CN1101205A - Self compensating jeting ballast - Google Patents

Abstract

The invention relates to a fluorescent lamp power-supply device whose output end can provide high-frequency voltage with basically continuous envelope, and the current obtainted from power-network is basically sinusoidal with same phase to that of said network voltage. The device is composed of a bridge self-oscillation device composed of an active branch of series transistor 1a and 1b and a passive branch of series capacitor 16a and 16b. Suitable choice of reactance for series capacitor can generate high-frequency voltage, which is rectified by diode 17a and 17b to compenste the rectifying current of the power network and use the voltage approximate to the peak voltage of power network to charge the decoupling capacitor. Advantages: small volume, low cost and automatic compensation.

Description

Self compensating jeting ballast

The present invention relates to by the electric device of a power supply network to the fluorescent lamp power supply.

For this purpose, developed multiple device, they will be described below them and shortcoming thereof corresponding to three types.

The characteristic that this device of the first kind provides not only had been suitable for the international standard electrical network but also had been suitable for supplying with the electric current of fluorescent lamp, but this device has some shortcomings, as all making it can not be applied in the manufacturing of jetting type (jetable) fluorescent lamp on volume, cost and the internal structure.

This device of second class has the cost that is adapted to described jetting type fluorescent lamp as suitable modern light fixture, does not meet the regulation to international electrical network promulgation but the major defect that this device has is electric current that it is drawn from electrical network.

This device of the 3rd class has little volume and low cost, and meet from the standard of electrical network current drawn, but its critical defect is the electric current of supplying with fluorescent lamp and is subjected to the very influence of modulation rate that it makes the life-span reduction of lamp and produces the sudden strain of a muscle frequency effect that the people is received.

This device of the first kind comprises an active filter, and it guarantees that this has just determined its volume and cost to the correction of the electric current of drawing from electrical network.

This device of second class does not comprise the filter that power network current is proofreaied and correct, and comprises high harmonic components in its electric current, peak factor and very low power factor that the people is received.

This device of second class does not use the flat wave capacitor device that rectifier power source is carried out filtering, and this has good characteristic with regard to having guaranteed from the electric current that electrical network is drawn, but as its cost, the efficient of interchanger is hanged down and reached the modulation that the electric current of supplying with lamp has largest enveloping.

Can remedy above these defectives according to device of the present invention.

The total execution mode according to the present invention, this device comprises the bridge-type self-oscillation device of traditional structure, this self-oscillation device comprises the active leg with two serial transistors on the one hand, comprises the passive leg with two series capacitors on the other hand.

Obtain from the high-frequency circuit that connects between the mid point of described two branch roads of this self-oscillation bridge and to guarantee described the transistor periodically energy of alternate conduction and energy powering between fluorescent lamp electrode.Being connected self-oscillation device bridge has a decoupling capacitor between the polarity common port to be charged by two rectifier bridges, their output is in series with the polarity of suitable direction, the nonpolarity input of first bridge is connected on the electrical network, and second nonpolarity input of bridge is by the high frequency voltage power supply of feeding back on the described circuit between the described branch road mid point of self-oscillation bridge.This voltage is to be obtained by the enough big reactance that the described capacitor that constitutes self-oscillation bridge passive leg provides.This voltage is added on the foregoing rectifier bridge through a potential isolation capacitor.The common port of described rectifier bridge is by a capacitor uncoupling, and a terminal of this capacitor is connected of self-oscillation bridge to be had on the polarity public terminal.Having produced one between the two ends of this capacitor has an electrical network rectifier power source phase place and has voltage with its maximum amplitude that equates substantially, it has guaranteed the electric current compensation almost completely of drawing from electrical network, and have voltage on the described decoupling capacitor terminal on the common port of polarity to keep weighing apparatus substantially at the self-oscillation device fixed.In the case, it is fixed that the envelope of the output current that applies between fluorescent lamp electrode is kept weighing apparatus too substantially, and the luminous flux of being launched shows and significantly do not dodge effect frequently thus.

