DE3644788A1 - Circuit arrangement for operating low-pressure discharge lamps in individual mode and tandem mode - Google Patents

Abstract

The novelty is an electronic ballast for low-pressure discharge lamps = fluorescent lamps having an operating frequency of 20 kHz to 40 kHz, the current path from the positively switching transistor to the negatively switching transistor being passed via inductances. Furthermore, a series circuit = tandem circuit of fluorescent lamps of any desired power level is provided, the preheating current being passed via an inductance to the starting capacitors, which inductance triggers a current-limiting pre-heating effect. For the tandem circuit having fluorescent lamps of relatively high performance, the pre-heating current is split via a diode and capacitor circuit in order that the heating filament is not overloaded. Furthermore, the operating frequency is maintained by means of an LC element, even if the smoothing level on the supply voltage and on the operating voltage of the lamps falls. Furthermore, elements which limit switching are used, which prevents the transistors being overdriven from the base. A separate contact holder of the supply voltage of the lamp and of the starting capacitor is provided for adaptation of two-pin lamps having built-in starters. Furthermore, power conversions are possible, with the same circuit arrangement for tandem operation and the operation of an individual lamp.

Description

In the area of ballasts and circuit arrangements for operation from low pressure discharge lamps = fluorescent lamps are different Circuit types known, but no series connection of lights Allow fabric lamps larger than 2 × 20 W and with high-frequency operation must have at least a 195 V DC supply.

This invention has for its object a high-frequency scarf to create arrangement that allows fluorescent lamps be Liebiger performance quantities z. B. 2 × 58 W linear luminaires in series and To operate independently, since in series = tandem operation the energy saving is significant, the operation of fluorescent lamps without electrolytic capacitor as smoothing capacitor upright get, with the smoothing level below the burning voltage of the Lamp may fall. With the circuit arrangement to be created allow lamps of different sizes with a ballast can be operated in order to reach the ballasts more flexibly and through the operation in series = tandem connection an almost 50% Energy saving occurs.

According to the invention the object is achieved in that a circuit arrangement is created which operate the lamps with an operating frequency between 20 KHz and 40 KHz, the primary winding g being divided into two paths in the frequency transformer, so that the current path from the emitter of one transistor to Collector of the other transistor is guided over the divided primary winding. In addition, the transformer is assigned an additional core with windings, which prevents the transistors from overdriving when the light output is high. The ignition current to the ignition capacitor is limited by an inductance, which can also be arranged on the current limiting choke and is connected between the output of the heating coil and the ignition capacitor.

When operating two lamps in series = tandem connection especially for larger services. B. 2 × 58 W corresponds to one standard fluorescent lamp 1.5 m long and 26 mm in diameter, or similar lamp types, several condensates are created over the lamps gates arranged, which meter the preheating current via the heating coil and maintains the required burning voltage for both lamps.

A diode circuit in combination with a The varistor split the spiral current to premature blackening of the Avoid lamp ends.

Since the energy savings in tandem operation - the greater, the less current flows over the coil - one is provided to create a new combination as a tandem fluorescent lamp. To the Maintain operating frequency even when the supply voltage falls below the burning voltage of the lamps is one additional inductance arranged parallel to the lamps.

Going further is for the operation of two-pin fluorescent lamps (PL lamps with intrigued starter) the contact in the socket subdivided so that the ignition capacitor only makes contact when the contact via the lamp is already closed.

Detailed circuit arrangements of the novelties are shown in FIGS. 1 to 13.

