CN201733501U - Primary-side constant-current control device of LED driver - Google Patents

Abstract

The utility model discloses a primary-side constant-current control device of an LED driver. The output end of a peak-sampling keeping module in the utility model is connected with the input end of a secondary-side current analog module, the output end of the secondary-side current analog module is connected with one input end of an average current ring, the other input end of the average current ring is connected with a sinusoidal half-wave reference module, the output end of the average current ring is connected with one input end of a multiplication module, the other input end of the multiplication module is connected with a sinusoidal half-wave generation module, the output end of the multiplication module is connected with one input end of a comparison module, the output end of the comparison module is connected with one input end of a driving-pulse generation module, an inductive-current zero-crossing detection module is connected with the other input end of the of the driving-pulse generation module, and the output end of the driving-pulse generation module is connected with a driving module. The utility model can realize high-power factor and output constant-current control without optically-coupled and secondary-side feedback circuits.

Description

The former limit of a kind of led driver constant-current control device

Technical field

The utility model belongs to the switch power technology field, relates to the former limit of a kind of led driver constant-current control device.

Background technology

The light characteristic of LED all is described as the function of electric current usually, rather than the function of voltage, and the forward voltage drop minor variations of LED can cause that bigger LED electric current changes, thereby causes the bigger variation of brightness.So, adopt constant pressure source to drive and can not guarantee the consistency of LED brightness, and influence reliability, life-span and the light decay of LED.Therefore, LED adopts constant-current source to drive usually.

For the purpose of safety, a lot of LED light fixtures all requires led driver to possess isolation features, promptly realizes the electrical equipment isolation that output and electrical network are imported.Therefore, current LED driving power adopts optocoupler that FEEDBACK CONTROL is carried out in the output sampling more.By to the sampling, modulate of LED electric current, utilize signal after optocoupler will be modulated to be sent to the control chip on former limit again.In the middle of control chip, this current signal compares with the current reference that sets, and with the duty ratio of control change device, forms negative feedback control, realizes constant current output.Because there is problem of aging in the optocoupler that isolated feedback adopts, influences the stability of circuit, the intensity of the electrical isolation that weakened simultaneously.

On the other hand, the extensive use of power electronic equipment causes severe contamination to utility network, and harmonic wave and idle problem come into one's own day by day.In order to alleviate the extent of injury of electric pollution, many countries have formulated corresponding standard one after another, as the harmonic standard IEEE555-2 of International Electrotechnical Commission and IEC1000-3-2 etc.Led driver is as a kind of power electronic equipment, when power surpass certain value (＞5W), also must force to satisfy above standard.Therefore, the high-power LED driver need adopt power factor correction (Power Factor Correction, be called for short PFC) technology, suppress harmonic wave effectively as active power factor correcting (Active Power Factor Correction is called for short APFC) technology.

Inverse excitation type converter is widely used in the middle low power led driver owing to low cost.The isolated form led driver great majority of the band power factor correction that constitutes of single-ended flyback converter at present adopt two-layer configurations: first kind of structure as shown in Figure 1: prime is a pfc circuit, and the back level is the DC-to-DC constant-current circuit that inverse excitation type converter constitutes; Another kind of structure is as shown in Figure 2: prime is the pfc circuit that inverse excitation type converter constitutes, and the back level is the DC-DC transfer circuit of constant current control.The shortcoming of two-stage circuit maximum is that the circuit elements device is many, the cost height.Therefore a kind of improvement project is to adopt the single-stage pfc circuit, the isolated form single-stage inverse-excitation type led driver of band power factor correction as shown in Figure 3 and secondary constant current control.Wherein, the sampling secondary current is passed through in constant current control, and feeds back to the control realization of former limit through optocoupler.There is the aging problem of optocoupler equally in this scheme, and secondary controlling of sampling circuit makes that the circuit elements number of devices is more in addition.Therefore, the former limit constant-current control device of research isolated high-power factor inverse-excitation type led driver is a challenging job.

Summary of the invention

The purpose of this utility model is at the deficiencies in the prior art, and the former limit of a kind of led driver constant-current control device is provided.

The technical scheme that the utility model technical solution problem is taked is:

The utility model comprises that peak value sampling keeps module, secondary current analog module, average current ring, half-sinusoid base modules, half-sinusoid generation module, multiplier module, comparison module, inductive current zero passage detection module, driving pulse generation module, driver module.

Peak value sampling keeps the input of the output termination secondary current analog module of module, an input of the output termination average current ring of secondary current analog module, another input termination half-sinusoid base modules of average current ring, an input of the output termination multiplier module of average current ring, another input termination half-sinusoid generation module of multiplier module, an input of the output termination comparison module of multiplier module, an input of the output termination driving pulse generation module of comparison module, inductive current zero passage detection module connects another input of driving pulse generation module, the output termination driver module of driving pulse generation module.

The utility model is as the control device of isolated form inverse-excitation type led driver, constitute Switching Power Supply jointly with the main circuit of inverse-excitation type led driver, the main circuit of traditional single tube inverse-excitation type led driver comprises input rectifier, input capacitance, absorption network, transformer, former limit switching tube, primary current sampling network, output rectifier and output capacitor.The main circuit of inverse-excitation type led driver of the present utility model also can be the change structural topology of traditional single tube reverse exciting topological, as two-tube inverse excitation type converter etc.

