CN101502184A - Striking and open lamp regulation for CCFL controller - Google Patents
Striking and open lamp regulation for CCFL controller Download PDFInfo
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- CN101502184A CN101502184A CNA2007800294041A CN200780029404A CN101502184A CN 101502184 A CN101502184 A CN 101502184A CN A2007800294041 A CNA2007800294041 A CN A2007800294041A CN 200780029404 A CN200780029404 A CN 200780029404A CN 101502184 A CN101502184 A CN 101502184A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/14—Circuit arrangements
- H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
- H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
- H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
- H05B41/285—Arrangements for protecting lamps or circuits against abnormal operating conditions
- H05B41/2851—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions
- H05B41/2855—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions against abnormal lamp operating conditions
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
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Abstract
An apparatus and method for igniting a lamp during a strike mode of an inverter comprising: sequentially controlling a duty cycle sweep and a frequency sweep of driving signals in the inverter to provide an increasing output voltage to the lamp. One embodiment advantageously includes a closed feedback loop to implement the duty cycle sweep and the frequency sweep such that an open lamp voltage is reliably regulated during the strike mode. For example, the closed feedback loop stops the duty cycle sweep or the frequency sweep when the output voltage to the lamp reaches a predetermined threshold and makes adjustments to the duty cycle or frequency the driving signals as needed to keep the output voltage at approximately the predetermined threshold if the lamp has not ignited.
Description
Require priority
The application requires on July 6th, 2006 to submit to and be entitled as the U.S. Provisional Patent Application No.60/806 of " Strikingand Open Lamp Regulation for CCFL Controller " based on 35U.S.C. § 119 (e), 714, on October 4th, 2006 submitted and be entitled as the U.S. Provisional Patent Application No.60/849 of " Compensation for Supply VoltageVariations in a PWM " to, 211, and on October 4th, 2006 submit and be entitled as the U.S. Provisional Patent Application No.60/849 of " PWM Duty Cycle Inverse Adjustment Circuit " to, 254 priority, wherein the full content of each part application is incorporated herein by reference.
Background of invention
Invention field
This invention relates to and is used to control the inverter controller of supplying with fluorescent lamp power, relates more specifically to have the inverter controller of reliable lamp starter and open lamp voltage adjustment (voltage regulation).
Description of Related Art
Need light but be used for producing in the limited multiple application of the required power of light and all use fluorescent lamp.A kind of fluorescent lamp of particular type is cold-cathode fluorescence lamp (CCFL).CCFL is used for being generally used for the backlight or edge light of the LCD (LCD) of notebook, web browser, automobile and industrial equipment and entertainment systems.Such fluorescent lamp need short time period high starting voltage (order of magnitude is 700-1, about 600 volts) so that the gas ionization that comprises in the fluorescent tube so that starter.After gas ionization in CCFL and CCFL light, need lower voltage to keep CCFL to open.
The CCFL pipe comprises gas and the small amount of mercury such as argon gas, xenon usually.After initial ignition stage and plasma formed, electric current flow through fluorescent tube and causes the generation of ultraviolet light.Ultraviolet light shines the phosphor material that is coated in the tube inner wall again, has produced visible light.
The circuit for power conversion that is known as inverter generally is used to drive CCFL.Inverter is accepted direct current (DC) input voltage and will exchange (AC) output voltage to offer CCFL.The electric current (being lamp current) of crossing CCFL by control flows is controlled the brightness (or light intensity) of CCFL.For example, lamp current can be amplitude modulation(PAM) or pulse-width modulation, with the brightness of control CCFL.
One type inverter comprises resonant circuit.This inverter comprises that use power metal oxide semiconductor field-effect transistor (MOSFET) provides direct current to arrive the conversion of interchange according to the switching transistor of semibridge system layout or full-bridge type layout.The drive signal that is in resonance frequency by utilization comes switch MOS FET to provide maximum power in inverter output place.For control output voltage and the electric current that flows through lamp, the frequency that inverter can change drive signal makes it towards resonance frequency or away from resonance frequency.
