MXPA98009217A - Ballast of multiple voltages and dark circuits for a system of transformation and voltage balastation driven by lamp - Google Patents

Abstract

A discharge lamp operation circuit is connected to an alternating current (AC) source, and has a discharge lamp and a semi-resonant circuit connected to the source of alternating current voltage and in series with a lamp. A start circuit to start the operation of the discharge lamp is also connected in the circuit. The switching of the lamp keeps the semi-resonant circuit in series in oscillation and the semi-resonant circuit in series keeps the lamp in operation after the operation has been initiated by the initiation circuit. Highly efficient energy transfer between the inductive and capacitive components of the system results in low loss and high energy factor. A variable capacitance circuit is provided to allow the use of the discharge lamp operation circuit with different line voltages, and to allow blackout

Description

BALLAST OF MULTIPLE VOLTAGES AND CIRCUITS OF DARKNESS FOR UÑ TRANSFORMATION SYSTEM AND VOLTAGE BALASTATION DRIVEN BY LAMP This is a continuation request in part of the previous application Serial No. 08 / 556,878, originally filed on November 2, 1995.

Field of the Invention This invention relates to a discharge lamp discharge circuit which uses the lamp as a switch to create the voltage necessary to drive the lamp in normal operation, and with multiple voltage and blackout ballast circuits for the same .

Background of the Invention Whenever the line or supply voltage is less than the open circuit voltage (OCV) required to operate a gas discharge lamp, the magnitude of supply voltage to the lamp must be increased in order to drive the lamp to operation. There must also be some technique to turn the lamp on and off again, either hot or cold. The starting voltage required is greater than the operating voltage of the lamp. Many different systems have been designed to provide this required volt-aje of lamp operation. The conditions described above, where the supply voltage is lower than the OCV required for lamp operation, are common because the lowest usable voltage is normally used due to economics and availability at the application site. One normally uses the exit lamp highest of lumen per watt which is frequently one of the higher voltage lamps. The lighting system must be consistent with the lighting requirements and must be operable at the available line voltage. If a 120 VAC supply is available, - c- lamps of certain types up to some known wattage level and lumen output can be operated; For the newer, more efficient metal halide lamps and the higher wattage lamps, a higher lamp supply voltage should be provided.

As 240-530 VAC, it may not be available. In these circuits, there are certain basic components, in addition to the lamp itself, that currently, including some form of ballast for transforming voltage and to control or limit the "... level of operating current and lamp energy. A semiconductor interrupting circuit is typically used to stagger the source voltage to provide the required lamp ignition and sustaining voltage. The lamp ignition circuit is normally present and it is common to switch this starting circuit on, out of operation, or to minimize its influence, after the lamp has entered its normal operating mode. Manifested differently, a lamp operation circuit most often includes a power source, which is normally a low-voltage AC source, some circuit elements to control the amount of wattage that is delivered to the lamp, and the lamp. The circuit usually includes other components for special purposes such as power factor control. Prior art lamp operation circuits have been based on interruption devices such as SCRs, Triacs, transistors or the like to do some of the voltage transformation and control interruption, and many of these circuits have included complex and expensive collections of circuits and components. The more components that are used, the more attention should be paid to the problems associated with heat dissipation and circuit and life failure regimes. Therefore, it is desirable to minimize the number of these components. It is also very desirable, especially in high wattage lamp circuits, to have a high operating power factor for the lamp and the operating circuit. This is sometimes a problem with circuits that use large inductive devices, and many prior art circuits include capacitive devices to correct the energy factor. The switching circuits that are used in the lamp operation circuits most frequently generate a low power factor and high line harmonics condition.

SUMMARY OF THE INVENTION In accordance with one aspect of the present invention, there is provided a driving circuit for a discharge lamp which uses a minimum number of components and which employs the characteristics of Q switching of the lamp itself for circuit operation to push the lamp. A further aspect of the present invention is a lamp operation circuit which is highly efficient and which in this way reduces the energy loss and heat dissipation associated with a selected level of light output, as compared to circuits of the prior art, and operates with a high energy factor. Still another aspect of the present invention is a highly efficient method for initiating and operating a high intensity discharge lamp (HID) that uses a minimum number of components. Briefly described, the invention includes a discharge lamp operation circuit connected to an alternating current (AC) source. The circuit has a discharge lamp, an inductor L and a capacitor C in which the intrinsic switching operations to the lamp collide-excite the inductor L and the capacitor C to an exchange of energy and transfer during each half cycle at a frequency higher than the frequency of the AC source. The inductor L and the capacitor C are connected in series with the lamp, and a circuit is provided to start the operation of the discharge lamp. Lamp switching maintains half-cycle operation, and the power transfer circuit keeps the lamp running after the operation has started, even though the source voltage is less than the lamp operating voltage. In another aspect, the present invention includes a discharge lamp operating circuit comprising a discharge lamp having a predetermined operating voltage or open circuit voltage (OCV), an inductive reactance, a capacitive reactance connected to a source of alternating current (AC) so that the reactances and the lamp are in a series circuit through the AC source. The AC source is capable of providing an AC voltage that has an RMS (square root mean) voltage in a 0 scale that is less than the OCV required by the lamp. A start circuit is connected to the lamp terminals. The inductance and capacitance values of the inductive and capacitive reactances are selected to be semi-resonant at a frequency - ^ 5 higher than the frequency of the AC supply so that, after the lamp has been switched on, the lamp is switched and causes an exchange of semi-redundant energy with the ballasts, thus maintaining the lamp in a condition stable operation 2Q up to full classification wattage. In accordance with yet another aspect, a discharge lamp operation circuit constructed and operated in accordance with the present invention is provided with a variable capacitance circuit for create a system of multiple voltages or compensation of input voltage. The variable capacitance circuit comprises a switching device and at least one capacitor C2 connected in parallel with the capacitor d, which is connected in series with the inductor L and the lamp of the discharge lamp operating circuit. The variable capacitance circuit can add or remove one or more capacitors C2 to C, parallel, where n is an integer, 'in accordance with the line voltage applied to the discharge lamp operating circuit. Consequently, a multi-voltage ballast is created using the same inductor L, the Ci capacitor and the lamp combination of the discharge lamp operation circuit, thus minimizing the number of components used to create a compensation system. input voltage. The switching device can be a relay or an electronic or mechanical switching device. The variable capacitance circuit may also comprise an input voltage sensing circuit for operating the switching device to add or drop the capacitance as needed, depending on the detected input voltage applied to the discharge lamp operating circuit. In accordance with yet another aspect of the present invention, a discharge lamp operation circuit with a darkening circuit is provided. The dimming circuit comprises a switching device and at least one capacitor CD2 connected in parallel with the capacitor C i, which is connected in series with the inductor L and the lamp of the discharge lamp operating circuit. When darkening is desired, at least one of the parallel CD2 capacitors is disconnected through the switching device.