Described peak value sampling keeps module to link to each other with the primary current sampling network of inverse-excitation type led driver main circuit, in each switch periods the primary current sampled signal is carried out peak value sampling and keeps, and extracts primary current sampled signal peak value.

Described secondary current analog module is received peak value sampling and is kept being used for simulating secondary output rectifier electric current after the module.The envelope of output rectifier current waveform is a half-sinusoid, and specific to the single switch cycle, secondary output rectifier current waveform is the linear right-angled triangle that descends of slope.The output waveform in the single switch cycle of secondary current analog module is a square wave, width equals the former limit switching tube turn-off time (approximating secondary output rectifier ON time), amplitude equals the primary current sampled signal crest voltage in single switch cycle, so the twice of area and secondary output rectifier current waveform area is proportional.

Described half-sinusoid base modules be used for producing amplitude fix, with the output voltage of inverse-excitation type led driver input rectifier with the half-sinusoid voltage signal of homophase frequently.

Described average current ring is the operational amplifier of a compensatory network, and the half-sinusoid benchmark that the output signal mean value of secondary current analog module and described half-sinusoid base modules are produced compares and error between the two is amplified.

Described half-sinusoid generation module be used for producing amplitude with input voltage change, with the output voltage of inverse-excitation type led driver input rectifier with the half-sinusoid voltage signal of homophase frequently.

The output that is input as the average current ring of described multiplier module and half-sinusoid produce the output of circuit, multiplier module be output as amplitude with input voltage change, with the output voltage of inverse-excitation type led driver input rectifier with the half-sinusoid voltage signal of homophase frequently.

The input of described comparison module is respectively the output signal of multiplier module and the primary current sampled signal of inverse-excitation type led driver.Comparison module compares the output signal of primary current sampled signal and multiplier module, and when the primary current sampled signal rises to when equating with the output signal of multiplier module, comparison module output is high level from the low level upset.

Described inductive current zero passage detection module detects the auxiliary winding voltage signal of transformer of inverse-excitation type led driver, and indirect detection goes out transformer excitation inductive current zero crossing.When the auxiliary winding voltage signal of transformer drops to zero, inductive current zero passage detection module output high level.

Described driving pulse generation module produces pulse signal according to the outputs level signals of comparison module and inductive current zero passage detection module: when low level of comparison module generation arrived the upset of high level, the pulse signal of driving pulse generation module reset to low level by high level; When low level of inductive current zero passage detection module generation arrived the upset of high level, the pulse signal of driving pulse generation module was set to high level by low level; Go round and begin again, produce pulse train.

Described driver module is used for strengthening the driving force of described driving pulse generation module.

Wherein, described inverse-excitation type led driver is operated in critical discontinuous mode (BCM).

Wherein, described half-sinusoid base modules can substitute with a direct current power supply, and device can operate as normal, but input power factor can variation.

Wherein, the operational amplifier of described average current ring can be voltage-type or current mode (transconductance type).

Further, the compensating network of described average current ring can be pure integral element, also can be the proportional integral link, and perhaps the proportion integration differentiation link belongs to known technology.

Wherein, described driver module can be the push-pull configuration (totem structure) that two bipolar transistors or metal oxide semiconductor field effect tube constitute, and belongs to known technology.

Based on above elaboration, core concept of the present utility model is: detect inverse-excitation type led driver transformer inductance current zero-crossing point by inductive current zero passage detection module, and when the transformer inductance current over-zero, open former limit switching tube, thereby make the inverse-excitation type led driver be operated in electric current critical discontinuous mode (BCM); Keep module that the primary current sampled signal is carried out peak value sampling and maintenance by described peak value sampling, obtain the peak envelope line of primary current sampled signal; Obtain after the peak envelope line of primary current sampled signal,, simulate area and the proportional signal of secondary diode current twice area by described secondary current analog module; The output signal of secondary current analog module is delivered in the average current ring, utilize the average current ring self to have the average value filtering function, input at the average current ring obtains and the proportional half-sinusoid signal of output current mean value, compare by half-sinusoid benchmark with the generation of half-sinusoid base modules, the error signal of the two is amplified through the compensating network of average current ring, obtain the direct current signal that an error is amplified; The half-sinusoid signal that the output of average current ring and half-sinusoid generation module produce multiplies each other through multiplier module, obtains half-sinusoid voltage signal same frequently with the output voltage of inverse-excitation type led driver input rectifier, homophase; The primary current sampled signal compares through the output of described comparison module and multiplier module, make the proportional multiplier module output signal of primary current sampled signal peak envelope line following and input rectifier output half-sinusoid, thereby realize the High Power Factor of inverse-excitation type led driver; The ON time of this exogenesis limit switching tube is adjusted automatically along with output current changes, thereby control output current mean value is steady state value.The constant current value of output current can be realized by the half-sinusoid benchmark that changes primary current sampling coefficient or change in the average current ring.

