CN103796401A - Electronic ballast and lamp - Google Patents
Electronic ballast and lamp Download PDFInfo
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- CN103796401A CN103796401A CN201210419621.4A CN201210419621A CN103796401A CN 103796401 A CN103796401 A CN 103796401A CN 201210419621 A CN201210419621 A CN 201210419621A CN 103796401 A CN103796401 A CN 103796401A
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Abstract
The invention relates to the field of lighting lamps, and provides an electronic ballast and a lamp. The electronic ballast and the lamp are simple and reliable. An inverter circuit, which is formed by an electric inductor, a capacitor and a diode, and an auxiliary circuit are arranged so that correction of waveform of input current is realized, a power switch circuit is enabled to work in a zero-voltage switch state, and thus power factor and working efficiency are higher. The number of the applied elements is less, and circuit structure is simple. Compared with existing lamps of the electronic ballasts, 20% input power can be saved under the situation of outputting the same luminous flux only by using two switch driving circuits.
Description
Technical field
The invention belongs to electric ballast application, relate in particular to a kind of electric ballast and light fixture.
Background technology
The advantages such as gaseous discharge lamp is to belong to energy-saving electrical light source, has been widely used in traffic, municipal administration, industrial light, and it has, and efficiency is high, the life-span is long.But the traditional inductance type ballast of the most of employing of gaseous discharge lamp a few days ago.There are many defects in inductance type ballast, as large in volume, heavy, consume a large amount of metal materials, and power factor is low, and utilization rate of electrical is low; And exist starting current to impact large etc. defect.At present corresponding with inductance type ballast is electric ballast, is also the one of ballast, refers to and adopts electronic technology to drive electric light source, makes it to produce the electronic equipment of required illumination.How making Gas lamp is the light high-performance that has again, the crucial selection that is electric ballast, the device that existing electric ballast adopts is a lot, increase implementation cost, test performance is not high, volume is large and heavy, has very large restriction for the application of the simple light illuminations of special dimension demand.
Summary of the invention
The object of the present invention is to provide one, solved existing circuit of electronic ballast complex structure, inefficiency, and the low problem of power factor.
The problem existing for above-mentioned prior art, a first aspect of the present invention provides a kind of electric ballast, comprise the civil power ac input end, front-end circuit, start-up circuit, inverter circuit and the fluorescent tube loop that connect successively, described front-end circuit is for extremely described start-up circuit of stable output direct current, described start-up circuit is used for exporting the startup signal of telecommunication to described inverter circuit, so that described inverter circuit work output alternation square-wave voltage is to described fluorescent tube loop, the electric current in described fluorescent tube loop is changed according to the frequency of described alternation square-wave voltage; Described inverter circuit comprises freewheeling circuit, the first switch driving circuit, second switch drive circuit and the transformer being made up of three windings;
Wherein, two outputs of described start-up circuit are connected to respectively the first end of described freewheeling circuit and the first end of second switch drive circuit, the afterflow cut-off end of described start-up circuit is connected to the second end of described freewheeling circuit, the startup control end of described start-up circuit is connected to the switch control end of described second switch drive circuit, to start described second switch drive circuit; Described freewheeling circuit is for providing continuous electric current, make described fluorescent tube loop have continuous current to flow through, described the first switch driving circuit is connected to the first end of freewheeling circuit and the second end of described freewheeling circuit, and second switch drive circuit is connected to the second end of described freewheeling circuit; Transformer is for generation of induced electromotive force, impel described the first switch driving circuit and described second switch drive circuit alternate conduction, wherein, the first winding of described transformer is connected between the driving control end of described the first switch driving circuit and the second end of described freewheeling circuit; The second winding of described transformer is connected between the driving control end of described second switch drive circuit and the first end of described second switch drive circuit; The tertiary winding of described transformer is connected between second end and described fluorescent tube loop of described freewheeling circuit, wherein, Same Name of Ends is one end of the first winding one end, one end that is connected to described fluorescent tube loop of the tertiary winding and driving control end that is connected to described second switch drive circuit of the second winding of being connected to the second end of described freewheeling circuit.
In conjunction with first aspect present invention, in the possible implementation of the first, described the first switch driving circuit comprises:
The first switch element, the first end of described the first switch element is connected to the first end of described freewheeling circuit;
Be connected to the first resistance between the second end of described the first switch element and the driving control end of described the first switch driving circuit, isolate for current limliting with by the induced electromotive force of the first winding of the second end of described the first switch element and described transformer;
Be connected to the second resistance between the 3rd end and second end of described freewheeling circuit of described the first switch element, for stable output voltage.
In conjunction with the possible implementation of the first of a first aspect of the present invention, in the possible implementation of the second, described second switch drive circuit comprises:
Second switch element, the first end of described second switch element is connected to the second end of described freewheeling circuit;
Be connected to the 3rd resistance between the second end of described second switch element and the driving control end of described second switch drive circuit, isolate for current limliting with by the induced electromotive force of the second winding of the second end of described second switch element and described transformer;
Be connected to the 4th resistance between the 3rd end and the first end of described second switch drive circuit of described second switch element, for stable output voltage.