BRIEF DESCRIPTION OF THE DRAWINGS In order to impart a complete understanding of the manner in which these and other objects are achieved in accordance with the invention, a particularly advantageous embodiment thereof will be described with reference to the following drawings, which form a part of this disclosure, and wherein: Figures 1 and 2 are schematic circuit diagrams of circuits usable to describe the principles of the present invention; Figure 3 is a graph illustrating the impedance and voltage-amp curves for a discharge lamp; Figure 4 is a schematic circuit diagram of a basic lamp operation or drive circuit in accordance with one embodiment of the invention; Figure 5 is a functional block diagram illustrating the movement of energy in a conventional lamp operation circuit; Figure 6 is a functional block diagram illustrating the movement of energy in a lamp operation circuit in accordance with the present invention; Figure 7 is a schematic circuit diagram of a lamp operation circuit in accordance with an embodiment of the invention with a start circuit that can be used with a lamp of the type having an internal starting electrode or requiring the double OCV to turn on. Figure 8 is an equivalent circuit diagram useful in understanding the operation theory of the operating circuits in accordance with the present invention; Figures 9-12 are illustrations of waveforms, taken at specified locations in one embodiment of the present invention; Figure 13 is a schematic circuit diagram of a lamp operation circuit 25 similar to that of Figure 7 with a form of power switching on and off using the lamp itself to break the power circuit; Figure 14 is a schematic circuit diagram of a lamp operation circuit similar to that of Figure 7 with a further form of power on and off switching; Figure 15 is a schematic circuit diagram of a further embodiment of the lamp operation circuit in which the particularities of the above circuits are combined; Figures 16 and 17 are schematic circuit diagrams showing desirable arrangements of components for use in an embodiment of the invention in a residence or the like; Figures 18 and 19 are schematic circuit diagrams of circuits in accordance with embodiments of the present invention with photosensitive control element; Figure 20 is a simplified schematic diagram illustrating the generation of the start open circuit voltage; Figures 21 and 22 are schematic circuit diagrams of fluorescent lamp start and operation circuits for operating single lamps in accordance with embodiments of the present invention; Figures 23 and 24 are schematic circuit diagrams of fluorescent lamp start and operation circuits for operating two lamps together, in parallel and in series respectively, in accordance with embodiments of the present invention; Figures 25, 26 and 27 are schematic circuit diagrams of a multi-voltage ballast circuit to allow the same discharge lamp operation circuit constructed and operated in accordance with the present invention to be used with different line voltages; and Figures 28 and 29 are schematic circuit diagrams of a darkening circuit for ] _ obscuring a discharge lamp operation circuit constructed and operated in accordance with the present invention.

Description of Preferred Modes 20 Metal Halide (MH) lamps, even low wattage MH lamps, are lamps of 85 to 140 volts and thus require OCVs of 216 volts or higher for ignition and operation. Mercury vapor lamps are also 130-140 lamps volts. Therefore, there is a problem of trying to operate these various lamps from 120 volt power sources, and yet, 120 volts is the most readily available line voltage where low wattage lamps are used. As mentioned above, when the line or supply voltage is less than the open circuit voltage. { OCV) required to operate a discharge lamp (e.g., a gas and / or vapor discharge lamp), the magnitude of the lamp drive voltage must be increased for lamp operation. Most discharge lamps require OCVs of 220 voltages (AC, RMS) or higher. Therefore, most conventional ballast circuits incorporate some kind of volatile step transformer element. There are a variety of types of ballast circuit known in the art that will not be discussed herein, primarily because the present invention eliminates the need for such circuits. A circuit in accordance with one embodiment of the present invention actually uses the discharge interruption mechanism of the lamp itself at least once every half cycle to excite an inductance and capacitance connected in series towards a snapshot and RMS OCV of about Double the input line voltage to drive the discharge lamp. Additionally, the selection of the magnitude of capacitance to limit the current through the lamp to the correct value allows to adjust the 5 wattage of lamp operation to the correct value in accordance with the lamp classifications, that is, the values established by the manufacturer of lamps. A basic, exemplary circuit that was used in the laboratory to demonstrate the principles of The present invention is shown in Figure 1. This circuit was connected to a 120 volt AC supply to operate a 175-watt mercury lamp of General Electric. However, other discharge lamps such as a halogen lamp can be used. metal, a mercury vapor lamp, a high-pressure sodium lamp, or a fluorescent lamp, among others. It included an inductive L reactor, which was a ballast designed for use with a 150 watt HPS lamp, in series with the 10 lamp and a C capacitor of 30 uf. This series circuit was connected directly through the supply line without intervening transformers or other devices. The input was 120 volts at 1.53 amps, providing 169 watts at an energy factor of 0.921. The operating voltage of lamp was 131.2 volts and the lamp wattage was left at 164.5 watts. The voltage drops across L and C were 61.4 volts and 129.5 volts, respectively. It should be noted that the measured lamp operating voltage was higher than the line voltage. The reason for this is that the lamp itself is the generator of its own driving voltage. This lamp operation is further illustrated by the circuit of Figure 2, in which a resistor R was set to a value which is the equivalent of the effective resistance of the lamp 10 in Figure 1 and was replaced by the lamp, the Other circuit components are the same as in Figure 1. In Figure 2, the input voltage was 120.5 volts at 1418 amps and it gave 121.1 watts at an energy factor of 0.708. The voltage across the resistor was 82.9 volts, significantly less than the voltage across the lamp in the circuit of Figure 1 and less than the line voltage. It is known that a discharge lamp can operate as an open circuit, a short circuit, a rectifier, and a switch with an effective resistance, depending on the filling material (e.g., argon, neon and xenon) and plasma ( v.gr., mercury, sodium and metals) and the control circuit associated with it. The difference between the circuits in Figures 1 and 2 is that the lamp in Figure 1 switches the energy in the circuit to generate the upper lamp drive voltage for itself. The equivalent resistor in Figure 2 only dissipates the energy because it has no switching mechanism. The present invention employs a lamp switching mechanism that is intrinsic to the lamp and the lamp plasma components that constitute it, and is not a separate element added internally or externally with respect to the lamp, to facilitate the transfer of energy with inductor L and capacitor C. Figure 3 illustrates the impedance and voltage-ampere curves of a -lamp operating discharge (ie, a 400 watt high pressure sodium lamp, for example). The lamp resistance increases and then decreases rapidly and, therefore, is shown as a peak curve. during the application of a required OCV, and after the resistance decreases, the lamp is ionized and conducts current as illustrated by the voltage-ampere curve. the voltage-ampere curve decreases to an omissable level until the lamp is activated again. As will be described below, the increase in lamp voltage causes the inductive reactor L and capacitor C to resonate, resulting in an exchange of energy with the lamp where the lamp is activated again according to the invention. Figure 4 shows a basic circuit according to the present invention for operating a HID lamp of a type that has no internal starting electrode and therefore requires high voltage pulse ignition. The circuit includes an AC source 12, an inductor 14 and a capacitor 16, which are all connected in series with the lamp 10. With the appropriately selected values for the inductive reactor and the capacitor, as will be discussed later, this is the driving circuit and basic operation of the present invention. The circuit of Figure 4 includes a start circuit that uses a portion 18 of reactor 14 between a branch 20 and the end of the reactor winding. An interruption discharge device such as a Sidac 22 and a capacitor 23 are connected in series with each other and in parallel with the portion 18. A resistor 24 is connected to the junction between the Sidac and the capacitor 23 and is in series with a diode 25 and a radio frequency (RF) reactance coil 26, the reactor coil being connected to the other side of the lamp 10 to which the capacitor 16 is connected. This forms a high voltage pulse initiation circuit 15 (HV ). This impulse start impulse circuit 15 of H.V. it is driven by a second start circuit that produces a higher voltage than the input voltage source of the order of s 3 x V? n OCV. This voltage higher than the line produces through the lamp the required lamp start OCV, as well as higher activation voltage for the start pulse circuit 15 of H.V. This circuit 17 is usable with lamps that have or do not have an internal start electrode. The second charging circuit 17 includes a diode 27, a resistor 29 of positive temperature coefficient (PTC) and a fixed resistor 31 connected in series between the input side of the inductor 14 and the lamp side of the capacitor 16. The circuit 17 it may also include a small bypass capacitor 28 to derive the high frequency energy generated by the start circuit beyond the AC source and the lamp. Briefly, this start circuit comprising the circuits 15 and 17 operates by charging the capacitor 23 through the resistor 24, the diode 25 and the reactance coil 26 during successive half cycles in a direction determined by the polarity of the diodes 25 and 27 The AC supply is 120 volts, and therefore it is not sufficient to drive the high voltage impulse start circuit 15 up to the interruption voltage (240 volts, for example) of the Sidac. Additionally, the AC supply does not provide sufficient OCV to allow the lamp to collect, i.e., cause an interruption in lamp impedance, which in turn causes sufficient current to be attracted to heat the electrodes and to start and warm up positively. - When the AC supply is connected, the capacitor 16 that charges the circuit, charges the capacitor 16 to V2 of the RMS source voltage (i.e., / 2 x Vln RMS) in the first half cycle through the PTC circuit 17 due to the cold resistance the PTC resistor which is low, typically 80 - ^ -. The resistor 31 is used to limit the fast peak input current through the load circuit components, especially the PTC resistor. The diode 27 is connected to poles to the load capacitor 16 as shown. In the next half cycle, the load on the capacitor 16 adds to the source voltage (twice the peak value, no load) and drives the capacitor 23 charging current through the diode 25. When the load on the capacitor 23 exceeds the Sidac interrupting voltage, the Sidac becomes conductive and the capacitor 23 discharges through the reactor portion 18, causing high voltage to develop through the entire reactor by autotransformer action. In this way, a high-voltage lamp ignition pulse is placed on top of the intermediate OCV (x V? N) that positively ignites and starts and stabilizes the lamp arc. The reactance coil 26 is included to be sure that the high high frequency voltage appears only through the lamp and not in the start circuit components. Once the lamp 10 attracts real full tracking energy, which has been forced by the intermediate OCV, the PTC resistor 29 is heated and its resistance increases to a high level (typically 80 k _ \ or more). The capacitors 16 and 23 are effectively removed from the operation of the start circuit, even though the capacitor 16 continues to be involved in the operation of the semi-resonant circuit in conjunction with the inductance 14. All the lamp start mechanism is effectively removed from the system and does not interfere with the lamp heating and the completely connected lamp operation where the lamp is supplying the switching action described herein. These start functions are automatically linked together (intermediate OCV and pulse generation) and the lamp condition at that point in time. Note also that when the input power is interrupted, the lamp reboots in approximately 2 to 3 minutes because, when the lamp is drawing current (de-ionizes), the capacitor 16 is charged until the PTC heating current falls to below the warming levels. The PTC 29 in this way rapidly cools to a low resistance state in which the lamp start process is allowed to occur again. When the lamp is operating normally and attracting normal current, the normal AC voltage appears through the capacitor 16. In this way, all generators of ionization function, start and lamp operation are automatically linked together to the state of the lamp . The circuit of Figure 4 is particularly useful for operating a 100-watt medium base metal halide lamp made by Venture Lighting International, Inc., of Solon Ohio. This lamp is rated to have an output of 9000 lumen. Its operating characteristics are provided in the following table. The lumens per watt is 86 compared to 82.6 for a HPS lamp of 100 watts 120 volts.