Fig. 1 circuit arrangement with separate current path between the emitter and the Collector, and inductive coil current limiting diode and power distribution for tandem operation,

Fig. 2 circuitry for tandem operation, wherein the voltage dividing capacitors are assigned to the lamps,

Fig. 3 circuit for two fluorescent lamps in DUO circuit at a final stage, in which only terminals 6 are led to the lamps,

Fig. 4 circuit arrangement with power conversion,

Fig. 5 circuit arrangement with an inductive coil and current limiting PTC-resistor,

Fig. 6 circuit configuration for tandem operation with diode Stromver distribution,

Fig. 7 circuit arrangement comprising a ge parallel with the lamp switched on the primary winding of the transformer,

Fig. 8 circuit arrangement for operating two-pin lamps with Portable starter,

Fig. 9 illustrates the arrangement of primary winding of the transformer,

FIG. 10 representation for new tandem lamps,

Fig. 11 circuit arrangement for operating with C-MOS transistors,

Fig. 12 circuit arrangement for tandem operation with individual capacitors,

Fig. 13 circuit arrangement of several tandem stages on an output stage.

description

The circuit arrangement as shown in Fig. 1, it contains inventively several new functions that are both physically and related to the circuitry. As shown in Fig. 1 Darge, a DC voltage of 311 V is applied in 1 plus and 2 minus. The DC voltage is generated by the 220 V / 50 Hz / 60 Hz network via rectifiers according to the prior art. The diode 3 is used as a pole fuse diode. Via the resistor 4 and diode 6 and capacitor 5 connected in series, the built-up potential is switched via diac 7 via the primary windings 15 and 16 of the transformer in the capacitor 24 via transistor g to minus and thus the generator circuit is a push-pull converter, the frequency depending can range from 20,000 Hz to 40,000 Hz.

In the previously known push-pull converter circuits for operation of fluorescent lamps is the current path from the emitter of the positive scarf tendency transistor to the collector of the negative switching transistor switched directly or the measuring functions via ohmic resistors pass on.  

In the inventive new circuit, the current path from the emitter of the positive switching transistor to the collector of the negative switching transistor led over inductively acting windings, which directly over corresponding secondary windings that are at the base of the transistors are switched, induction induced the switching determine the operation of the transistor. With this circuit arrangement a short-circuit current across both transistors is kept low because the output stage blocks both transistors in the event of a short-circuit current.

The current flow to lamps 30 and 31 takes place via primary winding 15 in series with current limiting choke 27 , the preheating current to capacitor 41 being limited via inductor 28 . With this current flow, a negative voltage + current is induced in the secondary winding 13 .

At the same time, a positive voltage + current is generated in the winding 12 and it switches on the transistor 9 , thus the lamp current flows through the winding 14 , collector 50 , emitter 52 to the minus. By flowing a current to minus through the winding 14 , the potentials change in the secondary windings 12 and 13 and transistor 9 switches off and transistor 8 switches on. If the switching processes of the transistors overlap, short-circuit currents would occur, which are reflected as loss power. Due to the current path via separate windings from emitter transistor 8 to the collector Transi stor 9 , a short-circuit current is almost impossible, since in the event of a short-circuit via windings 14 and 15, the induction in the windings is canceled and both transistors are blocked. So that the positive switching transistor 8 blocks faster in such a case, it receives a small bias voltage via resistor 48 to emitter 49 . Since there are two operating states when operating fluorescent lamps, 1. the ignition phase and 2. the operation. Since the ignition phase can be critical especially with fluorescent lamps with high powers, the winding 16 is connected in series with the ignition capacitor 42 as the primary winding, where the secondary windings 17 and 18 are arranged on a common core. The windings 17 and 18 can be connected in parallel to the windings conditions 12 and 13 , two Zener diodes polarized against one another being connected in series with the winding. The winding 18 is opposite to the winding 12 and the winding 17 is opposite to the winding 11 , a counter potential to the windings is also induced.

If a large voltage or current is required during the ignition process via the lamps, this is input to the primary winding 16 . If the transistor 8 is switched on via the secondary winding 13 with a positive voltage, a negative voltage is generated in the winding 17 which, when a limit value which is determined via the Zener diodes is reached, switches through to the base and initiates a blocking. In the opposite case, the positive voltage is blocked so far that a premature switch-on is avoided. The Zener diodes, which are polarized against one another, therefore differ in their blocking values.

