NL8302449A - Electronic ballast for gas discharge lamp circuit - has tuned electronic inverter circuit resonating between 20khz and 300khz - Google Patents

Abstract

The electronic ballast supplies high frequency alternating current to gas discharge lamps and is connected to a three phase supply rectified to direct current before electronic inversion to between 20 and 30 kHz. The inverter circuit, suitable for use as an electronic ballast, takes DC power from a rectifier circuit and comprises two transistors (44,45) forming the active elements of a high-power, push-pull, class-B, tuned-collector, current-driven oscillator. The tuned circuit comprises inductors or windings (52,53) of an inverter transformer (54), and is tuned to resonate at a frequency of at least 20kHz in order to enhance lamp efficiency, be inaudible, and to make possible the use of small and practically loss-free circuit components. The same high frequency transformer (54) may have additional windings to produce heating supplies for the lamp filament heaters.

Description

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Betr .: Electronic system.

The present invention in its most extensive form relates to an electrical system for supplying high-frequency alternating current to gas discharge lamps. The system is adapted to be connected to commercially available AC power supply lines, preferably a three-phase power source. The system includes means for rectifying the alternating current to a relatively smooth direct current on a safe voltage for transmission over ordinary building wiring, and electronic means for inverting the direct current into a high frequency alternating current, for example 20-30 kHz, and a suitable voltage for supplying gas discharge lamps, with or without means for heating the wires, and for directing the current through the lamps. The invention in its least extensive form relates to the said electronic means in the form of an electronic or solid-ballast circuit.

Proposals for driving gas discharge lamps at frequencies higher than the commercially available alternating current at 50 - 60 Hz have hitherto been made with claims of better energy efficiency than if conventionally operated at the commercially available frequency . Among the foreseen benefits for higher frequencies was the possibility of using smaller, lighter and cheaper accessories for the gas discharge because, although a great many improvements have been made to ballast circuits and other accessories, designed for 60-period operation since gas discharge lamps were first marketed, the components of the control circuitry, such as transformers, inductors and capacitors, at a certain frequency reach a size and weight limit, and this limit generally decreases the higher the frequency. However, the use of higher frequencies initially included a number of difficulties, the high being cost and the relatively low efficiency of the commercially available sales equipment. Some subsequent developments indicated that sufficient improvement in frequency conversion had been made to allow more general use. Controllers and circuits for use at higher frequencies have been proposed for use in particular applications and for possible general use.

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Thus, the potential benefits of "operating gas discharge lamps on frequencies" above 60 periods per second were "widely recognized by those skilled in the art, primarily based on experimental work and on some installations in particular end-of-year situations" i960. The realization of the foreseen benefits of operating gas discharge lamps at a higher frequency waited for the development of circuitry, systems and turnover equipment which would be satisfactory both from the point of view of efficiency and reliability on the one hand, and costs on the other.

10 The need for alternating current at frequencies above 3000 periods, which was felt in areas other than gas discharge lamp illumination, prompted researchers to examine the transistor as a possible tool for meeting the need. The success in the development of circuits was based on transistors for converting DC to AC at high. frequencies for use in these other areas prompted the development of circuits based on transistors prior to use with gas discharge lamps. The transistor enabled solid-state or ballast circuits for gas discharge lamps, and by 1976 a solid-state ballast circuit consisting of a 20 sine wave oscillator at 20 kHz operated with 120V single phase AC with a diode bridge rectifier and a frequency sieve to generate a 170 V DC switching power supply

The base circuit was basically a sine wave class C oscillator with a frequency screen choke to ensure more efficient transistor switching. Two particular applications for the ground circuit have been proposed, i.e. one in particular for Uo W fluorescent tubes with rapid ignition, and the other for higher ignition voltages required by most 2 1/2 inch gas discharge lamps with instantaneous ignition. The circuit was small and about 90% efficient, and was predicted to "probably become the" standard "for all arc lamp ball load circuit work in the future". The forecast did not materialize in the intervening period of nearly six years.

The circuits for supplying AC to said solid-state rectifiers include single-phase and three-phase supply lines. A three-phase supply has advantages over a single-phase supply, in particular by producing a relatively smooth 8302449

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- 3 - third DC after rectification.

An element in a preferred present rectifying circuit comprises a known rectifier, as described previously, in the form of the six-anode mercury arc rectifier, fed by a triangular star-switched transformer, the neutral of the six secondary windings being fed by a load. and smoothing choke is connected to the cathode.

Certain proposed systems have suggested a centrally disposed inverter circuit for supplying high frequency energy to a large number of lamps via a distribution system, for example to all lamps in a large building. These systems have been unsuccessful on the market for a number of reasons. One is that the failure of the central inverting circuit, which is necessarily large and complex, results in severe discomfort in the illuminated area before recovery of the special equipment can be accomplished. Distribution of high-frequency energy over a considerable distance introduces additional energy losses. Sound noise at hearing frequencies and high-frequency noise radiated from higher pipes at higher frequencies are other difficulties. In addition, the wiring for such a system is complicated and difficult to install when using "rapid ignition" lamps, because the wires of these lamps must be supplied with power to heat them, where if the power for the wires are also distributed from a central point as well as the high frequency current, the wiring costs are increased many times.

In the most common known practice, single phase energy of 60 Hz was distributed to be rectified with each luminaire. In a large building, this requires many rectifiers, and large, usually electrolytic capacitors and perhaps large inductors. Chokes used for these purposes are ineffective, expensive and noisy, while electrolytic capacitors are unreliable, temperature sensitive and have limited life. Only capacitor frequency sieves used lead to a very low energy factor for the system, and consequently to large energy transfer losses.

35 Previously proposed systems for obtaining the advantage of high frequency operation of the lamps by rectifying AC to provide DC to high frequency inverters, 8302449

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- k - and for "operating with the necessary high energy factor, high efficiency and low noise, sailing far too costly or having made unacceptable arrangements in operation and reliability, no one has succeeded in providing a system that has proved acceptable the market, and that affordable, safe, economical, reliable, efficient and smooth ballast circuit, and a system for operating at frequencies in the range of 20 - 30 kHz or higher.

The invention meets this long-felt need.

The invention in its most extensive form consists of a system for supplying high-frequency AC, preferably from a low-frequency AC source, containing rectifying means for converting the AC to DG, and inverters for converting DC in high-frequency AC. The inverters can power one, a few, or a large number of gas discharge lamps, usually fluorescent tubes, for example, all fluorescent tubes in a large building, optionally with tube damping means.

In a less extensive form, the invention consists of electronic means, often referred to herein as electronic or solid ballast circuit for use in the system for (a) providing the necessary ignition voltage to the tubes when the resistance to current supply is relatively high , (b) limiting the current supply in the tube circuit during operation of the tube when the resistance to current supply is relatively low, and (c) optionally supplying current for heating the wires or electrodes in the tubes, at Preferably at a relatively high level for igniting tube operation, and at a much lower level during operation.

The system preferably includes a distribution center, usually containing a single central transformer, which can be connected to the commercially available AC power source, preferably three-phase current, the primary winding being designed to receive the energy from the source on the line voltage, which is usually too high for safe distribution in the building, and the secondary of which is designed to power the building distribution center with current at an appropriate building voltage. If the available power source is at a suitable voltage for distribution throughout the building, a central transformer is not required. The distribution system of the building includes 8302449 - 5 - a number of intermediate centers, for example one for each floor, if it is not an extensive area, or a number if the area of the floor is too extensive to suffice from a single intermediate center for an effective distribution. From the intermediate center 5, the usual building needs can be provided by means of a transformer, the primary of which is developed for the distribution voltage from the center, and the secondary is designed for switching to outputs of use, etc., which are usually fed by lines with 110 - 2 ° 0. At a strategically placed intermediate center, a rectifier is provided for converting the AC to DC to power a number of inverters near the lamps. The transformer in the intermediate center is preferably connected in a triangular arrangement with the primary windings, and in the star arrangement in the secondary, the common center connection of the windings serving as a connection for a neutral or earth conductor. Preferably, the secondary windings contain not only the usual three windings, but three additional windings, which are wound in the manner described below to thereby feed a six phase current to the rectifiers. A six-phase current, after rectification, has a relatively small ripple voltage, which makes rectification to an almost smooth direct current relatively simple and inexpensive. The rectifier preferably includes two six-phase diode groups, which provide direct current to a positive and to a negative terminal for connection to positive and negative leads, which with the above neutral or ground lead form a DC distribution system for supplying the inverter circuits. There is one inverter circuit as an element in the electronic ballast circuit for each luminaire or group of neighboring luminaires, depending on the number of tubes per luminaire. The present inverters can supply one to four or more single tubes more without overload. A person skilled in the art can easily determine the number of pipes and fittings to be fed by each ballast circuit, from the permissible loads on the pipes and inverters.

The ballast circuit includes inverters for converting the DC, received from the above-described system, into a high-frequency AC, for example 20 - 30 kHz, a transformer for this high-frequency AC for converting the voltages generated in the inverters 8302449 * w - 6 - mwg in the correct voltage for operating the houses and, if desired, heating the wires thereof. Means for smoothing the DC before it is converted to AC may be included if deemed necessary or desirable. Furthermore, means may be provided for facilitating ignition of the housings, as well as means for limiting the flow of current through the housings after this current has started to conduct. The inverters and associated means form the electronic or solid ballast circuit.