Table 1 Values of Cir- L = 0.22 H C = 15 uf Freq. of Sin-cuito tonización 87. 7 V? N I1B W? N P. F. V1P I1P W? P Wloss 120 1. 13 104. 1 0 -. 77 100. 7 1. 13 97. 3 6. 8 In the operation circuit itself, the selection of the values of the inductor 14 and capacitor 16 is particularly important. These circuit values are selected to allow the semi-resonant operation of the reactors 14 and 16 at a frequency that is higher than and compatible with the frequency of the source. By "semi-resonant" it is implied that the rectors 14 and 16 are not self-resonating, but are resonant when the lamp switching 10 excites them and therefore are capable of being struck by the switching action of the own lamp to cause an exchange of resonant energy between the inductive and capacitive reactors and the switching lamp. The lamp is excited by generating current pulses by the reactors 14 and 16 after each half cycle of excitation by the lamp. The reactors operate at a frequency higher than the source frequency to generate current pulses in each half cycle of the power source. This is a fundamental principle of the operating system of the present invention. It is well known that a series resonant circuit includes an inductor having an inductance L, a capacitance C and some resistance r, mostly the resistance of the inductive component, which is usually kept as small as possible for better operation of the circuit. A series resonant circuit with appropriately selected component values resonates at some frequency f0 which is called the resonance frequency. At f0, the impedance of the circuit is minimal and at other frequencies the impedance is higher. At resonance, (l) 2trf0L = 1 2 V taC The most efficient energy transfer occurs when the impedances of the effective energy source and the energy dissipator are equal. These are the conditions that exist in a resonant circuit, as well as in the semi-resonant circuit of the present invention wherein the exchange of lamp switched energy between LC elements 14 and 16, voltage source 12 and load 10 of Lamp is responsible for the operating current through the lamp. The efficiency of the circuit illustrated in Figure 4 is therefore very high, as is the energy factor. Within each half cycle of the source 12, the lamp 10 switches the current passing through it, and also switches the semi-resonant circuit (i.e., the reactors 14 and 16), "shock" of the semi-circuit. resonant towards semi-resonance during each half cycle of the energy frequency. Figure 5 is a block diagram of the energy flow for a conventional operating circuit for a metal halide HID lamp of 1000 watts. For this example, Lamp 36 to be activated is a metal halide lamp of 1000 watts. The purpose of this diagram is to explain the energy flow and energy losses in a conventional system for comparison with the system of the invention. A source 30 of low voltage AC power supplies approximately 1109 watts of power to a device 32 which is for the purpose of increasing the voltage of the lamp. In a conventional circuit, this voltage increaser is typically a high loss transformer device that loses approximately 29 watts in heat, the remaining 1080 watts are delivered to a device 34 that controls the amount of energy that is left flow to the lamp 36. Typically, this is a ballast that loses a minimum of approximately 80 watts in the form of heat.The remaining 1000 watts are supplied to the lamp that generates approximately 300 watts in the form of light, the remaining 700 watts being lost as heat The amount of energy lost as heat in the lamp itself, of course, is a function of the efficiency of the lamp itself and has nothing to do with the operating circuit. Even though HID lamps are remarkably inefficient, however, they are the most efficient practical converter, currently known, of electric power to light. The significant fact about this flow chart is approximately 109 watts are lost in the operating circuit as heat from components 32 and 34. Figure 5 can be compared to the energy flow diagram in Figure 6 which essentially shows the same class of information as Figure 5, except as it applies to the operation circuit of the present invention. Again, the goal is to supply 1000 watts of power to the MH lamp. To do this, the low voltage AC supply 40 provides approximately 1033 watts to a voltage increaser and flow controller 42 (i.e., the semi-resonant circuit capacitor C). Device 42 loses only about 1 watt in the form of heat and performs the functions of devices 32 and 34 of Figure 5. The remaining 1032 watts are provided to an energy flow smoothing device 44 (i.e. inductor L of semi-resonant circuit) that loses approximately ^ 32 watts in the form of heat. This leaves 1000 watts that are provided to the lamp 36 that produces light with the same efficiency as in Figure 5. It will be recognized that the system of Figure 6 exhibits a significantly improved efficiency as far as the operating circuit itself is concerned, losing only 33 watts compared to 109 watts with a typical circuit of the prior art. In addition, the lamp operation circuit of the present invention (e.g., the circuit illustrated in Figure 4) allows for improved lamp designs having higher lumens per watt (LPW). Figure 7 is a schematic diagram of a further embodiment of a discharge lamp operating circuit constructed in accordance with an embodiment of the present invention. It comprises a different and simpler starting circuit 19 which can be used if the lamp being operated has an internal starting electrode and does not require high voltage pulses for initial ionization. The circuit of Figure 7 provides an OCV RMS of x V? N and a peak voltage of 2 s ^ 2 x V? N to start the lamp. As is well known in the art, lamps of certain types, such as mercury vapor lamps and metal halide lamps, made by various manufacturers, are made with a starting electrode adjacent to a main electrode of the lamp, but electrically connected to the opposite main electrode, thereby producing a raised field adjacent to an electrode. Initially, an arc occurs between the main electrode and the starting electrode. After a short ionization interval of the filling gas at an electrode having the raised field, the ionization is dispersed from electrode to electrode inside the lamp, an internal bimetallic switch short-circuits the starting electrode after the lamp is heated to prevent the electrolysis of sodium and mercury. In Figure 7, the AC source 12 is connected to an inductive reactor 30 which is in series with the lamp 10 and the capacitor 16. In this circuit, the reactor 30 does not have a shunt, or the shunt, if present , it is not used. The start circuit 19 includes a diode 32 in series with a current limiting resistor 33 and is connected in parallel with the lamp. When the source 12 is connected, the current flows through the diode 32 and the resistor 33 to charge the capacitor 16 in each half cycle of the AC source, effectively increasing the load on the capacitor 16. After some number of cycles, depending on the magnitude of the source voltage, the value of the capacitor 16 and the resistor 33, the increased OCV ionizes the gas inside the lamp and starts the lamp. This circuit 19 approximately doubles the half-cycle peak input voltage and the RMS magnitude by v 3 x V? N. Then, the start circuit 19 is essentially inactive since the capacitor 16 never has an opportunity to charge the lamp start voltage again since the lamp operating current exceeds the relatively low load current supplied through the diode network 32 and resistor 33. Capacitor 16 and inductive reactor 30 are selected to have values that resonate with lamp switching at a frequency higher than the supply frequency, as described in relation to Figures 1 and 4. The following. example is related to a metal halide lamp (MH) of 1000 watts which is a type of lamp used frequently in groups to illuminate a stadium or, in less dense arrangements, to illuminate the interiors of industrial and commercial buildings, aircraft placers and manufacturing plants. The following data was collected using an exemplary circuit configured in accordance with Figure 7, operated at the various supply voltages indicated in the following table. The inductive reactor 30 was a reactor designed for use with a 400 watt HPS lamp (in a conventional circuit) and has 0.116 Henries at 4.7 amps. A capacitor 16 of 31 uf was used and the starting circuit resistor 33 had a value of 30 k-í? >; -. The values are as follows: V? N is the input voltage in RMS volts of AC I? N is the input current in AC amps Wjn is the input energy in watts P.F. is the energy factor Vlp is the voltage across the lamp during the operation, I? p is the lamp current W? p is the energy supplied to the lamp during operation, in watts, Wjoss is the loss of circuit during the operation, in watts, Vc is the voltage across capacitor 16, and Vi is the voltage across reactor 30.