In conjunction with the possible implementation of the first of a first aspect of the present invention or the possible implementation of the second, in the third possible implementation, described the first switch element is transistor, the first end of very described the first switch element of the current collection of described the first transistor, the base stage of described the first transistor is the second end of described the first switch element, the 3rd end of very described the first switch element of the transmitting of described the first transistor.
In conjunction with the third possible implementation of a first aspect of the present invention, in the 4th kind of possible implementation, described second switch element is transistor seconds, the first end of the very described second switch element of the current collection of described transistor seconds, the base stage of described transistor seconds is the second end of described second switch element, the 3rd end of the very described second switch element of the transmitting of described transistor seconds.
In conjunction with the 4th kind of possible implementation of a first aspect of the present invention, in the 5th kind of possible implementation, described freewheeling circuit comprises:
Be connected to the first electric capacity between the first end of described freewheeling circuit and the second end of described freewheeling circuit, and be connected to the 5th resistance between the first end of described freewheeling circuit and the second end of described freewheeling circuit, wherein said the first electric capacity and described the 5th resistance composition charge-discharge circuit, for being tending towards cut-off state at described second switch drive circuit from conducting state, and described the first switch driving circuit is in the time of cut-off state, continuous electric current is provided, makes described fluorescent tube loop have continuous current to flow through.
In conjunction with a first aspect of the present invention the 5th in possible implementation, in the 6th kind of possible implementation, described start-up circuit comprises:
The 6th resistance, for current limliting, one end of described the 6th resistance is connected to the first end of described freewheeling circuit;
Be connected to the second electric capacity between the other end of described the 6th resistance and the first end of described second switch drive circuit;
Be connected to the bidirectional trigger diode between described the 6th resistance and the serially connected nodes of described the second electric capacity and the base stage of described transistor seconds; And,
Be connected to the first diode between the serially connected nodes of described the 6th resistance and described the second electric capacity and the second end of described freewheeling circuit;
Wherein, described the 6th resistance and described the second electric capacity composition integrating circuit, in the time that the voltage of described the second electric capacity rises to the avalanche breakdown voltage of described bidirectional trigger diode, described the second electric capacity discharges through described bidirectional trigger diode, discharging current adds to the base stage of described transistor seconds, triggers described transistor seconds conducting; In the time that the voltage of described the second electric capacity is low to moderate the avalanche breakdown voltage of described bidirectional trigger diode, described discharging current is through described the first diode output.
In conjunction with the 6th kind of possible implementation of a first aspect of the present invention, in the 7th kind of possible implementation, described front-end circuit comprises:
Be connected to the electromagnetic interference filter circuit of civil power ac input end, for suppressing conducted interference;
And be connected to the rectification circuit of described electromagnetic interference filter circuit, for output smoothing d. c. voltage signal.
In the 7th kind of possible implementation in conjunction with a first aspect of the present invention, in the 8th kind of possible implementation, described front-end circuit also comprises the insurance resistance being connected between described civil power ac input end and described electromagnetic interference filter circuit, for surge current suppression.
A second aspect of the present invention provides a kind of light fixture, and any electric ballast providing in a first aspect of the present invention or the several possible execution mode in conjunction with a first aspect of the present invention is provided described light fixture.
Electric ballast provided by the invention and light fixture, simple and reliable, by the inverter circuit that inductance, electric capacity and diode form being set and auxiliary circuit is realized the correction of input current waveform and make power switch circuit be operated in zero voltage switch state, there is higher power factor and operating efficiency.Number of elements used is relatively less, and circuit structure is simple, compared with the light fixture of existing electric ballast, only needs two switch driving circuits just can realize in the situation that exporting equal luminous flux and can save 20% input power.
Accompanying drawing explanation
In order to be illustrated more clearly in technical scheme of the present invention, to the accompanying drawing of required use in embodiment be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is the theory diagram of the electric ballast that provides of the embodiment of the present invention.
Fig. 2 is the circuit diagram of the electric ballast that provides of the embodiment of the present invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described.
Referring to Fig. 1 and Fig. 2, as shown in Figure 1, the electric ballast that the present embodiment provides comprises front-end circuit 110, start-up circuit 120, inverter circuit 130 and fluorescent tube loop 140, and inverter circuit 130 comprises freewheeling circuit 131, the first switch driving circuit 132, second switch drive circuit 133 and transformer 134.Wherein, inverter circuit 130 arranges the first end L1 of freewheeling circuit and the first end L2 of second switch drive circuit, freewheeling circuit 131 arranges the first end X1 of freewheeling circuit and the second end X2 of freewheeling circuit, the first switch driving circuit 132 and second switch drive circuit 133 are respectively arranged with driving control end, the driving control end of the first switch driving circuit 132 is q1, and the driving control end of second switch drive circuit 133 is q2.
