EP1565042A2 - Electronic ballast for fluorescent lamp using silicon-controlled phase-luminosity modulator for adjusting luminosity - Google Patents

Abstract

The present invention relates to an electr onic ballast of a fluorescent lampusing a silicon-controlled phase-luminosity modulator for adjusting luminosity.The ballast comprises: (a) a filter and rectification circuit having an output portand connected to a municipal alternating current power supply; (b) a frequency-controland switch circuit having an output port; including an integrated circuit (IC)for controlling frequency and producing switch -triggering signals; (c) an outputcircuit, having an input port connected to the output port of the frequency -controland switch circuit; (d) light -modulating signal processing circuit, connected to theoutput port of filter and rectification circuit and the input port of frequency controland switch circuit; (e) direct -current high voltage stabilization circuit, with an inputport connected to the output port of filter and rectification circuit, an output portconnected to the input port of frequency control and switch circuit, and feedbackport connected with the output circuit. This electronic ballast requires only threesimple circuits and few components. Thus, it can be manufactured at a lowercost with a smaller dimension. With its stable capacity of light modulating, theballast of the present invention can be applied easily and widely, especially in theintegrated and compact fluorescent lamps.

Description

FIELD OF THE INVENTION

This present invention relates to a light modulating device for fluorescentlamps, and in particular to an electronic ballast for fluorescent lamp using asilicon-controlled phase-luminosity modulator for adjusting and maintaining stableluminosity.

BACKGROUND OF THE INVENTION

It is always desirable that the light of fluorescent lamps could bemodulated as an incandescent lamp applying a commonly used silicon-controlledlight modulator, as shown in FIG. 1. However, it is not easy for a fluorescent lampto apply a general silicon-controlled phase-luminosity modulator since it is a non-linearload with a dynatron chara cteristic. With the improvement of electronicballast technology, studies on applications of silicon-controlled phase-luminositymodulator on adjusting luminosity for fluorescent lamps have been reported onboth patent literatures and technical magazines, and related products have beendeveloped. Nevertheless, in order for the light modulating capacity to reach thestable, uniform and non-flickering levels, the ballasts usually have complicatedcircuits with numerous components, resulting in high manufactur ing costs andbulky size. Thus it is hard to apply this technology widely. On the other hand, if the circuits are simplified, flickering will result and light will become non-uniformduring modulation. It is therefore desirable to find better light modul ating controlcircuit to improve light modulation technology for fluorescent lamps.

A fluorescent lamp applying a silicon-controlled phase-luminositymodulator for adjusting luminosity was disclosed in Chinese Patent No.CN01269679.X. Although the phase-modulating light modulation wasaccomplished in this light-modulated fluorescent lamp, it is advantageous toenhance the effect and capacity of light modulating.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a novel electronic ballastfor a fluorescent lamp using a silicon-controlled phase-luminosity modulator toadjust luminosity in order to overcome the shortcomings of prior ballasts withcomplicated circuits, numerous components, high manufacturing cost, bulkydimensions, difficulties in being applied widely, and frequent flickering and nonuniformlight modulation.

In order to achieve the above objective, the present invention provides anelectronic ballast for a fluorescent lamp applying silicon-controlled light modulatorfor adjusting luminosity. The ballast according to the present invention iscomprised of:

(1) (a) a filter and rectification circuit, connecting with a municipal alternatingcurrent power supply; (b) a frequency control and switch circuit, including anintegrated circuit (IC) which controls frequency and produces switch-triggeringsignals, two switch transistors Q1, Q2 and the corresponding resistors and capacitors; (c) an output circuit, including inductances and capacitors, with itsinput port connect ing with the output port of above frequency control andswitch circuit; (d) a light-modulating signal processing circuit connecting withthe output port of filter and rectification circuit and the input port of frequencycontrol and switch circuit; (e) a d irect-current, high-voltage stabilization circuit,with its input port connecting with the output port of filter and rectificationcircuit, output connecting with the input port of frequency control and switchcircuit, and feedback port connecting with out put circuit;

(2) a frequency-control negative-feedback circuit, with its output port connectedto IC-6 of the above frequency control and switch circuit, and an input portconnected to the output circuit;