Table 1 w, P.F. Vip IIP W-ip W1O Vc Vx 249 2.88 689 .961 250.4 2.87 674 15 263 3.41 848.942 251.3 3.43 820 28 277 4.06 1037.920 260.4 4.05 2004 33 342 189 291 4.56 1191 .898 272.8 4.52 1148 43 381.1 208 305 5.43 1406 .846 272.1 5.43 1348 58 459.7 248 The various input voltages indicated in Table 1 were used to determine the operating characteristics of the exemplary circuit in response to voltage variations from the input voltage design, which is 277 volts, to evaluate the operation of the circuit under realistic conditions in which the line voltage can vary significantly. It will be noted that the lamp continued to operate under these conditions and that the lamp operating energy remained close to the programmed energy. It will also be noted that the energy loss of the total circuit varied between 2% and 4% of either the lamp wattage or the volt-ampere input, proving that it is an efficient system. Note that the lamp voltage was close to the supply voltage. The value of "31 uf for the capacitor was selected to allow the circuit to deliver the correct wattage for the classification of this lamp, that is, (2) Ic = Ilamp = 2 -zr fCVc10-6 The value of L is selected for provide LC tuning at a frequency higher than the 60 Hz line frequency to allow time in each half cycle for the natural, lamp-induced half-cycle resonant energy transfer to occur within the time interval of a half cycle In this way, selecting 84 Hz as the frequency tuned for this example, (3) f0 = 1 = 84 Hz and the resulting frequency during actual operation of the circuit is higher than the line frequency of 60 Hz and lower than the frequency 84 Hz tuning, as will be described later The term "compatible frequency" is used to indicate that the circuit operates at a higher frequency and close to, but not exactly at source sequence. Due to the ability of the circuit to operate the lamp under conditions of supply voltage variation, there is no need for input voltage regulation devices that are large, heavy, and / or expensive and a source of considerable energy loss and life of reduced product. While the use of said device is not impeded in order to achieve closer control of color or the like, it is not necessary. With all prior art lighting systems of this general type, a primary consideration is how to package the lamp and its supporting electrical circuit components and heating problems. For a lamp rated to operate at 1000 watts or more, this is a serious problem because the components previously required to operate the lamp commonly occupy a volume of 28,316 to 56.63 liters and generate enough heat to prevent plastic housings and parts. However, with the system of the present invention, the component size can be reduced by about half. Additionally, the heat due to the loss of energy is so drastically reduced that a much wider variety of sizes, materials and types of accommodation is possible and economical. The following discussion will refer to Figure 8 which shows a circuit according to the invention, but with the components represented as individual impedances so that the design and operating characteristics can be discussed in a mathematical sense. In Figure 8, the inductor L is represented by a resistor and a coil, the lamp is represented by a lamp of equivalent resistance r and the capacitor by means of a capacitive C reactance. This circuit will be discussed using a 1000 watt MH lamp characteristic as an example. The values in the above table will be used corresponding to an input voltage of 277 volts. The effective working Z impedance of the circuit is provided by dividing the input voltage by the current, 277 / 4.06, which is equal to 68.2 _a .. However, it is also possible to calculate the impedance of the circuit in Figure 8 using (4) - Z = Rlosses + Rlamp + J (X¡. ~ C) The resistance of the resistive portion of the inductor is equal to the watts lost divided by the square of the current, that is, 33 divided by 16.48 which is equal to 2 ^ D-. The lamp resistance is found from the same ratio, that is, 1004 divided by 16.48 which is equal to 60.9n. XL is 85.7-0-In this way, -Z = 2 + 60.9 + j (43.7-85.7) = 62.9 - '41 .9 If the input voltage current is calculated, 277 volts, divided by the calculated impedance, 75.6, the result is 3.66 A. This value is too low because the test results show that the actual current is 4.06 A. However , if the expression Ia «u = (1.1JV / Z is used, and if the current is then calculated again as above, the result is a current of 4.03 A. This is very close to the measured value. , the input voltage seems to be 10% higher than the measured value.Note also that the total reactance XL + Xc can be reduced by 38% (on paper) resulting in an effective impedance of 68.1T, This is very close to the value needed to provide a current of .03 A. If the current value of 4.03 A above is used, the energy factor becomes 3.35 / 4.03 = 0.83 which is not correct. happening in the circuit that provides the actual test values d e 4.06 A and an energy factor of 92% is that the frequency of half effective cycle of the system is higher than the line frequency and that the reactance (XL + Xc) falls due to the frequency of half cycle of real LC operation . Referring again to the following equation of total impedance, it will be remembered that the calculated value for -Z was (62.9 - j41.9) ^ x with 75.6 being the magnitude of non-vector, providing a current flow of 3.66 A and a factor of energy of 83%. While this is based on the actual circuit values for L, C and R in the circuit, we know that these calculated values were not correct. To make the impedance equation conform to what is actually happening in the semi-resonant gas-induced circuit of the present invention, the recalculation is as follows. A total circuit impedance value of 68.2.A is required to fill the measured current flow of 4.06 A. and 'we know that the energy dissipation resistance of 62.9.A can not be changed, so that the -Z equation is converts (62.9 - j26) which fills both the current measured values and the energy factor, ie (6) ir = (4.06) 2 (62.9) = 1037 watts of input (7) / (62.9) 2 + (-26) 2 = 57, 1 (8) ^ = 277 = 4.06A. Z 68.1 and (9) P F = 62.9 = 0.92 P F 68.1 which is consistent with the measured values The XL and X reactances have measured voltage drops of 189 volts and 342 volts, respectively. Dividing these voltage values between the 4.06 A current provides calculated values of 46.55 Q (L) and 84.24 0 (C). Combining these values provides a theoretical reactance of j ("46.55 - 84.24) or -37.69 Q. However, we know that this total reactance is - 26 Q. In this way, the total reactance must be influenced by the semi-resonance induced by the switching lamp in this circuit whose mechanisms have already been defined Modifications XL and Xc can be described as follows, (10) j (XL - Xc) = j (2T7fL - 1) = -j. 2 f íC Resolving this expression for f with values of L = 0.116 and C 31 x 10- provides a frequency, or switching regime, of f = 68 Hz. This is not the same as the line frequency of 60 Hz, nor is it a value which would be obtained by solving the usual expression for resonant frequency using the known circuit values.