Front-end circuit 110, start-up circuit 120, inverter circuit 130 and fluorescent tube loop 140 are connected successively, front-end circuit 110 is connected to the front-end circuit 110 of civil power ac output end, be used for stable output direct current to start-up circuit 120, start-up circuit 120 starts the signal of telecommunication to inverter circuit 130 for exporting, so that inverter circuit 130 work output alternation square-wave voltages are to fluorescent tube loop 140, the electric current in fluorescent tube loop 140 is changed according to the frequency of alternation square-wave voltage.
Wherein, two outputs of start-up circuit 120 are connected to respectively the first end X1 of freewheeling circuit 131 and the first end K1 of second switch drive circuit 133, the afterflow cut-off end of start-up circuit 120 is connected to the second end X2 of freewheeling circuit 131, the startup control end of start-up circuit 120 is connected to the switch control end k2 of second switch drive circuit 133, to start second switch drive circuit 133; Freewheeling circuit 131 is for providing continuous electric current, make fluorescent tube loop 140 have continuous current to flow through, the first switch driving circuit 132 is connected to the first end X1 of freewheeling circuit 131 and the second end X2 of freewheeling circuit 131, and second switch drive circuit 133 is connected to the second end X2 of freewheeling circuit 131; Transformer 134 is for generation of induced electromotive force, impel the first switch driving circuit 132 and second switch drive circuit 133 alternate conduction, wherein, the first winding N1 of transformer 134 is connected between the driving control end q1 of the first switch driving circuit 132 and the second end X2 of freewheeling circuit 131; The second winding N2 of transformer 134 is connected between the driving control end q2 of second switch drive circuit 133 and the first end K1 of second switch drive circuit 133; The tertiary winding N3 of transformer 134 is connected between the second end X2 and fluorescent tube loop 140 of freewheeling circuit 131, wherein, Same Name of Ends is one end of the first winding N1 one end, one end that is connected to fluorescent tube loop 140 of tertiary winding N3 and driving control end q2 that is connected to second switch drive circuit 133 of the second winding N2 of being connected to the second end X2 of freewheeling circuit 131, and Same Name of Ends is one end that in diagram, black round dot indicates.
The circuit structure of the electric ballast that the present embodiment provides is simple and reliable, by the inverter circuit 130 that inductance, electric capacity and diode form being set and auxiliary circuit is realized the correction of input current waveform and make power switch circuit be operated in zero voltage switch state, there is higher power factor and operating efficiency.Number of elements used is relatively less, circuit structure is simple, compared with the light fixture of existing electric ballast, only need the first switch driving circuit 132 and second switch drive circuit 133 just can realize in the situation that exporting equal luminous flux and can save 20% input power.
As the optional execution mode of one, refer to Fig. 2, the circuit diagram of the electric ballast that Fig. 2 provides for the embodiment of the present invention.As shown in Figure 2, the front-end circuit 110 of the electric ballast that the present embodiment provides comprises insurance resistance FUSH, electromagnetic interference filter circuit and rectification circuit, and wherein, electromagnetic interference filter circuit comprises capacitor C 1, capacitor C 2 and inductance L 1; Rectification circuit comprises diode D1, diode D2, diode D3, diode D4 and capacitor C 3.Secondly, the start-up circuit 120 of the electric ballast that the present embodiment provides comprises resistance R 1, capacitor C 4, diode D5 and bidirectional trigger diode DB.And the freewheeling circuit 131 of the electric ballast that the present embodiment provides comprises resistance R 2 and capacitor C 5.The first switch driving circuit 132 of the electric ballast that the present embodiment provides comprises transistor Q1, resistance R 3 and R4; The second switch drive circuit 133 of the electric ballast that the present embodiment provides comprises transistor Q2, resistance R 5 and resistance R 6.And the fluorescent tube loop 140 that the present embodiment provides comprises inductance L 2, capacitor C 6, filament LAMP, capacitor C 7 and capacitor C 8, wherein filament LAMP comprises a end, b end, c end and d end.
Wherein, the annexation of each element in front-end circuit 110 is as follows:
Insurance resistance FUSH, as overcurrent and short circuit current protection component, for surge current suppression, is connected between civil power ac input end first end SI and one end of inductance L 1.
In electromagnetic interference filter circuit, the annexation of each element is as follows:
Capacitor C 1, is connected to being connected between common port and civil power ac input end the second end SD of insurance resistance FUSH and inductance L 1; Capacitor C 2, is connected to the other end of civil power ac input end the second end SD and inductance L 1.Wherein, inductance L 1, capacitor C 1 and capacitor C 2 form π type electromagnetic interface filter, the electromagnetic interference producing for alleviating high-frequency inverter circuit 130, and wherein, capacitor C 1 and capacitor C 2 can be used safety electric capacity.