Therefore this device has guaranteed good function, and promptly the electric current of drawing from electrical network has satisfied the regulation of the rules record of described content, and the electric current that is applied between fluorescent lamp electrode has low modulation rate.In addition, this installs that available low cost is implemented and resulting volume is very little.

This device is applicable to the jetting type electronic-module construction to the special-purpose what is called " compactness " of fluorescent lamp power supply, and the integral type light source of so-called " light beam " has the standard sources of one or more fluorescent lamps.

Fig. 1 is that expression is exclusively used in the accompanying drawing of implementing a mode of apparatus of the present invention.

This execution mode as described above, comprises first active leg of being made up of serial transistor 1a and 1b and the self-oscillation bridge that constitutes another passive leg of being made up of series capacitor 16a and 16b.The polarity public terminal that has of this self-oscillation bridge links to each other with the two ends of decoupling capacitor 14, this capacitor 14 is by the rectifier bridge charging of two series connection, by mains supply, and the nonpolarity input of the second cover stream bridge that is made of the diode 17a and the 17b of two corresponding polarity is by the high frequency feedback power voltage supply through 15 inputs of potential isolation capacitor via anti-interference reactor 9 for the nonpolarity input of first rectifier bridge 13.

Described high frequency feedback voltage is to obtain from the mid point of the passive leg of above-mentioned vibration bridge.Between another mid point of this passive leg mid point and above-mentioned active leg, be connected a high-frequency circuit, from this circuit, obtain an energy in order to the alternate cycle conducting control of assurance, and impose on fluorescent lamp 19 from wherein obtaining another part output energy to transistor 1a and 1b.Be added to for voltage on the nonpolarity input of bridge of double diode element 17a and 17b suitable amplitude, determine in this wise capacitor 16a and 16b reactance value and, so that the amplitude of the formation required voltage between their common-midpoint and a described common port that polarity arranged of the electric current total value by described these capacitors.Formed the integration of this high-frequency rectification voltage between the two ends of capacitor 18, and produced a low-frequency ac voltage, its peak value is substantially equal to the line voltage peak value by rectifier bridge 13 rectifications.According to the execution mode of realizing this device of the present invention, described high-frequency circuit is a series circuit, and it comprises inductance 20, guarantees that through it emitting cathode of heating lamp is connected in parallel on the capacitor 4 on the fluorescent lamp 19, and elementary group of 7b of control transformer 7.The inferior limit winding 7a and the 7c of this control transformer have corresponding polarity, alternately periodically conducting of oxide- semiconductor control transistors 1a and 1b respectively.The effect of the parallel branch that is formed with diode 3a and 3b respectively by resistance 2a and 2b reduces its change of current loss when being to form described transistorized Control current.

Diode 5a and 5b guarantee that the described active leg mid point of self-oscillation device and its have two peripheral passages of high-frequency ac current between the polarity common port.

The start-up function of this self-oscillation device is by resistance 6, electric capacity 12, and the conventional trigger circuit that bidirectional diode 11 and blocking diode 10 are formed guarantees.

After this device energising, capacitor 14 by one basically direct current voltage charging and be substantially equal to the crest voltage of electrical network between terminal A and the B, this is because the rectifier power source of bridge 13 is because the auxiliary voltage that forms at capacitor 18 two ends causes on the other hand on the one hand.In the case, be subjected to by the compensation of the rectifier bridge rectified current of diode 17a and 17b by the electric current of rectifier bridge 13 rectifications, therefore, it has the envelope with the basic sine of line voltage homophase.Because the voltage between capacitor 14 two ends is continuous basically, thereby the envelope of high-frequency output voltage itself also keeps continuously basically, it is equivalent to have low modulation rate by the electric current of fluorescent lamp 19, so the sudden strain of a muscle that the luminous flux that fluorescent lamp produces has frequency effect is negligible.

Because this result, the electric current of obtaining from electrical network has low-down harmonic constant, approaches 1.414 peak factor and near 1 power factor.

Fig. 2 is the accompanying drawing of expression according to another execution mode of apparatus of the present invention.

In this case, capacitor 4 no longer guarantees the heating of lamp 19 negative electrodes, and only is merely to be in parallel with lamp 19.