This tells us that the apparent operating frequency, or the energy impulse transfer rate, is at a frequency higher than the line frequency during each half cycle. The line frequency does not completely dictate the frequency of operation of the system because the switching lamp mechanism shock of half cycle excites the LC network in series towards a modified form of operation that, in effect, displaces the new instantaneous ignition of the lamp towards forward within half cycle as a result of circuit voltage amplification of "lamp" drive voltage, as illustrated in Figures 9-12. The effective lamp drive OCV is 0 times the normal OCV. Figure 9 shows the input voltage Vin, the voltage across the inductive reactor Vl and the lamp current Ilp at the beginning. Figure 10 shows the Ve and Vlp voltages of capacitor and lamp at the start, with the lamp current repeated for comparison. Figures 11 and 12 show these respective characteristics during operation. Therefore, the switching lamp circuit makes it appear that the XL is ((68-611 / 69) 100, or 13%, higher than the normal wL value of 43.7 0 and the magnitude Xc that is (60 / ( 68-60)) xl00, or 7.5%, lower than the normal value of 85.7 Q. This is partly because the circuit is smaller and lower cost than the conventional ballast.Note also that this circuit causes the discharge lamp operation energy is higher than what is usually obtained.A normal PF lamp is around 90% to 91%, but in this circuit the power factor is 1004 / (260 x 4.06) = 95.1%. This more closely resembles a resistor in its power and quality dissipation mechanisms With respect to the efficient energy transfer from the AC source to the lamp load, the circuit of the present invention satisfies the well-known theorem of Thóvenin, which tells us that the transfer of energy between two devices the electrical is maximum when the impedances of the two devices are equal. The lamp resistance is (1004 / (4.06) 2) = 60.9Q. The source impedance as seen by the lamp is Z0 = (L / C) = (.116 / 31 x 10 ~ 6 = 61.2 0- These values are very close to being equal, which must be the power operation Most efficient and highest operating energy factor When selecting circuit values for a lamp, it should be recognized that the values may be different for different lamps, ie a circuit for a 1000-watt lamp made by a manufacturer has circuit values that may not be better for a 100-watt lamp made by another manufacturer, because the switching characteristics of any lamp depend, in part, on the filling gas, the plasma components used, the composition and the geometry of the lamp and electrode The most direct procedure is to select a capacitor that provides a current capable of supplying the current rated for the lamp using equation (2) above. the inductance is selected so that the circuit is tuned to a resonant frequency above the line frequency and so that the circuit impedance is approximately correct. Some experiment must be done to find the frequency-inductance combination for the most efficient operation of the lamp. Below are some examples of circuit values for specific lamps.

Table 2 Type of Lamp: 40-50 Watts Mercury, General Electric, rated 0.6 A. Values of L = .408 H C = = 7.5 u f Frequency Circuit: Tuning 91 Hz v? N I? N? N P.F. V.p 37P ip W? Oss 120.562 50.6.749 100.588 45.6 5 Table 3 Lamp type: 80-watt mercury L = .28 H C = 12 uf Frequency Circuit Tuning 86.8 Hz v? N I, "lB P.F Vip lie i p Wloss 120 .88 87.4 .819 105 0 .1 7.3 Table 4 Lamp type: Mercury of 175 watts Values of L = .079 -H C = = 29 uf Frequency of Circuit Tuning 105.4 Hz V, "I1B w? N P.F. Vlp IIP ip WJ0SS 120 1.68 180.0 .89 133 1.68 175.5 5.3 Table 5 Type of lamp: Mercury of 125 Watts Values of L = 0.114 H C = 20 uf Circuit Frequency Tuning 105.4 V1B I? N W? N P.F. Vlp 1F Wip W? Ose 120 1,274 128.5 0.86 120.5 1,274 124.8 Table 6 Lamp type: Metal halide of 1500 watts Values of L = 0.4 H C = 59 uf Circuit Frequency Tuning 104 Hz Vln i "Wla P.F. lp Ilp WVV, lp WVV, loss 277 5.92 1532.924 280.2 5.92 1504 2í Although the above examples only list one input voltage in each case, it will be recognized that the circuits operate their respective lamps at lower and higher voltages than the aforementioned value. The scale of voltages varies from lamp to lamp, again depending on factors such as those noted above and the dynamic impedance and construction of the lamp. It will also be recognized that different combinations of circuit component values can be used with most lamps. The lamps can operate with various combinations of values, even though such changes can result in different characteristics such as watts actually delivered to the lamp, energy factor, immersion tolerance, lumen output, immunity to line voltage variation and L.P.W. of system reached. As an example, in the following Table 7, there are values used with a 175-watt mercury lamp. The inductor values were changed considerably, the capacitor values being changed very little.

Table 7 Lamp type: Mercury 175 watts v1B I. »W1B P.F. V.p wlp L (H) C (uf) 120 1,535 178,961 144.1 170 .117 28 120 1,665 180,891 134.1 176 .077 28 120 1,754 180,854 131.1 176 .067 28 120 1.78 176 .819 138.7 172 .049 27 120 1.87 176 .785 138.4 173 .042 27 120 1.89 176 .773 139.7 172 .0385 27 In the circuit of the present invention, the lamp can be used as the ON-OFF switch accessory, eliminating the need for expensive special inductive lighting load switches, relays, heavy duty contact types or lighting contractors. The power switch is changed when the lamp is changed. In the above descriptions, no mention has been made of connecting or disconnecting the lamp, the assumption being that the AC supply itself was switched. However, it is very possible to provide simple switching within the circuit of the invention. Figure 13, which uses the same starting circuit as Figure 7, illustrates the principle of this and includes the switch 35 normally open in series with the diode 32 and the resistor 33. The circuit illustrated in Figure 13, which is connected to the AC source 12, it does not do anything until the switch 35 is closed. When the switch 35 is closed, the charging current begins to flow to the capacitor 16 which starts the lamp 10 when the load on the capacitor 16 is sufficiently large . As far as the start function is concerned, the switch 35 may be a momentary contact switch or a simple push-to-start switch, because the circuit is inactive after startup.