When tandem operation of fluorescent lamps of higher wattages z. B. 2 × 58 W, a larger operating voltage across both lamps 30 and 31 must be maintained. This larger operating voltage also means a greater load on the heating coils 32 and 35 . So that no overload of the heating coil 32 and 33 occurs, the current is divided into two paths. The positive half-wave of the lamp current is conducted via the current limiting choke 27 , diode 43 , coil 32 via a further ignition current choke 28 to the ignition capacitor 41 and after capacitor 42 via diode 43 and winding 16 . The negative half-wave conducted through current limiting choke 27 , diode 44 to capacitor 41 , and via diode 44 , ignition current choke 28 , coil 32 , winding 16 to capacitor 42 .

Thus, the current across the coil is divided depending on the capacities of the capacitors 41 and 42 .

The capacitors 39 and 40 form a voltage divider via the lamps and are connected via line 38 to the series connection of the lamps 30 and 31 . Thus, the lamps ignite one after the other and voltage across the heating filaments 32 and 35 is reduced. So that the lamps 30 and 31 can also be changed during operation, an overvoltage voltage element 47, a varistor is arranged above the lamps, which short-circuits a half-wave when a lamp is removed, which forms as a high voltage. The other side of the preheating current on the coil 35 is divided via the diodes 45 and 46 .

In FIG. 2 a tandem circuit is shown for medium power, the additional base current limitation can be eliminated on the secondary windings serially connected Zener diodes. The current limiting choke 56 leads the current via coil 32 to the capacitor 41 , and also via coil 35 to the capacitors. The heating current through the filaments 33 and 34 is conducted through the capacitors 57 and 58 .

Depending on the size of the capacitors, the preheating current can be divided over the helix.

With this circuit arrangement, the lamps can be used during operation can be changed without damage.

FIG. 3 shows a duo circuit, the additional windings 17 and 18 being arranged on the same core as 12 and 13 with opposite poles. The winding 18 is arranged on the same transformer core as the winding 12 , the winding 13 and 17 is arranged on a different transformer core. The primary windings 14 and 15 are arranged so that a current flows through the windings 14 and 15 in the coils 12, 13, 17 and 18 over both separate transformer cores, equal to the transformer core with winding 12 and 18 and transformer core 2 with winding 13 and 17 Voltage is induced.

With this push-pull transformer arrangement, a further core and winding can be omitted. The current to lamps 134 and 135 flows to each lamp 134 = 59 and to current limiting choke assigned to lamp 135 = 61 .

The lamps are preheated by the ignition current choke 60 and 62 . The lamp 134 is assigned the ignition and operating capacitor 64 and the lamp 135 the ignition and operating capacitor 63 . This circuit arrangement for the duo operation of fluorescent lamps still has an economical effect in the installation. Since only six lines from the lamps to the ballast according to the circuit arrangement Fig. 3, the points 59, 60, 61, 62, 65 and 66 need to be switched, there is already a saving compared to the previously known electronic ballasts.

In Fig. 4 a circuit arrangement is shown, which built up in the push-pull circuit such as Fig. 2, wherein the circuit arrangement for a tandem circuit in the simplest form shown. Only one ignition capacitor 72 is connected via the lamps 30 and 31 . With this circuit arrangement, fluorescent lamps can also be used with larger powers. B. 2 × 58 W are fired and operated, the current limiting inductor 67 must have a larger number of turns and a correspondingly larger air gap for the same impedance to limit the ignition current accordingly.

Since the task is to operate different powers with the same ballast, the current limiting choke contains taps as shown in 68 and 69 . The required power level can be selected via the lamp connection 69 . The power is automatically adjusted via the split primary winding 14 and 15 , depending on the lamp voltage. Taps 68 and 69 for lamps 30 and 31 are thus additional adaptation options via dialing line 69 .

In Fig. 5, a circuit arrangement is shown how this can be selected for a cell lamps with high power. On the transformer of the push-pull converter, two primary windings 80 and 81 are arranged for under different current paths. The secondary windings 82 and 85 and 83 and 84 are arranged on each transformer core of the transformer. These secondary windings control the Tran sistorschaltvorgänge described 3 as shown in Fig. 1 and Fig..

The primary windings 80 and 81 are arranged in parallel in such a way that the lamp and preheating current is connected via the winding 81 , only part of the preheating current flowing through the winding 80 .