(3) a light modulating signal processing circuit having a voltage divider and avoltage control oscillator wherein the voltage divider is set up by connectingresistor R1, NPN transistor Q3 and resistor R4 in series, and the voltagecontrol oscillator is composed of connected voltage stabilization tube Z2, Z3,diode D8, resistors R6, R7, R8, capacitor C9 and connecting to port IC-7 ofthe integrated circuit (IC);

(4) a direct-current high-voltage stabilization circuit described previouslycomposed of diodes D6 and D7 connected in series and capacitor C19,wherein one point of C19 connects the point between D6 and D7, and theother point connects the output circuit;

(5) a frequency-control negative-feedback circuit comprised of a parallel circuit oftwo RC in series, R15, diode D11 and Zener diode Z5, wherein the parallelcircuit of two RC in series includes R16/C18 and R17/C17, respectively, and the lamp current negative feedback circuit includes diode D11, Zener diodeZ5, resistor R17 and capacitor C17; and

(6) an integrated circuit (IC) such as type L6574.

Since the electronic ballast of the present invention requires only threesimple circuits and few components, it can be manufactured at a lower cost witha smaller dimension. With its stable capacity of light modulating, it can be appliedeasily and widely, especially on the integrated and, compact fluorescent lamps.

Further objects and advantages of this invention will be apparent from thefollowing detailed description of a presently preferred embodiment which isillustrated schematically in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a circuit connection for light modulatingof a fluorescent lamp applying a silicon-controlled phase-luminosity modulator.

FIG. 2 is a circuit flowchart of an electronic ballast for a fluorescent lampusing a silicon-controlled phase-luminosity modulator for adjusting luminosity inaccordance with the present invention.

FIG. 3 is a circuit diagram of an electronic ballast for a fluorescent lampusing a silicon-controlled phase-luminosity modulator for adjusting luminosity inaccordance with the present invention.

FIG. 4 shows the curve relationship of light-modulating phase angle andlight-modulating voltage on frequency control (Line 1) and light-modulating phaseangle and direct-current high voltage (Line 2) using a triode as a non-linearresistor in the light-modulating signal processing circuit.

FIG. 5 shows the curve relationship of light-modulating phase angle andlight-modulating voltage on frequency control (L ine 1) and light-modulating phaseangle and direct-current high voltage (Line 2) using a general linear resistor in thelight-modulating signal processing circuit.

FIG. 6 is a filter and rectification circuit diagram of another embodiment ofan electronic ballast for a fluorescent lamp using a silicon-controlled phase-modulatingphase-luminosity modulator for adjusting luminosity in accordancewith the present invention.

FIG. 7 is a light-modulating signal processing circuit diagram of anotherembodiment of an electronic ballast for a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity in accordance withthe present invention.

FIG. 8 is a light-modulating signal processing circuit diagram of a furtherembodiment of an electronic ballast for a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity in accordance withthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EM BODIMENT

Referring to FIG. 2 and FIG. 3, the, electrical ballast of the presentinvention includes a filter andrectification circuit 1, a frequency control andswitchcircuit 2, anoutput circuit 3, a light-modulatingsignal processing circuit 4 and adirect-current high-voltage stabilization circuit 5.

The filter andrectification circuit 1 comprises filter components, π-shapefilter and bridge rectifier. Through the light modulator its input port connects to amunicipal alternating current power supply, thereby the high-frequency disturbingwave is filtered out and the input alternating current voltage is transformed asdirect current pulse voltage. The filter and rectification circuit shown in FIG. 6 canadditionally comprise resistor R18 parallel connected directly to input port, andresistor R19 parallel connected to input port after connecting a capacitor in series.The effect of light modulating will be enhanced based on selecting suitableresistors and capacitors properly, thus allowing more silicon-controlled phase-modulatingphase-luminosity modulators to be applicable to more fluorescentlamps capable of light modulating.

Frequency control andswitch circuit 2 includes an integrated circuit IC,such as type L6574, which controls frequency and produces a switch-triggeringsignal. Its input port VS connects with the output port of filter andrectificationcircuit 1 through resistor R3 and provides a working voltage for the IC. Switchtransistors Q1, Q2 are composed of two field effect transistors, and theircorresponding resistor and capaci tor components are applicable to producecontrollable high-frequency, high voltage with the input port connected with theoutput port of direct-current highvoltage stabilization circuit 5 described below.