In rectification circuit, the annexation of each element is as follows:
The anode of diode D1 is connected to respectively the connection common port of negative electrode, capacitor C 2 and the inductance L 1 of diode D3; The anode of diode D2 is connected to respectively negative electrode, civil power ac input end the second end SD of diode D4.
And the negative electrode of the negative electrode of diode D1 and diode D2 is connected to the first end X1 of freewheeling circuit jointly, the anode of the anode of diode D3 and diode D4 is connected to the first end K1 of second switch drive circuit jointly.Wherein, diode D1, diode D2, diode D3 and diode D4 composition bridge rectifier, become direct current by the alternating current of civil power ac input end input.
And capacitor C 3, make the pulsating dc voltage of exporting through the connecting circuit of diode D1, diode D2, diode D3, diode D4 become relatively galvanic current pressure for discharging and recharging, be connected between the first end X1 of freewheeling circuit and the first end K1 of second switch drive circuit.Wherein, capacitor C 3 can realize with electrochemical capacitor, and its positive pole can be connected to the first end X1 of freewheeling circuit.
In start-up circuit 120, the annexation of each element is as follows:
Resistance R 1 is connected between the first end X1 of freewheeling circuit and one end of capacitor C 4, forms integrating circuit with capacitor C 4, charge to capacitor C 4.And the other end of capacitor C 4 is connected to the first end K1 of second switch drive circuit.
Bidirectional trigger diode DB is connected to being connected between common port and the base stage of transistor Q2 of resistance R 1 and capacitor C 4, when the charging voltage that the integrating circuit forming when resistance R 1 and capacitor C 4 provides to capacitor C 4 arrives the avalanche breakdown voltage of bidirectional trigger diode DB, triggering pair goes out diac DN conducting, thereby to the Base injection electric current of transistor Q2, make transistor Q2 conducting, and then circuits for triggering starting of oscillation.
Diode D5, for after circuit starting of oscillation, inverter circuit 130 is isolated, the anodic bonding of diode D5 is to the be connected common port of resistance R 1 with capacitor C 4, the negative electrode of diode D5 is connected to the second end X2 of freewheeling circuit, and, when after circuit starting of oscillation, the switch alternate conduction frequency of transistor Q1 and transistor Q2 is high, cause the charging voltage major part that capacitor C 4 obtains to be exported through diode D5, the charging voltage of capacitor C 4 does not reach the avalanche breakdown voltage of bidirectional trigger diode DB, therefore after circuit starting of oscillation, no longer conducting of bidirectional trigger diode DB.
In inverter circuit 130, the annexation of each element is as follows:
Each element annexation in freewheeling circuit 131 is as follows:
Capacitor C 5, as afterflow electric capacity, is connected between the first end X1 of freewheeling circuit and the second end X2 of freewheeling circuit;
Resistance R 2, the bypass resistance while discharging and recharging for capacitor C 5, is connected between the first end X1 of freewheeling circuit and the second end X2 of freewheeling circuit; Wherein, resistance R 2 and capacitor C 5 form freewheeling circuit 131, for being tending towards cut-off state at transistor Q2 from conducting state, and transistor Q1 is in the time of cut-off state, provide continuous current to fluorescent tube loop 140, when the transistor Q1 making at inverter circuit 130 and transistor Q2 alternate conduction cause Dead Time to exist, there is electric current continuously to flow through fluorescent tube loop 140.
The annexation of each element in the first switch driving circuit 132 is as follows:
Transistor Q1, as switch, the collector electrode of transistor Q1 is connected to the first end X1 of freewheeling circuit, and the base stage of transistor Q1 is connected to one end of resistance R 3, and the emitter of transistor Q1 is connected to one end of resistance R 4.
Resistance R 3, for current limliting, provides base voltage to the base stage of transistor Q1, and resistance R 3 is connected between the base stage of transistor Q1 and one end of the first winding N1 of transformer 134.
Resistance R 4, for stable output voltage, is connected between the emitter of transistor Q1 and the second end X2 of freewheeling circuit.Wherein, the peripheral drive circuit that resistance R 3 and resistance R 4 are used as switch for transistor Q1, execution mode has multiple, as long as it is just feasible as the drive circuit of switch purposes to meet transistor Q1, way of realization does not form the restriction to the embodiment of the present invention.
The annexation of each element in second switch drive circuit 133 is as follows:
Transistor Q2, as switch, the collector electrode of transistor Q2 is connected to the second end X2 of freewheeling circuit, and the base stage of transistor Q2 is connected to one end of resistance R 5, is also connected to bidirectional trigger diode DB, and the emitter of transistor Q2 is connected to one end of resistance R 6.
Resistance R 5, for current limliting, provides base voltage to the base stage of transistor Q2, and resistance R 5 is connected between the base stage of transistor Q2 and one end of the second winding N2 of transformer 134.