The invention will be explained in more detail with reference to the drawing, in which: Fig. 1 is a block diagram of a preferred embodiment of the system, showing the commercial three-phase power source, a central transformer for the building, which can be located in a central power space for decreasing the high supply voltage to a voltage suitable for distribution from the central transformer to intermediate centers, where the AC is rectified directly to DC, preferably a three-conductor DC transfer system for supplying a number of inverters, which provides the desired high-frequency power for operating the tubes; Fig. 2 schematically shows the secondary windings of the transformer, for example in the rectifier, with associated parts for providing three-conductor direct current for the inverter circuits; FIG. 3 depicts an embodiment of a suitable primary winding of the transformer of FIG. 2; Fig. k schematically shows an additional secondary winding in the transformer in the central power space or in the transformer in the inverting circuit for obtaining single phase or turn AC for use in utility outlets, for driving motors of an air-handling equipment, a cleaning equipment , appliances etc.; FIG. 5 is a sketch similar to FIG. U showing means for obtaining single phase current at 120/2 / 0V; FIG. 6 is a circuit diagram of an inverter circuit which can be used as an electronic ballast circuit in the system 35 of FIG. 1; FIG. 7 is a circuit diagram of a portion of a known transistor-equipped inverter circuit; 8302449 - 7 - FIG. 8 shows a modification of a portion of the circuit of FIG. 6, showing the mode of series-firing the plurality of rapid ignition fluorescent tubes; FIG. 9 is a circuit diagram of a portion of the circuit 5 of FIG. 6 modified to provide annealing of the cathode from fluorescent tubes; FIG. 10 illustrates another modification of a portion of the circuit of FIG. 6 to provide means for reducing the energy supplied after ignition to the electrodes of the tubes; Fig. 11A is a schematic of a circuit supplying a wire heating current to the two wires or electrodes of a two level fluorescent tube, viz. a full heating current upon ignition of the tube operation and a greatly reduced glow current, for example about one-third of the normal annealing force during tube operation; Figure 11B is a schematic diagram of the right portion of the circuit of Figure 11A modified to provide constant heating power to the wires of the tube; Fig. 11C is another modification of the right portion of the circuit of Fig. 11A to achieve the same result but with slightly different circuitry on the transformer; Fig. 12 shows ways of switching a plurality of tubes across the high voltage high frequency lines of an inverter circuit using both capacitor and choke ball load circuits to obtain a favorable power factor in the high frequency supply lines; FIG. 13 is a circuit diagram of an inverter circuit, similar to the embodiment shown in FIG. 6, but with modified means 30 for supplying power to the bases of two transistors, and another circuit of the Zener diode in the circuit; FIG. 14 is a schematic diagram of the circuit which switches the inverting circuit to two pairs of series-connected fluorescent tubes having means for heating the wires of all tubes and using both capacitor and choke ballast circuits for high power at the output of the inverting circuit; and FIG. 15 is a schematic diagram of the circuitry of the inverter circuit 8302449-8 to a plurality of tubes, two of the tubes. are in series and this pair is connected in parallel with a single tube ever the leads of the high-frequency high-voltage secondary winding of the transformer, with a saturable choke for damping the tubes.

As stated above in the summary of the invention, the invention in its most extensive form consists of a system for supplying a high frequency AC to a number of luminaires for gas discharge lamps, usually fluorescent tubes. The preferred system 10 is now described and is configured to receive low frequency (50 - 60 Hz) AC from a commercially available source at the random voltage provided by the source, transform it, if necessary, into a voltage suitably is for distribution, and transfer thereof to rectifying means, which produce a three-conductor DC circuit which supplies power to the inverting means for converting the DC into a high-frequency, high-frequency AC. Each inverter circuit supplies the high-frequency (20 - 30 kHz or higher) current to at least one fixture, adapted to receive at least one fluorescent tube.

The armature wiring switches the wires or electrodes of the tubes to the high-voltage high-frequency leads of the inverter circuit. However, the invention is not limited to this preferred embodiment, but provides a system which obtains the current for driving tubes in the luminaires of the present circuit from a DC source instead of, or as an emergency add-on to the above AC source, 25 as described in more detail below.

Referring first to FIG. 1, the system is powered by a commercially available source (not shown), which is connected through terminals 1a, 1b and 1c of the primary winding of a transformer 2. In most countries on Earth, commercially sold power generated and transferred as a low-frequency (50-60 Hz) alternating current, and to minimize IE losses on transfer, the voltage in the generator is transformed up by transformers to a much higher voltage than the output of the generator, and then transformed downward, usually in a series of voltage drops to voltages, which are considered safe for the various components of the transfer system from the high voltage line to the entrance of consumer homes. Sometimes this 8302449 9 * - 9 - supply voltage in the hereafter is 110 - 2 ^ 0 V, which is considered a safe voltage for distribution in a human inhabited building, such as a house, a stable, a shop, a department store, a church, an opportunity for convenience, etc. In many cases, especially in recent years, the force at a much higher voltage is brought to the consumer's dwellings, especially when the building to be fed is a church, a school, an office construction, etc. It is common practice in such cases to provide a central transformer space in the building for accommodating the transformer needed to reduce the voltage supplied to a voltage that is suitable for the building in which it will be divided.

The transformer 2 represents such a central transformer, and the primary winding is insulated for safe operation on the high supply voltage. The secondary winding has the correct number of gains regarding the number of turns in the primary winding to transform the voltage down to the voltage for distribution in the building, and to make it available for switching to the building distribution system by output lines or terminals 3a, 3b and 3c. The primary windings for a three-phase circuit 20 may have a triangular or Y circuit in the same manner as the secondary windings may be switched.

The building distribution system shown is a three-conductor circuit from transformer 2, and shown through lines k, 5 and 6, which are connected to secondary terminals 3a, 3b and 3c.

The lines U, 5 and 6 are connected to a number of rectifying means 7 in intermediate centers in the distribution system. Four such rectifying means are shown by way of example in Fig. 1 and are designated 7a, 7b, Je and 7d for convenience, although the general designation 7 is used in the following description thereof. Generally, each floor of a large building has at least an intermediate center, where, if the floor space is larger than can be efficiently fed by a single intermediate center, a floor has two or more intermediate centers at strategic locations.

If commercial energy is present at a suitable building voltage in the yard of a building, the transformer 2 is not needed, and the building distribution system starts with the lines ^, 5 and 6, which are directly connected to the power source, but still need at an 8302449-10 center in the building to receive the power and distribute it to the pipes going to the tosseneentra.

Each rectifying means 7 receives the low-frequency alternating current around the building voltage at the input or primary side thereof, and supplies the power from the output or secondary side, for example as three-conductor direct current, to lines 8, 9 and 10.

Reference is now made to Figures 2 and 3, which together comprise rectifying means associated with a three-phase transformer, comprising an iron core (not shown), a primary winding 11 IQ and a secondary winding 18. Instead of a three-phase transformer, three single-phase transformers can be used. For a rotary current supply, the primary winding 11 has three windings 12, 13 and 11+, which are triangular-shifted to provide three input terminals 15, 16 and 17 in FIG. 3, to which, as shown, the lines 5 and 6 are switched.

The secondary winding 18 of the rectifier transformer comprises six windings 19, 20, 21, 22, 23 and 2k with a common central circuit 25, which forms a connection 26 on the output side of the rectifying means 7 · The connection 26 may be grounded, 20 as healed at 27, and is sometimes referred to herein as the common, neutral, or ground terminal. The conduit 9, which according to fig.

1 is connected to the terminal 26 of the rectifying means 7a, is sometimes also referred to herein as the neutral, common or grounded lead.

The rectifier transformer is constructed, wound and switched as described on page 573 and completed in fig. * + 86, p. 57 ^ of the textbook entitled "A Course in Electronical Engineering", Vol.

II, "Alternating Currents," Fourth Edition by Chester L. Dawes, McGraw-Hill Book Co., 19 ^ 7. The by the rectifier Yes. Current supplied to lines 8, 9 and 10 and the voltages across these lines are relatively smooth. When the EMF of each winding is plotted against time, the envelope of the successive positive peaks has a maximum variation of $ 13.3, that is, the minimum EMF equals 0.867 when the peak or maximum EMF across the center circuit 25 and the terminals 28, 29, 30, 31, 32 and 33 of the six secondary windings is taken as a unit, as shown in Fig. U87 (a), page 57 ^ of Dawes for the envelope of the sine wave waves E1, E2, E3, EU, Ξ5 and m 8302449>. * - 11 - 26. By optionally using a smoothing inductance and / or capacitance in the load line, as mentioned above for the present circuits, the ripple voltages in the load current become even smaller so that they can be made without a serious error neglected, as was the case in the entirely different load circuit of the mercury arc rectifier described by Dawes on pages 533 - 576.

of the terminals 28 - 33 of each of the secondary windings 19 - 2b is connected at the midpoint of a fork-shaped conductor, 10 which is provided in one leg with an outwardly directed diode 3, and in the other leg with an inwardly directed diode The cathode of each diode 3b is connected to a common lead 36, and the anode of each diode 35 is connected through the corresponding leg of the forked lead to another outer end of a secondary winding 19-2b. Similarly, the anodes of each of the six diodes 35 are connected to a common lead 37, and the cathodes are each connected through the associated fork end leg to a different outer end of a secondary winding 19-2b. The common line 36 is connected to the terminal 38, and the common line 37 to the terminal 39 on the output side of the rectifier 7. The terminal 8 is connected to the terminal 38, and the terminal 39 to the lead 10, as shown. in Figures 1 and 2. The voltage between terminals 26 and 38 is, except for polarity, equal to the voltage between terminals 26 and 39, and the voltage between terminals 39 and 38 is twice that as shown in Fig. 2. What these voltages are is a matter of design of the secondary windings with respect to the primary windings. In practice it is satisfactory if the peak voltage across a secondary winding is 170 V, so that the DC voltage across terminals 26 and 38 and across terminals 26 and 39 is also about 170 V, the voltage across terminals 38 and 39 are double that or 3 ^ 0 7.

The rectifier transformer can also be used to provide AC power to energize AC loads, such as 35 use outlets and AC motors. For example, in the United States today it is common practice to distribute power to large buildings as turn AC at 277A80 V, and lighting systems directly from -8302449 -12-.

to energize this "source, The outlets and other" loads require 120 (110 - 130) V, and it is now common practice to use several dry transformers throughout the building to convert three phase U80 V to 120 / 208 V. The voltage standards in 5 other countries may deviate from this, but the transformer used in the rectifier shown in Fig. 2 will in any case supply current with the desired phase and voltage, for example phase current of 120 V, to a load, if the load connected to terminal 28, 30 or 32, and to neutral point 25, or a three-phase current to a load, if the load is connected to terminals 28, 30 and 32, or a single phase current of 208 V to a load, if the load is connected to terminals 28 and 30 or 28 and 32 or 30 and 32. Furthermore, single phase outputs of 120/2 ^ 0 V can be obtained from terminals 28 and 31 and neutral point 25 in a triplicate 15, as schematically shown in FIG. 5, or equally from terminals 29 and 32 or 30 and 33 and the neutral point 25. The output terminals for the circuits of FIGS. H and 5 are on the output side of the rectifier 7 (although they are not rectified and are not shown in FIG. 1), and are conveniently labeled with the respective designations 28, 30 and 32, and 28, 25 and 31. The rectifier of FIG. 2 includes a three-phase transformer, as used in power distribution systems in modern buildings, to provide power for AC loads of 120, 208 or 2 ^ 0 V. By jointly using the same transformer in the present DC power supply system, lower costs of the total system then achieves in known high-frequency lighting systems.