The beneficial effects of the utility model are: the former limit constant-current control device of the isolated high-power factor inverse-excitation type led driver that the utility model proposes, need not optocoupler and secondary feedback circuit, and can realize High Power Factor and output constant current control.Because adopt single-level circuit, and saved optocoupler and secondary feedback circuit, former limit core control circuit can be integrated into single-chip, number of elements reduces, and circuit is more reliable.Control method of the present utility model in addition makes the former limit switching tube of inverse-excitation type led driver be operated in electric current critical discontinuous mode (BCM), has promoted circuit efficiency, and has reduced the electromagnetic interference of circuit.

Description of drawings

Fig. 1 is the traditional band power factor correction and the led driver of constant current control two-layer configuration;

Fig. 2 is the led driver of power factor correction of another kind of band and constant current control two-layer configuration;

Fig. 3 is the isolated form single-stage inverse-excitation type led driver of band power factor correction and secondary constant current control;

Fig. 4 is the main circuit connection diagram of the utility model and inverse-excitation type led driver;

Fig. 5 is the first specific embodiment schematic diagram of the present utility model;

Fig. 6 is the principle waveform analysis figure of secondary current analog module simulation secondary current;

Fig. 7 is the second specific embodiment schematic diagram of the present utility model;

Fig. 8 is the 3rd a specific embodiment schematic diagram of the present utility model;

Fig. 9 is the 4th a specific embodiment schematic diagram of the present utility model

Figure 10 is the 5th a specific embodiment schematic diagram of the present utility model;

Figure 11 is the main circuit connection diagram of the step-up/step-down circuit of the utility model and non-isolation.

Embodiment

Below in conjunction with specific embodiment and accompanying drawing the utility model content is elaborated.

With reference to Fig. 4, the former limit of a kind of led driver constant-current control device comprises that peak value sampling keeps module 21, secondary current analog module 22, half-sinusoid base modules 23, average current ring 24, half-sinusoid generation module 25, multiplier module 26, comparison module 27, inductive current zero passage detection module 28, driving pulse generation module 29 and driver module 30.

Application of the present utility model is the main circuit of inverse-excitation type led driver, comprises input rectifying bridge B ₁, input capacitance C _In, transformer T, absorb network, former limit switching tube Q ₁, primary current sampling network, output rectifier (select diode D for use ₁) and output capacitor C _o

Peak value sampling keeps module 21 to link to each other with the primary current sampling network of inverse-excitation type led driver main circuit, in each switch periods the primary current sampled signal is carried out peak value sampling and keeps, and extracts primary current sampled signal peak value.

Peak value sampling keeps module specifically can select the disclosed peak sampling hold circuit of Chinese patent (publication number: CN 101615432) for use.

Secondary current analog module 22 is connected on peak value sampling and keeps being used for simulating the twice current waveform of output rectifier after the module 21.With reference to Fig. 5, switching tube M ₁And resistance R ₁Constitute the side circuit of secondary current analog module 22.M wherein ₁Control signal produce by driving pulse generation module 29, identical with the former limit of inverse-excitation type led driver switching tube drive signal logic.

Further, the switching tube M in the secondary current analog module 22 ₁Can be metal oxide semiconductor field effect tube, igbt or bipolar transistor.

Fig. 6 is the key waveforms that the inverse-excitation type led driver is operated in former secondary under the electric current critical discontinuous mode, with reference to the detailed description of 6 pairs of secondary current principle of simulations of figure:

V among the figure _{GS_M1}﹠amp; v _{GS_Q1}Be the former limit of inverse-excitation type led driver switching tube M ₁And Q ₁Drive waveforms; i _PriIt is the former limit of inverse-excitation type led driver switching tube current waveform; i _SeeIt is inverse-excitation type led driver secondary output rectifier current waveform; v _SampleIt is the output waveform that peak value sampling keeps module 21; v _{DS_M1}Be switching tube M ₁The voltage waveform at drain electrode and source electrode (collector and emitter) two ends, v _{DS_M1}Amplitude equal the peak value of primary current sampled signal.Can see according to Fig. 6, as long as the inverse-excitation type led driver is operated in the electric current critical discontinuous mode, at single switch in the cycle, v _{DS_M1}Area be proportional to the secondary current area.

The mean value of output rectifier electric current within a switch periods

For:

${\stackrel{\‾}{I}}_{\sec }=\frac{{\∫}_0^{\mathrm{DT}}{i}_{\sec }\mathrm{dt}}{T}---\left(3\right)$

Wherein T is the switch periods of inverse-excitation type led driver, and D is the duty ratio of inverse-excitation type led driver.The output rectifier current waveform can be obtained output current I averaging of whole power frequency period _oExpression formula, as the formula (4).

$I_o=\frac{{\∫}_0^{T_{\mathrm{grid}}}\stackrel{\‾}{I_{\sec }}\mathrm{dt}}{T_{\mathrm{grid}}}---\left(4\right)$

Wherein, T _GridBe the electrical network cycle, for Chinese electrical network, T _Grid=0.02 second.