Mode according to this what is called " Fast starting ", the heating of described negative electrode be by with inductance 20 coupling and on current potential with the secondary coil 20b of its isolation, and second secondary coil 20a guarantees that the latter is made of a spindle nose in main inductance 20 outputs.

Identical in the remainder of this circuit and the above-mentioned execution mode.

Fig. 3 is the accompanying drawing of expression according to another execution mode of device of the present invention.

In this case, the output energy of supplying with fluorescent lamp 19 no longer resembles the situation of using " energy delivery " in the example of front, but according to the mode of " voltage tradition ", it wherein only is that elementary winding 23c is connected in the high-frequency circuit that is provided with between self-oscillation device two branch road mid points by means of a transformer 23.

One makes lamp 19 and the partially isolated secondary winding 23d of remaining circuit provide work capacity to this fluorescent lamp on current potential.The secondary winding 23e of heated cathode and 23f have guaranteed that described lamp can work according to " Fast starting " mode.

A capacitor 4 can be connected in parallel on the lamp 19, but and it is optional.

Obviously in this case, can replace the heating that provides by winding 23e and 23f with the heating of flowing through electric current in as shown in fig. 1 and the negative electrode series capacitors 4 lamp 19.

According to this execution mode, that capacitor 16a and 16b go up each intrinsic reactance and replaced by the reactance of single capacitor 16, the latter serves the same role.

Fig. 4 is the accompanying drawing of the expression a kind of execution mode similar to above-mentioned execution mode, but the mode that is oxide-semiconductor control transistors 1a and the conducting of 1b alternate cycle with its difference is different, here no longer by means of an independent control transformer, but utilize two secondary winding 23a being coupled with transformer 23 and 23b to control.The corresponding polarity that has these windings can play the foregoing effect identical with winding 7a and 7b.

In addition, this circuit is also that with the difference of foregoing circuit the mode of self-oscillation device triggering starting is different, these circuits for triggering are connected with capacitor 22 by a threshold voltage element 21 and are formed, and this series circuit connects between the public terminal that polarity is arranged of self-oscillation device through the base emitter junction of transistor 1b or through control winding 23b.

At last, this circuit and foregoing circuit do not exist together and also are the resistance 8 of a positive temperature coefficient in parallel on capacitor 18, and its effect is the voltage between restriction capacitor 14 two ends when the device energized, as long as at this moment lamp 19 is not by build-up of luminance.The resistance 8 of this positive temperature coefficient also can be in parallel with capacitor 16, and at this moment it will be operated in the alternating current state.

Fig. 5 is the accompanying drawing of expression according to a last execution mode of the present invention.

Device as described herein can make the present invention be applied in the electric ballast, and it can play required various functions; Security personnel under the lamp aging conditions, the lamp current adjustment under the voltage ripple of power network situation, the electrical network security personnel under the situation etc. of boosting suddenly ...

First difference of it and circuit noted earlier is: half that utilize rectifier bridge 17 replaces diode 17a and 17b, second half of this bridge is connected on inductance 20 and the public output of a terminal of lamp 19 with its nonpolarity input, and be middle by the capacitor 37 of a little value.This device has guaranteed the unrestricted advantage of alternating voltage between capacitor 18 two ends.

Second difference is: the elementary winding of inductance 20 is two-wire coilings here, and it is corresponding to two winding 20d and 20e, and their input is connected on the two ends of resistance 38, and this resistance 38 forms with transistor 1a and 1b again and is connected in series.And the output of described two-wire winding links together, and is connected with a terminal of lamp 19.This and resistance 38 is connected specialized circuitry and has guaranteed to suppress to flow through transistorized overcurrent when the transistor work change of current.

The 3rd difference that is different from foregoing circuit is: distribute bridge by be connected with capacitor 15 reactance that forms of capacitor 24.In this circuit, capacitor 24 is obtained the part of the high frequency voltage that forms on capacitor 16 two ends, in order to by being applied on the two ends of capacitor 14 after the diode 25a of suitable polarity and the 25b rectification again.With this understanding, just can make the crest voltage between capacitor 18 two ends under any circumstance all be limited in equaling substantially on the value of electrical network crest voltage, and the not issuable variation of the impedance of spot 19.