Resistance R 6, for stable output voltage, is connected between the emitter of transistor Q2 and the first end X1 of freewheeling circuit.Wherein, the peripheral drive circuit that resistance R 5 and resistance R 6 are used as switch for transistor Q2, execution mode has multiple, as long as it is just feasible as the drive circuit of switch purposes to meet transistor Q2, way of realization does not form the restriction to the embodiment of the present invention.
Each winding connection of transformer 134 is as follows:
The first winding N1 of transformer 134 is connected between the other end of resistance R 3 and the second end X2 of freewheeling circuit, and wherein, the other end of resistance R 3 is get along well connected one end of base stage of transistor Q1 of resistance R 3.
The second winding N2 of transformer 134 is connected between the other end of resistance R 5 and the first end K1 of second switch drive circuit, and wherein the other end of resistance R 5 is get along well connected one end of base stage of transistor Q2 of resistance R 5.
The tertiary winding N3 of transformer 134 is connected between the second end X2 and inductance L 2 of freewheeling circuit.
Wherein, in the two ends of transformer 134 first winding N1, being connected to one end that two ends in one end and the transformer 134 second winding N2 that are connected to inductance in the two ends of one end, transformer 134 tertiary winding N3 of the second end X2 of freewheeling circuit are connected to resistance R 5 is Same Name of Ends, three Same Name of Ends that are transformer 134 windings take three ends of black round dot mark in diagram.By three windings of transformer 134, utilize Mutual Inductance Coupling characteristic and magnetic core saturation characteristic, control the alternate conduction of transistor Q1 and transistor Q2.
In fluorescent tube loop 140, the annexation of each element is as follows:
The tertiary winding N3 acceptance of the bid that inductance L 2 is connected to transformer 134 is marked with between the Same Name of Ends of black round dot and a of filament LAMP end.
And capacitor C 6 is connected between the b end of filament LAMP and the c end of filament LAMP.
Wherein, inductance L 2 forms series resonant circuit with capacitor C 6, provides starting resistor for lamp, and the square-wave pulse of inversion output is carried out to filtering by the voltage between capacitor C 6 two ends, makes to flow through the electric current near sinusoidal ripple of filament LAMP.In the present embodiment, the Q value of inductance L 2 and the decision of capacitor C 6 provide the size of the voltage that starts lamp.
And capacitor C 7, as capacitance, for filament LAMP electric current provides stable alternating current path, is connected between the first end X1 of freewheeling circuit and the d of filament LAMP end.In the present embodiment, the optional withstand voltage polypropylene capactive that is greater than 1.25 times of circuit crest voltages of capacitor C 7 is realized.
Capacitor C 8, as capacitance, for filament LAMP electric current provides stable alternating current path; Be connected between the d end and the first end K1 of second switch drive circuit of filament LAMP.In the present embodiment, the also optional withstand voltage polypropylene capactive realization that is greater than 1.25 times of circuit crest voltages of capacitor C 8.
The circuit working principle of the electric ballast that the present embodiment provides is as follows:
After in the civil power AC signal that loads 220V, 50Hz between civil power ac input end first end SI and civil power ac input end the second end SD being, after rectifying and wave-filtering, produce the direct voltage of about 311V at the two ends of capacitor C 3.Then the integrating circuit being made up of resistance R 1 and capacitor C 4 charges to capacitor C 4, in the time that the voltage in capacitor C 4 reaches the avalanche breakdown voltage of bidirectional trigger diode, bidirectional trigger diode conducting, capacitor C 4 is discharged to the base stage of transistor Q2, provide driving voltage, driving transistors Q2 conducting to the base stage of transistor Q2.
After transistor Q2 conducting, the flow direction of electric current from the positive pole of capacitor C 3 successively through a of the b end of the c end of the d end of capacitor C 7, filament LAMP, filament LAMP, capacitor C 6, filament LAMP, filament LAMP hold, inductance L 2 is to the tertiary winding N3 of transformer 134.To the tertiary winding N3 of transformer 134, current signal flow to the collector electrode of transistor Q2, flow to the negative pole of capacitor C 3 through transistor Q2.Because when electric current flows through the tertiary winding N3 of transformer 134, can make tertiary winding N3 produce an induced electromotive force that stops this electric current to increase, the polarity of induced electromotive force is Same Name of Ends for just, the polarity of voltage of the Same Name of Ends that black round dot indicates is for just.And, the induced electromotive force that tertiary winding N3 produces can be coupled to respectively the first winding N1 and the second winding N2, the induced electromotive force that the first winding N1 and the second winding N2 produce makes the polarity of Same Name of Ends of self all for just, thereby the induced electromotive force of the first winding N1 generation makes the base potential of transistor Q1 for negative, do not reach the condition of driving transistors Q1 conducting, therefore make transistor Q1 remain off.On the contrary, the upper induced electromotive force producing of the second winding N2 has further increased the driving voltage of the base terminal of transistor Q2, then make the base current of transistor Q2 increase, further cause the electric current of the collector electrode of transistor Q2 to increase, therefore cause the induced electromotive force that tertiary winding N3 produces to strengthen, thereby the induced electromotive force on the first winding N1 and the second winding N2 is also strengthened, therefore form the induced electromotive force that positive feedback produces to strengthen the second winding N2, the base current of transistor Q2 further increased.