If desired, DC output voltages other than plus and minus 170 V can be obtained from the rectifier of FIG. 2. Thus, lower voltages can be obtained by simply switching the twelve diodes 3¼ and 35 on branches (not shown) to the secondary windings. 19-2, and higher voltages can be obtained by providing extensions (not shown) to these windings. The DC outputs of plus and minus 120 V are particularly desirable based on previously established standards for possible use in applications other than the present lighting system.

The three-conductor DC distribution system has the advantage over a two-conductor DC system that narrower wires can be used, the 8302449 secondary windings 19-2¼ being used more fully, each winding being conductive twice during each period, no DC being supplied in either of these windings, nor in the neutral line 25 if the DC loads are equal on the positive and negative lines 36 and 37, and the positive DC power source can remain in operation in the event of the negative power supply failure, and other way around.

During operation of the illustrated rectifier, each of the six secondary windings 19-2¼ produces a sine oxalic AC voltage, which ranges from minus 170 to plus 170 V over a period of time, based on the 10 turn current excitation of the primary winding 11 of the transformer. the voltages of the outer terminals 28-33 of the six secondary windings have their positive peaks at several consecutive times equidistant within a period of the low-frequency current. At any time, one of terminals 28, 15 29m 30, 31, 32 or 33 is more positive than any other terminals in this group, and approximately 170 V more positive than neutral point 25. The diode 3 ^ connected to the more positive terminal switches that connection to the conductor 36. The remaining five diodes are in non-conductive states at that time. With the passage of time, each of the other five diodes 3¼ one-by-one, in turn, conducts switching of the most positive winding on conductor 36. Thus, conductor 36 remains approximately 170 V more positive at all times then the neutral point 25, and the AC transformer voltages are rectified to a DC voltage.

The six diodes are 35. similarly operating one-by-one to switch the negative terminal of group 28 - 33 to conductor 37, which remains approximately 170 V more negative than neutral point 25. The rectifier of FIG. 2 produces good DC output with little ripple voltage of about b-, 5% while maintaining a high power factor of about 95.55 'in the three-phase power supply circuit h3 30 5, 6.

The three-conductor DC lines 8, 9 and 10, fed from the terminals 38, 26 and 39 of the rectifying means 7a, respectively, are connected to a number of loads across lines 8 and 9 for one load circuit, and across lines 9 and 10 for another load circuit, which loads can be balanced for the greatest possible efficiency. Each load is an inverter connected to fluorescent tubes 67 in various 30302449 ψ *.

- ι u - the numbers and setups. Six such inverters are shown in FIG. 1 as an example. They have been given the letter designations a - f for the sake of convenience, however, in the following description of the inverters shown in Fig. 6, the general designation Uo is used, and the description of the circuit according to Fig. 6 applies to each inverter 1; 0a - ^ Or. The inverters ^ Oa, UOc and ^ Oe are connected in parallel over lines 8 and 9, while inverters 1 + Ob, HOd and UOf are connected in parallel over lines 9 and 10. Although, for example, a total of 10 six inverters given, the invention includes any desired number thereof in the output circuit of a single rectifier 7 of one which allows as much as the allowable load of the rectifier. Any person skilled in the art can easily determine the maximum number of inverters with a certain allowable load, which allows the allowable load of the rectifier. Each of the rectifying means Tb, 7c and 7d also has a load circuit described and illustrated for the rectifying means 7a.

The fluorescent tubes 67 in FIG. 1 are provided with captions for identifying them with the particular inverter 20 Oa, UOb, Ij-Oc, ^ 0d, UOe, and UOf, which feeds them with high frequency alternating current. Thus, the tubes supplied by the inverter circuit J + Qa are designated 6J & I and 67a2, which are connected in series, 67a3 and 67a, which are connected in parallel, èja 5 and 67a6, each of which is powered separately. Similarly, the tubes supplied by the inverting circuit UOb are denoted 67b 1 and 67b2, each fed separately, and 67b3 and S'J'bk connected in parallel. Likewise, the tubes fed by the inverting circuit ^ 0c are denoted 67c1, 67c2 and 67c3, all fed separately, the tubes fed by the inverting circuit ^ 0d are each denoted 67d1 and 67d2, each are fed separately, the inverted circuit ^ 0e fed tubes designated 67e-1 and 67e2 and connected in parallel, and the tube fed by inverting circuit UOf is designated Ö7f.

Fluorescent tubes must be electrically connected to the high-frequency AC and kept in place during use. In general, it is common in this field to use luminaires as the receiving or holding means, with one or more pairs of spaced-apart socket outlets mounted in the luminaires as the 8302449 means for electrical switching of the tubes to the high-frequency AC of the inverter circuit. The standardized socket outlets for filament lamps allow the removal and replacement of a lamp. Each socket outlet has one or two contacts for electrically engaging the contact pins or terminals at the ends of the fluorescent tube. In filament lamps, each end has two contact pins, to which the wire is connected, where when the lamp is properly installed in the socket outlet, the wire is connected to the heating power source at each end.

As shown in Fig. 6, the inverter 40 includes a positive input terminal 41 and a negative input terminal 42.

These connections 41 and 42 can be connected to the direct current lines of the rectifying means 7, for example over the lines 8 and 9 or over the lines 9 and 10. In case a different DC power source is used than the rectifying means 7, As provided for, according to the invention, the connections 41 and 42 are connected to the source to be used, for example a battery circuit for emergency use or for remote use of a commercial power source, a solar cell, a fuel cell, etc. output side of the inverter means 40 there are two output terminals 43 and 43a for the high frequency current generated in the inverter means 40 by means now described in detail. The entire circuit from input terminals 41 and 42 to output terminals 43 and 43a each includes inverter 40a, 40b, 40c, 40d, 40e and 40f.

The inverters 40 further comprise two transistors 44 and 45, which are the active elements of a current driven, class 3 balance oscillator with tuned receiving electrode and high power. An oscillator of the kind intended to produce a large amount of AC power from a DC source is commonly referred to in this field as an inverter circuit, which name. is generally used herein to encompass such elements of the present circuit as described herein.

Transistor 44 has a base 46, a collector 47 and an emitter 48. Transistor 45 has a base 49, a collector 50 and an emitter 51. The tuned circuit includes inductors or windings 52 and 53 of an inverter transformer 54, which magnet kera 55, for example, a ferrite core. Windings 52 and 53 have a common center 57 and end terminals 58 and 59 which are again connected to collectors bj and 50 through lines 65 and 70 respectively. This circuit is tuned to oscillate or resonate at a frequency of at least 20 kHz for (1) improving the efficiency of the fluorescent tube and (2) being inaudible and (3) enabling the use of small and practically loss-free noise. -keling components. The collector inductors 52 and 53 are found on the magnetic core 55 of the transformer 5b along with other windings, which are described below »During operation, a high AC voltage with a sinusoidal waveform appears across the terminals 58 and 59 of the inductors 52 and 53. A feedback winding 61 is applied to a core 55, and a transformer junction induces a much smaller voltage therein than in the windings 52 and 53 due to the small number of turns. The end terminals of the feedback winding 61 are connected to the bases k6 and b9 of the transistors Uk and U5, respectively. The polarity of the feedback voltage is chosen to provide positive feedback from the collectors to the bases as needed to maintain or maintain oscillation. The transistors operate in an efficient alternating switching manner, one at a time being completely turned off, while the other being saturated, at which time it is fully turned on and equals a closed switch.

The feedback signal at the bases causes switching from one state to another. The transistor with the more positive base voltage 25 is saturated or in the "in" state. The transistor with the more negative base voltage is in the "off" state. A short transition interval is required to complete switching from one state to the other.

Direct current, supplied in the inverter means kO of the rectifying means 7 or other power source, as described above, enters the positive terminal Ui, which is connected by a conductor 62 to the center terminal 57 of the windings 52 and 53 via a fuse 63, a diode 6b and a choke or winding j6 on a magnetic core 66. The choke j6, as described more fully below, serves to maintain a constant current in line 62. Instead of being located in line 62, this choke may be located in line 69, if desired. At the central connection point 8302449 - η - junction 57 », the current must take one of two different cocks. This cock comprises the choke or winding 52, the terminal 58, the line 65, the collector 1 * 7, the emitter 1 * 8 of the transistor 1 * 1 *, the line 68 and the line 69, which feed the current back to the equal-5 direct means T or another source via connection 1 * 2. The current takes this cock when the transistor bh is in the conducting state.

The other cock taking the current when the transistor bh turns off and the transistor b5 turns on includes the winding 53, the terminal 59, the line TO, the collector 50, the emitter 51 of the transistor 1 + 5, the line 69 and the connection 1 * 2, so that the current through this second cock is fed back to the equalizing means 7 or another source. The current which is alternately supplied by the windings 52 and 53 of the transformer 5b produces an alternating voltage in each winding on the core 55, which is the desired result of the comparison of the inverter means 1 * 0.

In general, transistors can turn on faster than they can turn off * As a result, one transistor turns on before the other transistor turns off completely. This results in an actual short circuit across the terminals 58 and 59 of the windings 52 and 53 for a short interval at each switching moment. This short circuit is rendered harmless because the choke j6 maintains a basically constant current through itself and associated circuit components, thus preventing transistor collector currents from increasing significantly during the short circuit or conductor overlap period. The transistors thus start and complete their switching operations in ideal conditions of practically no collector voltage and an externally limited collector current.

A resistor 71 in a lead 72, which switches the conductor 62 at, for example, the junction of adjacent terminals of the diode 6k and a choke j6 with the center point of the feedback winding 61, conducts a small current from the positive DC input terminals supply 1 * 1 and the choke 62 to the ports 1 * 6 and 1 * 9 of the two transistors kh and 1 * 5 via the feedback winding 61, respectively. This is the only source for the base current when the inverter circuit for the is first switched on and is essential for reliable ignition. When oscillations build up, most of the base current of the voltage induced in the feedback winding 61, as described in more detail below.

