CN1054726C

CN1054726C - Circuit arrangement

Info

Publication number: CN1054726C
Application number: CN93101443A
Authority: CN
Inventors: 丁·黄
Original assignee: Koninklijke Philips Electronics NV
Current assignee: Koninklijke Philips NV
Priority date: 1993-01-30
Filing date: 1993-01-30
Publication date: 2000-07-19
Anticipated expiration: 2013-01-30
Also published as: CN1090458A

Abstract

The present invention relates to a minitype fluorescent lamp which is combined with a high-frequency DC/AC converter. A feedback capacitor is connected between a low-frequency AC voltage source and the converter so as to improve the power factor of the combination.

Description

Ballasting circuit

The present invention relates to be applicable to the ballasting circuit of high-frequency operation fluorescent lamp, it comprises:

Be used to be coupled to the ac input end of the mains supply of low-frequency ac voltage,

Be connected across described ac input end and be used for the rectifying device of the described low-frequency ac voltage of rectification;

Be coupled to the electric capacity storage facility of described rectifying device output;

A direct current one exchanges a converter, comprising:

Be coupled to the direct-flow input end of described electric capacity storage facility;

Be used to produce switching device from the high-frequency current of described rectified AC voltage;

A load circuit that comprises the electric light link and be coupled to described switching device;

Make the feedback circuit that is coupled to an ac input end by a terminal that is included in the load circuit that at least one impedance in the load circuit and switching device separate.

The present invention also relates to comprise the compact fluorescent lamp of this ballasting circuit.

The similar circuit of circuit defined in the 1st section in a kind of and this paper has been described in European patent EP 0360156.Yet in sort circuit, the public terminal of switching device and load circuit is connected with ac input end.

In No. the 92203651.2nd, european patent application, first section defined a kind of ballasting circuit described.According to the structure of direct current one interchange one converter, feedback circuit can comprise element, but also can be a load circuit and as many as zero the ac input end of its impedance.Have now found that this ballasting circuit has higher power factor when being used for controlling low wattage fluorescent lamp., under the situation of the fluorescent lamp that consumes higher-wattage with this ballasting circuit control, power factor is lower often, does not perhaps even meet government standard with regard to the line current distortion.

The purpose of this invention is to provide and be applicable to that control consumes the fluorescent lamp of higher-wattage and the ballasting circuit with high power factor.

This purpose is also to be equipped with the situation of the increasing apparatus that comprises capacitive means and inductance device to be issued at ballasting circuit, described capacitive means is connected between the described ac input end, and described inductance device is connected between described capacitive means and the described rectifying device.

Between the operating period, the electric capacity storage facility charges to such current potential via feedback circuit and increasing apparatus at electric light, promptly when the amplitude of low-frequency ac voltage during near its maximum, draws peak value shaping electric current from power supply.Suppress the essential improvement that these peak value shaping electric currents mean power factor.

For preventing that fluorescent lamp from having direct current during use, if feedback circuit comprises that a capacitor is favourable.

In a good embodiment according to ballasting circuit of the present invention, described rectifying device comprises: first series circuit that connects two diodes of described direct-flow input end, with another series circuit of two diodes that connect described direct-flow input end, be included between second tie point between two diodes of first tie point between two diodes that described capacitive means in the described increasing apparatus and described inductance device be connected on first series circuit and second series circuit.In the present embodiment, rectifying device comprises a diode bridge, and increasing apparatus then is connected between the input of this diode bridge.Found that this good embodiment is a fairly simple circuit that high power factor can be provided.

In another good embodiment according to ballasting circuit of the present invention, described rectifying device comprises a series circuit that connects two diodes of described direct-flow input end, described storage capacitive means comprises a series circuit that connects two capacitors of described direct-flow input end, is included in described capacitive means in the described increasing apparatus and described inductance device and is connected between first tie point and second tie point between two capacitors between two diodes.Rectifying device among this another good embodiment and store capacitive means and form a voltage multiplie.This feature makes this another good embodiment be highly suitable for the low-frequency ac voltage amplitude occasion lower with respect to modulating voltage.