With reference to Fig. 6, V _{DS_M1}Mean value within a switch periods can be obtained by formula (5):

${\stackrel{\&OverBar;}{V}}_{\mathrm{DS}\_\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HSA00000242761800031.png"\; state="\{\{state\}\}">M</figure-callout>}1}=2K_1\frac{N_s}{N_p}{\stackrel{\&OverBar;}{I}}_{\sec }---\left(5\right)$

K wherein ₁Be primary current sampling coefficient, N _pBe the former limit of the inverse-excitation type led driver transformer number of turn, N _sIt is the inverse-excitation type led driver transformer secondary number of turn.By equation (5) as seen, after current sample coefficient and the transformer number of turn are all determined, With

Be directly proportional.

Half-sinusoid base modules 23 be used for producing amplitude fix, with the output voltage of inverse-excitation type led driver input rectifier with the half-sinusoid voltage signal of homophase frequently.

Average current ring 24 is for comprising compensating network and operational amplifier.With reference to the embodiment of Fig. 5, the output of secondary current analog module 22 is through resistance R ₂Connect the operational amplifier negative terminal input in the average current ring 24, half-sinusoid base modules 23 connects the operational amplifier anode input in the average current ring 24.Because the average current ring has switch periods average value filtering effect, so the mean value of secondary current analog module 22 output signals after the operational amplifier anode input signal of the average current ring 24 switch periods ripple that has been filtering.This signal and half-sinusoid base modules 23 compare, and error is amplified through average current ring 24 between the two, and average current ring 24 is output as the superposeed low-frequency ripple of twice AC network frequency and the DC level of HF switch ripple.

Half-sinusoid generation module 25 be used for producing amplitude with input voltage change, with the output voltage of inverse-excitation type led driver input rectifier with the half-sinusoid voltage signal of homophase frequently.With reference to the embodiment of Fig. 5, half-sinusoid generation module 25 passes through resistance R ₃And R ₄Dividing potential drop realizes.R wherein ₃The high level output of one termination inverse-excitation type led driver input rectifier, the other end and R ₄An end link to each other; R ₄Other end ground connection.R ₃And R ₄Continuous point be the output of described half-sinusoid generation module 25.

The input of multiplier module 26 (selecting independent multiplier for use) is respectively the output of average current ring 24 and the output of half-sinusoid generation module 25.Because the output of average current ring 24 is a direct current level substantially, half-sinusoid generation module 25 is output as and the same half-sinusoid signal of homophase frequently of the output of inverse-excitation type led driver input rectifier, therefore the product of the two, promptly multiplier be output as one have slightly distortion, with the output of inverse-excitation type led driver input rectifier with the half-sinusoid signal of homophase frequently.

Comparison module 27 comprises first comparator, and its negative terminal input connects the output of multiplier, and the anode input connects the output of inverse-excitation type led driver primary current sampling network.When the primary current sampled signal touches the output level of multiplier, the output level of comparison module 27 is high level from the low level upset.The effect of comparison module 27 is to make former limit switching tube current waveform envelope follow the output signal of multiplier.Since multiplier be output as with the output of inverse-excitation type led driver input rectifier with the half-sinusoid signal of homophase frequently, therefore the former limit switching tube current waveform envelope through overregulating after also is the output of the inverse-excitation type led driver input rectifier half-sinusoid with the frequency homophase.

Suppose that former limit switching tube current waveform envelope function is: I _Pk| sin ω t|, wherein ω=2 π/T _Grid, I _PkBe former limit switching tube peak current, then can release the mean function of secondary rectifying tube electric current in a switch periods and be:

${\stackrel{\&OverBar;}{I}}_{\sec }=\frac{(1-D)}{2}\frac{N_p}{N_s}{I}_{\mathrm{pk}}\left|\sin \mathrm{\&omega;t}\right|---\left(6\right)$

According to formula (4), the mean value of output current is:

$I_o=\frac{(1-D)}{2}\frac{N_p}{N_s}\frac{{\&Integral;}_0^{T_{\mathrm{grid}}}{I}_{\mathrm{pk}}\left|\sin \mathrm{\&omega;t}\right|\mathrm{dt}}{T_{\mathrm{grid}}}---\left(7\right)$

According to formula (7), V _{DS_M1}Mean value within a switch periods is:

${\stackrel{\&OverBar;}{V}}_{\mathrm{DS}\_\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HSA00000242761800031.png"\; state="\{\{state\}\}">M</figure-callout>}1}=2K_1\frac{N_s}{N_p}{I}_{\sec }=K_1(1-D)I_{\mathrm{pk}}\left|\sin \mathrm{\&omega;t}\right|---\left(8\right)$

Because the benchmark of average current ring 24 is the fixing half-sinusoid benchmark of amplitude, by equation (8) as can be known, because the effect of average current ring 24, make K ₁(1-D) I _PkBe constant.Because current sample COEFFICIENT K ₁Be constant, when input voltage changes or load variations makes I _PkWhen changing, the average current ring is by adjusting feasible (1-D) I of duty ratio _PkRemain constant.By equation (7) as can be known, as (1-D) I _PkRemain constant, output current mean value can remain unchanged, and promptly realizes constant current output.