Summary of the invention
One aspect of the present invention is an inverter, and this inverter has control sequentially and is used to make the duty ratio scanning of lamp starter and at least one drive signal of adjusting open lamp voltage and the closed feedback loop of frequency scanning.In one embodiment, closed feedback loop comprises detector circuit, control voltage generator and two electric pressure converters.When the output voltage of detector circuit monitors inverter and the output voltage of indicating inverter are greater than predetermined threshold.The generation of control voltage generator can be with set rate from the control voltage signal of first level to the variation of second level when inverter enters the trigger mode (strike mode) that is used for making the lamp starter.The output that the control voltage generator is coupled to detector circuit, and when contravarianter voltage was indicated in the output of detector circuit greater than predetermined threshold, the control voltage signal stopped to change with set rate.An electric pressure converter is exported in response to first scope generation, first control of control voltage signal values, and another electric pressure converter produces second in response to second scope of controlling voltage signal values and controls output.In one embodiment, first scope of control voltage signal values and second scope be crossover not, so that do not occur simultaneously in the duty ratio scanning and the frequency scanning of starter drive signal between trial period.In another embodiment, duty ratio scanning and frequency scanning crossover partly.Can stop duty ratio scanning or frequency scanning and be adjusted into expectation open lamp voltage level with output voltage with inverter.In addition, when the lamp starter (for example when lamp conduction surpasses the electric current of predeterminated level) or when overtime condition occurs under the situation that does not have starter at lamp, the trigger mode termination.
In one embodiment, a kind of method of lamp (for example fluorescent lamp) starter that makes comprises that duty ratio scanning and the frequency scanning sequentially controlled in pulse-width modulation (PWM) controller offer lamp with the output voltage that will increase.For example, this method is controlled two parameters (duty ratio and frequency) of lamp starter and open lamp voltage adjustment in a kind of mode of novelty.This method allows the starter during the trigger mode of PWM controller and the operation that do not stop of open lamp voltage regulation scheme.
This method advantageously provides reliable lamp starter and open lamp voltage adjustment in the application with wide operating range variable (for example cell voltage, transformer parameter, modulation characteristic, printed circuit board (PCB) ghost effect etc.).In one embodiment, lamp is coupled to Secondary winding of transformer.When the voltage on the secondary winding (for example secondary voltage or modulating voltage) was enough high, lamp just triggered.In one embodiment, secondary voltage depends on three parameters: be coupled to the duty ratio of the signal (for example switching signal) of primary winding, the frequency of switching signal, and the cell voltage that is applied to elementary winding.
This method also provides accurately (or improvement) adjustment (for example, when lamp lost efficacy) to open lamp voltage during trigger mode.In one embodiment, ignition scheme is worked together with open lamp voltage regulation scheme.For example, if lamp does not occur or defectiveness during trigger mode, the PWM controller is just adjusted secondary voltage to prevent to damage secondary winding so.Open lamp voltage regulation scheme advantageously with secondary voltage control (or restriction) in being enough to make the secondary voltage window (or scope) of lamp starter and do not damage secondary winding.Open lamp voltage regulation scheme has reduced the overshoot in the secondary voltage, and has adjusted secondary voltage on wide range of variables.For example, the adjustment of open lamp crest voltage specifies in 5% in one embodiment.
In one embodiment, in notebook that duty ratio and frequency change or laptop computer application backlight, use the present invention on the wide region at lamp starter and open lamp voltage adjustment.The present invention also can be applicable to use TV, automobile and other application backlight into visual display.The present invention is control duty ratio and frequency (for example, wherein the overshoot minimum in the secondary voltage) in stable closed feedback loop advantageously.In application with different lamps, transformer, printed circuit board layout, cell voltage etc., the combination of duty ratio control and FREQUENCY CONTROL provides flexibility, to produce the secondary voltage that is enough to trigger lamp under the situation of the maximum rating that can not surpass secondary winding.For example, the present invention guarantees to trigger frequency can be too not low or too high, and for low relatively cell voltage, duty ratio can be too not low, or for high relatively cell voltage, duty ratio can be too not high, or open lamp voltage can not surpass the secondary voltage rated value.
In one embodiment, cold-cathode fluorescence lamp (CCFL) controller is connected to the elementary winding of transformer, to control the power to the CCFL that is coupled to the transformer secondary output winding.The CCFL controller control one group of switch (for example by alternately open and close semiconductor switch) with in elementary winding, produce have the frequency determined by the CCFL controller and a duty ratio exchange (AC) signal.In one embodiment, select the elementary of transformer that number of secondary turns is compared to increase the voltage on the secondary winding.Secondary winding is the part of high Q value resonant circuit, and described resonant circuit comprises together with the stray inductance of this secondary winding of resistance, capacitor and other ghost effect of being coupled to this secondary winding.
Secondary peak voltage is the parameter that lamp starter and open lamp voltage adjustment are concerned about.The secondary voltage that makes the CCFL starter is high relatively (for example 1.5 kilovolts).Secondary voltage depends on cell voltage, duty ratio and the frequency that is applied.Because secondary winding is the part with high Q value resonant circuit (or secondary tank circuit) of brink (steep skirt), so secondary voltage can change near resonance frequency in response to rapid variation of frequency or duty ratio.Because different modulation characteristics and printed circuit board (PCB) ghost effect, resonance frequency can change significantly.