It is found that if in the end among two sections described embodiment, feedback circuit is received in two tie points, so just can realize very effective energy back.

By the filter that is bound up between described ac input end and the described rectifying device, can avoid the interference of high-frequency current to the low frequency ac potential source.

When being studied in conjunction with the accompanying drawings, will from following description and appended claims, obviously see other purposes of the present invention, feature and advantage.Wherein:

Fig. 1 shows that is embodied a small fluorescent lamp control circuit of the present invention;

Fig. 2 shows another embodiment as the input circuit of Fig. 1 control circuit;

Fig. 3 shows along with a conduction in the middle of the pair of switches element, by the electric current of Fig. 1 circuit circulation;

Fig. 4 show along with this to another conduction in the middle of the switch element, by the electric current of Fig. 1 circuit circulation;

Consult Fig. 1, this illustrates a compact fluorescent lamp LA who is coupled to the LC resonant circuit that comprises inductance coil L2 and capacitor C6.That be connected in parallel with electric light LA is a positive temperature coefficient resistor PTC, and this PTC is positioned at and a circuit that provides the capacitor CT of protection to connect for resistance PTC.Resistance PTC made before the electrode winding of electric light LA applies full voltage to its heating.What be connected in parallel with the elementary winding of transformer T1 equally, is resistance R 8.This resistance is walking around the elementary current bypass that causes low self-oscillation frequency, and the result makes the electric current of upper frequency by inductance coil L2 and electric light LA.

What received the resonant circuit that comprises inductance coil L2 and capacitor C6 is the elementary winding of transformer T1.The secondary winding W1 of transformer T1 receives the base stage of transistor Q1 via resistance R 3.Another secondary winding W2 of transformer T1 receives the base stage of transistor Q2 via resistance R 4.Transistor Q1 and Q2 provide the high frequency DC/AC inverter for using electric light LA.Capacitor C9 and C10 receive respectively between the base stage and emitter of transistor Q1 and Q2.Resistance R 2, RS, R6, R7 and capacitor C11 and diac D3 are formed for making the start-up circuit of transistor Q1 and Q2 work on required high frequency.Resistance R 6 and R7 form a bleeder circuit, and this circuit is because capacitor C11 and resistance R 2 and unbalance.If capacitor C11 charging is fully, cause diac D3 conducting, then make transistor Q1 enter operating state.

Along with transistor Q1 conducting, the elementary meeting of transformer T1 is in time started working in the corresponding inelastic region of its B-H loop.At this moment, Circuits System just is ready to conducting always all the time in next half cycle of the high frequency voltage that control circuit produced of the disclosure.Along with transistor Q1 conducting,, just be cut off to the conduction of its base stage by secondary winding W1 if nonlinear operation begins.As a result, the lower half of high frequency voltage will cause the energising by the secondary winding W2 of transformer T1, and the secondary W2 of transformer T1 receives the base stage of transistor Q2 so that in that its conducting of half period chien shih via resistance R 4.

Zener diode D4 and D5 and capacitor CS are connected in parallel, to play being based upon the restriction of the maximum voltage on electrolytic capacitor C2 and the C3.These electrolytic capacitors and half-bridge formula diode D1 and D2 are connected in parallel.Capacitor C2 and C3 provide " multiplication of voltage " that be commonly referred to circuit effect.

Is effective via the energy that capacitor C4 and CS and diode D1 and D2 return to the voltage that manifests on the inductance coil L1A from resonant circuit.This voltage is supplied with electrolytic capacitor C2 and C3, and be added on the alternating voltage circuit.By suitable selection capacitor C4 and CS, the effect of half-bridge formula translation circuit is just as the high frequency booster converter, so that the voltage on each buffering electrolytic capacitor is brought up to the numerical value that is higher than the circuit crest voltage.This has improved circuit power factor and has reduced the interior current harmonics of circuit.This improved power factor means that circuit absorbs the input current of much less.The effect of capacitor C8 is used for shaping is carried out in the high-frequency ac pulse just as buffer capacitor.