The 4th difference that is different from foregoing circuit be, semiconductor element 33 in parallel on capacitor 16, and its instantaneous conducting is subjected to the control of threshold values element 34.The latter's trigger voltage is taken from potentiometer 35 or a resistance bridge, and wherein input E is connected and terminal I with a reference voltage terminal, terminal H or the same with the input G of inductance 20 coupling winding 20g.This circuit allows to offer the power of 19 1 predetermined mean values of lamp, but does not contain so change by device from the power factor of electrical network current drawn.

Also be with the difference of foregoing circuit: under the situation that influence input charging occurs, especially under the situation that lamp 19 wears out, forbid the safety protective circuit of self-oscillation device work.

This circuit comprises a semiconductor element 27 that is connected with the diode 26 of corresponding polarity, its conducting be by cause with capacitor 30 and the threshold voltage element that is connected with the bridge circuit of resistance 31 and 32, be connected under the input of resistance bridge the terminal H, the I that have reference voltage, etc. one on.In this way, when this reference voltage surpasses reservation threshold, just caused the conducting of semiconductor element 27, and the half-wave current in described high-frequency circuit is shunted, therefore the work to the self-oscillation device has produced stable inhibition, the self-oscillation device is in outage and be linked into A again, may not can behind the power supply between the B terminal restarts, and this circuit can allow circuits for triggering that a new start trigger pulse is provided.

This semiconductor element 27 can be connected on other aspect of high-frequency circuit and on transistor 1a and the 1b control circuit, also can guarantee to serve the same role.

Be with another difference of foregoing circuit: anti-interference filter 9 be not to be connected on the nonpolarity input circuit of rectifier bridge 13 under the present situation, but be connected it have on the polarity output circuit, so that produce the effect of strengthening high frequency filter by capacitor 18.

With last difference of foregoing circuit be: be to use " energy transmission " in this embodiment, the periodicity conducting that transistor 1a and 1b are replaced is to be guaranteed by winding 20c and 20f with inductance 20 couplings.

According to device of the present invention, as described above, can realize a kind of electric ballast, it is suitable for equipping the fluorescent lamp of jetting type or non-jetting type, and cost is reduced, and volume reduces, and meets the regulation of international electrical network from the electric current that electrical network is drawn.

Certainly the present invention also can produce the modification beyond above-mentioned, so the present invention should only not be limited on the application mode of special consideration, and it should comprise all modification on the contrary.

Claims (18)

1, device by the power supply network power supply, but comprise high frequency self-oscillation device with bridge architecture of forming by another passive leg of first active leg of serial transistor 1a and 1b and series capacitor 16a and 16b, described bridge the polarity common port is arranged by capacitor 14 decouplings, this capacitor 14 continues charging by a series connection circuit, this series circuit comprises the polarity output terminal that has that the polarity output terminal and second rectifier bridge are arranged of first rectifier bridge, the nonpolarity input of first rectifier bridge is connected with described electrical network, the nonpolarity input of second rectifier bridge is by the suitable amplitude voltage power supply of the high-frequency energy that is taken from the conversion of described self-oscillation device, this device is used for the power supply of fluorescent lamp, it is characterized in that: under the average operating frequency of self-oscillation device, suitably select capacitor 16a and 16b reactance and, so that have the public end of polarity to form a high frequency voltage at the mid point and one of the self-oscillation device of described passive leg, this high frequency voltage offers on the nonpolarity input circuit of the diode 17a of suitable polarity and second rectifier bridge that 17b forms, can between the two ends of high frequency decoupling capacitor 18, obtain the low-frequency voltage that maximum amplitude is substantially equal to described line voltage peak value thus, this low-frequency voltage plays the effect of compensation to the electrical network rectified current of decoupling capacitor 14 charging, is according to the mode work of " energy transmission " or " voltage transmission " from high-frequency output circuit to the power supply of described fluorescent lamp 19.

2, according to the device of claim 1, it is characterized in that: capacitor 16a and 16b can be replaced by the single capacitor 16 of a nonpolarity common port that is connected to the self-oscillation device, the reactance that this capacitor has equal above-mentioned two condenser reactances and.