In one embodiment, use square wave switching signal (or drive signal) in elementary winding, to produce AC signal.The square wave switching signal is made up of the odd harmonic frequencies of the amplitude ratio that the duty ratio with this square wave switching signal is determined.Energy in each pulse of square wave switching signal is assigned in these harmonic frequencies.The square wave switching signal of burst pulse causes having the secondary voltage of the high-pressure peak of relative narrower.Cause having than the square wave switching signal of broad pulse relatively low peak value broad, the secondary voltage of sinusoidal shape more.When the duty ratio (or pulsewidth) of square wave switching signal when further increasing, the increase of secondary voltage peak value can reduce gradually.
In one embodiment of the invention, controller changes the duty ratio of drive signal during the phase I of trigger mode, and changes the frequency of drive signal during the second stage of the trigger mode that is used for making the CCFL starter.As required ground, regulate duty ratio (for example, from the minimum to the maximum duty cycle), then regulating frequency (for example, from the lower frequency to the upper frequency) has many advantages.At first, closed loop adjustment (for example, the open lamp voltage adjustment) is easier control and compensation, because can not change closed loop gain in the starting stage that changes (or scanning) duty ratio.Secondly, by making the secondary voltage maximization---this realizes by before frequency is scanned duty ratio being scanned maximum duty cycle---of stability at lower frequencies, increased loop stability.When frequency when resonance frequency increases, closed loop gain promptly changes.Leaving the stability at lower frequencies of resonance frequency, closed loop gain can not change sharp.Therefore, make the secondary voltage maximization at low frequency place that loop stability is provided, it can cause more stable open lamp voltage adjustment.The 3rd, it is helpful earlier duty ratio being scanned in the application with high relatively cell voltage, and wherein low relatively duty ratio is enough to trigger CCFL, and high relatively duty ratio can cause that secondary voltage surpasses the rated value of maximum open lamp voltage.The 4th, can prevent transformer saturated (wherein elementary winding shows as short circuit) by from the minimum to the maximum duty cycle, duty ratio being scanned.This duty ratio scan method allows when arriving transformer and make CCFL in relatively low duty ratio before saturated starter safely.The saturated product that depends on cell voltage and drive signal pulsewidth of transformer.
In another embodiment of the present invention, controller changes the frequency of drive signal during the phase I of trigger mode, and changes the duty ratio of drive signal during the second stage of the trigger mode that is used for making the CCFL starter.Earlier frequency scanning had advantage equally to the order of duty ratio scanning again.For example, transformer can transmit more multipotency under the upper frequency relatively.In some application of using the transformer that the safe enough coefficient is not arranged, can be saturated when transformer is operated in relative low frequency and high duty ratio.Therefore, a kind of trigger sequence is at first scanning drive signal to the relative high frequency rate from relative low frequency under the low duty ratio relatively, then as required ground, drive signal is scanned to relative high duty ratio from relative low duty ratio under the relative high frequency rate.Drive signal from low but fixing duty ratio, and at first the scanning to driving signal frequency is a kind of safer method that prevents that transformer is saturated, because the work of higher frequency has reduced saturated danger, duty cycle limit is not made as especially therein in the application of feed forward circuit of function of cell voltage.
In order to summarize the present invention, this paper has described some aspect of the present invention, advantage and novel feature.Should be appreciated that arbitrary specific embodiment according to the present invention not necessarily can obtain all these advantages.Therefore, can be according to realizing or optimizing the mode of teaching a kind of advantage or one group of advantage shown in this paper and not necessarily realizing other advantage of this paper institute's teaching or suggestion and specialize or realize the present invention.
The accompanying drawing summary
Fig. 1 is used for block diagram to the inverter of fluorescent lamp power supply according to one embodiment of the invention.
Fig. 2 is the circuit diagram of an embodiment of electric pressure converter shown in Figure 1.
Fig. 3 illustrates the multiple waveform from the circuit simulation of inverter.
Fig. 4 explanation illustrates the multiple waveform that open lamp voltage is adjusted.
Fig. 5 provides the broadening figure of waveform shown in Figure 4.
Describe in detail
Further describing of several embodiment of the present invention hereinafter will be described with reference to the drawings.Fig. 1 illustrates the circuit block diagram that is used for an embodiment of the inverter of lamp (for example CCFL) 100 power supply.The closed feedback loop that this inverter comprises the starter of controlling lamp 100 without a break and provides open lamp voltage to adjust during the trigger mode of inverter.In one embodiment, closed feedback loop comprises voltage detector circuit 102, control voltage generator 104, first electric pressure converter 106 and second electric pressure converter 108.