The diode 64 is optional, and, if used, prevents melting of the fuse 63 if the input terminals Ui, 42 are connected to the DC supply lines 8, 9 or 9, 10 with the wrong polarity. .

A diode 73 switches the base 46 of the transistor 74, and a diode 74 switches the base 49 of the transistor 45 to the line 69 via a resistor 75 and a winding 80 on the core 66, when used in the manner described below.

10. The difference in operation of the present circuit and the conventional prior art basic switching device can be clearly understood by comparing FIG. 7 with FIG. 6. In FIG. 7, like parts are labeled with the same reference numerals as used in FIG. 6. with a caption a.

The conventional prior art basic switching device comprises two transistors 44a and 45a, a single diode 73a connected in series with a choke 80a and a resistor 75a, which assembly is the center tap of the feedback winding 61a. switches on the emitters 48a and 51a of the two transistors and 44a and 45a. The purpose of this circuit is to efficiently provide a large DC component of a base current by rectifying the low voltage of the feedback winding 61a. The base-emitter junctions of the transistors provide the rectifying effect, and the choke 80a maintains the base current in at least one transistor during the switching moments when the feedback AC voltage passes through zero. The diode 73a only prevents the discharge of the small ignition component of the base current from the resistor 71a. None of the bases can exceed the emitters by more than about 0.8 V due to the transistor characteristics. This requires that the majority of the feedback voltage across the winding 61a. if negative voltage appears at the base of the "off" transistor, whatever it is at any given time. Also, the center tap of the winding 61a is driven negative twice in each period at one time in each period that each base goes negative. When the center tap goes negative, current is supplied upward from the diode 73a, the choke 80a and the resistor 75a to continue in the base of the transistor turned on. This current is mainly responsible for turning on the transistors. As previously stated, the choke 80a keeps the current by itself substantially constant to provide a constant current source for one or the other of the bases.

With this known circuit, the maximum voltage across the feedback winding winding 31a is necessarily only a few V by limitation by the allowable load in terms of the peak voltage of the emitter base connection points of the transistors. A significant portion of this voltage is lost in diode 73a and in the emitter base junction points of the transistors. Thus, when the feedback voltage is lowered due to low line voltage, as may be experienced during a "partial eclipse" and at other times, the base control voltage becomes unreliably low, and an intermittent oscillation condition may occur. in particular, the transistors cannot become saturated but can conduct current, while a high voltage is present from the collector to the emitter, thereby increasing power scattering, which can quickly damage the transistors.

With the present circuit, as shown in FIG. 6, two diodes 73 and 72 are each connected at one end of the feedback winding 61 instead of having a single diode at the center tap, as shown in the prior art circuit according to fig.

7. This doubles the voltage available for rectification, and allows stable operation up to such low input voltages, so that the transistors are sufficiently protected from all low voltage states.

The choke 80 is not always necessary in Figures 6 and 7. However, if used, the choke can decrease peak base current and reduce the force scattered in resistor 75a (Fig. 7) or resistor 75 (Fig. 6}. A more economical way to use the equal choke 80a in Fig. T if desired, for the choke 3Ca to replace some wire windings 80 about the core 66 of the choke 76, as shown in FIG. 6, is connected in series with the resistor 75. The transformer operation of the main choke coil. circuit Jo then induces the same voltage in these single windings 80, 35 that choke 80a ideally has, but without the cost of an additional magnet core and bobbin. Winding 80a adds an AC voltage to the bottom of resistor 75, equal to the AC component 8302449 - 20 - component of the voltage of the feedback winding 61 at the top of the spring position 75, leaving only a DC voltage across the spring position 75, resulting in the same c constant base current, such as provided in the prior art by the additional choke 80a.

Preferably, a small capacitor 83 is connected between the junction 57 of the collector windings 52 and 53 and the feedback winding 61. This capacitor helps accelerate the switching by subtracting base current from the base of the transistor at the appropriate time. turns off, and by adding base current to the turning on transistor a moment later.

A diode 84 and a Zener diode 85, when used, are connected in series with each other and across the choke 76, as shown, to limit the maximum, positive voltage that can be applied to the transistor circuit. A dangerous voltage, which may destroy the transistor, may otherwise occur during the transition state when the inverting circuit is first turned on to the low impedance voltage source of the central rectifier 7.

A diode 86 may be placed across the DC input leads. This 20 diode conducts only for a moment when the DC input power is turned off. The diode provides a controlled path in case of the current stored in the choke 76 when that current can no longer pass through the input line 62. Diode 86 also reduces arc operation at the switch (not shown) which turns off the DC input voltage 25. Diodes 84 and 86, Zener diode 85 and capacitor 83 form a transient suppression circuit.

In the preferred embodiment shown, the different windings are placed on the transformer core 55- This prevents the use of two more expensive separate transformers, as are commonly used in the prior art.

The AC output of the inverter can be used in many ways, FIG. 6 illustrates the manner in which three or more fluorescent tubes 67a5, 6ja6 and 67a7 can be driven with "rapid ignition". These tubes have filament electrodes at each end thereof, which wires must be heated by supplying current produced by a low voltage. For the purpose of description, the wires in the tube 67a5 are designated 90a5 and 91a5, 8302449-21 - those in the tube 6ja6 with $ 0a.6 and 91a6 and those in the "tube 6TaT with 9QaT and 91a7, respectively. wires 90a5, 90a6 and 90a7 are obtained from the low voltage heating coil 92 on the magnetic core 55 · The wires 91a5, 91a6 and 91a7 at the opposite end of each tube required separate heating coils 93, 9h and 95 on the same core, as shown Fluorescence and other gas discharge tubes are characterized by negative impedance, making direct parallel operation impractical Each tube requires a ball load impedance in series with it to limit the current Chokes or capacitors can perform the ballast operation without wasting energy The capacitors 96, 97 and 98 are shown as ballast circuits in Fig. 6. The windings 52 and 53 form a high-frequency power b ron with a sinusoidal high voltage for the tubes. The voltage of these windings is almost entirely determined by the DC voltage to the inverter circuit, however, the voltage applied to the tubes can be independently selected by tapping one or each of the windings 52 and 53, as shown at the branch 99 for a lower voltage. A higher voltage can be obtained by extending each or both of the windings with additional turns (not shown, but according to FIG. 8) beyond the points where the transistor collectors are connected.

A completely separate, secondary winding (not shown, but according to FIGS. 11-1 * 0 on core 55 with any desired voltage can be used for the tubes, and with full transformer insulation, if necessary or desirable.

Other load devices are possible, and more (or less) than three tubes can be provided by the system of Fig. 6, as shown in Fig. 1 and previously described, and in Figs. 11-1 h, 30 as described below. . This parallel operating system allows the removal of part of the tubes from the fixture to reduce the light intensity without any noticeable influence on the other tubes. The tubes can also be operated in series or in series-parallel, especially if there are an even number of tubes. Such an embodiment reduces the number of ballast capacitors required and fully enables damping by adjusting ballast capacity, as described more fully below.

8302449 - 22 -

Many fluorescent and other gas discharge tubes do not require separately heated wires, and if such tubes are used, heating coils 92, 93, 9½ and 95 are not required.

Fig. 8 shows the portion of the circuit of FIG. 6 that can be modified for series operation of two 101 and 102 rapid ignition tubes. Components in the circuit of FIG. 8, which correspond to components in the circuit of FIG. 6, have been given the same reference numeral with the postscript b, and need not be discussed further here. A greater voltage than that between the 10 transistor collectors is obtained by adding one or more extension windings 103 and 104 to core 55b. The windings 92b, 106 and 110 then provide heating power for the tube wires 105, 107, 108 and 109. A single capacitor 111 provides for limiting or ballasting the current for the two tubes.

Rapid ignition fluorescent tubes are easily attenuated by decreasing the capacitance of the ballast capacitor 111 of FIG. 8. A simple means is to make the capacitor 111 from a number of individual capacitors, which capacitors are manually or remotely controlled in different capacitors. combinations can be switched into the circuit by conventional switching means (not shown).

Another means that can be adjusted for adjustable zone illumination is to turn on different values of capacitor 111 according to a desired illumination level. Damping by adjusting the ballast capacitor allows a full ignition voltage at all light levels, and is therefore better than voltage reduction methods. The preferred damping method described keeps the thread tensions constant as is usually desired in damping.

Damping can also be easily achieved by the circuit shown in Figure 1U 30, as fully described below.

The inverting circuit ^ 0 can be easily adapted to use electronic control of the cathode annealing. This only requires a modification of a part of the circuit according to Fig. 6. Such a modified part of the circuit 35 is shown in Fig. 9, with parts comparable to parts in Fig. 6 having the same reference numerals with a postscript c , and need no further description here. A separate transformer 112, comprising a magnetic core 113, a primary winding 114 with terminals 115 and 116, which can switch the primary winding to an AC source of any frequency, and a series of secondary windings 92c, 93c, 9c and 95c for heating the filaments of the tubes o7a5c, 6ja6c and 6? ATc, which operate independently of the inverting circuit, always keep the wires heated, so that wire windings of the inverting circuit itself are not required.

DC power in the inverter circuit is controlled by the transistor 11U, which can be turned on and off by a low 10 level signal (less than 1 V) between the base 115 and ground 1l6. This method of switching is better and easier to implement than switching in an AC circuit. A mechanical switch can, if desired, replace the transistor 11 ^.

Pig. 10 shows a modified form of the circuit of FIG. 8, in which similar parts have been given the same reference numerals with a postscript d. The filaments of the tubes 101d and 102d are fed from a transformer 5 ^ d instead of directly from the constant voltage inverting transformer 5¼ of Figures 6 and 8. The primary winding 52d of the transformer 5 ^ d receives the voltage input from the voltage across the tubes. Before the arc strikes in the tubes, there is little voltage drop in the ballast capacitor 111d, and practically the entire inverter switching voltage is applied to the primary winding of the transformer 5d. This results in a relatively high output in the secondary windings 92d, 106d and 10dd of the transformer 5½ for fast heating of the wires. As soon as the arc starts, the tube arc voltage drops significantly, reducing the voltage on all windings of the transformer 5 ^ d and, in particular, reducing the heating voltages on the windings 92d, 106d and 110d. A reduced heating-30 τη jugs voltage means that less power is consumed, and the circuit operates more efficiently than usual. Switches are not required to effect a reduction in heating power unlike in practice in some prior art systems. Placing the heating windings on the transformer 5½ simplifies the design of the already complicated transformer 5 ^ Due to the high frequency used, the transformer 5 ^ d can be very small, inexpensive and free of power loss. It should be noted that the heaters are not turned off completely, as this is detrimental to the life of some wires. The greatest damage to wires usually occurs during ignition when they are bombarded by heavy ions before they reach the correct operating temperature.