Theoutput circuit 3 comprises inductances and ca pacitors. Theconnection of its input port and the output port OUT of frequency-control andswitch circuit 2 produces resonance and heats up the fluorescent lamp filamentto enable normal working of the fluorescent lamp.

The light-modulating signalproces sing circuit 4 is novel in this invention. Itconnects to the output port of filter andrectification circuit 1 and another inputport IC-7 of frequency control andswitch circuit 2. Consequently, the lower lightmodulating frequency control voltage on IC, the higher working efficiency on IC.The light modulatingsignal processing circuit 4 is composed of a voltage divider,configured in series of resistor R1, NPN transistor Q3 and resistor R4, and avoltage control oscillator, composed of voltage stabilization tube Z2, Z3, diode D8,resistors R6, R7, R8, and capacitor C9, and connecting to port IC-7 of theintegrated circuit (IC). With this voltage divider, it is possible to provide therequired relationship for sharp, nonlinear changed light modulating pha se angleand light modulating frequency-control voltage. The sampling point B of lightmodulatingsignal processing circuit 4 connects with the output port of filter andrectification circuit 1 and presents as direct-current pulse voltage. It is evidentthat the virtual value of this voltage is inversely proportional to the light-modulatingphase angle of the silicon-controlled phase-luminosity modulator, i.e.the larger is the phase angle, the lower the voltage virtual value. With circuitprocessing, the larger the phase angle, the lower the output voltage by frequencycontrol and the lower light modulating voltage by frequency control entering theintegrated circuit IC and consequently resulted in, higher IC working frequency. Itis shown that light modula tion is achievable based on the corresponding changesin the working frequency of the fluorescent lamps with the changes on the phaseangle. In order to have the ideal state existing in the relationship curve of phaseangle and light modulating voltage by frequency control, a NPN transistor is usedin the voltage divider in the circuit. For example, if the base of NPN transistor Q3 is connected with current bias resistor R2, it will provide a resistor changing non-linearlywith the voltage at point B, resul ting in non-flickering, uniform and stablelight modulating with the sharp changing required on the resistor.

Besides NPN transistor, N-channel field effect transistor (N-channelMOSFET) can be used as Q3 in the light-modulatingsignal processing circuit 4as shown in FIG. 7. Using voltage divider configured in series connecting resistorR1, field effect transistor Q3 and resistor R4, it is feasible to have the desired,sharply non-linearly changed relationship of light modulating phase angle andlight modulating frequency-control voltage to enable the light modulation to reachan ideal state. In another application sample shown in FIG. 8, light modulatingsignal processing circuit 4 is composed of a voltage divider, configured in seriesconnecting resistor R22, N-channel MOSFET Q3 and resistor R24, a voltagecontrol oscillator, composed of voltage stabilization tube Z2, Z3, diode D7,resistors R25, R26, R27, and capacitor C10, and further connects withconnection port IC-7 and IC-15 of integrated circuit IC (such as type UBA2014).Light-modulatingsignal processing circuit 4 can stabilize the working state duringthe light modulation of the fluorescent lamp without flickering and improve theeffects of light modulation.

In order to provide stable direct-current high voltage, the input port ofdirect-current high-voltage stabilization circuit 5 is connected with the output portof the filter andrectification circuit 1, and the output port of the latter in turnconnects with frequency-control and switch circu it 2. The feedback port isconnected withoutput circuit 3 and then feeds high-frequency electrical energy ofoutput circuit 3 back to the storage capacitor in the direct-current high-voltage stabilization circuit 5. The direct-current high-voltage stabilization circuit 5 iscomposed of diodes D6 and D7 connected in series, and capacitor C19 with oneof its points connecting the point between diodes D6 and D7. It obtains high-frequencyenergy from one point of C14 with connection to output circuit, and thehigh-frequency energy through C19 enters storage capacitor C4 after rectificationof D6, thus eliminating lamp flickering.