For example, voltage detector circuit 102 receives first feedback signal (VSNS) of indication output voltages (or the voltage on the lamp 100), and produces and indicate output voltage when greater than the output corresponding to the predetermined voltage level of first reference voltage (VREF1).Control voltage generator 104 produces and can change with first set rate control voltage (VC) of (for example from first level to second level), up to the voltage on the output indicator of voltage detector circuit 102 greater than predetermined voltage level (for example when VSNS greater than VREF1 time).Voltage detector circuit 102 makes control voltage generator 104 stop to change with first set rate, and regulates control voltage so that the output voltage of inverter is adjusted to about predetermined voltage level in response to first feedback signal.For example, when first feedback signal surpasses first reference voltage, can be by reduce to regulate control voltage (for example capacitor 120 is by the partial discharge of resistance 144) by second set rate.Therefore, if lamp 100 does not occur during trigger mode, output voltage is adjusted to about predetermined voltage level to prevent to damage inverter assembly (for example high voltage transformer) so.
Provide control voltage to first electric pressure converter 106 and second electric pressure converter 108.First electric pressure converter 106 produce to be determined the first control output of the drive signal duty ratio during the trigger mode in response to first scope of control voltage.Second electric pressure converter 108 produce to be determined the second control output of the driving signal frequency during the trigger mode in response to second scope of control voltage.For example, during trigger mode, optionally the first control output and the second control output are offered pwm circuit 110 is used to control the power of supplying with lamp 100 with generation pwm signal.In one embodiment, pwm circuit 110 be implemented in have voltage detector circuit 102, control voltage generator 104, first electric pressure converter 106 and second electric pressure converter 108 Common Controller integrated circuit 154 in.
In one embodiment, pwm signal is offered bridge driver 112 is used for control switch network 114 corresponding semiconductor switchs with generation a plurality of drive signals.The supply voltage (for example basic DC source voltage or VBAT) that switching network 114 will exchange polarity is coupling on the elementary winding of transformer 116 to produce basic communication voltage on the secondary winding of transformer 116.Lamp 100 is coupled to the secondary winding of transformer 116.
In the embodiment shown in fig. 1, switching network 114 is shown as including the full-bridge type switching network of four transistor M1, M2, M3, M5.Other switching network layout (for example semibridge system, push-pull type etc.) also is possible.In one embodiment, the secondary winding of transformer 116 stops that by resonant inductor 150 and direct current electric capacity 152 is coupled to lamp 100.Resonant inductor 150 can be leakage inductance rather than the stand-alone assembly with the secondary winding association.Resonant inductor 150 is parts of secondary resonance circuit, and this secondary resonance circuit also comprises resistance, capacitor and is coupled to secondary winding to set up other ghost effect (not shown) of resonance frequency.
In an application, control the initial condition that begin have zero volt of voltage (VC), and increase to preset value (for example, VDD or supply voltage) with set rate in trigger mode.Can produce control voltage by many methods of using different circuit layouts, and Fig. 1 illustrates a kind of generation control voltage method.For example, end during peak detector transistor (or nmos pass transistor M0) 118 beginnings, and capacitor (C0) 120 charges to produce control voltage with the RC variational rate on capacitor 120 by pull-up resistor (pull-up resistor) 122.
Control voltage is provided for the input terminal (or input port) of first and second electric pressure converters 106,108.In one embodiment, electric pressure converter 106,108 has limited and the input range of crossover not.For example, first electric pressure converter (or electric pressure converter #1) 106 has the first limited input range (for example 0-1 volt), and second electric pressure converter (or electric pressure converter #2) 108 has the second limited input range (for example 1-2 volt).When control voltage was in corresponding limited input range, the output of each electric pressure converter changed.
Fig. 2 is the schematic diagram of an embodiment of electric pressure converter.On first resistance (R1) 200, produce reference voltage.For example, for first electric pressure converter 106, reference voltage is about 0.5 volt.The value that can select this reference voltage and second resistance (R2) 202 is to determine the input range of (or restriction) electric pressure converter.To offer input port (V input) from the control voltage (VC) of Fig. 1.PMOS source follower (M6 and M7) 215,212 by separately moves reference voltage and control voltage level.In the differential voltage (VDIFF) between the input voltage at input port place (V input) and the reference voltage as can be seen on second resistance (R2) 202.To be increased to by the electric current of second resistance (R2) 202 conduction by in the electric current of transistor M2 204 conduction or therefrom deduct.The current reference that transistor M2 204 conduction obtain from the band-gap circuit that comprises transistor M4 214.Comprise 208 pairs of current references of current mirror circuit of transistor M9, M8, M5 and M0 and get mirror image, on output resistance (R0) 206, to produce output voltage (V output) by the summation of the electric current of second resistance (R2) 202 conduction.Current mirror gain and output resistance (R0) 206 can be used to measure and be offset input voltage on first resistance 200 and the differential voltage between the reference voltage.The detail of the output of electric pressure converter depends on and will be coupled to the circuit of output voltage.