The lamp current is limited via the winding 75 , with the heating current being limited via the winding 75 and 76 to the capacitor 78 . A limiter dependent on the temperature is connected via the ignition current limiting choke. Thus, one can in the diagram of Fig. 5 76 and 77, a PTC resistor switch via an inductor or a NTC in series with the inductance, to the ignition current limit on the preheating current for the lamp power to ge währleisten.

In FIG. 6, the Gegentaktübertragertechnik as described in Fig. 2, shown with the tandem circuit of Fig. 1 deviates. Over current limiting choke 90 , the lamp current is carried, the current distribution over the filaments 32 and 35 through the diode pairs 43 and 44 and diode pairs 45 and 46 are only halved.

In the case of lamps with a higher operating voltage and greater power, the lamp circuit should be selected as described in FIG. 1, the circuit shown in FIG. 6 offering good operational reliability.

In Fig. 7, the same circuit arrangement as shown in Fig. 5 is shown, wherein the temperature element is an NTC element and is connected in series with the inductance of the ignition current limiting inductor.

Further are the secondary windings of the push-pull transformer, which are each assigned to a common core, such as windings 82 and 91 of one and windings 83 and 90 on the other core.

The primary windings 80 and 81 comprise both cores, so that the switching operation takes place with the main control via primary winding 81 , but contains a limiting countermeasure via the current flowing through the primary winding 80 to the capacitor 79 .

In Fig. 8 a push-pull converter principle is shown that its function is maintained even when the supply voltage in 92 and 93 falls below the level of the lamp lamp voltage. The push-pull transformer primary with the winding 97 and secondary 95 and 96 is constructed on the same principle as Fig. 2, although in the circuit, the division of the current paths from transistor 8 to Tran transistor 9 via the primary windings 14 and 15 can be omitted.

Technologically, no electrolytic capacitors should be used for DC smoothing, especially in circuits exposed to heat. Since unsplit winding capacitors are too large in structure for the corresponding farades, a circuit arrangement is created in FIG. 8 which enables fluorescent lamps to be operated with a low DC smoothing effort, the smoothing level being allowed to drop below that of the burning voltage of the fluorescent lamps, although the Operation is maintained.

FIG. 8 shows a fluorescent lamp 101 with an intrigued starter 102 and associated capacitor 136 , as is already available in the prior art with PL starters, which have only two connecting pins, under PL lamps. Since there are also PL lamps without built-in starter with four pins available in the trade, a circuit arrangement is shown here, with which you can operate both types = 2-pin and 4-pin lamps.

Via the second primary winding 99 , which is connected in series with the primary winding 97 and capacitor 100 , the transistors 8 and 9 are kept in operation even when the supply voltage and the operating voltage are below the secondary windings 95 and 96 , so that no uncontrollable state in the Power stage over the transistors can occur.

The current is conducted via lamp 101 to 103 via current limiting choke 98 . In order that the lamp can be started, the capacitor 138 must additionally be switched via the lamp.

If the lamp is changed during operation, a high ignition voltage would be built up via the capacitor and the output stage would fail. To avoid this, the contacts are divided in the jack so that the pins 104 and 108 first make contact with 107 and 103 , then when the lamp engages via 109 and 137 and 105 and 106 the ignition capacitor 138 switches on. The lamp poles 104, 105, 108 and 137 are divided only for a better understanding, in practice the contacts in the socket are divided so that the pin receives the contact one after the other when inserted.

The capacitor 138 can also on one side, for. B. 106 to 103 be firmly connected to a potential. Thus, only one contact needs to be shared in the socket.

In four-pin lamps, the poles of one lamp side are in contact with 107 and 109 , and the other lamp side is in contact with contacts 103 and 106 .

In Fig. 9, the transformer with toroidal cores 110 and 112 is shown, where the primary windings 14 and 15 with the secondary windings 12 and 13 are arranged. This primary winding arrangement can of course also be used in the circuit arrangements FIG. 5, FIG. 7 and FIG. 8.