A temporary shunt is provided through the lamp to disconnect the lamp. In Figure 13, the momentary contact switch 37 and the current limiting resistor 38 are connected in parallel with the lamp. Briefly, the closing switch 37 removes the lamp 10 from the circuit of Figure 13 long enough to cause the lamp to turn off (deionize), thereby disconnecting the lamp 10 and the other circuit components shown. For this purpose, it is preferred to have the start switch 35 as a momentary contact switch so that the circuit will not restart when the switch 37 is released. It should be noted that the resonant circuit does not initiate the oscillation by itself. In this way, when the system is disconnected, it does not attract current, a significant advantage over many circuits of the prior art. Only after the lamp is turned on first by activating the start switch 35, © 1 lamp switch or "shock excitation" of the resonant circuit and ignition is started. The lamp operation continues until the disconnect switch is pushed. Another advantage of the circuit of the present invention is related to cases that sometimes occur at the end of the life of the lamp. Metal halide lamps sometimes break or break at the end of lamp life, which can cause hot arc tube material to fall into the illuminated area. To prevent this potential safety hazard, an enclosed fixture with an access door or a covered arc tube lamp design is used. however, lamp breakage occurs because the drive voltage is conventionally supplied to the lamp from a source that does not respond to the activity of the lamp, that is, whether the lamp is failing or not, the drive is still supplied. However, with the lamp operation circuit of the present invention, this does not occur because the driving voltage depends on the lamp switching operation and, therefore, is not generated as the lamp fails. The OCV simply falls to the line voltage that is too low to drive the lamp at any level. The two switching functions can be incorporated into a single connection-disconnection switch arrangement as shown in Figure 14. A terminal of a three-position switch 40 is connected to a start circuit that includes the diode 32 and the resistor 33. A second terminal of the switch is connected to an open circuit, and the third position is connected to the. resistor bypass 38 to disconnect the lamp. Preferably, the switch is of the conventional center return spring type, so that it occupies the open circuit position unless manually operated. Moving the switch to position 1 starts the lamp, and moving it to position 3 switches off the lamp. The switches of Figures 13 and 14 can also be implemented using semiconductor devices. The "disconnected" circuit can be implemented by connecting a small Triac (not shown) or the like in parallel-with the lamp. Connecting the Triac for two or more cycles with a control circuit extinguishes the lamp in the same way as the switch 37. A Triac can also be used to replace the switch 35. Because these semiconductor devices are switching limited current and voltage, they do not need to dissipate great energy and may be smaller than relays, switches or other control devices. The circuit of Figure 7 has been used with a variety of lamps including high pressure sodium and mercury lamps in a variety of energy classifications with excellent results.

With the 400-watt HPS lamp, a 57-amp capacitor and Henry 0.77 reactor were connected to the circuit and fixed to a 120 VAC supply. With an input power of 436 watts, the lamp operated at 409 watts with a lamp voltage of 97.7 and lamp current of 4.92 amps. The energy factor was 73.4 and the energy loss was 27. Figure 15 shows a circuit that incorporates some peculiarities of the circuits discussed above. Switching on and off has been omitted for simplicity but can be incorporated as indicated above. The operation circuit of Figure 15 includes an AC source 12, a bypass capacitor 28 connected in parallel with the source and an inductive reactor 14. A bypass 20 in the reactor is connected to the start circuit having a Sidac 22 in series with a capacitor 23 connected through the end portion 18 of the reactor. A resistor 24 is connected to the joint between the Sidac 22 and the capacitor 23 and o is in series with a diode 25 and an RF choke 26. A separate series circuit including a diode 32, a resistor 33 and a reactor coil 34 is connected in parallel with the lamp. Finally, a capacitor 16, which is selected to resonate with the reactor 14, is connected from the lamp to the other side of the AC supply. The operation of the circuit will be understood from the previous discussions. Additional variations in the above circuits can be designed using values of L and C for the semi-resonant circuit components to be semi-resonant at frequencies of 2 or more even multiples of the line frequency. This has the important advantage of allowing the reduction of the size of the circuit components. It is well known that a component such as a capacitor or inductor designed to operate at 120 Hertz can be considerably less than a component, otherwise electrically equal, designed to operate at 60 Hertz. With the system of the present invention, the components made to accompany the lamp are no longer limited to the frequency fs of the AC source and can thus be made smaller. The term "compatible frequency" should therefore be understood to include a frequency fk that approximates nfs, where n is any even integer. Due to the significantly lower energy loss which is an important feature of the operating circuit of the present invention, the use of gas discharge lamps such as mercury, HPS and HID lamps and fluorescent lamps becomes feasible for private residences. apartments and offices in contexts that were not practical before. Figures 16 and 17 illustrate ways in which these can be implemented. In Figure 16, a lamp 44 is connected to a semi-resonant circuit including inductive and capacitive components 45 and 47 which are placed in series in a hot wire leading to the lamp. A start circuit may also be included if necessary, depending on the type of lamp, as discussed above with reference to Figures 4 and 7. A connection-disconnection circuit of the type shown in Figure 14 has a switch 40, diode 32 and resistor 33. Switch 40 is movable from a neutral position shown in any of the positions connected or disconnected and operates as described above. Of particular importance is the fact that the circuit components except for the lamp can be easily accommodated in a wall box 46 of the type normally used for a lever-type switch-disconnect switch, and that only two wires 48 and 49 are They extend to the lamp itself. As a result, a wiring for a lamp of this type is not more complicated or expensive than for a conventional incandescent lamp. Figure 17 shows another embodiment of a gas discharge lamp 50 arranged for use in a house with the components 51 and 52 of semi-resonant circuit in the neutral line and contained within a wall box 54 together with a connecting circuit and disconnection of the type shown in Figure 13. This type of connection-disconnection uses push-button switches and operates as described above. Again, only two wires 56 and 57 extend from the wall box to the lamp, making the task of wiring a simple one. The use of the lamp as the primary switching element to be switched on and off when triggered by a small switch, as discussed in relation to Figures 13 and 14, can to be used with great advantage in photocell operation of the lamp. It is common practice to use a photoelectric control (PE) to connect a lamp when the ambient light is low and disconnect it when the ambient light is high. • Many outdoor luminaires and 2Q accessories employ this technique, but the circuits tend to be unreliable and expensive and have a short life. Not only does the cadmium sulfide (CdS) cell fail under a high wattage that is exposed to current products, but the relay contacts frequently welded together with balancing and jumping on the reactive loads of ballast lamp electrical circuits. When these circuits fail, the lamp is left connected 24 hours a day until the photocell is replaced. In accordance with the present invention, when the lamp is changed, the main switching device for the function of EXAMPLE is also changed. The circuit of Figure 18 employs the principle of the present invention. The AC source 59 is connected to a series circuit which includes an inductive reactor 60, a lamp 61 and a capacitor 62 having selected values as discussed above. A first control circuit is connected through the input side of the reactor and has a PTC resistor 65, a resistor 66 and a SCR 67 in series. A CdS cell 68 and a gate resistor 69 are connected to the gate, anode and cathode of the SCR. On the other side of the reactor 60 is connected a second control circuit that includes a PTC resistor 70 in series with a Triac 71. A second CdS cell 73 and a "gate" resistor 74 are connected to the gate, anode and cathode of the Triac 71. When it is dark, the resistance of the CdS cell 68 is high, allowing the SCR 67 to open to a conductive state (CONNECTED) by the diode action, The current through this circuit loads the capacitor 62 and starts the lamp as described above.After the lamp is started, the increased resistance of the PTC resistor 65 removes this circuit from the system and the lamp continues to operate.In daylight -when the ambient light level is high, the resistance of the CdS 73 goes down and triggers the Triac 71, providing a low resistance path through the lamp and causing it to deionise and extinguish.After the lamp is disconnected, the current through the PTC resistor increases its temperature, eliminating the second control circuit of operation. The lamp is then ready to start again when the daylight disappears. Fig. 19 shows an additional embodiment of a circuit operating in a manner similar to that of Fig. 18, except with only one CdS cell. In Figure 19, the first control circuit includes a PTC resistor 76 in series with a resistor 77 and an SCR 78. A gate resistor 79 is connected to the gate of SCR 18 and to a diode 80. The other control circuit it includes a PTC resistor 82 in series with a Triac 83. n gate resistor 84 is connected to the Triac gate which also connects to diode 80.