In the embodiment shown in fig. 1, during trigger mode, optionally will offer first and second input terminals of pwm circuit 110 from the output of first electric pressure converter 106 and second electric pressure converter 108.In one embodiment, pwm circuit 110 comprises oscillator 124, PWM comparator 126 and optional feed forward circuit 128.Optional feed forward circuit 128---is coupling between first input end of first input end of pwm circuit 110 and PWM comparator 126 if present---.The voltage at the first input end of pwm circuit 110 place determines that the lead-out terminal---it also is the lead-out terminal of pwm circuit 110---of PWM comparator 126 locates the pulsewidth (or duty ratio) of pwm signal.Oscillator 124 is that second input terminal of PWM comparator 126 produces sawtooth waveform.The frequency of sawtooth waveform is determined by the voltage at the second input terminal place of pwm circuit 110.
In (or during operational mode) during the steady state operation, second input terminal that optionally reference voltage (VREF3) of basic fixed is offered pwm circuit 110 thinks that inverter sets up the operating frequency of basic steady.During operational mode, first input end of pwm circuit 110 optionally is coupled to the current feedback loop that comprises error amplifier 130.For example, current feedback loop senses is by the electric current of lamp 100 conduction, and the current feedback signal (ISNS) of generation indicator light levels of current.In one embodiment, current feedback signal be with the sensing resistor 132 of lamp 100 series coupled on the voltage that produces.Capacitor 134 is used for filtering with sensing resistor 132 parallel coupled alternatively.Current feedback signal is offered full-wave rectifier 136 think that first input end of error amplifier 130 produces basic direct current signal.The voltage (VREF2) of indicative of desired lamp current amplitude is offered second input terminal of error amplifier 130.In one embodiment, error amplifier 130 is trsanscondutance amplifiers, and capacitor (C1) 138 is coupled to the lead-out terminal of error amplifier 130 to be the first input end generation error voltage of pwm circuit 110 during operational mode.Error voltage is used for regulating the pulsewidth (or duty ratio) of pwm signal of output place of pwm circuit 110 to realize the lamp current amplitude of expectation during operational mode.
In one embodiment, first electric pressure converter 106 is configured to that 0-1 is lied prostrate input voltage and converts at the valley of the sawtooth waveform that is produced by oscillator 124 and the output voltage in the peak value.For example, sawtooth waveform can have 3 volts peak-peak voltage and 1 volt valley (or skew) voltage.The output voltage of first electric pressure converter 106 is offered first input end of PWM comparator 126 as reference voltage.When the sub reference voltage of locating of the first input end of PWM comparator 126 changed, the duty ratio of the signal at the lead-out terminal place of PWM comparator 126 changed (for example not having the scanning or the change of remarkable discontinuity).In the embodiment shown in fig. 1, between first input end of the output of first electric pressure converter 106 and PWM comparator 126, show optional feed forward circuit 128.As hereinafter further institute's descriptions, optional feed forward circuit 128 can make other adjusting to the duty ratio of the signal at the lead-out terminal place of PWM comparator 126 in response to mains voltage variations.
In one embodiment, second electric pressure converter 108 is configured to the 1-2 volt input voltage from control voltage (VC) converted to and is used for the output voltage that to several times (for example twice) in initial frequency the frequency of oscillator 124 scanned from initial frequency (for example, conventional lamp running frequency).Other frequency scanning scope also is possible.Because control voltage is from zero volt beginning oblique ascension (ramps), and the input range of first electric pressure converter 106 is less than the input range of second electric pressure converter 108, so the output voltage of first electric pressure converter 106 will change (or scanning) before the output voltage of second electric pressure converter 108.
In the above-described embodiments, select the input range of electric pressure converter 106,108, then be in the frequency and scan in predetermined (or maximum) duty ratio so that the output of PWM comparator 126 at first is in the duty ratio in initial frequency scans.Preferably, duty ratio and frequency scanning are uncorrelated and can not influence each other simultaneously.In one embodiment, predetermined duty cycle is subjected to the restriction of feed forward circuit that duty ratio and the cell voltage that applied are interrelated.For example, feed forward circuit is regulated the variation of duty ratio with the compensation cell voltage that applied.Submit and be entitled as the U.S. Provisional Patent Application of owning together the 60/849th of " Compensation for SupplyVoltage Variations in a PWM " on October 4th, 2006, No. 211 and on October 4th, 2006 submit and be entitled as the U.S. Provisional Patent Application the 60/849th of " PWM Duty Cycle Inverse AdjustmentCircuit " to, disclose the details of some feed forward circuits in No. 254, wherein these open integral body by reference are incorporated into this.