The first capacitor C1A is coupled to tie point 15 between diode D1 and the D2 from input 11 and 13.The first inductance coil L1A is coupled to tie point 17 between electrolytic capacitor C2 and the C3 from input 13.Like this, the first capacitor C1A and the first inductance coil L1A provide current channel for the charging of electrolytic capacitor C2 and C3.This shows that usually said " multiplication of voltage " effect is that the normal use for electric light LA is provided by capacitor C2 and C3.Capacitor C1B and inductance coil L1B are provided for preventing that high-frequency signal from entering the LC filter of the incoming line of ballasting circuit.Capacitor C1B and capacitor C1A are parallel coupled, and inductance coil L1B and inductance coil L1A are series coupled.Bowling silk F receives end points 13 so that the protection to big electric current accident condition to be provided.

In Fig. 2, half-bridge is replaced by full electric bridge D1-D4.Because this circuit and an electric light that uses than Fig. 1 circuit need the electric light of small voltage to use together, just do not need the multiplication of voltage effect, so save capacitor C3.Capacitor C1A and inductance coil L1A are received on the diagonal of full electric bridge.

By reference Fig. 3 and 4, person of skill in the art will appreciate that the explanation of the operation principle of relevant Fig. 1 circuit.For the purpose of illustrating, suppose: the individual pulse that comes from diac D3 has made transistor Q1 conducting.Suppose simultaneously and on capacitor C2 and C3, produced sufficient direct current supply voltage to support self-oscillation.For the purpose of illustrating, the line voltage distribution on end points 11 and 13 is assumed to be near the no-voltage crosspoint.Along with transistor Q1 conducting, capacitor C2 plays the effect (see figure 3) of a voltage source, promptly from the collector electrode of transistor Q1 through elementary, the inductance coil L2 of transformer T1 with by capacitor C6, the lamp load network that C7 electric light LA and resistance PTC form provides electric current to emitter.As shown in Figure 3, this electric current also flows through capacitor C4, tie point 15, capacitor C1A and inductance coil L1A.When transistor Q2 conducting, the electric current that causes flowing through the secondary winding W1 of transformer T1 by the elementary electric current of transformer T1, to strengthen base stage one emitter current supply to transistor Q1, so make Q1 remain on its conducting state result by positive feedback, electric current rises by above-mentioned all elements.The rate of climb of this electric current is mainly controlled by the induction coefficient of inductance coil L2.This electric current continues rising till the magnetic hysteresis loop of the iron core of transformer T1 reaches first nonlinear area.

When the transformer action of transformer T1 becomes when non-linear, the base current of deriving from secondary winding W1 sharply descends transistor Q1 is ended, so just interrupted flowing through the primary current of transformer T1.When this thing happens, transformer T1 was because its primary current of forfeiture and the effect of recovery linear transformer suddenly.As a result, secondary winding W2 derived current enters brilliant base-emitter tie point of not managing Q2, thereby makes this transistor turns.Along with transistor Q2 conducting, the effect of capacitor C3 is just as a voltage source (see figure 4), and the electric current by the elementary of inductance coil L1A, capacitor C1A, tie point 15, capacitor C4, lamp load network (being made up of capacitor C6 and C7, electric light LA and resistance PTC), inductance coil L2, transformer T1 and the collector electrode one emission collection tie point by transistor Q2 promptly is provided.This elementary electric current by transformer T1 causes electric current to flow through the secondary winding W2 of transformer T1 so that by the electric current supply of positive feedback reinforcement to the base-emitter of transistor Q2.Situation during with transistor Q1 conducting is the same, rises up to starting working till second nonlinear area of its magnetic hysteresis loop in the primary current of transformer T1.When this situation of generation, the base drive electric current of transistor Q2 descends, and makes this transistor become not conducting.This effect of transistor Q2 makes flows through the elementary current interruptions of transformer T1, and it causes secondary winding W1 to be provided with electric current to the base stage of transistor Q1 once more.This makes this transistor turn back to its conducting state again to continue this cycle of oscillation so that control oneself.As a result, transistor Q1 and Q2 alternate conduction and by to produce alternating current like this by the lamp load network.