The control, provided by the transformer 5d, shortens this time of bombardment and ensures extended tube life, as well as improved operating energy efficiency.

Fig. 11A shows a circuit which can supply a high current to the wires of a heated wire fluorescent tube if the 10 "tube is first turned on at the beginning of a lighting period, and can automatically reduce the current supply through the wires once stable operation This circuit includes an inverter circuit, represented by block 120 (which may have the same circuit as described above or another circuit, which accomplishes the same operation), a ballast circuit, represented by block 122 (which may be any electronic part fulfilling this operation, such as a choke or capacitor, an electrical circuit 12h between the inverting circuit and the ballast circuit, a lead 125 from the ballast circuit 122 to a load 126 to be described more fully below, and a return circuit 128 to inverter circuit 120. The depicted load includes a power transform ator 130, one terminal of which is connected to lead 125, and the other to lead 128, and a fluorescent tube 132, having a filament 13 at one end and a filament 136 at the other. The current for the wire 13 is supplied from one end of the autotransformer 130 through a tap 138 only one turn or a few turns from that end, while the current for the wire 136 is supplied from the other end of the autotransformer through a tap 1 ^ 0 just one turn or a few turns from the other 30 end.

After the inverter circuit 120 is turned on and before the arc is struck between the cathodes or wires 131 and 136 of the lamp or tube 132, very little electrical current is supplied by the lamp and ballast circuit. Accordingly, there is very little voltage drop in the ballast impedance 122, and in principle all voltage from the inverting circuit 120 appears across the entire winding of the transformer 130, Voltages suitable for rapidly heating the 8302449 - 25 wires or cathodes 13¼ and 136 are induced in the final inventions of the autotransformer outside the branches 138 and 100 respectively.

After a short heating time, sufficient electrons are emitted from the cathodes or wires 13¼ and 136 to allow a light arc to be established between the cathodes. Then a large electric current is supplied by the lamp and the ballast circuit, and a large voltage drop occurs in the ballast circuit. The voltage remaining across the lamp terminals (between the wires or cathodes) drops to a much lower value, for example to more or less about 10 half of the previous value. This lamp voltage is applied to the autotransformer, so that the voltage in each part of the autotransformer winding drops to the lower value. Specifically, the voltage in the heating coils outside the taps 138 and 10U0 drops, and the cathode heating voltage decreases to the lower value. The direct heating power for the cathodes is dependent on the square of the voltage, so that the heating power drops to significantly less than half the previous value. Usually 2/3 of the energy used for the direct cathode heating can be saved by this means. It should be noted that no switches, electronic or otherwise, are required, and that the lamp-ballast wire transformer circuits are connected to the inverter circuit by only two conductors. Thus, the circuit is inexpensive and suitable for use in a lamp fixture separate from the one containing the inverter circuit. As such, a system comprising a plurality of one or two lamp fixtures may be driven from a common inverter circuit which must be loaded to full capacity to save.

Not only does the autotransformer 130 enable energy savings, but this is done without the disadvantage of certain known ballast circuits, which completely shut off the heaters. A certain voltage maintained along the length of each cathode causes the arc between the cathodes to first form between the ends of the cathodes where the voltage difference is greatest. A critical place is formed where most of the electron emission takes place. When the electron-emitting oxide is burned away from one end of each cathode, the critical site moves to an adjacent site, which has the second highest voltage, and continues in an orderly manner along the entire wire for an extended period of time. the entire usable 8302449 - 26 - lamp life. If a certain voltage is not provided across the wire, the critical spot can become out of control and never reach certain areas of the cathode that still have good oxide coatings. A premature failure of the cathode is the result.

In summary, one feature of the invention provides means for maintaining sufficient voltage across each cathode to promote orderly displacement of the critical spot while saving 2/3 of the cathode heating power.

A wire transformer, similar to 130, but with additional wire windings, some of which are nonconductively connected together, such as in an autotransformer, but insulated, such as in a conventional transformer, can provide two more lamps, which are connected in series are switched in a common extension of the circuit described above.

In applications where it is not necessary to save heating power, the heaters in this system, as in. The prior art is energized directly from additional windings (not shown) on the main invert transformer or one or more intermediate transformers, the primary windings being connected at the output of the inverter for the ballast impedances.

Fig. 11B represents a modification of the circuit of FIG. 11A which provides a constant heating power. In this figure, parts which are the same as comparable parts in Fig. 11A are provided with the same reference numerals with a postscript a, and thus need not be described again for the circuit according to Fig. 11B. The important difference of the circuit of FIG. 11B with respect to the circuit of FIG. 11A is that the wire transformer 130a is connected across leads 12a and 128a between terminals 1 2 and iW1 to be connected to an inverter circuit (not shown), for example, such as 120, and the ballast circuit 122a. The wire 13 ^ a is supplied with current by a short secondary winding 1 ^ 6. The wire 13ea is electrically supplied with a tap on the winding 130a on one turn or a few turns from one end thereof. The voltage across the transformer is unaffected by the voltage drop in the ballast impedance 122a and does not discernibly change with the current supply, so that the voltages supplying current to wires 131a and 136a remain substantially constant during operation of the lamps. The high 8302449 - 27 - frequent transformer 130a. is preferably a transformer provided with a magnetic core, for example ferrite core 1 ^ 8.

Fig. 11C shows another circuit modified from that of FIG. HA, the comparable parts of which are also provided with reference numerals corresponding to the parts in FIG. IIA, but with a postscript b. The difference is that the autotransformer I30b has taps 138b and 11 Ob on a winding or single windings from the ends of the winding connected to lines 125b and 128b, and lines to wires 13Vb and 136b are connected to 10. end connections of the transformer, instead of the branches on the winding. The operation of the circuits of FIGS. UB and 11C is basically the same as described for the circuit of FIG. 11A. The full voltage of the lines 12h-o and 128c is supplied to the two lamps 152 and 15 ^ when the lamp is switched on (as is the case with the circuits according to Fig. 1 IA and 11C), but the voltage in is significantly reduced during operation by the voltage fields across the ballast capacitor 16U and the ballast choke 182.

The second circuit 184 includes a single fluorescent tube 186, 20 with a wire 188 at one end, and a wire 190 at the other end. This circuit receives a constant wire strength from an intermediate circuit transformer 192, connected across lines 124c and 128c through lines 194 and 196, respectively. Wire 188 is fed with heating current through a transformer 198 having a high-frequency core 200, e.g., ferrite. . One end of the auto-transformer winding 192 forms the primary winding of the transformer 198.

The secondary winding is a winding 202, which is connected at one end to one end of the wire 188, and at the other end to a lead 204, which is connected at one end to the other end of the wire 188, and the other end at the junction of this circuit of the winding 202 to the line 20h and a connection of the ballast capacitor 206. The other connection of the capacitor 206 is connected by a line 20¾ to the line 124c. Of the wire 190, one end is connected through a line 210 to the line 196, and the other end is connected through a line 212 to a branch 214 on the energy-saving format winding 1j? 2.

The third circuit 216 carries the same reference numerals for 8302449-28 parts corresponding to the circuit 18¼ with postscript a, and is the same as the second circuit 18h, except that the separate transformer 198 is canceled using single turns of the autotransformer circuit at both ends, for example by switching one end of the wire 188a to a branch 202a on the winding 192a a few turns from the end. The wires of the lamp 186a receive controllable power from this circuit, i.e. the glow current is reduced after the lamp light arc is fired.

The fourth circuit 218 is the same as the circuit 216, except that the ballast capacitor 206a has been replaced by a ballast choke coil 20eb. Other parts have the same reference numerals as the corresponding parts in circuits 18¼ and 216 with subscript b, and need not be described further. The inclusion of the ballast capacitor 206a in the circuit 216 with the ballast choke 206b 15 in the circuit 218 gives a high power factor.

The circuits 1-8¼ »216 and 218 operate, in the same way as for all circuits, in principle in the same manner to provide. a full voltage from the inverter circuit, to which leads 12ta and 128c are connected across the lamp upon ignition, and a greatly reduced voltage after it is in constant operation. In the circuit 18¼, a full voltage is applied to the wires at all times, while the voltage applied to the wires in circuits 216 and 218 is automatically reduced as the voltage across the lamps decreases.

The fifth circuit 220 comprises two fluorescent tubes 222 and 22¼ in series over the lines 12ta and 128c, and fed by a single glow transformer 192c. The tube 222 has one wire 226, which is connected at one end to a tap 202c on the transformer winding winding 192c, as in circuit 216, and at the other end at the end of the transformer winding 192c, and through the capacitor 206c. and lead 208c to lead 12ta. The wire 190c at one end of the tube 228c is connected at one end to the branch 2lhc on the transformer winding 192c on single turns from the end, and at the other end through the lines 210c and 198c on the line 128c. The neighboring end wires 22T and 228 of the tubes 222 and 22¼ are respectively connected in parallel over the terminals of a short winding 230 which forms a secondary winding of a transformer having the primary winding 192c. Optionally, a small capacitor 8302449 - 29 - 232 (or choke), switched over the housing 22k (or instead over the housing 222) can be used to aid ignition and the need for high voltage for good operation. Reduce.

The sixth circuit 23 ^ is the same as the circuit 220 except that the capacitors 206c and 232 are replaced by the inductances 206d and 232d, respectively. Other parts of the circuit 23 ^ have the same reference numerals as the corresponding parts of the circuit 220 with the postscript d and need not be described in detail.

The circuits 220 and 23k operate in principle in the same manner as the circuits 216 and 218, except that two tubes are connected in series in the circuits 220 and 23 instead of a single tube in the circuits 216 and 218.