In other embodiments, select (or restriction) electric pressure converter 106,108 input range so that frequency scanning appear at before the duty ratio scanning.For example, as above described with reference to figure 2, can change the input voltage range of electric pressure converter 106,108, and input voltage range discussed above can put upside down between electric pressure converter 106,108, so that frequency scanning at first occurs.Utilizing relative low battery voltages (for example about 7 volts) to trigger in the situation of lamp 100, frequency scanning is more effective, and is utilizing high relatively cell voltage (for example about 20 volts) to trigger in the situation of lamp 100, and duty ratio scanning is more effective.In another embodiment, the input voltage range crossover of electric pressure converter 106,108 is to provide crossover between duty ratio scanning and frequency scanning.
Fig. 3 illustrates an emulation, wherein is illustrated in 10 volts of application under the cell voltage situation control voltage 300, secondary or modulating voltage 302 and switching signal 304 and time relation.For example, when control voltage 300 when approximately zero volt ramps to about 2 volts, the duty ratio of modulating voltage 302 and switching signal 304 at first scans, then when maximum duty cycle to their frequency scanning.The change that scans frequency scanning from duty ratio comes mark with wire note " A ".In standard application, when modulating voltage 302 was high enough to trigger lamp or surpass predetermined open lamp voltage corresponding to the VREF1 among Fig. 1, control voltage 300 stops oblique ascension and scanning stops.In the emulation shown in Fig. 3, how allow control voltage to continue oblique ascension influences modulating voltage 302 so that continuous sweep to be shown.For example, because the duty ratio of switching signal 304 increases, modulating voltage 302 beginnings increased in time up to the time by line A mark.Afterwards, because the frequency of switching signal 304 increases, modulating voltage 302 continues to increase in time up to frequency and surpasses resonance frequency with the secondary resonant tank association.When frequency increased to above resonance frequency, modulating voltage 302 began to reduce, because when frequency was left resonance frequency and moved, the voltage gain of secondary resonant tank reduced.
With reference to figure 1, an embodiment who is used for adjusting the voltage detector circuit 102 of open lamp voltage during trigger mode comprises full-wave rectifier 140, comparator 142, transistor M0 (for example NMOS) 118 and resistance R 0 144.The capacitor divider circuit that comprises capacitor C6 146 and capacitor C11 148 is used for monitoring transformer-secondary voltage, and produces the sensing voltage (for example first feedback signal or VSNS) of the input terminal that will offer full-wave rectifier 140.Comparator 142 compares the output and the benchmark VREF1 of full-wave rectifier 140.If the output of full-wave rectifier 140 (for example exporting crest voltage) surpasses benchmark VREF1 (such as during the open lamp situation), then comparator will make transistor M0118 conducting control voltage so that transformer-secondary voltage keeps (or being adjusted) at predetermined open lamp voltage level (or amplitude) to regulate.Therefore, transistor M0 118, capacitor C0 120, resistance R 0 144 and pull-up resistor 122 constitute peak detector circuit.In one embodiment, select the ratio of resistor R0 144 and pull-up resistor 122 so that capacitor C0 120 has discharge rate and slower charge rate faster.
Because the control voltage of adjusting starter is coupled in the output of voltage detector circuit 102, so formed closed feedback loop.Closed feedback loop is adjusted transformer-secondary voltage by regulating control voltage, approximates reference voltage V REF1 up to the output of full-wave rectifier 140.Fig. 4 illustrates (or the open lamp voltage of the transformer-secondary voltage as the function of time that is shown waveform 502, the voltage on the secondary winding of transformer 116 for example), with the control voltage that is shown waveform 504 as the function of time, and the example to the relation between one of drive signal that semiconductor switch applied in the switching network 114 as the function of time that is shown waveform 500.Fig. 5 more specifically illustrates the part of Fig. 4 of the excellence adjustment of confirming open lamp voltage.For example, when making an appointment T1, transformer-secondary voltage reaches predetermined level and controls voltage level and close (or stopping to increase) so that transformer-secondary voltage is remained on predetermined level approximately.
In one embodiment, two single-pole double throws (SPDT) switch is used for switching (or selection) between the trigger mode of Fig. 1 and operational mode.For example, the starter that can detect lamp 100 to switch to operational mode from trigger mode.In one embodiment, when current feedback signal (ISNS) surpasses threshold value is determined starter by monitoring.In the embodiment shown in fig. 1, the output of full-wave rectifier 136 can be compared to determine the starter of lamp 100 with threshold voltage VREF2 or independent voltage reference.When thinking that lamp 100 is lighted, the switching of SPDT switch also latches to the operational mode position.In the operational mode position, oscillator 124 is coupled to the reference voltage V REF3 that oscillator frequency is set to operational mode frequency (for example, initial or minimum trigger mode frequency).In case optionally the output of adjusting the error amplifier 130 of lamp current amplitude when lamp 100 is lighted is coupled in the input of feed forward circuit 128.