With reference to Fig. 5, inductive current zero passage detection module 28 is for comprising second comparator and time delay module, and the negative terminal input of second comparator connects the auxiliary winding different name end of inverse-excitation type led driver transformer, anode input grounding.Assist the winding voltage signal zero crossing by detecting transformer, but indirect detection goes out the transformer inductance current zero-crossing point.When the voltage signal zero passage that detects the auxiliary winding of transformer, second comparator output high level.Because the auxiliary winding voltage signal zero crossing of inverse-excitation type led driver transformer exists certain hour poor with resonance potential the lowest point between the former limit switching tube drain-source utmost point (or collector electrode and emitter), promptly inverse-excitation type led driver transformer is assisted the resonance potential the lowest point of winding voltage signal zero crossing between will the leading a little former limit switching tube drain-source utmost point.By time delay module, this time difference is compensated, it is open-minded to obtain the resonance potential the lowest point of former limit switching tube between the drain-source utmost point.

Further, but the anode of second comparator in the inductive current zero passage detection module 28 is imported the also direct voltage source of reconfiguration one low amplitude value, reduces the error that causes because of the ground wire interference.

Driving pulse generation module 29 can adopt rest-set flip-flop to realize, wherein the R pin connects the output of comparison module 27, the S pin connects the output of inductive current zero passage detection module 28: when low level of comparison module 27 generations arrived the upset of high level, the output signal of driving pulse generation module 29 reset to low level by high level; When low level of inductive current zero passage detection module 28 generations arrived the upset of high level, the output signal of driving pulse generation module 29 was set to high level by low level, so goes round and begins again, and produces output pulse sequence.

The output of driving pulse generation module 29 is delivered to the gate pole of the former limit of inverse-excitation type led driver switching tube through driver module 30, and the output of driving pulse generation module 29 is simultaneously directly as the switching tube M in the secondary current analog module 22 ₁Gate signal.

Fig. 7 is second embodiment of the present utility model, and other parts all embodiment with shown in Figure 5 are identical, with the difference of Fig. 5 be that Fig. 7 has provided 23 1 kinds of embodiments of half-sinusoid base modules.Half-sinusoid base modules 23 comprises divider, resistance R ₅, resistance R ₆And capacitor C ₁Wherein, R ₅One termination inverse-excitation type led driver input rectifier B ₁The high level output, the other end and R ₆And C ₁One end of parallel branch links to each other, R ₆And C ₁Other end ground connection in parallel.R ₅, R ₆And C ₁Constitute anode output voltage dividing potential drop and the filtering of electric network, R to input rectifier ₅With R ₆, C ₁Tie point voltage is a direct voltage that has superposeed less low-frequency ripple, and its mean value is directly proportional with inverse-excitation type led driver input ac voltage peak value.The divisor end A of the divider in the half-sinusoid base modules 23 meets R ₃And R ₄Tie point, dividend end B and R ₅, R ₆And C ₁Tie point link to each other, the two signal is divided by in divider (A/B), make divider be output as constant amplitude, with the output of inverse-excitation type led driver input rectifier with the half-sinusoid signal of homophase frequently.

Fig. 8 is the 3rd embodiment of the present utility model.Be mainly that with difference embodiment illustrated in fig. 7 present embodiment has provided secondary current analog module 22, half-sinusoid generation module 25, half-sinusoid base modules 23 and multiplier module 26 another kind of specific implementations respectively.With reference to figure 8, (1) secondary current analog module is by switching tube M ₁₁With switching tube M ₂₂Form; Switching tube M ₁₁Source ground, switching tube M ₁₁Drain electrode meet switching tube M ₂₂Source electrode, switching tube M ₁₁Gate pole connect the Q end of driving pulse generation module; Switching tube M ₂₂Drain electrode meet the output that peak value sampling keeps module, switching tube M ₂₂Gate pole connect driving pulse generation module reversed-phase output

(2) half-sinusoid generation module 25 comprises resistance R ₉With transistor M ₂, resistance R ₉A termination inverse-excitation type led driver input rectifier B ₁The high level output, resistance R ₉The other end, transistor M ₂Base stage, collector electrode be half-sinusoid generation module output, transistor M ₂Emitter utmost point ground connection; Inverse-excitation type led driver input rectifier B ₁The half-sinusoid voltage signal of output is through R ₉With transistor M ₂Convert the half-sinusoid current signal to; Wherein, transistor M in the half-sinusoid generation module 25 ₂Can be metal oxide semiconductor field effect tube, igbt or bipolar transistor.(3) multiplier module 26 comprises multiplier, image current module ii I (the 3rd image current module) and resistance R ₁₀The image current module ii I R that obtains and flow through ₉The proportional half-sinusoid current signal of branch current, and through resistance R ₁₀Convert voltage signal to, receive the input negative terminal of multiplier; (4) half-sinusoid base modules 23 comprises divider, image current module I (the first image current module), resistance R ₇, capacitor C ₂, image current module ii (the second image current module) and resistance R ₈The image current module I R that obtains and flow through ₉The proportional half-sinusoid current signal of branch current, and through resistance-capacitance network R ₇And C ₂Obtain and the proportional d. c. voltage signal of inverse-excitation type led driver input ac voltage amplitude, receive the divisor end B of divider; The image current module ii R that obtains and flow through ₉The proportional half-sinusoid current signal of branch current, and through resistance R ₈Convert voltage signal to, receive the dividend end A of divider; The two signal is divided by in divider (A/B), the divider output of half-sinusoid base modules 23 produce constant amplitude, with the input rectifier output voltage waveforms with the half-sinusoid voltage reference signal of homophase frequently.The image current module can be made of metal oxide semiconductor field effect tube or bipolar transistor, belongs to known technology.