3, according to the device of claim 1 and 2, it is characterized in that: fluorescent lamp 19 is connected with inductance 20 with capacitor 4 in parallel reaching.

4, according to the device of claim 1 and 2, it is characterized in that: fluorescent lamp 19 is connected between the terminal of a secondary winding of isolating transformer 23, and its elementary winding is connected between the active leg and passive leg of self-oscillation device bridge.

5, according to claim 1,2,3 and 4 device is characterized in that: the control of the alternate cycle conduction of transistor 1a and 1b is to guarantee that by the secondary winding 7a of control transformer and 7b its elementary winding is connected with inductance 20 or connected with the elementary winding 23c of transformer 23.

6, according to claim 1,2,3 and 4 device is characterized in that: the control of the alternate cycle conduction of transistor 1a and 1b is by guaranteeing with the winding 20c of inductance 20 and transformer 23 couplings and 20f or winding 23a and 23b respectively.

7, according to the device of claim 5, it is characterized in that: the heating of fluorescent lamp 19 negative electrodes is that secondary winding 20a and the 20b with inductance 20 coupling guarantees.

8, according to the device of claim 6, it is characterized in that: the heating of fluorescent lamp 19 negative electrodes is to be guaranteed by secondary winding 23e and 23f with transformer 23 couplings.

9, according to the device of claim 1 to 8, it is characterized in that: positive temperature coefficient resistor 8 in parallel on the capacitor 18, the overvoltage at capacitor 14 two ends when being used for the restraint device starting.

10, according to the device of claim 1 to 9, it is characterized in that: the start trigger circuit of self-oscillation device is made up of the series circuit of a threshold voltage element 21 and a capacitor 22, and this series circuit has between the polarity common port via base stage one emitter junction of transistor 1b or via this transistorized control windings in series two at the self-oscillation device.

11, according to the device of claim 1 to 10, it is characterized in that: a potential isolation capacitor 15 and be connected the mid point of described active leg and the mid point of described passive leg between high-frequency circuit be in series.

12, according to the device of claim 1 to 11, it is characterized in that: between base stage one emitter junction of each transistor 1a and 1b and separately control winding, connected one respectively by resistance 2a and diode 3a and a parallel branch of forming by resistance 2b and diode 3b, described diode has such polar orientation, so that can limit described transistorized change of current loss.

13, according to the device of claim 1 to 12, it is characterized in that: the reactance of a capacitor 24 combines with the reactance of capacitor 15, so that the maximum amplitude of the voltage that forms at capacitor 18 two ends is no more than the crest voltage of electrical network, described capacitor 24 is connected with the diode 25a of suitable polarity and the bridge circuit of 25b, and the latter can make the energy between capacitor 14 two ends recover.

14, according to the device of claim 1 to 13, it is characterized in that: the elementary winding of inductance coil 20 or transformer 23 is two-wire coilings, their input is connected with every end of resistance 38 respectively, this resistance then is connected in series with transistor 1a and 1b, and their output forms a single output that is connected in high-frequency output circuit.

15, according to the device of claim 1 to 14, it is characterized in that: diode 17a and 17b can be by half replacements of rectifier bridge 17, second half of described rectifier bridge is by capacitor 37 power supplies, and another free end of this capacitor 37 is connected with the common port of lamp 19 and inductance 20.

16, according to the device of claim 1 to 15, it is characterized in that: a semiconductor element 33 is connected between the terminal of capacitor 16b or capacitor 16, be used for the voltage between their terminals of moment elimination, this is because to reference voltage tap circuit voltage rising devices sensitive role.

17, according to the device of claim 1 to 16, it is characterized in that: semiconductor element 27 is connected the output of inductance 20 or transformer 23 elementary winding outputs and self-oscillation device one has between the polarity common port, and it is by means of a job that reference voltage tap circuit voltage rising devices sensitive is suppressed the self-oscillation device with stationary mode.

18, according to the device of claim 1 to 17, it is characterized in that: anti-High-frequency Interference inductance 9 is in series with the polarity output circuit that has of electrical network rectifier bridge 13.

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