Positive feedback effect causes transistor Q2 saturated gradually, now, the collector current increase of transistor Q2 reaches after maximum the magnetic core magnetic permeability of transformer 134, magnetic conductance starts to decline rapidly, and the upper induced electromotive force producing of the first winding N1, the second winding N2 and tertiary winding N3 also sharply declines.Wherein, the induced electromotive force of the decline that the second winding N2 produces declines the base voltage of transistor Q2, and then the electric current that makes the collector electrode of transistor Q2 starts to decline, make tertiary winding N3 produce an induced electromotive force that stops this electric current to reduce, the polarity of induced electromotive force is that Same Name of Ends is negative, and the polarity of voltage of the Same Name of Ends that black round dot indicates is for negative.And, the induced electromotive force that tertiary winding N3 produces can be coupled to respectively the first winding N1 and the second winding N2, it is all negative that the induced electromotive force that the first winding N1 and the second winding N2 produce makes the polarity of the Same Name of Ends of self, thereby the induced electromotive force of the second winding N2 generation makes the base potential of transistor Q2 for negative, do not reach the condition of driving transistors Q2 conducting, therefore make transistor Q2 in cut-off.On the contrary, the base voltage that the upper induced electromotive force producing of the first winding N1 makes transistor Q1, for just and voltage rising, makes transistor Q1 be tending towards conducting.
When transistor Q1 will conducting, when transistor Q2 has ended, if freewheeling circuit 131 is not set, on the filament LAMP in fluorescent tube loop 140, do not have electric current to flow through, thereby arrange after freewheeling circuit 131, electric current is continuously provided can to the circuit of electric ballast, is not opened circuit in fluorescent tube loop 140.Wherein, the flow through electric current of tertiary winding N3 starts to carry out reverse charging to being used as the capacitor C 5 that afterflow uses in freewheeling circuit 131.Now, diode D5 is as isolation, and the electric current that resistance flows through tertiary winding N3 flows through D5, avoids circuit abnormal.
When transistor Q1 conducting, in the situation of transistor Q2 cut-off, the flow direction of electric current is passed through transistor Q1 to resistance R 4 successively from the positive pole of capacitor C 3, then the d of c end, filament LAMP of b end, capacitor C 6, filament LAMP of a end, filament LAMP of tertiary winding N3, inductance L 2, filament LAMP of flowing through holds, capacitor C 8, then to the negative pole of capacitor C 3.The sense of current of visible light tube loop 140 directions during with transistor Q2 conducting is completely contrary, thereby the voltage that inverter circuit 130 is exported is square-wave voltage.Because when electric current flows through the tertiary winding N3 of transformer 134, transistor Q1 conducting, the electric current that flows through resistance R 4 increases, can make tertiary winding N3 produce an induced electromotive force that stops this electric current to increase, the polarity of induced electromotive force is that Same Name of Ends is negative, and the polarity of voltage of the Same Name of Ends that black round dot indicates is for negative.And, the induced electromotive force that tertiary winding N3 produces can be coupled to respectively the first winding N1 and the second winding N2, it is all negative that the induced electromotive force that the first winding N1 and the second winding N2 produce makes the polarity of the Same Name of Ends of self, thereby the upper induced electromotive force producing of the second winding N2 has further increased the driving voltage of the base terminal of transistor Q1, then make the base current of transistor Q1 increase, further cause the electric current of the emitter of transistor Q1 to increase, therefore cause the induced electromotive force that tertiary winding N3 produces to strengthen, thereby the induced electromotive force on the first winding N1 and the second winding N2 is also strengthened, therefore form the induced electromotive force that positive feedback produces to strengthen the first winding N1, the base current of transistor Q1 is further increased.
Positive feedback effect causes transistor Q1 saturated gradually, now, the emitter current increase of transistor Q1 reaches after maximum the magnetic core magnetic permeability of transformer 134, magnetic conductance starts to decline rapidly, and the upper induced electromotive force producing of the first winding N1, the second winding N2 and tertiary winding N3 also sharply declines.Wherein, the induced electromotive force of the decline that the first winding N1 produces declines the base voltage of transistor Q1, and then the electric current that makes the emitter of transistor Q1 starts to decline, make tertiary winding N3 produce an induced electromotive force that stops this electric current to reduce, the polarity of induced electromotive force is Same Name of Ends for just, and the polarity of voltage of the Same Name of Ends that black round dot indicates is for just.And, the induced electromotive force that tertiary winding N3 produces can be coupled to respectively the first winding N1 and the second winding N2, the induced electromotive force that the first winding N1 and the second winding N2 produce makes the polarity of Same Name of Ends of self all for just, thereby the induced electromotive force of the first winding N1 generation makes the base potential of transistor Q1 for negative, do not reach gradually the condition of driving transistors Q1 conducting, therefore make transistor Q1 in cut-off.On the contrary, the base voltage that the upper induced electromotive force producing of the second winding N2 makes transistor Q2 for just and voltage rise gradually, make transistor Q2 be tending towards conducting.