The diode and the gate of the Triac are connected to cell 85 of CdS. As with the previous circuit, the. resistance, dark of the CdS 85 cell allows the SCR 78 to become conductive, initiating the lamp. After starting, the PTC 76 effectively eliminates the operation SCR circuit. When it is turned on, the low light resistance of the CdS cell triggers the Triac to conduction extinguishing the lamp. The development of open circuit voltage (OCV) that is necessary to start the lamp will be discussed now. For this purpose, reference will be made to the circuit in Figure 20 which includes one. AC source 88, inductor 89 and a capacitor 90 connected in series with a lamp 91. A diode 92 and resistor 93 are connected through the lamp to aid in the development of the required OCV. The source of 'CA is one. 120 VAC source which means that the peak value of the source is approximately 170 volts. With the diode 92 set to poles as shown, the capacitor 90 charges in the first half positive cycle of the supply, and a voltage is developed that is substantially equal to the peak voltage of the AC source (e.g., approximately 170 V). In the initial development of the OCV of initiation, the inductor does not play a significant part. The circuit of this 54 - way can be seen as a series circuit with an input voltage e "in series with the capacitor replaced by a 170 volt battery.The effect of the capacitor / battery voltage is to raise the input sine wave in the amount of the load, causing the input voltage to the circuit to vary (in instantaneous values) between 340 volts and zero.The OCV then the square root of the sum of the squares of the DC voltage in the capacitor / battery and the RMS value of the input of CA, ie OCV V (Vdc): (VCA) = 208 V RMS In a more general explanation, where E = (? / 2 ~) e and e = Emaxsi n t. OCV + E2 v / e2 + ((/ 2) e) 2 = v "e2 + 2 t = ^ e.

Where e = 120, the OCV = / e x 120 = 208 volts RMS. The concept of the basic circuit of the. present invention is also usable with fluorescent lamps in addition to the high intensity discharge lamps discussed above. Figure 21 shows an operation circuit including an inductance 95 and a capacitor 96 connected to a 120 VAC source. The lamp filaments 97 and 98 of a fluorescent lamp 100 are connected in series with the inductance-capacitor circuit and with a 26-watt high-voltage pulse initiation circuit 101. The start circuit includes a first series circuit having a coil of reactance 102 in series with a diode 103 and a resistor 104 of PTC a. through the filaments. A capacitor 106 and a derivative inductor 107 are in series with each other and in parallel with the first circuit. A resistor 108 and a Sidac 109 are connected between the diode 103 and the inductor branch and a capacitor 110 is connected between the Sidac and the other side of the PTC resistor 104. Initially, the PTC resistance 104 is low and the filament heating current passes through the first series circuit. This current heats the PTC resistor and raises its resistance. At the same time, capacitor 110 is charging through resistor 108, the load level increasing as the PTC resistance increases. When the charge level in the capacitor 110 reaches the interruption voltage of Sidac, the capacitor discharges through the Sidac and the branch end of the inductor 107, generating a pulse that is applied to the lamp. By this time, the lamp filaments are heated and the lamp is switched on. The operation of the lamp is similar to that described above in which the lamp itself hits the circuit 95 and 96 L-C towards semi-resonance and switches the energy between the L-C circuit and the lamp. This will not be described again. In the circuit of Figure 21, diode 103 can be omitted and its function filled by a serial PTC diode-resistance circuit connected through the input side of the circuit as shown in the Figure. Figure 22 shows a further embodiment of a fluorescent lamp operation and start circuit of the present invention in which a 120 VAC source 115 is connected in series with an inductor 116, a capacitor 117, the filaments 118 and 119 of a fluorescent lamp 120 and an initiator including a diode 122 and a PTC resistor 123. "This circuit uses the capacitor 117 to start.When the resistance 123 of cold PTC is low and the heating current flows through the filaments of lamp, charging capacitor 117. When the filaments are hot and the voltage on capacitor 117 reaches the required OCV of / 3 xe, the lamp is started Figure 23 shows a circuit for operating two fluorescent lamps in parallel and includes an inductance 126 connected to the filaments 127 and 129 of the lamps 132 and 133, respectively, a diode 135 is connected in series with a resistor 136 of PTC, with the filament 128 of the lamp 132 and n a capacitor 137. Similarly, the filament 129 is connected in series with a diode 138, a PTC resistor 139 and a capacitor 140. The other sides of both capacitors are connected back to the source. These parallel circuits operate essentially like the circuit of Figure 22, the individual capacitors 137 and 140 being charged to opposite polarities through their respective diode-PTC circuits while the lamp filaments are heated. When sufficient charging and heating has occurred, the lamp is started, as described above. Figure 24 shows a circuit for operating two fluorescent lamps in series from a 277 VAC source. The source is connected through an inductance. 145 to the filament 146 of a lamp 147, then through a series circuit including a diode 148 and a resistor 149 of PTC and the other filament 150 of the lamp 147. The series circuit also includes the filament 152 of the lamp 153, one resistor 154 of PTC, the other filament 155 of lamp 153 and through capacitor 156 on the other side of the. source. As with any series circuit, the source voltage is divided by the loads, but the current is the same through it. In this way, the capacitor 156 is charged through the diode 148 and the PTC resistors as the filaments are heated. When the capacitor reaches the correct OCV for both lamps and the filaments are heated, the lamps are switched on. Figure 25 is a schematic circuit diagram of a multi-voltage ballast circuit 160 to allow a single discharge lamp operating circuit constructed and operated in accordance with the present invention for use with different line voltages. The discharge lamp operating circuit comprises one. lamp 162 (e.g., a metal halide lamp (MH) of 400 watts), an inductor L and a capacitor Ci which are connected in series and which operate as described above.