In another preferred application example, the electronic ballast of thepresent invention additionally includes a frequency-controlnegative feedbackcircuit 6. With its output port connected to IC-6 of frequency-control andswitchcircuit 2 and its input port connected to output circuit, the decreasing signals oflamp current is being negatively fed back to integrated circuit IC by frequencycontrol when the current of fluorescent lamp decreases very sharply withmodulation. The frequency-controlnegative feedback circuit 6 comprises aparallel circuit of two RC connected in series (i.e. R16/C18 and R17/C17), R15,diode D11 and Zener diode Z5. The circuit composed of R15, R16, R17, C17 andC18 provides a voltage on IC-6 to reach the threshold voltage required byintegrated circuit IC. Lamp current negative feedback circuit is composed ofdiode D11, Zener diode Z5, R17, and C17. With res istor R15,circuit 6 connectsto IC-VS and IC-10 of integrated circuit. It is common knowledge that flickeringhappens when lamp current decreases very sharply by modulating. Accordingly,the decreased signal of lamp current is fed back negatively to frequencycontrolled IC, so that flickering can be avoided.

The invention relates to an electronic ballast for a fluorescent lamp using asilicon-controlled phase-modulating phase-luminosity modulator. It can be combined with a fluorescent tube as an integrat ed fluorescent lamp, or work asan independent electronic ballast and operates as such after it is connected to afluorescent lamp. Whether the ballast is integrated or separated, it should beconnected to a silicon-controlled phase-modulating phase-luminosity modulatorin order to accomplish light modulation, as shown in FIG. 1.

The present invention provides for frequency-modulating light modulation.In order to provide ballast function for a working lamp tube, it is necessary to seta ballast inductor in the working circuit of a fluorescent lamp to avoid burning thelamp by a strong current. Inductor inductance increases with increased workingfrequency, hence the current through the lamp tube decreases, and the luminousflux of lamp decreases correspon dingly, thus modulating the brightness of thelamp.

As a special technology of light modulating for a fluorescent lamp using asilicon-controlled phase-luminosity modulator, the biggest difficulty is thatfluorescent lamps flicker when light modulation drops in the middle and latestages, particularly when the fluorescent lamp is nearly extinguished. Based onpractices and comprehensive analysis, it was found that the flickering arises from:(1) when using frequency-modulating light modulation mode, it is difficult for thelamp to maintain stable discharge in the late stage of light modulation sincedirect-current high voltage decreases to a very low level; (2) since fluorescentlamp is a special non-linear load, its voltage wave shape input to the electronicballast presents serious distortion, even jumping distortion in the middle and latestage of light modulation when a fluorescent lamp is combined with a silicon-controlled phase-luminosity modulator to accomplish luminosity adjustment. Consequently, flickering occurs due to unstable power supply to the lamp tube.Based on the above analysis and practice, three technical measures are used assolutions. The first solution is to alter the change relationship between light-modulatingphase angle and light-modulating frequency-control voltage fromsmooth change to sharp change, i.e. light-modulating frequency-control voltagedecreases more quickly when phase angle increases. This means workingfrequency increases more rapidly to cause current decreases more in the lamp,thus mitigating power supply load, while direct-current high-voltage decreasesonly slightly. Consequently, it maintains relatively high direct-current voltage.The second solution is that high-frequency energy feedback stabilizationprovided on direct-current high voltage of electrical ballast causes direct-currenthigh voltage of light modulation to increase with certain degree of compensation.The third solution is that the lamp flickering can be prevented by the frequencynegative feedback circuit set for avoiding twinkling caused by resonance fromsharp decrease of lamp current when the light is being modulated too fast.