When transistor Q2 will conducting, when transistor Q1 has ended, if freewheeling circuit 131 is not set, on the filament LAMP in fluorescent tube loop 140, do not have electric current to flow through, thereby arrange after freewheeling circuit 131, electric current is continuously provided can to the circuit of electric ballast, is not opened circuit in fluorescent tube loop 140.Wherein, the flow through electric current of tertiary winding N3 starts to carry out reverse charging to being used as the capacitor C 5 that afterflow uses in freewheeling circuit 131.Now, diode D5 is as isolation, and the electric current that resistance flows through tertiary winding N3 flows through D5, avoids circuit abnormal.
Then transistor Q2 conducting again, transistor Q1 is in cut-off state, and the circuit of electric ballast repeats to make transistor Q1 and transistor Q2 alternate conduction, and alternately cut-off, so circulation, enters the lower state of concussion, and inverter circuit 130 is exported square-wave voltage continuously.
The series resonant circuit that square-wave voltage process inductance L 2 and capacitor C 6 form, to carry out the voltage waveform of filtering output near sinusoidal ripple through this circuit.Because this sine wave frequency approaches the series resonance frequency of the series resonant circuit that inductance L 2 and capacitor C 6 form, in capacitor C 6, produce very high starting resistor, and then lamp can be lighted.
The electric ballast that the present embodiment provides is by the inverter circuit 130 that inductance, electric capacity and diode are set form and auxiliary circuit is realized the correction of input current waveform and make power switch circuit be operated in zero voltage switch state, has higher power factor and operating efficiency.Number of elements used is relatively less, and circuit structure is simple, compared with the light fixture of existing electric ballast, only needs two switch driving circuits just can realize in the situation that exporting equal luminous flux and can save 20% input power.
As the optional execution mode of one; the electric ballast that the present embodiment provides also comprise diode D6 and diode D7; wherein; diode D6 is connected between the first end X1 of freewheeling circuit and the second end X2 of freewheeling circuit; for the protection of transistor Q1; to prevent transistor Q1 reverse breakdown, inverse electromotive force can discharge by diode D6.
In like manner, diode D7, for the protection of transistor Q2, to prevent transistor Q2 reverse breakdown, inverse electromotive force can discharge by diode D7, and wherein, diode D7 is connected between the second end X2 and the first end K1 of second switch drive circuit of freewheeling circuit.
Be more than the preferred embodiment of the present invention, it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications are also considered as protection scope of the present invention.
Claims (10)
1. an electric ballast, comprise the civil power ac input end, front-end circuit, start-up circuit, inverter circuit and the fluorescent tube loop that connect successively, described front-end circuit is for extremely described start-up circuit of stable output direct current, described start-up circuit is used for exporting the startup signal of telecommunication to described inverter circuit, so that described inverter circuit work output alternation square-wave voltage is to described fluorescent tube loop, the electric current in described fluorescent tube loop is changed according to the frequency of described alternation square-wave voltage; It is characterized in that, described inverter circuit comprises freewheeling circuit, the first switch driving circuit, second switch drive circuit and the transformer being made up of three windings;
Wherein, two outputs of described start-up circuit are connected to respectively the first end of described freewheeling circuit and the first end of second switch drive circuit, the afterflow cut-off end of described start-up circuit is connected to the second end of described freewheeling circuit, the startup control end of described start-up circuit is connected to the switch control end of described second switch drive circuit, to start described second switch drive circuit; Described freewheeling circuit is for providing continuous electric current, make described fluorescent tube loop have continuous current to flow through, described the first switch driving circuit is connected to the first end of freewheeling circuit and the second end of described freewheeling circuit, and second switch drive circuit is connected to the second end of described freewheeling circuit; Transformer is for generation of induced electromotive force, impel described the first switch driving circuit and described second switch drive circuit alternate conduction, wherein, the first winding of described transformer is connected between the driving control end of described the first switch driving circuit and the second end of described freewheeling circuit; The second winding of described transformer is connected between the driving control end of described second switch drive circuit and the first end of described second switch drive circuit; The tertiary winding of described transformer is connected between second end and described fluorescent tube loop of described freewheeling circuit, wherein, Same Name of Ends is one end of the first winding one end, one end that is connected to described fluorescent tube loop of the tertiary winding and driving control end that is connected to described second switch drive circuit of the second winding of being connected to the second end of described freewheeling circuit.