Fig. 12 shows the great versatility of the present circuitry for modification without changing the operating principles to operate with a constant glow voltage or to achieve a voltage reduction across the wires of the lamps with a consequent reduction of the heating current during operation. after ignition with maximum voltage and at high power factor.

In Fig. 13, an altered means is slightly different from the means shown in Fig. 6 in that the current through the resistor T1d with a relatively high resistance, for example 100 k SL, (a) directs to the base 5 & L and (b) through a winding 6ld and a resistor 2 ^ 0d with a relatively low resistance, for example 10 - 4, to the base ^ 9d, and the feedback windings 79d and 79ad are placed on the core 55d in each connection lead from the resistor 75d to diode 73d and diode 7d, respectively. Thus, the base k6d is connected to the base ^ 9d by the diode 73d, the two windings 79d and 79ad in series and the diode 7 ^ d, and to the lead 69d by the diode 73d, the winding 79d, the resistor 75d and the choke 78d for feeding the bases of the transistors Wid and 1 * 5d.

Current passing through this resistor 71d provides a very small initial bias current to ensure reliable ignition. The operation of the modified circuit is referred to FIG. 13 13 as follows. At least one of the transistors becomes conductive and passes the current from the terminal Md through the choke 7od, the center tap 57d and alternately through the primary windings 52d and 53d 8302449-30 - of the main inverting transformer 5d. Thus, a voltage is applied to the winding 52d, 53d, which induces a voltage in the low-voltage feedback winding O1d on the same core 55d. A terminal of the winding 6ld is connected to the base U6d of the transistor 5 Mid. The other terminal of terminal 61d is connected to the base ^ 9d of transistor U5d by the aforementioned resistor 2 ^ 0d. The polarity of the feedback winding 61d is such that what the transistors do is amplified. I.e. that if the transistor W-d initially conducts more than the transistor i + 5d, the feedback signal tends to make the transistor Wd more conductive, and the transistor 5d is rendered non-conductive. Capacitor 60d resonates with windings 52d, 53d and inverts voltage polarity intermittently in all windings on core 55d. First one transistor is conducting and then the other. The winding 76d maintains a constant current by itself, so that the sum of the two collector currents of the transistors must be constant. In the transition interval during switching from one transistor to the other, and when both transistors are partially conductive and the windings 52d and 53d short-circuited, the winding 7 & d ensures that no excessive current 20 is supplied.

Voltage is also induced in the higher voltage feedback windings 79d and 79ad, switched through the slow diodes 73d and 7d at the bases b6d. and U9d and at a midpoint on resistor 75d, wherein when the oscillations build up sufficiently to make diodes 73d and 7d d conductive by this voltage, most of the transistor base current is supplied from this new source. It is much more efficient to obtain the base current from the single turns of these two windings on the core 55d than from the 120 V input source. Only 1.2 mA of the base current is supplied by the resistor 71d, while about 80 mA of this two windings 79d and 79ad. This embodiment saves about 9 W. The diodes 73d and 7 ^ d also have other important operations. They, of course, force the ignition current to pass from the resistor 71d into the transistor bases instead of being drained by the resistor 75d. The diodes 73d and 7d also also switch the two attractive high voltage feedback windings 79d and 79ad at the two bases on the moment of switching to provide a large feedback signal to ensure fast switching and very fast switching off for one transistor and fast switching on for the other. The diodes 73d and 7½ are slow diodes, having a longer charge storage time than the transistor and 44d and Md. Thus, while one diode is normally conductive, the other is conducting opposite conductors for a short time until the transistor to which it is connected is completely turned off. However, before the hasis is driven too far negative, that diode ceases to be conductive, and the base can only drop as far as allowed by the low voltage feedback winding 6ld (for example, to about -4.5 V).

The voltage at the common junction of the two feedback leads 79d and 79ad with the resistor 75d has a negative DC component of about 4.5 V with respect to the terminal 42d, and an AC component consisting of a series of half sinusoidal waves. It appears that the AC component at this common connection point has the same waveform as that at the center tap 57d, except for polarity and amplitude. The AC component at the center tap 57d appears across the winding j6d. By adding a second winding 78d with very few turns on the same core 66d and switching it in the manner shown, the AC component of the voltage between the spring position 75d and the winding 7öd can be made almost completely equal to that of the junction of the resistor 75d with the two feedback leads 79d and 79ad. The potential across resistor 75d is therefore substantially a pure 4.5 V DC voltage, and a constant current of about 80 mA 25 is provided through resistor 75d and in one of the bases of transistors 44d and 45d. Since the sum of the collector currents is kept constant by the inductance 76d, it is correct and effective to also have the sum of the base currents constant.

If the voltage at the center tap 57 of FIG. 6 or 30Jd of FIG. 13 ever rises sufficiently far above the terminal 41 or Md, the Zener diode 85 or 85d becomes conductive to prevent further rise to protect the transistors . An abnormally high voltage may occur at center tap 57 and 57d for a few periods when turned on. The diode 84 is used to prevent the conductivity of the diode 85 when the voltage at the center tap 57 drops below that at the terminal M, as occurs during normal operation.

8302449 - 32 -

Diode 86 and diode 36d operate only "when turned off to allow a current drain path in windings 6 and 76d, respectively.

The capacitor 8ld- helps reduce radio noise, which is fed back into the DC power line. Inductances 76 and 71d are also very effective in this regard, although that is not the main effect thereof.

A secondary winding 237d may be wound on the core 55d of the transformer 5d to provide output terminals 10. H3d and ^ 3ad at the ends thereof instead of or, if desired, in addition to the output terminals U3 and k $ a. according to fig. 6.

Tubes can be connected to any pair of terminals in this modified circuit of FIG. 13 to basically the same manner as shown for the tubes 67 in FIG. 6 using ballast capacitors or ballast inductances or both.

Each tube or pair of tubes operates independently of the others, and has its own ballast choke or capacitor. By using both inductors and capacitors, the reactive effects on the inverter circuit cancel each other out. The loading power factor is therefore high, and the frequency of the inverting circuit is relatively independent of the loading when some of the tubes are removed.

Air gaps are used on both the chokes and transformers 5 ^ and 76, as well as on the ballast chokes. A DC input voltage of about 120 V was selected due to the commercial availability in the United States of switches and circuit breakers with this allowable load, which also allows incandescent lamps to be driven from the same circuit. Other voltages can be used when switches and circuit breakers with other allowable loads are commercially available.

Lamp wires in the modified circuit of FIG. 13 may be energized with 1-windings on the core of the transformer 5 ^ d, in the same manner as in FIG. 6. One winding can feed one end of all lamps connected to each other. may be switched, however, requiring separate windings at the ballast ends. Also, one or more separate glow transformers can be used to reduce the number of wires to lamps, which are not in the same fixture with the inverter circuit, or to reduce the glow power after the lamps are turned on.

The circuit of FIG. 6 and the modified circuit of FIG. 13 can be changed by adding a diode in lines 65 and 65d, and a diode in lines TG and TOd, which serve to ensure the absence of a reverse supply of power in lines 65, 65d and 70, JOd.

The switching of the anode of the Zener diode 85, 85d in the circuit, which is connected in FIG. 6 (by the diode 8 &) across the choke coil 76, is directly connected in the modified circuit according to FIG. base U6d of the transistor kkd, and by the winding 6ld and the resistor with the lower resistor 2k0d at the base ^ 9d of the transistor ^ 5d. The anode of the Zener diode can instead be directly .. ...

are connected to line 69, 69d. The circuit of the lead 62 to the lead 72 through the Zener diode 85 "b and 8kd causes the DC input voltage (120 V) to be added to the conductor voltage of the Zener diode 85, which must be designed for conducting it is approximately 120 V for the required maximum of 2k0 7 at the midpoint 57 · In the modified circuit of FIG. 13 and the aforementioned modification thereof, wherein the diode 8h is canceled and the anode of the Zener diode 85d is directly connected to the base k6d or line Ö9d, dg must conduct Zener diode 85d at about 2 ^ 0 7. Diode 8k prevents, if used, conducting Zener diode 85 when the cathode of Zener diode 85 drops below 120 V, as intermittently occurs during normal operation 25. The direct connection of the anode of the Zener diode 35 to the negative input terminal U2, when connected directly to line 69, is the most obvious alternative, but requires an hog there is an assembly of voltage and current in the Zener diode 85 than the other circuits described.

The modified circuit of FIG. 13, wherein the anode of the

Zener diode 85d is directly connected to the base U6d, can be further modified by adding two other diodes 299 and 300. From the diode 299, the cathode is connected to the collector VTd of the transistor hhd, and the anode to the junction of the anode of the diode 73d and the feedback winding 79d, and of the other the cathode is connected to the collector 50d of the transistor 5d, and the anode to the junction of the anode of the diode 7d-d and the feedback winding 8302449 - 3b - 79ad. With these two diodes in the circuit, the allowable resistor load of the resistor 75d can be selected to provide all of the base current, which the transistors do not need, of normal or high bias through these two diodes 299 and 300. (hence extraction diodes) from the base is tapped to the collector of each of the transistors as it approaches saturation. As a result, the transistors cannot fully saturate and can turn off faster than when they can saturate heavily. These two diodes 299 and 300 can therefore further serve to set the in-digest circuit for picking up transistors which differ greatly in current bias. While these two other diodes have hitherto only been described for the circuit, with the anode of the Zener diode 85 connected directly to the base H6d, they can also be used in the other described circuits if the advantages just described are in a whether more of these circuits are desired.

Switching the anode of the Zener diode 85d at the base of one of the transistors Wd and U5d causes at least one of these transistors to become highly conductive when the diode 85d becomes conductive. Current supplied by the collectors of the transistors Mkl and ^ 5d 20 can limit their collector voltage as effectively as current through the Zener diode 85d, but with the advantage that the transistors Hld and ^ 5d can conduct much larger currents than the Zener diode 85d in this condition. Thus, by using the Zener diode 85d to turn on the transistors Wtd and k5d, an inexpensive Zener 25 diode with relatively low current can be used.

The control circuits just described for transistors bk and * + 5 represent a significant improvement on circuits known in the art. Two independent feedback windings of the main inverter transformer are used to optimally meet conflicting requirements. It is desirable to have a large feedback voltage during the switching time to turn off one transistor and turn on the other with a minimum overlap time when both transistors are partially conductive. However, a sufficiently large feedback voltage for this purpose causes too much reverse base voltage for the switched off transistor between the circuits, if only one feedback winding is used, as according to fig. 6 and J.