In order to realize above three solutions and to obtain good lightmodulation without lamp flickering, three special circuits have been used in thepresent invention. The first special circuit is light modulatingsignal processingcircuit 4 used to obtain ideal relationship curve of light-modulating phase angleand light-modulating frequency-control voltage. As we known, since the waveshape of input voltage transferred to fluorescent lamp through controllable phase-modulatinglight modulator takes on a tangent phase angle shape, this meansthat the larger the tangent phase angle, the lower the virtual voltage transferredto fluorescent lamp whether the light-modulating phase angle increases. Therefore, light-modulating phase angle is inversely proportional to input virtualvoltage. After high-frequency is filtered and rectified (see 1 in FIG 3), inputvoltage at point B takes on the same shape as input voltage waveform but onlypositive, and twice as high as input voltage. As B is a sampling point for a lightmodulating signal, virtual voltage of B is inversely proportional to light-modulatingphase angle. With R1, Q3, and R4, the electrical signal becomes a voltagedivider. A NPN transistor Q3 connecting current bias resistor R2 forms a resistorwith non-linear change with voltage at point B. Thus, a sharply change in thisresistor is needed. Divided voltage on resistor R4, changed as direct-currentvoltage through filtration by capacitor C6, then entering the voltage-controloscillator composed of Z2, R6, D8, R7, Z3, R8, C9 and IC, creates correspondingfrequency with light-modulating frequency-control voltage to accomplishfrequency modulation. It is known that frequency-control voltage is proportional tothe virtual voltage value at point B, i.e. frequency-control voltage is inverselyproportional to phase-modulating angle. This means that the larger the phaseangle; the lower the frequency-control voltage thus resulting in higher IC workingefficiency, hence frequency-altering light modulation for fluorescent lamp isaccomplished.

The characteristic of frequency modulation for a 15W fluorescent lampinstalled in the electrical ballast circuit as shown in FIG. 3 is measured in thisstudy. FIG. 4 shows the curve relationship of light-modulating phase angle andlight-modulating voltage on frequency control (Line 1) and light-modulating phaseangle and direct-current high voltage (Line 2) using a NPN transistor as a non-linearresistor in light-modulating signal processing circuit. In order to investigate the function of NPN transistor Q3 as a non-linearly changed resistor in light-modulatingsignal processing circuit 4, a NPN transistor Q is replaced by ageneral linear resistor (23 ° phase angle). The results are shown in FIG. 5. In FIG.4, frequency-control voltage is 0.2V (point M in FIG. 3), whereas direct-currenthigh voltage is as high as 190V when phase angle is 130 ° when the lamp isnearly extinguished. However, in FIG. 5, which shows the curve relationshipbetween light-modulating phase angle and light-modulating voltage by frequencycontrol and direct-current high voltage respectively, using a general linear resistorin light-modulating signal processing circuit, frequency-control voltage is still ashigh as 0.9V, whereas direct-current high voltage decreases to 110V and thelamp flickers with phase angle of 120 °, when it is nearly extinguished. Flickeringat that insta nt results from not being capable of keeping the lamp's burning pointwith the sharp decrease on direct-current high voltage. In addition, low workingfrequency, resulted from high light-modulating frequency-control voltage, goesagainst maintaining discharge thus resulting in the lamp flickering. It is evidentfrom the above analysis that it is useful to prevent lamp flickering by applyingNPN transistor Q3 as non-linear resistor in the circuit. In order to obtain moreproper curve of light-modulating frequency-control voltage, it is necessary toadjust R2, R1, and R4 in FIG. 3.

The second special circuit is a direct-current high-voltage stabilizationcircuit composed of C19, D6 and D7. The high-frequency feedback energy out ofone point of capacitor C14 (see figure 3) supplies energy to electrolysis capacitorC4 through rectification of D6. Reduction of fluorescent lamp flickering is achieved by properly adjusting energy feedback amount (i.e. adjusting thecapacitance of C19 capacitor) to prevent the divi ded voltage of electrolysiscapacitor to decrease too fast due to light modulation. This stabilizes direct-currenthigh voltage.

The third special circuit is a controlnegative feedback circuit 6. It isfeasible to apply negative feedback to prevent fluor escent lamp flickering due tosudden quick frequency changes when light modulation is too fast. In this circuit,sampling of feedback signal is derived from the sharp changes of current throughthe lamp tube. The current changes are being transformed to voltage changes,and then transferred to IC, resulting in negative feedback on frequency change.As shown in figure 3, lamp current runs through D11, C17, R17 and Z5, and adirect-current voltage value corresponding to current value is formed on R17. Arequired threshold voltage suitable for IC comprises R15, R16, R17 and C17,C18. It is therefore possible to accomplish frequency-control negative feedbackwith superposition of above two voltages to IC.