Though described some embodiment of the present invention, these embodiment only provide as example, rather than in order to limit the scope of the invention.In fact, novel method described herein and system can be embodied as multiple other form, and can make multiple omission, replacement and change in the form of method and system described herein and do not deviate from spirit of the present invention.Claims and equivalent thereof are intended to cover these forms or the modification as falling into the scope of the invention and spirit.
Claims (20)
1. inverter that is used to make the lamp starter comprises:
Be configured to during the trigger mode of described inverter to produce the control voltage generator of the control voltage signal that changes to second level from first level with first set rate,
Be configured to receive described control voltage signal and produce first electric pressure converter of the first control output in response to first scope of described control voltage signal values, the described inverter of the wherein said first control output control drives the duty ratio of signal; And
Second electric pressure converter that is configured to receive described control voltage signal and produces the second control output in response to second scope of described control voltage signal values, the driving signal frequency of the described inverter of the wherein said second control output control, and first scope of at least a portion of second scope of described control voltage signal values and described control voltage signal values crossover not, sequentially control duty ratio scanning and the frequency scanning that described inverter drives signal thereby have.
2. inverter as claimed in claim 1, it is characterized in that, also comprise the output voltage that is configured to monitor described inverter and produce indication when the output voltage of described inverter greater than the detector circuit of the output of predetermined threshold, when wherein the output voltage of indicating described inverter when the output of described detector circuit was greater than described predetermined threshold, described control voltage signal stopped to change with described first set rate.
3. inverter as claimed in claim 2, it is characterized in that, when described lamp did not have starter before the output voltage of described inverter arrives described predetermined threshold, described detector circuit was regulated described control voltage signal and is about predetermined threshold with the output voltage that keeps described inverter.
4. inverter as claimed in claim 2, it is characterized in that, described control voltage generator is included in the resistor and the capacitor of series coupled on the voltage source, on described capacitor, produce described control voltage signal, and when the output voltage of described inverter during greater than described predetermined threshold, described detector circuit makes described capacitor discharge with second set rate.
5. inverter as claimed in claim 1, it is characterized in that, described drive signal scans to relative high duty ratio from relative low duty ratio during first ignition stage, and during second ignition stage, scan to the relative high frequency rate from relative low frequency, described second ignition stage follows described first ignition stage closely.
6. inverter as claimed in claim 1, it is characterized in that, described drive signal scans to the relative high frequency rate from relative low frequency during first ignition stage, and during second ignition stage, scan to relative high duty ratio from relative low duty ratio, described second ignition stage follows described first ignition stage closely.
7. inverter as claimed in claim 1 is characterized in that, also comprises:
Pulse-width modulation circuit with first input and second input, described first input optionally is coupled in the wherein said first control output during the trigger mode of described inverter, and the output of described pulse-width modulation circuit is used for producing described drive signal; And
Be configured to produce the pierce circuit of second ramp signal of importing, described pierce circuit optionally is coupled in the wherein said second control output during the trigger mode of described inverter input.
8. inverter as claimed in claim 7, it is characterized in that, also comprise the feed forward circuit between first input that is coupling in described first control output and described pulse-width modulation circuit, wherein said feed forward circuit changes the voltage of first input of described pulse-width modulation circuit with the offset supply variation in voltage.
9. inverter as claimed in claim 7, it is characterized in that, the error amplifier that also comprises the supervisory lamp electric current, wherein with the output selectivity of described error amplifier be provided to first input of described pulse-width modulation circuit, and during the operational mode of described inverter, the voltage of basic fixed optionally is provided to the input of described pierce circuit.
10. inverter as claimed in claim 9 is characterized in that, is determined in the trigger mode of described inverter and the selection between the operational mode by described lamp current.
11. a method that is used to make the lamp starter comprises:
Produce control voltage, wherein said control voltage has the first value scope that is used for the controlling and driving signal dutyfactor and is used to control the second value scope of described driving signal frequency, and the power of described lamp is supplied with in wherein said drive signal control; And
Make described control voltage offer described lamp to duty ratio scanning and the frequency scanning that second level changes sequentially to control described drive signal with the output voltage that will increase from first level.
12. method as claimed in claim 11 is characterized in that, also comprises:
Indicate described lamp during starter or when the output voltage on the described lamp arrives predetermined threshold when current feedback signal, stop described duty ratio scanning or described frequency scanning; And
Utilize the voltage feedback signal of the output voltage on the described lamp of indication to regulate described control voltage, arrived after the described predetermined threshold, the output voltage on the described lamp is held in is about described predetermined threshold with the output voltage on described lamp.