8302449 - 35 -

A VI ρπ r. <=> Current from the + DC source 4ld is supplied by the resistor 71d to provide a very small amount of bias to the bases of transistors 44d and 45d. This is sufficient for the transistors to start oscillation in the usual manner, ie that the outputs of the collectors of the two transistors are connected to the transformer 54d by the windings 52d and 53d, which are again magnetically coupled to the transistor bases 46d and 49d via the low voltage mnggf.g-riigyprnpglw! vv ^ iing 6ld on the core of the same transformer. The feedback polarity is such that an oscillation-10 state is amplified and maintained, each transistor passing alternating current from the positive DC voltage source 41 through the choke j6d, line 62d, and then through the winding 52d or 53d of transformer 54d, and back to the negative power supply terminal 42d.

When the amplitude of the oscillation increases sufficiently, the diodes 73d and 74d are alternately turned on and off by voltage induced in the high voltage feedback windings 79d and 79ad in the modified circuit of Fig. 13, as described.

The base current is greatly increased by current from any of these feedback windings, and the bases are currently efficiently controlled essentially from this source. Although the voltage of these feedback windings is high compared to the voltage of the winding 6ld, it is still small compared to the input voltage at terminals h-1d and 42d, which means that the base current is obtained more efficiently of these feedback windings then of the drop resistance high resistance 71d.

Diodes 73d and Jhd are cheap. slow low voltage diodes, which have a longer charge storage time than the transistor bases 46 and 49. This means that when the anode of one of the diodes 73 and 74 goes negative with respect to the cathode, that diode does not immediately turn off but is conductive. and removes all of the stored charge in the base of the connected transistor. The other diode has already been switched on before. Thus, during this critical switching time, the high voltage feedback windings are directly connected to both bases by the very low impedance diodes 73d and 74d, and the low voltage winding is effectively isolated by the resistor 240d. As the voltage of the base of the switch-off transistor drops 8302449 -3 6 - to a safe level below, the associated diode arrives at the end of the stored charge (while also supplying power, baptizing the series resistor) and is de-energized. negative peak base voltage is therefore, as desired, determined only by the low voltage winding 6ld. Current supplied by the collectors hj and 50 of the transistors 44 and 45 can limit the collector voltages as efficiently as current through the Zener diode 85, but with the advantage that the transistors can conduct much larger currents than the Zener diode 85 must in this circuit. conduct. Thus, by using the Zener diode 85 10. Before turning on the transistors, an inexpensive Zener diode with a relatively low current can be used.

Fig. 14.shows a circuit connecting essential components of an inverter circuit to two pairs of series fluorescent tubes connected in series with means for heating the wires of all tubes and using both the capacitor and the choke-ballast circuit for a high power factor . Terminal 241 switches the inverter on the positive terminal, and terminal 242 switches the inverter on the negative terminal of a power supply line (not shown). Current supplied from the terminal 241 in the inverter circuit passes through the winding 243, which is equal to the winding j6 in the circuit of FIG.

6, to the center tap 244 of the two windings 245 and 246 of the primary winding of a transformer 247, provided with a magnetic core, for example, a ferrite core 248. The transformer 247 25 has a secondary main winding 249, which provides the output circuit of the inverting circuit. A number of short secondary windings, described below, are also provided. The free end connection of the winding 245 is connected to a line 250. The free end connection of the winding 246 is connected to a line 251. A condensate 30 satpr 252, equal to the capacitor 60 of FIG. 6, is connected to one connection to lead 250, and to the other terminal on lead 251. Lead 250 is also connected to transistor 255 through diode 253 · Similarly, lead 251 is connected through diode 254 to transistor 256- Transistor 255 has a base 35 257, a collector 258, to which the diode 253 is connected, and an emitter 259. The transistor 256 has a base 260, a collector 261, to which the diode 254 is connected, and an emitter 2β2. The bases are powered by a secondary low voltage winding 263 on the core 2k8 of the transformer 2¾7, d, wz, so that they are feedback windings with very few turns, eg two turns. The emitters 259 and 262 are connected together the negative connection indicated above 5 2¾2.

Tubes 26h and 265 are connected in series across the aforementioned inverter circuit output circuit as well as tubes 266 and 267. A short secondary winding 268 on core 2h8 of transformer 2¾7 supplies heating current for wire 269 at a first end 10 of the tube 264. Ballast for the tubes 26¾ and 265 is provided by a choke 270, which is connected to one connection to a connection of the secondary winding 2 ^ 9 »and to the other connection to the line, which switches the winding 268 to wire 269 as shown. Another short secondary winding 271 on core 2b8 15 supplies wire heating current to wire 272 at the second end of tube 26¾ and to wire 273 at a first end of tube 265.

Another short secondary winding 27¾ on core 2¾8 provides wire heating current to wire 275 at the second end of tube 266, and wire 276 and first end of tube 267. An additional short secondary winding 277 on core 2¾8 provides wire heating current to the wire 278 at the first end of the tube 266. The tubes 266 and 267 have a capacitor ballast circuit 279 connected to one terminal on the line that switches the coil 277 to the wire 278 and to the other terminal to the same terminal 25 of the secondary winding 2¾9 as the choke 270. A last short secondary winding 280 is connected at one end to the other terminal of the secondary winding 2¾9, and at the other end to the wire 281 at the second end of the tube 267 and at the wire 282 fl-sm the second end of the tube 265, whereby these two wires are connected in parallel over the lines from the windings 280. The operating Five of this circuit is obvious in light of the discussion above of other inverter output circuits, and need not be repeated. The combination of choke and capacitor ballast circuits in the circuit provides a high power factor in the choke coil output circuit,

The circuit shown in Fig. 1 kan can be changed to feed four parallel connected tubes instead of two parallel connected pairs of two series connected tubes. The components of the inverter circuit and their circuitry together in the modified circuit are the same as of the components of the inverter circuit in the circuit of FIG. 1 ^, and the changes are in the circuits of the four parallel-connected fluorescent tubes. These are all connected in parallel with the secondary winding 2k9 in substantially the same manner as the three paralleled fluorescent tubes of FIG. 6 are connected to the terminals and ^ 3a. A transformer, such as the transformer 5 ^ of FIG. 6 is 10. in other words, provided with a secondary winding, such as the secondary winding 2k $ in FIG. 1, which is connected at one terminal to a winding, such as the winding 92, and the four wires at the end of the tubes, fed by a single short winding such as the winding 92, and on the other terminal to the four wires at the other end of the tubes, which have separate, short, secondary windings. Thus, a connection of the secondary winding is connected in parallel with each of the two tubes by a ballast choke on the wire circuit, which contains a short secondary winding, such as the winding 268 of FIG. 1 ^, and at the end of the other two tubes 20 by a ballast capacitor on the wire circuit, which includes a short secondary winding, such as the winding 277 of FIG. 1U. The circuit of a single short winding, such as the winding 92 of FIG. 6, and 280 of FIG. 1U, is on each of the wires at the other end of the four tubes connected in parallel, like the wires of the three tubes of FIG. 6 are connected to the winding 92. The operation of this circuit is evident from the descriptions of the output circuits of the previous inverters. The assembly of choke and capacitor ballast circuits in the tube inverter output circuit, as described, again ensures a high power factor in the output circuit.

A further modification of the circuit of FIG. 11 * is the addition of ignition aids for the two pairs of series-connected fluorescent tubes. The ignition aids are two capacitors, one of which switches the wire circuit 268 to the wire circuit 271 and the choke 270, and the other connects the wire circuit 27 ^ to the wire circuit 277 and the capacitor 279 · These ignition aids have the property of reducing the ignition voltage, needed 8302449 - 39 - for striking the arc between the cathodes (wires) on the first and second ends of the houses.

Fig. 15 shows a damping circuit comprising an inverting circuit similar to the inverting circuit of FIG. 14 and another inverting output circuit. Components in the circuit according to fig.

15 have the same reference numerals as corresponding parts in the circuit of FIG. 1b with the postscript c. The output circuit of FIG. 15 includes three fluorescent housings 26hc, 265c and 266c, of which housings 26bc and 265c are connected in series, which assembly is connected in parallel with housing 266c over the terminals of the secondary winding 2 ^ 9c of the inverter transformer 2bjc. The casings connected in series have a capacitor ballast circuit 279c between the line which switches the short winding 268c to the wire 278c and the connection of the secondary winding 2 ^ 9c. The parallel-switched housing 266c has a choke half-load circuit 28h between the line which switches the short winding 277c to the wire 278c of the housing 266c and the terminal of the secondary winding 249c. The short windings 268c, 274c and 280c receive a voltage induced therein by the primary winding 287, which receives voltage from the winding 249c of the inverter transformer 247c.

An auxiliary circuit 289 is provided which, in series, has a primary winding 290 of a saturated choke 291 provided with a magnetic core 292, for example, ferrite, and an adjustable resistor 293, connected to the DC terminals 241c and 242c or other DC source. The secondary winding of the choke 291 is a short winding 294, a connection of which is connected through the line 295 to a capacitor 297, which is connected to the line, which switches the short winding 268c to the wire 278c, and to a choke 298 on the core 292, connected to the lead, which switches the short winding 277c to the wire 278c of the housing 266c.

The ballast capacitor circuit 297c and the ballast choke circuit 28b conduct small currents to the associated housings for highly damped operation. Supplemental power is supplied from the halla capacitor 297 and halla choke 298 through the saturation 35 choke windings 294 for clear operation. The amount of additional current is controlled by the DC current in the winding 290 of the saturated choke, which DC current is again controlled manually or automatically by means of the adjustable resistor 293 or some other similar means. In this way, the light intensity can be changed in response to changing needs.

In all inverters, a small capacitor can be used to switch the lead from the positive DC terminal (lead 62 in Figure 6 and the corresponding lead in the other figures) or the lead to the negative DC terminal (lead 69 in Fig. 6 and the corresponding lead in the other figures) to the metal structure (ground) of the tube fixture, allowing the ballast circuit 10 to meet U.S. safety regulations of Underwriters Laboratories regarding fixture leakage current.