Accordingly, the discharge lamp operating circuit employs the discharge interrupting mechanism, of the lamp itself 162 at least once every half cycle to excite the inductor L and capacitor d connected in series towards an instant OCV and RMS call. of about twice the line voltage, input to drive the discharge lamp 162. The multi-voltage ballast circuit 160 further comprises a variable capacitance circuit 164 in accordance with a mode of the. present invention to create a system, compensation of multiple voltages or input voltage. The variable capacitance circuit 164 comprises the capacitors and d connected parallel to one another and to the capacitor d, and the switches 166 and 168, respectively. The switches 166 and 168 are operated to add or remove the capacitor d- or both of the capacitors and d parallel, depending on the line voltage applied to the multi-voltage ballast circuit 160. For example, as shown in Figure 25, the switches 166 and 168 are both open. In this way, only the capacitor d is connected to the lamp 162 and to the inductor L for the operation of the semi-resonant circuit in conjunction with the inductor L and for the current supply rated to the lamp 162. In the illustrative circuit illustrated in FIG. the figure , the lamp is a 400 watt MH lamp and the line voltage is preferably 277 volts. The capacitor d is preferably 22 pfu. When the line voltage is decreased to 240 volts, for example, an additional parallel capacitance of 3 uf is added by closing the switch 166, as shown in the Figure 26, to supply sufficient current to the lamp 162. An additional parallel capacitance of 3 uf can be added by closing the switch 168, as shown in Figure 27, and therefore, adding a total of 6 uf of capacitance to the operating circuit of discharge lamp when the line voltage is still further decreased to 208 volts. Consequently, a ballast of multiple voltages is created using a single configuration of inductor L, capacitor d and lamp 162, which are operated using one of three different line voltages, using parallel switched capacitances, thereby minimizing the number of components used in a discharge lamp operation circuit that has input voltage compensation capability. The multi-voltage ballast circuit 160 can be configured to operate with different line voltages and different types of lamps during capacitance selection, (e.g., as discussed above in relation to equation (2)) and the inductance L. Additionally, the multi-voltage ballast circuit 160 may be configured to operate with only two different line voltages or with more than three line voltages, depending on the configuration of the capacitors and switches in the variable capacitance circuit 164. . For example, the capacitances da - where n is an integer, can be connected in parallel with each other and parallel to the capacitor d and selectively switched by a switching mechanism to operate the discharge lamp operating circuit using one of n voltages of different line. In addition, the capacitances may be arranged in series with each other, as opposed to being parallel, and a switch provided in parallel with at least one of the series capacitances to selectively derive the capacitance and change the amount of current supplied to the lamp. . The switching mechanism may be a switch for each capacitance (eg, switches 166 and 168), although other switch arrangements may be used. Switches 166 and 168 can be operated manually or controlled automatically (eg, electronically or electromagnetically or using a processor (not shown)). The switches can be a relay or an electronic switching device such as a Triac, for example. The variable capacitance circuit may also be provided with an input voltage sensing circuit 167, as shown in FIG. 27, to operate switches 166 and 168 to add or drop capacitance as needed, depending on the detected input voltage. , applied to the discharge lamp operation circuit. Figure 28 is a schematic circuit diagram of a dimming circuit 170 for obscuring a discharge lamp operation circuit constructed and operated in accordance with the present invention. The discharge lamp operating circuit comprises one. lamp 172 (e.g., a.400 watt metal halide lamp (MH)), an inductor L and a capacitor CD1 which are connected in series and operate as described above. Consequently, the discharge lamp operation circuit employs the discharge interruption mechanism of the lamp 172 itself at least once every half cycle to excite the inductor L and capacitor connected in series to the call of an instantaneous OCV and RMS of approximately double the input line voltage to drive the discharge lamp 172. The dimming circuit 170 further comprises a variable capacitance circuit 174 in accordance with one embodiment of the present invention. The variable capacitance circuit 174 comprises the capacitor CD2 connected in parallel with respect to the capacitor CD1, and a switch 176. The switch 176 is operated to add or eliminate the capacitor CD2, depending on whether the darkening of the lamp 172 is desired or not. . In this way, both capacitors CD1 and CD2 are connected to the lamp 172 and to the inductor L for the operation of the semi-resonant circuit in conjunction with the inductor L and for the power supply to operate the lamp 172 at full power. When the darkening of the lamp 172 is desired, the switch 176 is opened to an OFF position to remove some of the capacitance, as illustrated in Figure 19. In the illustrative circuits illustrated in Figures 28 and 29, the lamp is a 400 watt MH lamp and the line voltage is preferably 277 volts. The capacitor d is preferably 17 uf and the switched capacitance CD2 is preferably 5 uf. As stated above with reference to Figures 25 and 26, the dimming circuit 170 can be configured to operate with different voltages of S3 line and different types of lamps during the selection of the capacitance (eg, as discussed above in relation to Equation (2)) and the inductance L. The switching mechanism to add or remove capacitance is preferably a switch manually operated, even when the switch 176 can be controlled automatically, electronically or electromagnetically through a processor (not shown). For example, switch 176 may be a relay or a Triac. In addition, the capacitances may be arranged in series with one another, as opposed to being parallel, and a switch provided in parallel with at least one of the capacitances in series, to selectively shunt the capacitance to change the amount of current supplied to the lamp. . The lamp operation circuit of the present invention utilizes the mechanism of interruption of discharge of the lamp itself each half cycle of the power source to excite a inductance (L) connected in series, capacitance (C) to the call of an OCV of approximately twice the input voltage to drive the discharge lamp, while the magnitude of capacitance is used to limit the load moving through the lamp to the correct steam, thereby adjusting the lamp operation wattage to the value Right. In this way, the need to put a semiconductor switching silicon energy switch in a high frequency ballast circuit (switching regulator or power supply approach) for a discharge lamp is eliminated because the. own discharge lamp is a gaseous energy semiconductor equivalent switching With the semi-resonant energy circuit itself and the lamp control circuit, the lamp itself becomes the switching function generator, reducing the need for or demand of energy management imposed on the silicon devices used to create the connection sequence (energy drive) then disconnection (to control energy) of the lamp used in current high-frequency ballast technology. Since this basic approach of using the lamp to effect the lamp drive voltage amplification and switching to process energy pulses to the lamp in a controlled manner applies the high frequency ballasting techniques and not only to the circuits of 50 Hz and 60 Hz, for example, a special fast ionization and deionization gas discharge lamp, or possibly a semiconductor circuit lamp having the interruption characteristic designed in. it can be built to operate at kilohertz or megahertz frequencies, and can be very compact and fed through a 60 Hz line. While certain advantageous embodiments have been selected to illustrate the invention, it will be understood by those skilled in the art that various modifications may be made therein without departing from the scope of the invention as defined in the appended claims.

Claims (9)

1. - A discharge lamp operating circuit comprising: an alternating current (AC) source at a predetermined frequency; a discharge lamp; a series resonant circuit connected to the source of alternating current voltage and in series with the lamp, the resonant circuit being tuned to a frequency higher than the predetermined frequency, the lamp repeatedly switching at a rate between the predetermined frequency and the frequency tuned to stimulate the resonant circuit in series towards oscillation and the series resonant circuit that keeps the lamp in operation; and a variable capacitance circuit connected in series with the lamp and comprising at least one capacitor and at least one switching device for selectively connecting and disconnecting the capacitor of the lamp and altering the amount of current supplied to the lamp from the source.

2. A discharge lamp operation circuit according to claim 1, wherein the series resonant circuit comprises a second capacitor connected in series with the lamp, the at least one capacitor being connected in parallel with and disconnected from the second. capacitor when the at least one switching device is in a closed position and an open position, respectively. 3.- A lamp operation circuit d & discharge according to claim 2, wherein the at least one switching device is opened to obscure the lamp. 4. A discharge lamp operation circuit according to claim 2, wherein the source is operable to generate one of a first AC voltage and a second AC voltage, the second AC voltage being greater than the first AC voltage, the at least one switching device being open and closed when the second AC voltage and the first AC voltage are generated, respectively. 5. A discharge lamp operation circuit according to claim 4, further comprising an input voltage sensing device for detecting which of the first AC voltage and the second AC voltage is supplied to the resonant circuit in series and "the lamp, the input voltage sensing device being operable to automatically switch the at least one switching device to an open and closed position when the first AC voltage and the second AC voltage are detected, respectively. A method for operating a discharge lamp provided with power by means of an alternating current power source, comprising the steps of: connecting a resonant circuit comprising an inductor and a capacitor in series with the lamp, exciting the inductor and the capacitor substantially every half cycle of the power source using an internal switching characteristic of the lamp, the the lamp and the resonant circuit cooperating together to at least semi-resonantly transfer transfer energy therebetween; and operating the switching device to selectively connect and disconnect a second capacitor connected to the resonant circuit. 7. A method according to claim 6, wherein the step of operation comprises the steps of. close the switching device to connect the second capacitor in parallel with the capacitor to operate the lamp at full power; and open the switching device to disconnect the second capacitor from the capacitor to darken the lamp. 8. A method according to claim 6, wherein the power source is operable to generate one of a first AC voltage and a second AC voltage using the source, the second AC voltage being greater than the first AC voltage, which further comprises the steps of: closing the switching device to connect the second capacitor in parallel with the capacitor when the first AC voltage is generated; and opening the switching device to disconnect the second capacitor from the capacitor when the second AC voltage is generated. 9. A method according to claim 6, further comprising the step of: detecting if one of a first voltage of AC and a second AC voltage is applied to the resonant circuit and the lamp; close the switching device to connect the second capacitor in parallel with the capacitor if the first AC voltage is applied; and open the switching device to disconnect the second capacitor from the capacitor if the second AC voltage is applied.