Since the self-oscillation of successful start-up circuit, operating frequency is just by the shape of the non-linear primary current together with the transformer T1 that is produced by lamp load network and inductance coil L2 of the B-H loop of transformer T1 and size, transistor Q1 and the base current of Q2, the RC delay network (R3 on the base stage of transistor Q1 and Q2, C9 and R4, C10) and determine the switching time of transistor Q1 and Q2.

In self oscillating regime, as the alternately result of open/close state of transistor Q1 and Q2, alternating current flows out from capacitor C2 and C3.This alternating current flows through the elementary of filament F1 and F2, capacitor C6, inductance coil L2 and transformer T1.The resistance PTC that connects with capacitor C7 provides extra resistive load on the series LC resonant circuit of being made up of inductance coil L2 and capacitor C6, (as mentioned above) can be used for preheating filament F1 and F2.When resistance PTC heating, its resistance increases.This causes the voltage on the capacitor C6 to increase till the electric light LA starting the arc in parallel with capacitor C6.After the electric light starting the arc, electric light makes the LC resonant circuit fall load, and the electric current by electric light basically by inductance coil L2, lamp arc voltage,, input supply power voltage on capacitor C2 and C3 and the self-oscillation frequency of circuit control.

Obviously, those skilled in the art should be conspicuous to various remodeling of foregoing, and content described herein only supplies the usefulness of explanation, and is not counted as restrictive.

Claims

1. be applicable to the ballasting circuit of high-frequency operation fluorescent lamp (LA), it comprises:

Be used to be coupled to the ac input end (11,13) of the mains supply of low-frequency ac voltage,

Be connected across described ac input end and be used for rectifying device (D1, the D2 of the described low-frequency ac voltage of rectification; D1-D4);

Be coupled to the electric capacity storage facility (C2, C3) of described rectifying device output;

A direct-current-alternating-current converter comprises:

Be used for producing the switching device (Q1, Q2) of high-frequency current from described rectification low-frequency ac voltage;

A load circuit that comprises the electric light link and be coupled to described switching device (T1, L2, C5, C6, C7, PTC);

Make the feedback circuit (C4) that is coupled to an ac input end (11) by a terminal of the described load circuit that is included at least one impedance in the load circuit and separates with described switching device;

It is characterized in that: this ballasting circuit also is equipped with the increasing apparatus (C1A, L1A) that comprises capacitive means (C1A) and inductance device (L1A), described capacitive means is connected between the described ac input end, and described inductance device is connected between described capacitive means and the described rectifying device.

2. ballasting circuit as claimed in claim 1 is characterized in that: described feedback circuit comprises a capacitor (C4).

3. as the ballasting circuit of claim 1 or 2, it is characterized in that: described rectifying device comprises: first tandem arrangement that connects two diodes (D1, D2) of described direct-flow input end, with another tandem arrangement of two diodes (D3, D4) that connect described direct-flow input end, be included between second tie point between two diodes of first tie point between two diodes that described capacitive means (C1A) in the described increasing apparatus and described inductance device (L1A) be connected in series in first tandem arrangement and second tandem arrangement.

4. as the ballasting circuit of claim 1 or 2, it is characterized in that: described rectifying device comprises a tandem arrangement that connects two diodes (D1, D2) of described direct-flow input end, described electric capacity storage facility comprises a tandem arrangement that connects two capacitors (C2, C3) of described direct-flow input end, is included in described capacitive means (C1A) in the described main increasing apparatus and described inductance (L1A) device and is connected in series between first tie point (15) and second tie point (17) between two capacitors between two diodes.

5. ballasting circuit as claimed in claim 3 is characterized in that: described feedback circuit (C4) is received described first tie point.

6. ballasting circuit as claimed in claim 4 is characterized in that: described feedback circuit (C4) is received described first tie point.

7. ballasting circuit as claimed in claim 3 is characterized in that: described feedback circuit (C4) is received described second tie point.

8. ballasting circuit as claimed in claim 4 is characterized in that: described feedback circuit (C4) is received described second tie point.

9. ballasting circuit as claimed in claim 1 is characterized in that: filter (C1B, L1B) is connected between described ac input end and the described rectifying device.

10. comprise according to one in the aforementioned claim or multinomial in the compact fluorescent lamp of ballasting circuit.