High-frequency current can pass or leak through the capacitance from the primary to the secondary winding of the main inverter transformer 54 and further through the inevitable capacitance from the tube to the fixture to the fixture itself. The added capacitor provides a short local path for this leakage current to return to the starting point (primary winding) without leaving the armature.

A further useful change of the inverter circuit limits the transistor collector voltages without the use of a Zener diode.

Referring to Fig. 13, this change involves moving the conductor 76d from the effectively series-connected location with the positive DC input lead 62d, and effectively daisy-chaining it with the negative lead 69d. More specifically, the lead 69d between the switching points on the capacitor 8ld and the emitter 8d 25 is broken, and the choke 76d is switched between these points, and the Zener diode 85d is connected to the emitter. Two ordinary diodes have also been added, so that both of their anodes are connected to the negative input terminal 42d. The cathode of one of the added diodes is connected to a tap near the center of the primary winding 52d, and the cathode of the other diode is connected symmetrically to a tap near the center of the primary winding 53d of the transformer 5 ^ d · When with this modified circuit an excess voltage appears at the collector of one of the transistors, said tap on the primary winding, switched on the other transistor, goes negative to turn on one of the added diodes and switching the constant DC input voltage across the portion of the primary winding between the center 8302449 - <- Μ - branch 57d and the top point, to which is the added conductive diode. switched. Thereafter, the voltage on none of the windings of the transformer 5 ^ d can rise further. Excess energy stored in the choke j6ö. is fed back to the DC 5 power source by these means rather than being scattered in the Zener diode or transistors. With this changed location of the choke J6d, the winding 7d on the same core 66d need not be an additional winding, but may be an extension of the winding 76d. This simplifies construction by reducing (by one) the number of terminals required for the choke j6d and the winding 78d, and by avoiding the need to isolate these windings from each other,

The present circuits, and in particular the electronic ballast circuits, are of great benefit to the public utility companies on account of their. efficiency, which makes it possible to save on capital investment. The circuits are also of great value to users of electrical power for lighting due to large savings, which can be made in the consumption of electrical power.

Fluorescent tubes are more efficient at high frequencies than commercially available 50-60 Hz AC, a fact which has been recognized for many years in this field, as discussed in the introduction to the description. Despite this recognition, no system is available on the market, providing the advantages of the present affordable, safe, economical, reliable, efficient and smooth system for operating at high frequencies, for example in the range of 20 - 30 kHz or higher or a ballast circuit, which provides safe, economical, reliable, efficient and flexible use in existing fluorescent tube installations, and in particular as part of a system powered by a three-phase power source. The system and the ballast circuit utilize the increased efficiency enabled by the high frequency in the range of 20 - 30 kHz, keep the force fleece to a practical minimum in the inverter circuit and the ballast circuit, keep costs low, obtain a high power factor (for example at least 90%), provide reliability by preventing the use of parts, such as electrolytic capacitors and by using a minimum number of parts, m 8302449 - h2 - obtain low noise, low radio noise and - little flickering.

The inverter circuit can be described as a symmetrical, current-limited transistors, class B balance oscillator with switched higher and lower feedback windings. The circuit is self-starting, highly efficient and stable over a wide range of input voltages with or without load.

While the system and ballast circuit have been described and illustrated with many modifications and embodiments, it is apparent to those skilled in the art that further modifications and embodiments can be provided within the scope of the description and claims without departing from the principles of the disclosed invention.

8302449

Claims (28)

1. Electronic halogen circuit for gas discharge lamps, comprising inverters, which contain input terminals for receiving and inverting a DC from a power supply thereof to a high-frequency AC, and supplying this AC to output terminals, characterized in that the inverters consist of a symmetrical, current-limited, class B dual-feedback balance oscillator, the high-frequency AC being at the proper voltage to provide the required ignition voltage for the gas discharge lamps, which voltage is to be connected to the output terminals 10 and ballast means for these gas discharge lamps . Circuit according to claim 1, characterized in that the inverting means consist of two transistors, of a transformer, of which a primary winding is connected to the collectors of the transistors, of two secondary feedback windings in the transformer, one of which has a relatively high voltage in the center is tapped and is connected at each end by a relatively slow diode to the base of another transistor, and the second has a relatively low voltage, which is connected to the bases of the transistors by a circuit, comprising resistors contains. Circuit according to claim 2, characterized by two extraction diodes, one of which is connected to one connection at the connection point of one side of the feedback winding with the higher voltage and the associated slow diode, and at the other connection at the connection point of the collector of the neighboring transistor and the transformer, and the other to one terminal is connected at the junction of the other side of the higher voltage feedback winding and the associated slow diode, and at the other junction at the junction of the the other side of the higher voltage feedback winding and the associated slow diode, and the other terminal at the junction of the collector of the other transistor and the transformer. 4. A circuit according to claim 1, characterized in that the inverter means comprise a choke, provided with a magnetic core for keeping the direct current substantially constant through the circuit of the means for inverting the DC into a high-frequency AC, and m 8302449 C -From a second choke on the magnetic core to keep the basic current substantially constant. Circuit according to claim 1, characterized by a DC supply means. Circuit according to claim 5, characterized in that the DC supply means is a battery. Circuit according to claim 5, characterized in that the DC supply means is a solar cell. Circuit according to claim 5, characterized in that the DC supplying means is a rectifier. Circuitry according to claim 8, characterized in that the rectifier comprises a single-phase diode bridge. 10. Circuitry according to claim 8, characterized in that the rectifier comprises a transformer, comprising a triangular-switched primary winding, which can be supplied with three-phase current of any commercially available voltage, phase and frequency, and an inductively connected circuit. secondary six phase winding. 11. Circuitry according to claim 1, characterized in that the gas discharge lamps consist of fluorescent tubes, the ballast circuit comprising a number of electrical switching means, which means can be switched at the output terminals for holding the fluorescent tubes. Circuit according to claim 11, characterized in that the ballast means are electrically switched at the output terminals and can ballast a tube in each of the electric switch means. Circuit according to claim 12, characterized by a choke, a capacitor or both a choke and a capacitor. lU. Circuit according to claim 11, characterized by a transformer, a primary winding of which is connected to the output terminals, and a secondary winding of which is connected to a load, which secondary winding has only an inductive coupling to the primary winding. Circuit according to claim 1, characterized in that the circuit is combined with a high-frequency AC lighting system containing rectifying means, provided with AC input means, which can be switched to a source of AC power with commercial voltage and frequency, and DC output terminals constituting the DC supply, 8302449 - U5 - connected to the input terminals for receiving DC, further electrical switching means for receiving a high frequency AC from the output terminals of the inverter means, and lamp receiving means, which may be at least a gas discharge lamp hold and switch each lamp 5 «· * · η the electrical switching means. Circuit according to claim 15, characterized in that the rectifying means includes means for voltage transformation for the AC input terminals for transforming the AC from the source AC power into the correct voltage for the distribution arrangements for the AC 10 mains commercial frequency, which facilities include at least single phase output terminals, rotary power output terminals or six phase output terminals. Circuit according to claim 15, characterized in that the rectifying means comprise AC output terminals which can be connected to distribution units for the commercial frequency AC. Circuit according to claim 16, characterized in that the means for transforming the voltage comprise a primary three-phase winding and a secondary winding comprising six windings, each connected at one end to a common center which is electrically is connected to a neutral output terminal, and the other end is connected to diode means for conducting positive current to a positive output terminal, and to diode means for conducting negative current to a negative output terminal. Circuit according to Claim 1, characterized in that it is combined with a lighting system for a high-frequency AC, which system comprises a centrally arranged rectifying means, further a number of lamp-receiving means, connected to the ballast means, each lamp-receiving means is a fixture capable of holding at least a fluorescent tube and supplying a high frequency AC thereto, the inverter means being supplied with a DC from the centrally disposed rectifier. 20. Circuitry according to claim 19, characterized in that the inverters are associated with and supply a number of adjacent, removable fluorescent tubes. Circuit according to claim 19, characterized in that the system comprises a transformer, provided with a primary multiphase winding, 8302449-1 * 6. - V that can be connected to a commercial multiphase AC Iron, and from a secondary, star-switched six-phase winding, connected to diode rectifiers, with the positive current connected to a positive output terminal, and a negative current to a negative 5 output terminal for supplying the DC to the inverters. Circuit according to claim 2, characterized in that it is combined with a high-frequency illuminant, which contains recording means, which can hold at least one fluorescent tube, provided with electrodes at each end thereof, connected to a wire, the transformer having a high-frequency magnetic core further, secondary high frequency heating coils are present on the core, and means are provided for switching the heating coils to the wires in the fluorescent tube. Circuit according to claim 22, characterized in that a further transformer is provided, which contains a primary winding, which receives the energization of voltage across a fluorescent tube, the heating windings being inductively coupled to the primary winding, whereby the glow current is automatically reduced when the tube voltage is reduced after the fire voltage has been established in the tube. 2k, Circuit according to claim 19, characterized by means for changing the current through a fluorescent tube. Circuit according to claim 2, characterized in that it is combined. with a high-frequency AC lighting system, consisting of 25 rectifying means for receiving and converting commercially available AC to DC and supplying it to the inverter means, from electrical switching means, switched to the transformer for receiving the high-frequency AC and lamp holding means, which can hold at least one gas discharge lamp, provided with electrodes. 30 in contact with the electrical switching means. Circuit according to claim 25, characterized in that the system comprises a number of inverting means, furthermore a number of electrical switching means, the ballast means limiting the current supplied in each lamp, when connected to the electrical switching means. Circuit according to claim 15, characterized in that the secondary six-phase winding has a grounded, neutral conductor common to the AC and DC parts of the system. 8302449 - - Circuit according to claim 19, characterized in that the lamp armature is connected by only two wires to the lamp receiving means in another armature. 29. Circuitry according to claim 25, characterized in that the inverter means comprise secondary heating windings in the transformer for making an electrical circuit on wires in lamps which are held in the lamp holding means. Circuit according to claim 29, characterized in that the primary winding of the transformer with the secondary heating windings, 10. is located over a lamp, whereby a relatively high current is supplied by the wires, before an electric arc is excited, and a relatively low current after a light arc has struck. Circuit according to claim 29, characterized in that means are provided for changing the current supplied by a lamp 15 during operation thereof. 32. Ballast circuit essentially as described and illustrated. 8302449