Fig. 9 is the 4th embodiment of the present utility model.Wherein, peak value sampling keeps module, average current ring, inductive current zero passage detection module, driving pulse generation module, driver module etc. all with embodiment illustrated in fig. 8 identical, is that with the main distinction embodiment illustrated in fig. 8 present embodiment has provided another embodiment of secondary current analog module 22 and comparison module 27 respectively.With reference to figure 9, (1) secondary current analog module is by switching tube M ₃₃And resistance R ₃₃Form; Resistance R ₃₃A termination switching tube M ₃₃Source electrode, resistance R ₃₃Other end ground connection; Switching tube M ₃₃Drain electrode meet the output that peak value sampling keeps module, switching tube M ₃₃Gate pole receive the reversed-phase output of driving pulse generation module

(2) comparison module 27 comprises first comparator, image current module I V (the 4th image current module), capacitor C ₃With switching tube M ₃The anode input of first comparator is by image current module I V, capacitor C ₃With switching tube M ₃The envelope that produces is the sawtooth signal of half-sinusoid, and wherein mirror current source module I V is used for obtaining and flowing through R ₉The proportional half-sinusoid image current of branch current signal; Switching tube M ₃Gate signal from the anti-phase output of driving pulse generation module 29

Switching tube M ₃Gate signal also can be directly after inverter is anti-phase, obtain by the positive output Q of driving pulse generation module 29; Further, M ₃Can be metal oxide semiconductor field effect tube, igbt or bipolar transistor.

Figure 10 is the 5th embodiment of the present utility model.Wherein, secondary current analog module 22 is with embodiment illustrated in fig. 7 identical, and other main modular are all with embodiment illustrated in fig. 9 identical in addition, and the main distinction is that the input of peak value sampling maintenance module among Figure 10 is image current module I V, capacitor C ₃With switching tube M ₃The envelope that produces is the sawtooth signal of half-sinusoid, but not the primary current sampling network shown in Fig. 9.Therefore among Figure 10, inverse-excitation type led driver main circuit has saved the primary current sampling network.

The utility model can be applied to isolated form output, also can be applied to non-isolation type output.Figure 11 is the main circuit connection diagram of buck (buck-boost) circuit of the utility model and a kind of non-isolation; Wherein, the specific implementation of each module can be with reference to figure 5, the specific embodiment shown in Fig. 7～Figure 10.

Claims (6)

1. the former limit of led driver constant-current control device, comprise that peak value sampling keeps module, secondary current analog module, average current ring, half-sinusoid base modules, half-sinusoid generation module, multiplier module, comparison module, inductive current zero passage detection module, driving pulse generation module and driver module, is characterized in that:

Peak value sampling keeps the input of the output termination secondary current analog module of module, an input of the output termination average current ring of secondary current analog module, another input termination half-sinusoid base modules of average current ring, an input of the output termination multiplier module of average current ring, another input termination half-sinusoid generation module of multiplier module, an input of the output termination comparison module of multiplier module, an input of the output termination driving pulse generation module of comparison module, inductive current zero passage detection module connects another input of driving pulse generation module, the output termination driver module of driving pulse generation module.

2. the former limit of a kind of led driver according to claim 1 constant-current control device is characterized in that:

Described secondary current analog module is by switching tube M ₁And resistance R ₁Form; Resistance R ₁A termination peak value sampling keep module, another termination switching tube M ₁Drain electrode and as the output of secondary current analog module, switching tube M ₁Source ground, switching tube M ₁Gate pole connect the Q end of driving pulse generation module;

Described average current ring is by the operational amplifier and the resistance R of compensatory network ₂Form; Resistance R ₂The output, the negative terminal of another termination operational amplifier of a termination secondary current analog module, the output of the positive termination half-sinusoid base modules of operational amplifier;

Described half-sinusoid generation module is by resistance R ₃And resistance R ₄Form resistance R ₃An end and resistance R ₃An end all be connected resistance R with another input of multiplier ₃Another termination inverse-excitation type led driver input rectifier B ₁The high level output, resistance R ₄Other end ground connection;

Described multiplier module comprises multiplier;

Described comparison module comprises first comparator;

Described inductive current zero passage detection module is made up of second comparator and time delay module, and the negative terminal input of second comparator connects the auxiliary winding different name end of inverse-excitation type led driver transformer, anode input grounding; The output termination time delay module of second comparator;

Described driving pulse generation module comprises rest-set flip-flop, the R end of the output termination rest-set flip-flop of comparison module, and inductive current zero passage detection module connects the S end of rest-set flip-flop, and the Q end of rest-set flip-flop is as the output of driving pulse generation module.

