit when load current is 0, the load current detection circuit inspectionThe load current is measured less than the threshold current, and starts timing, when the leakage current detection circuit detect it is describedLeakage current be less than it is described release threshold value when, timing terminates, as at the first time between institute's timing.
Preferably, after the first delay time, then generating and releasing when the input voltage is lower than the threshold voltageElectric current.
Another technical solution of the invention is to provide a kind of LED control circuit with flowering structure,
Using circuit structure and method of the invention, compared with prior art, have the advantage that the program of the present invention canApplied to Linear Driving scheme, the threshold voltage is zero-crossing values, and when input voltage zero passage, load current is zero at this time,Second time was set as delay time, enables leakage current, when controllable silicon dimmer conducting, to be greater than input currentElectric current is maintained, leakage current is greater than the maintenance electric current of controllable silicon dimmer, for maintaining the conducting of controllable silicon dimmer；Work as loadWhen electric current is greater than the maintenance electric current of controllable silicon dimmer, leakage current is not enabled, and reduces power consumption, and the present invention is guaranteeing light modulation effectUnder the premise of fruit, the power consumption of leadage circuit is reduced, system effectiveness and system reliability are improved.
Specific embodiment
The preferred embodiment of the present invention is described in detail below in conjunction with attached drawing, but the present invention is not restricted to theseEmbodiment.The present invention covers any substitution made in the spirit and scope of the present invention, modification, equivalent method and scheme.
In order to make the public have thorough understanding to the present invention, it is described in detail in the following preferred embodiment of the present invention specificDetails, and the present invention can also be understood completely in description without these details for a person skilled in the art.
The present invention is more specifically described by way of example referring to attached drawing in the following passage.It should be noted that attached drawing is adoptedWith more simplified form and using non-accurate ratio, only to facilitate, lucidly aid in illustrating the embodiment of the present inventionPurpose.
Refering to what is shown in Fig. 3, illustrating the circuit structure of leadage circuit embodiment one of the invention, linear drive is applied to itFor in dynamic LED control circuit.LED control circuit includes leadage circuit and LED drive circuit, the leadage circuit by withIn solve under controllable silicon dimmer as input current it is too small caused by flicker problem, and overcome skill present in the prior artArt defect.Its input power is exchange input, and the exchange input exports straight after controllable silicon dimmer U02 and rectifier bridge U01The input voltage vrec of stream, i.e., as the input voltage of LED load.Exchange input is connected to whole by controllable silicon dimmer U02Bridge U01 is flowed, the positive output end of rectifier bridge is connect with the anode of diode D00, LED drive circuit anode and the diode D00Cathode connection.Certain capacitive can be presented in usual LED drive circuit, therefore, two poles are added between vrec and LED drive circuitPipe D00；When the absolute value of exchange input reduces, due to capacitive, voltage can reduce relatively slow LED drive circuit, be addedVrec voltage follow can be exchanged the absolute value of input with the sampling resistor of input voltage vrec detection circuit by diode D00,To guarantee the accuracy sampled to input voltage.
The leadage circuit includes current regulating circuit and control circuit of releasing, and the current regulating circuit includes adjustingHomogeneous tube M00 and concatenated current source I10 is managed with the adjustment, resistance also can be used and concatenated form is managed in adjustment.Current sourceOne end of I10 is connected to the positive output end of rectifier bridge, and the other end of adjustment pipe M00 is connected to the negative output terminal of rectifier bridge U01.WhenInput voltage vrec is lower than threshold voltage, then logic circuit U12 controls current regulating circuit and generates leakage current, the vent dischargeStream is iblr, and leakage current is always existed, until load current iin2 is greater than threshold current, the logic circuit U12Controlling leakage current is 0.
The control circuit of releasing is connect with the control terminal of the adjustment M00 pipe；It is examined by input voltage detection circuitInput voltage vrec is surveyed, when the input voltage vrec is lower than the threshold voltage, then adjusts the control of pipe M00 by adjustingSo that current regulating circuit generates leakage current, it is electric until loading to detect load current iin2 by load current detection circuit at endStream is greater than threshold current, then makes leakage current iblr be zero by adjusting the control terminal of adjustment pipe.The leakage current inspectionSlowdown monitoring circuit is used to flow through the leakage current iblr of current regulating circuit, can be with by detection leakage current iblr in conjunction with timingAt the time of judging input voltage lower than threshold voltage.
When input voltage vrec is lower than threshold voltage, be delayed the second time T2, then enabled leakage current, can reduce mostThe big angle of flow, thus the power consumption of releasing when reducing the big angle of flow.Threshold voltage ordinary circumstance in the present embodiment refers to zero crossing,But according to the reality of circuit, then and zero point has certain deviation, for example, the introducing of diode D00, then zero crossing one at this timeAs be diode D00 forward conduction pressure drop.