While the invention has been described, disclosed, illustrated and shownin various terms of certain embodiments or modifications which it has presumedin practice, the scope of the invention is not intended to be, nor should it bedeemed to be, limited thereby and such other modifications or embodiments asmay be suggested by the teachings herein are particularly reserved especially asthey fall within the breadth and scope of the claims here appended.

Claims (13)

1. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity comprising in combination:

   (i) a filter and rectification circuit, connectable with an alternatingcurrent power and having an output port;

   (ii) a frequency control and switch circuit, including an integratedcircuit (IC) which controls frequency and produces switch-triggeringsignals, two switch transistors Q1, Q2 and thecorresponding resistors and capacitors and having an output portand an input port;

   (iii) an output circuit, including inductances and capacitors, with itsinput port connecting with the output port of said frequency controland switch circuit;

   (iv) a light-modulating signal processing circuit connecting with theoutput port of said filter and rectification circuit and the input port ofsaid frequency control and switch circuit; and

   (v) a direct-current, high voltage stabilization circuit with its input portconnecting with the output port of said filter and rectification circuit,an output connecting with the input port of frequency control and aswitch circuit, and feedback port connecting with said output circuit.
2. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 1, including a frequency-control negative-feedback circuit with its output port connecting withthe IC of the frequency control and switch circuit, and input port connecting withthe output circuit.
3. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 1, wherein the lightmodulating signal processing circuit includes a voltage divider and a voltagecontrol oscillator, wherein said voltage divider is set up by connecting resistor R1,NPN transistor Q3 and resistor R4 in series and wherein said voltage controloscillator is composed of connected voltage stabilization tube Z2, Z3, diode D8,resistors R6, R7, R8, capacitor C9 and a connecting point with the integratedcircuit (IC).
4. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 3, wherein said NPNtransistor Q3 is used as a N-channel field effect transistor (N-channel MOS FET).
5. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 1, wherein saiddirect-current high-voltage stabilization circuit comprises diodes D6 and D7connected in series and capacitor C19 with one point of C19 connected to a pointbetween D6 and D7, and another point of C19 connected to the output circuit.
6. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 1, wherein thefrequency-control negative-feedback circuit comprises a parallel circuit of two RCin series, R15, diode D11 and Zener diode Z5, whereby said parallel circuit ofsaid two RC in series includes R16/C18 and R17/C17, and said lamp currentnegative feedback circuit includes diode D11, Zener diode Z5, resistor R17 andcapacitor C17.
7. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 1, wherein the typeof integrated circuit IC is L6574.
8. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 1, wherein the typeof integrated circuit IC is UBA2014.
9. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 1, wherein the filterand rectification circuit comprises filter components, π-shape filter and bridgerectifier, whereby said input port is connected to a municipal alternating currentpower supply with light modulator.
10. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 9, wherein the filterand rectification circuit further comprises resistor R18 connected in paralleldirectly with input port, and resistor R19 connected in parallel with input port aft erconnecting capacitor in series.
11. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 2, wherein the lightmodulating signal processing circuit includes a voltage divider and a voltagecontrol oscillator, wherein said voltage divider is set up by connecting resistor R1,NPN transistor Q3 and resistor R4 in series and wherein said voltage controloscillator is composed of connected voltage stabilization tube Z2, Z3, diode D8,resistors R6, R7, R8, capacitor C9 and a connecting point with the integratedcircuit (IC).
12. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 2, wherein saiddirect-current high-voltage stabilization circuit comprises diodes D6 and D7connected in series and capacitor C19 with one point of C19 connected to a pointbetween D6 and D7, and another point of C19 connected to the output circuit.
13. An electronic ballast of a fluorescent lamp using a silicon-controlledphase-luminosity modulator for adjusting luminosity of claim 2, wherein thefrequency-control negative-feedback circuit comprises a parallel circuit of two RC in series, R15, diode D11 and Zener diode Z5, whereby said parallel circuit ofsaid two RC in series includes R16/C18 and R17/C17, and said lamp currentnegative feedback circuit includes diode D11, Zener diode Z5, resistor R17 andcapacitor C17.

Images