3. the former limit of a kind of led driver according to claim 1 constant-current control device is characterized in that:

Described secondary current analog module is by switching tube M ₁And resistance R ₁Form; Resistance R ₁A termination peak value sampling keep module, another termination switching tube M ₁Drain electrode and as the output of secondary current analog module, switching tube M ₁Source ground, switching tube M ₁Gate pole connect the Q end of driving pulse generation module;

Described half-sinusoid base modules comprises divider, resistance R ₅, resistance R ₆And capacitor C ₁Resistance R ₅An end, resistance R ₆An end and capacitor C ₁An end all be connected resistance R with the divisor end of divider ₅Another termination inverse-excitation type led driver input rectifier B ₁The high level output, resistance R ₆An end and capacitor C ₁The equal ground connection of an end, an input of the dividend termination multiplier of divider, the divider output is as the output of half-sinusoid base modules;

Described average current ring is by the operational amplifier and the resistance R of compensatory network ₂Form; Resistance R ₂The output, the negative terminal of another termination operational amplifier of a termination secondary current analog module, the output of the positive termination half-sinusoid base modules of operational amplifier;

Described half-sinusoid generation module is by resistance R ₃And resistance R ₄Form resistance R ₃An end and resistance R ₃An end all be connected resistance R with another input of multiplier ₃Another termination inverse-excitation type led driver input rectifier B ₁The high level output, resistance R ₄Other end ground connection;

Described comparison module comprises first comparator;

Described inductive current zero passage detection module is made up of second comparator and time delay module, and the negative terminal input of second comparator connects the auxiliary winding different name end of inverse-excitation type led driver transformer, anode input grounding; The output termination time delay module of second comparator;

Described driving pulse generation module comprises rest-set flip-flop, the R end of the output termination rest-set flip-flop of comparison module, and inductive current zero passage detection module connects the S end of rest-set flip-flop, and the Q end of rest-set flip-flop is as the output of driving pulse generation module.

4. the former limit of a kind of led driver according to claim 1 constant-current control device is characterized in that:

Described secondary current analog module is by switching tube M ₁₁, switching tube M ₂₂With inverter U ₁₁Form; Switching tube M ₁₁Source ground, switching tube M ₁₁Drain electrode meet switching tube M ₂₂Source electrode, switching tube M ₁₁Gate pole connect the Q end of driving pulse generation module; Switching tube M ₂₂Drain electrode meet the output that peak value sampling keeps module, switching tube M ₂₂Gate pole meet inverter U ₁₁Output; Inverter U ₁₁Input connect the Q end of driving pulse generation module;

Described half-sinusoid base modules comprises divider, resistance R ₇, resistance R ₈, capacitor C ₂, the first current mirror module and the second current mirror module; Resistance R ₇An end and capacitor C ₂An end ground connection, resistance R ₇The other end, capacitor C ₂The other end, the first current mirror module output all be connected with divider divisor end; The first current mirror module input connects the output of half-sinusoid generation module; Resistance R ₈An end and the output of the second current mirror module all be connected resistance R with divider dividend end ₈Other end ground connection, the output of the input termination half-sinusoid generation module of the second current mirror module;

Described average current ring is by the operational amplifier and the resistance R of compensatory network ₂Form; Resistance R ₂The output, the negative terminal of another termination operational amplifier of a termination secondary current analog module, the output of the positive termination half-sinusoid base modules of operational amplifier;

Described half-sinusoid generation module is by resistance R ₉With transistor M ₂Form resistance R ₉A termination inverse-excitation type led driver input rectifier B ₁The high level output, resistance R ₉The other end, transistor M ₂Base stage, collector electrode be half-sinusoid generation module output, transistor M ₂Grounded drain;

Described multiplier module comprises the 3rd current mirror module, resistance R ₁₀And multiplier, an input of multiplier is as an input of multiplier module, and the 3rd current mirror module input is as another input of multiplier module, the 3rd current mirror module output, resistance R ₁₀An end all be connected resistance R with another input of multiplier ₁₀Other end ground connection;

Described comparison module comprises first comparator;

Described inductive current zero passage detection module is made up of second comparator and time delay module, and the negative terminal input of second comparator connects the auxiliary winding different name end of inverse-excitation type led driver transformer, anode input grounding; The output termination time delay module of second comparator;

Described driving pulse generation module comprises rest-set flip-flop, the R end of the output termination rest-set flip-flop of comparison module, and inductive current zero passage detection module connects the S end of rest-set flip-flop, and the Q end of rest-set flip-flop is as the output of driving pulse generation module.