Refering to what is shown in Fig. 4, illustrating the flow diagram of leadage circuit embodiment shown in Fig. 3 one, detailed process is as follows: first examiningSurvey whether input voltage vrec is lower than threshold voltage, if so, the second time T2 of delay, if otherwise continuing to test input voltagevrec；It is delayed after T2, so that leakage current is enabled, i.e. generation leakage current iblr；It is then detected that load current iin2 whetherNot less than threshold current, the threshold current is generally higher than the maintenance electric current of controllable silicon dimmer, if then continuing to test negativeElectric current iin2 is carried, if it is not, enabling leakage current iblr not, i.e., so that leakage current is zero.
Refering to what is shown in Fig. 5, illustrating the circuit structure of leadage circuit embodiment two of the invention, linear drive is applied to itFor in dynamic LED control circuit.Embodiment one and embodiment two the difference is that, wherein the control circuit of releasingIncluding input voltage detection circuit and load current detection electric current, leakage current detection circuit is not used, while will input electricityPress the structure of detection circuit and load current detection electric current more specific.
Input voltage detection circuit passes through electric resistance partial pressure, sampled input voltage vrec, sampled voltage and reference voltage VREF1Compare, when sampled voltage is greater than reference voltage VREF1, then the output ZVD of comparator U10 is low；When sampled voltage is less than ginsengWhen examining voltage VREF1, the output ZVD of comparator U10 is height.Input voltage vrec detection circuit is used to detect the mistake of input voltageZero point.Since certain capacitive can be presented in LED drive circuit, diode D00 is added between vrec and LED drive circuit.When the absolute value of exchange input reduces, due to capacitive, voltage can reduce relatively slow LED drive circuit, joined two polesVrec voltage follow can be exchanged the absolute value of input with the sampling resistor of input voltage vrec detection circuit by pipe D00, to protectDemonstrate,prove the accuracy sampled to input voltage.Input voltage vrec detection circuit is not limited only to the mode in the embodiment, other are defeatedEntering voltage detecting mode can also use in the embodiment involved in the embodiment below.When LED drive circuit is linearWhen circuit, it can be adopted by the way that sampling resistor R40 is added between the negative output terminal of the output end in LED drive circuit to rectifier bridgeSample LED current, since the electric current of input voltage vrec detection circuit is much smaller than LED current, is passed through when diode D00 conductingThe electric current of sampling resistor R40 is approximately electric current iin2.Especially when LED current is larger, it is equal to electric current by the electric current of resistance R40iin2.The sampled voltage of sampling resistor R40 is RS, is connected to the negative input end of comparator U40, the positive input terminal of comparator U40Meet reference voltage VREF4.When RS voltage is greater than VREF4, the output ZC of comparator U40 is low；Otherwise U40 output is height.It is negativeThe detection mode for carrying electric current iin2 is not limited only to the mode in the embodiment, since Linear Driving is employed herein, usesThe mode of sampling resistor is come to detect electric current be eaily.
Refering to what is shown in Fig. 6, illustrating the flow diagram of leadage circuit embodiment shown in Fig. 5 two, linear drive is applied to itFor in dynamic LED control circuit.Refering to what is shown in Fig. 7, illustrating the work wave of leadage circuit embodiment two.In conjunction with Fig. 6 and 7The course of work and signal corresponding relationship of embodiment two is further described.
The output ZVD of input voltage vrec detection circuit and the output ZC of load current iin2 detection circuit are all connected to patrolCircuit U 12 is collected, the output of logic circuit U12 is connected to the input of leadage circuit.Logic circuit judges that input voltage vrec is detectedWhether the output ZVD of circuit is height, i.e. whether detection input voltage vrec is lower than certain value (generally zero crossing), when ZVD isHeight, then be delayed the second time T2, and output VG is drawn high, i.e. the t11 moment in Fig. 7 (that delay T2 is not added in waveform diagram).It is suitableIt can be used for reducing TRIAC maximum conduction angle when lengthening T2, the power consumption of releasing when can further decrease the big angle of flow.At this point, byIt is less than the forward conduction voltage drop VF of LED load in voltage vrec, therefore LED current is zero, i.e. ZC is height.Between t11-t12,Since controllable silicon dimmer does not turn on, input voltage vrec be it is low, VG be always it is high, leadage circuit is enabled, but leakage currentIt is 0.At the t12 moment, controllable silicon dimmer conducting, since input voltage vrec is lower than the forward conduction voltage drop VF of LED load,LED current is 0, i.e. iin2=iLED=0, iin3=iblr, and the electric current iblr of leadage circuit is for maintaining controllable silicon dimmerConducting.It is still high that pressure drop RS, which is zero, ZC, on resistance R40.At the t13 moment, when the positive pressure that input voltage vrec reaches LED is ledLead to pressure drop, have electric current in LED load, and the electric current can maintain silicon-controlled normally, at this point, ZC signal is become by heightLow, the output VG of logic circuit is lower by height, and leadage circuit does not enable, switching tube M00 shutdown, leakage current 0.In t13-T14 moment, input voltage vrec are always more than the positive pressure conduction voltage drop VF of LED.At the t14 moment, input voltage vrec is less than LEDPositive pressure conduction voltage drop VF, LED current 0, and leadage circuit does not enable, therefore input current iin3 is also 0, when t15It carves, ZVD is height, and leadage circuit is enabled.