2. electric ballast as claimed in claim 1, is characterized in that, described the first switch driving circuit comprises:
The first switch element, the first end of described the first switch element is connected to the first end of described freewheeling circuit;
Be connected to the first resistance between the second end of described the first switch element and the driving control end of described the first switch driving circuit, isolate for current limliting with by the induced electromotive force of the first winding of the second end of described the first switch element and described transformer;
Be connected to the second resistance between the 3rd end and second end of described freewheeling circuit of described the first switch element, for stable output voltage.
3. electric ballast as claimed in claim 2, is characterized in that, described second switch drive circuit comprises:
Second switch element, the first end of described second switch element is connected to the second end of described freewheeling circuit;
Be connected to the 3rd resistance between the second end of described second switch element and the driving control end of described second switch drive circuit, isolate for current limliting with by the induced electromotive force of the second winding of the second end of described second switch element and described transformer;
Be connected to the 4th resistance between the 3rd end and the first end of described second switch drive circuit of described second switch element, for stable output voltage.
4. electric ballast as claimed in claim 2 or claim 3, it is characterized in that, described the first switch element is transistor, the first end of very described the first switch element of the current collection of described the first transistor, the base stage of described the first transistor is the second end of described the first switch element, the 3rd end of very described the first switch element of the transmitting of described the first transistor.
5. electric ballast as claimed in claim 4, it is characterized in that, described second switch element is transistor seconds, the first end of the very described second switch element of the current collection of described transistor seconds, the base stage of described transistor seconds is the second end of described second switch element, the 3rd end of the very described second switch element of the transmitting of described transistor seconds.
6. electric ballast as claimed in claim 5, is characterized in that, described freewheeling circuit comprises:
Be connected to the first electric capacity between the first end of described freewheeling circuit and the second end of described freewheeling circuit, and be connected to the 5th resistance between the first end of described freewheeling circuit and the second end of described freewheeling circuit, wherein said the first electric capacity and described the 5th resistance composition charge-discharge circuit, for being tending towards cut-off state at described second switch drive circuit from conducting state, and described the first switch driving circuit is in the time of cut-off state, continuous electric current is provided, makes described fluorescent tube loop have continuous current to flow through.
7. electric ballast as claimed in claim 6, is characterized in that, described start-up circuit comprises:
The 6th resistance, for current limliting, one end of described the 6th resistance is connected to the first end of described freewheeling circuit;
Be connected to the second electric capacity between the other end of described the 6th resistance and the first end of described second switch drive circuit;
Be connected to the bidirectional trigger diode between described the 6th resistance and the serially connected nodes of described the second electric capacity and the base stage of described transistor seconds; And,
Be connected to the first diode between the serially connected nodes of described the 6th resistance and described the second electric capacity and the second end of described freewheeling circuit;
Wherein, described the 6th resistance and described the second electric capacity composition integrating circuit, in the time that the voltage of described the second electric capacity rises to the avalanche breakdown voltage of described bidirectional trigger diode, described the second electric capacity discharges through described bidirectional trigger diode, discharging current adds to the base stage of described transistor seconds, triggers described transistor seconds conducting; In the time that the voltage of described the second electric capacity is low to moderate the avalanche breakdown voltage of described bidirectional trigger diode, described discharging current is through described the first diode output.
8. electric ballast as claimed in claim 7, is characterized in that, described front-end circuit comprises:
Be connected to the electromagnetic interference filter circuit of civil power ac input end, for suppressing conducted interference;
And be connected to the rectification circuit of described electromagnetic interference filter circuit, for output smoothing d. c. voltage signal.
9. electric ballast as claimed in claim 8, is characterized in that, described front-end circuit also comprises the insurance resistance being connected between described civil power ac input end and described electromagnetic interference filter circuit, for surge current suppression.
10. a light fixture, is characterized in that, described light fixture comprises the electric ballast as described in as wherein arbitrary in claim 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210419621.4A CN103796401A (en) | 2012-10-29 | 2012-10-29 | Electronic ballast and lamp |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210419621.4A CN103796401A (en) | 2012-10-29 | 2012-10-29 | Electronic ballast and lamp |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103796401A true CN103796401A (en) | 2014-05-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210419621.4A Pending CN103796401A (en) | 2012-10-29 | 2012-10-29 | Electronic ballast and lamp |
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| Country | Link |
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| CN (1) | CN103796401A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107734778A (en) * | 2017-11-13 | 2018-02-23 | 江西美的贵雅照明有限公司 | LED drive power circuit and luminaire |
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| CN107734778A (en) * | 2017-11-13 | 2018-02-23 | 江西美的贵雅照明有限公司 | LED drive power circuit and luminaire |
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Application publication date: 20140514 |