In Fig. 10, a tandem circuit arrangement with only one Zündkonden capacitor 72 is shown. Here it should be shown how energy-saving tandem lamps can be created. There are two options here, namely 1. for tandem operation, bridges are supplied, which are inserted over the poles when the lamp is inserted on each end of lamps 116, 124, 125 and 119 and the heating coil 120, 121, 122, 123 over bridges.

The bridges 116, 119, 124 and 125 can be both zero ohms in resistance but also have a low resistance, which makes it possible for a small preheating current to flow across the filaments 120, 121, 122 and 123 . At an operating frequency over the lamps of 20 KHz to 40 KHz as described in all the circuits mentioned above, the preheating current through the filament of the lamps is not so important, since the circuit remains in operation even when the heating filaments 122 and 123 are in the Tandem connection 73 are defective. Thus, you can turn the lamps, ie if the filament 121 is defective due to the pre-heating current, insert the lamp with the filament 121 at the poles 124 and 126 , the lamp is ready for operation again. Furthermore, new fluorescent lamps can be created where a parallel resistor is arranged to the filament, or where the filament is replaced by such a resistor.

In Fig. 11, the transmitter 130, shown 131, 132 and 133 for use with C-MOS transistors 138 and 129 is. Where in circuit arrangements with bipolar transistors the control is more current-dependent, the control is more voltage-dependent in the C-MOS transistors 128 and 129 . Due to the current flow through the primary winding 130 and 131 , a higher voltage must be induced accordingly in the secondary windings 132 and 133 .

In Fig. 12, the current limiting choke is divided into two windings 143 and 146 . The winding 143 is connected in series with the primary winding of the transformer 144 , which conduct the current of the positive-switching transistor. For the current of the negative conducting transistor, the primary winding 145 is switched in series with the winding 146 of the current limiting choke. In this circuit arrangement, a short-circuit current is already limited inductively. The tandem arrangement of the lamps, the voltage divider capacitors 57 and 58 are each assigned to a lamp.

In FIG. 13, several tandem stages with the lamps 139, 140, 141 and 142 are assigned to a tandem stage. Each tandem stage has its own current limiting choke; the choke 147 for the lamps 139 and 140 and the choke 148 for the lamps 141 and 142 .

The aforementioned circuit arrangements can go further can be varied according to the requirements combined the listed arrangements.

At the tandem circuit like Fig. 1, Fig. 4, Fig. 6 and Fig. 10, lamps can also be connected in individual operation without any change in the circuit arrangement, the connection 38 falls ent.

Depending on the requirements and adjustments - according to the physical properties of the lamps - as in Fig. 1 primary winding 16 and the associated secondary windings 17 and 18 with the series connected Zener diodes 19 and 21 and 20 and 22 can be omitted from the circuit arrangement. The same applies to the LC 79 and 80 in Fig. 5 and Fig. 7, which are arranged above the lamps with the associated secondary windings 84 and 85 with series connected Zener diodes 86, 87, 88 and 89 .

Since fluorescent lamps require a high ignition voltage when ignited, a series resonant circuit is formed in series with the ignition capacitor via the ignition current limitation and inductance, which increases the ignition voltage and thus requires less current, as in the circuit arrangement FIGS . 5 and 7 with inductance 76 and capacitor 78 is shown.

The circuit arrangements can go further Circuits for tandem operation of 2 × 100 W lamps deduce.

The DUO circuit shown in Fig. 3 = 2 lamps can of course also be operated with one lamp, so that you have individual operation.

The additional clearing windings 17 and 18 and the associated Zener diodes 19, 20, 21 and 22 can also be omitted if the physical properties of the lamps allow this, as the frequency stage in FIG. 4 shows.

The ferrite cores for the frequency stage transformer can be both ring cores and other core forms that are secondarily separated, that is to say that the secondary windings 12 and 13 have separate cores, with the primary windings 14 and 15 being arranged over both, as in FIG. 9 shown.

The diode circuit via the lamps can also be used for single persons be used because the diode circuit with the Surge element a reverse polarity protection and a short provide final strength for the circuit arrangement.