13. method as claimed in claim 11 is characterized in that, the first value scope of described control voltage and the second value scope be crossover not.
14. method as claimed in claim 11 is characterized in that, occurs described duty ratio scanning before the frequency scanning of described drive signal.
15. method as claimed in claim 11 is characterized in that, described frequency scanning occurs before the duty ratio scanning of described drive signal.
16. method as claimed in claim 11, it is characterized in that, the duty ratio of described drive signal changes to high level relatively from low-level relatively during initial ignition stage, and the frequency of described drive signal changes to the relative high frequency rate from relative low frequency during ignition stage subsequently.
17. an inverter circuit comprises:
Be used to produce from the device of first level to the control signal of second level variation;
Be used to use described control signal sequentially to carry out the duty ratio scanning of drive signal and frequency scanning offers load with the output voltage that will increase device; And
When being used for feedback signal when described output voltage or when described load conduction is higher than the electric current of second threshold value, stop the device of described duty ratio scanning or described frequency scanning greater than first threshold.
18. inverter circuit as claimed in claim 17, it is characterized in that, also comprise being used for regulating described control signal to adjust device in response to described output voltage feedback signal during greater than described first threshold the output voltage of described load when described output voltage feedback signal.
19. inverter circuit as claimed in claim 17 is characterized in that, described duty ratio scanning is before described frequency scanning.
20. inverter circuit as claimed in claim 17 is characterized in that, described frequency scanning is before described duty ratio scanning.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US80671406P | 2006-07-06 | 2006-07-06 | |
| US60/806,714 | 2006-07-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101502184A true CN101502184A (en) | 2009-08-05 |
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ID=38895470
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2007800294041A Pending CN101502184A (en) | 2006-07-06 | 2007-07-05 | Striking and open lamp regulation for CCFL controller |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN101502184A (en) |
| TW (1) | TW200810605A (en) |
| WO (1) | WO2008006024A2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102065600A (en) * | 2010-03-16 | 2011-05-18 | 成都芯源系统有限公司 | LED dimming driving system |
| CN104220950A (en) * | 2012-03-29 | 2014-12-17 | 德克萨斯仪器股份有限公司 | Power supply control method for constant current constant power control |
| CN116073642A (en) * | 2023-01-28 | 2023-05-05 | 艾科微电子(深圳)有限公司 | Control circuit and method of power conversion circuit and power conversion system |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101051146B1 (en) | 2008-03-04 | 2011-07-21 | 페어차일드코리아반도체 주식회사 | Inverter driving device and lamp driving device including the same |
| US8049438B2 (en) * | 2008-08-18 | 2011-11-01 | O2Micro, Inc. | Driving circuits and controllers for controlling power to a load |
| CN104344928B (en) * | 2013-07-26 | 2017-02-22 | 北京航天计量测试技术研究所 | Amplifying circuit for raising balance micro torque calibration instrument measurement linearity |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69919138T2 (en) * | 1998-02-13 | 2005-08-18 | Lutron Electronics Co., Inc. | ELECTRONIC DIMMER |
| US6040661A (en) * | 1998-02-27 | 2000-03-21 | Lumion Corporation | Programmable universal lighting system |
| US6137240A (en) * | 1998-12-31 | 2000-10-24 | Lumion Corporation | Universal ballast control circuit |
| DE60120751D1 (en) * | 2000-11-02 | 2006-07-27 | Koninkl Philips Electronics Nv | DIGITAL BALLAST |
-
2007
- 2007-07-05 TW TW096124472A patent/TW200810605A/en unknown
- 2007-07-05 CN CNA2007800294041A patent/CN101502184A/en active Pending
- 2007-07-05 WO PCT/US2007/072862 patent/WO2008006024A2/en active Application Filing
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102065600A (en) * | 2010-03-16 | 2011-05-18 | 成都芯源系统有限公司 | LED dimming driving system |
| CN104220950A (en) * | 2012-03-29 | 2014-12-17 | 德克萨斯仪器股份有限公司 | Power supply control method for constant current constant power control |
| CN104220950B (en) * | 2012-03-29 | 2017-09-12 | 德克萨斯仪器股份有限公司 | Power control method for Constant Current Constant Power Control |
| CN116073642A (en) * | 2023-01-28 | 2023-05-05 | 艾科微电子(深圳)有限公司 | Control circuit and method of power conversion circuit and power conversion system |
Also Published As
| Publication number | Publication date |
|---|---|
| TW200810605A (en) | 2008-02-16 |
| WO2008006024A2 (en) | 2008-01-10 |
| WO2008006024A3 (en) | 2008-05-29 |
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Application publication date: 20090805 |