Refering to what is shown in Fig. 8, illustrating the circuit structure of leadage circuit embodiment three of the invention, linear drive is applied to itFor in dynamic LED control circuit.Embodiment three and embodiment two the difference is that, the two judges that input voltage vrec is lowDifferent in the mode of threshold voltage (i.e. zero crossing), for embodiment two by way of directly comparing, embodiment three then passes through timingMode, advantage is without electric resistance partial pressure sampling is carried out, since the divider resistance in embodiment two needs high-tension resistive, and highPiezoresistance is at high cost in the chip, and poor with low resistance matching, is unfavorable for the integrated of circuit.It needs to sample vent discharge simultaneouslyTiming node of the road as judgement, therefore on the basis of example 2, increase leadage circuit detection circuit.
With reference to shown in Fig. 9 (a), illustrate to obtain the flow chart element of first time T1 in leadage circuit embodiment three of the inventionFigure, wherein first time T1 be load current iin2 zero crossing (from electric current be greater than 0 to electric current be 0) to input voltage vrec mistakeTime between zero point.CTL signal in logic circuit is for recording whether logic circuit has kept first time T1.WhenWhen CTL=1, T1 is not kept in expression, is also sampled to first time T1；As CTL=0, T1 has been kept in expression.When system is initial, CTL=1.When vrec is greater than the forward conduction voltage drop VF of diode, then load current iin2 has electric current, thanOutput ZC compared with device U40 is low；When vrec is less than VF, then it is height that load current iin2, which is 0, ZC, and logic circuit U12 is enabled to be let outDischarge stream, i.e. control VG are height.Unlike embodiment two, when being sampled to first time T1, in the t14- of Fig. 7T15 moment, leadage circuit still enable, and resistance R50 detects the electric current on leadage circuit, when leakage current iblr is 0, compareThe output ZCBLD of device U50 is height.At this point, logic circuit U12 record between the rising edge of ZC and the rising edge of ZCBLD whenBetween, it is recorded as T1, and T1 is saved in logic circuit U12.After logic circuit U12 has saved first time T1, CTL is set toIt is 0, and at the t14-t15 moment, leadage circuit is not enabled.
With reference to shown in Fig. 9 (b), illustrate in leadage circuit embodiment three of the invention, after obtaining first time T1, detectionThe flow diagram of input voltage vrec zero crossing.Since one of purpose of embodiment two and three seeks to judge input voltageThe signal relation of the zero crossing of vrec, the two can be combined with each other or replace.Therefore in this attached drawing, the corresponding signal in Fig. 8 is usedThe comparison result ZVD for coming input voltage and threshold voltage in phenogram 5, corresponding signal is substituted into.When logic circuitAfter keeping T1, then it can not detect vrec voltage and obtain ZVD signal.ZVD=0 when initial, i.e. expression input voltage vin areHeight, logic circuit U12 judge whether LED drive circuit has electric current, that is, judge whether ZC signal is 1, when LED drive circuit electric currentIt is 0, then ZC=1 is delayed after T1, then ZVD=1, i.e., expression input voltage is 0 to get having arrived input voltage zero cross signal.ContinueJudge ZC signal, when the absolute value of input voltage is greater than LED pressure drop VF, then LED drive current has electric current, i.e. ZC=0, then ZVD=0.ZVD signal is updated to the flow diagram in Fig. 6, the flow diagram of Fig. 6 can be obtained.
Refering to what is shown in Fig. 10, illustrating the work wave of leadage circuit embodiment three of the invention.Based on the present embodimentWaveform is slightly different with embodiment two, but is consistent the technical issues of its solution with the resolving ideas of technical problem.
In addition to this, although embodiment is separately illustrated and is illustrated above, it is related to the common technology in part, in this fieldThose of ordinary skill apparently, can be replaced and integrate between the embodiments, be related to one of embodiment and record is not knownContent, then can refer to another embodiment on the books.
Embodiments described above does not constitute the restriction to the technical solution protection scope.It is any in above-mentioned implementationMade modifications, equivalent substitutions and improvements etc., should be included in the protection model of the technical solution within the spirit and principle of modeWithin enclosing.