Claims (24)

1. The novelty of the invention is characterized in that the current path from the positive switching transistor to the negative switching transistor is performed via separate primary windings of the transformer ( Fig. 1, 14 and 15 ) and the preheating current limitation via an inductance ( Fig. 1, 28th ) is performed, which is arranged in series with the current limiting choke ( Fig. 1, 27 ), the preheating current in tandem operation through the diode circuit ( Fig. 1, 43 and 44 and 45 and 46 ) to the capacitors ( 39, 40, 41 and 42 ) is divided and a voltage limiting element ( FIGS. 1, 47 ) is switched via the lamps arranged in series = tandem; the circuit arrangement of 2 lamps in tandem circuit ( Fig. 1) on the same circuit by omitting the connection ( Fig. 1, 38 ) can operate a single lamp. 2. Continuing to 1, the novelty characterized in that a primary winding ( 16 ) is connected in series with the ignition capacitor ( 42 ), with whose secondary windings ( 17 and 18 ) Zener diodes ( 19, 20, 21 and 22 ) are connected in series. 3. Going to 1, characterized in that the winding ( 17 ) is arranged opposite to the winding ( 13 ) and winding ( 18 ) opposite to the winding ( 12 ). 4. Going to 1 characterized in that the mutually polarized Zener diodes ( 19 and 21 and 20 and 22 ) have different values. 5. Going to 1 characterized in that the inductance Preheating limit is arranged on the current limiting choke. 6. Going to 1 characterized in that the positive switching transistor is biased by a resistor ( 48 ). 7. Going to 1 characterized in that the voltage limiter element ( 47 ) is a varistor. 8. Going to 1, characterized in that the preheating current through the diodes ( 43, 44, 45 and 46 ) and the capacitors ( 41 and 42 ) is limited. 9. Going to 1, characterized in that the capacitors ( 39 and 40 ) are connected in series and is connected as a voltage divider in the central connection ( 36 and 37 ) between the lamps via ( 38 ). 10. The novelty characterized in that in the circuit arrangement for parallel operation of two lamps as shown in FIG. 3, only six connections are made to the lamps. 11. Going to 10 characterized in that the ignition capacitors ( 63 and 64 in 65 ) are connected together. 12. The novelty is characterized in that only 4 connections as shown in FIG. 4 are led to the lamp for tandem operation. 13. Going further to 12 is characterized in that for tandem operation as shown in FIG. 1 and FIG. 6, only 5 connections to the lamp are made. 14. Continuing to 12, characterized in that for tandem operation according to the circuit arrangement Fig. 2 and Fig. 12 six connections to the lamp. 15. Further to 12, characterized in that the power can be changed over taps ( 68 and 69 ) on the current limiting choke ( 67 ). 16. Going to 12, characterized in that the inductance ( 71 ) to limit the preheating current to the capacitor ( 72 ) automatically changes the current to the capacitor during the power changeover. 17. Going to 12, characterized in that a PTC resistor is connected across the current limiting inductance ( Fig. 5, 76 ). 18. Further to 12, characterized in that an NTC resistor ( 149 ) is arranged in series for winding the current limiting inductance ( Fig. 7, 76 ). 19. The novelty characterized in that arranged via an LC element as Fig. 8, ( 99 and 100 ), the operating frequency is maintained when the supply voltage drops below the level of the lamp lamp voltage. 20. Moving on to 19 characterized in that the electrolyte condensate sator for smoothing can be omitted. 21. Continuing to 19, characterized in that the plug contact for two-pin fluorescent lamps is divided so that when the lamp is inserted, the connection of the two potentials ( 103 and 107 ) is first made before the connection to the ignition capacitor ( 138 ) represents is. 22. Further to 19, characterized in that in the opposite case as claimed in claim 21 when removing the two-pin lamp, the capacitor is previously contactless before the poles ( 104 and 108 ), the potentials ( 103 and 107 ) cancel the contact. 23. Further to 19, characterized in that the contacts ( 107 to 108, 104 to 103 ) receive connection via the pole pins of the lamp before the contacts ( 109 to 137 and 105 to 106 ) get contact. 24. Continuing to 19, characterized in that the capacitor ( 136 ) is firmly attached to the potential on one side.