5. the former limit of a kind of led driver according to claim 1 constant-current control device is characterized in that:

Described secondary current analog module is by switching tube M ₃₃, resistance R ₃₃With inverter U ₃₃Form; Resistance R ₃₃A termination switching tube M ₃₃Source electrode, resistance R ₃₃Other end ground connection; Switching tube M ₃₃Drain electrode meet the output that peak value sampling keeps module, switching tube M ₃₃Gate pole meet inverter U ₃₃Output; Inverter U ₃₃Input connect the Q end of driving pulse generation module;

Described half-sinusoid base modules comprises divider, resistance R ₇, resistance R ₈, capacitor C ₂, the first current mirror module and the second current mirror module; Resistance R ₇An end and capacitor C ₂An end ground connection, resistance R ₇The other end, capacitor C ₂The other end, the first current mirror module output all be connected with divider divisor end; The first current mirror module input connects the output of half-sinusoid generation module; Resistance R ₈An end and the output of the second current mirror module all be connected resistance R with divider dividend end ₈Other end ground connection, the output of the input termination half-sinusoid generation module of the second current mirror module;

Described average current ring is by the operational amplifier and the resistance R of compensatory network ₂Form; Resistance R ₂The output, the negative terminal of another termination operational amplifier of a termination secondary current analog module, the output of the positive termination half-sinusoid base modules of operational amplifier;

Described half-sinusoid generation module is by resistance R ₉With transistor M ₂Form resistance R ₉A termination inverse-excitation type led driver input rectifier B ₁The high level output, resistance R ₉The other end, transistor M ₂Base stage, collector electrode be half-sinusoid generation module output, transistor M ₂Grounded drain;

Described multiplier module comprises the 3rd current mirror module, resistance R ₁₀And multiplier, an input of multiplier is as an input of multiplier module, and the 3rd current mirror module input is as another input of multiplier module, the 3rd current mirror module output, resistance R ₁₀An end all be connected resistance R with another input of multiplier ₁₀Other end ground connection;

Described comparison module comprises first comparator, the 4th current mirror module, switching tube M ₃And capacitor C ₃, the negative terminal of first comparator connects the output of multiplier module, and the output of first comparator is the output of comparison module, the anode of first comparator, the 4th current mirror module output, capacitor C ₃An end all with switching tube M ₃Drain electrode connect capacitor C ₃The other end and switching tube M ₃Source ground, switching tube M ₃Gate pole connect rest-set flip-flop

End, the 4th current mirror module is defeated as termination half-sinusoid generation module output;

Described inductive current zero passage detection module is made up of second comparator and time delay module, and the negative terminal input of second comparator connects the auxiliary winding different name end of inverse-excitation type led driver transformer, anode input grounding; The output termination time delay module of second comparator;

Described driving pulse generation module comprises rest-set flip-flop, the R end of the output termination rest-set flip-flop of comparison module, and inductive current zero passage detection module connects the S end of rest-set flip-flop, and the Q end of rest-set flip-flop is as the output of driving pulse generation module.

6. the former limit of a kind of led driver according to claim 1 constant-current control device is characterized in that:

Described secondary current analog module is by switching tube M ₁And resistance R ₁Form; Resistance R ₁A termination peak value sampling keep module, another termination switching tube M ₁Drain electrode and as the output of secondary current analog module, switching tube M ₁Source ground, switching tube M ₁Gate pole connect the Q end of driving pulse generation module;

Described half-sinusoid base modules comprises divider, resistance R ₇, resistance R ₈, capacitor C ₂, the first current mirror module and the second current mirror module; Resistance R ₇An end and capacitor C ₂An end ground connection, resistance R ₇The other end, capacitor C ₂The other end, the first current mirror module output all be connected with divider divisor end; The first current mirror module input connects the output of half-sinusoid generation module; Resistance R ₈An end and the output of the second current mirror module all be connected resistance R with divider dividend end ₈Other end ground connection, the output of the input termination half-sinusoid generation module of the second current mirror module;

Described average current ring is by the operational amplifier and the resistance R of compensatory network ₂Form; Resistance R ₂The output, the negative terminal of another termination operational amplifier of a termination secondary current analog module, the output of the positive termination half-sinusoid base modules of operational amplifier;

Described half-sinusoid generation module is by resistance R ₉With transistor M ₂Form resistance R ₉A termination inverse-excitation type led driver input rectifier B ₁The high level output, resistance R ₉The other end, transistor M ₂Base stage, collector electrode be half-sinusoid generation module output, transistor M ₂Grounded drain;

Described multiplier module comprises the 3rd current mirror module, resistance R ₁₀And multiplier, an input of multiplier is as an input of multiplier module, and the 3rd current mirror module input is as another input of multiplier module, the 3rd current mirror module output, resistance R ₁₀An end all be connected resistance R with another input of multiplier ₁₀Other end ground connection;

Described comparison module comprises first comparator, the 4th current mirror module, switching tube M ₃And capacitor C ₃, the negative terminal of first comparator connects the output of multiplier module, and the output of first comparator is the output of comparison module, the anode of first comparator, the 4th current mirror module output, capacitor C ₃An end all with switching tube M ₃Drain electrode connect capacitor C ₃The other end and switching tube M ₃Source ground, switching tube M ₃Gate pole connect rest-set flip-flop

End, the 4th current mirror module is defeated as termination half-sinusoid generation module output;

Described inductive current zero passage detection module is made up of second comparator and time delay module, and the negative terminal input of second comparator connects the auxiliary winding different name end of inverse-excitation type led driver transformer, anode input grounding; The output termination time delay module of second comparator;

Described driving pulse generation module comprises rest-set flip-flop, the R end of the output termination rest-set flip-flop of comparison module, and inductive current zero passage detection module connects the S end of rest-set flip-flop, and the Q end of rest-set flip-flop is as the output of driving pulse generation module.

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