Abstract: A drive circuit arrangement for a gas discharge lamp includes a) a self resonating inverting for providing a drive voltage across a load impedance, the inverter having a pair of field effect transistors which operate in anti-phase, b) a tank circuit for canceling the reactive component of the load impedance coupled to the inverter, c) a voltage division circuit which provides a given fraction of the drive voltage to the gates of the field effect transistors, and d) a phase shifting means comprising an inductance in series with the tank circuit for shifting the phase of the given fraction of the drive voltage. The voltage division circuit is provided with a voltage limiter which in operation provides a further phase shift to the given fraction of the drive voltage when the drive voltage exceeds a given threshold value, increasing the resonant frequency of the inverter and limiting the peak drive voltage.

Abstract: An electronic ballast for reducing blackening of a high intensity discharge lamp, reducing stress on both the lamp and ballast components caused by excessive voltage and current flow and increasing the lamp's effective life. These advantages are achieved through a ballast controller which readjusts the operating frequency of the lamp during each of the three phases of lamp start-up to limit lamp voltage to a predetermined level.

Abstract: A ballast circuit for energizing a lamp includes an inverter circuit having a switching element with a conduction state controlled by a control circuit which limits a voltage applied to the lamp. In one embodiment, the control circuit includes an integrated circuit providing a conduction control signal to a duty cycle control circuit. The conduction control signal alternately biases the switching element to conductive and non-conductive states at a first duty cycle when the lamp voltage is below a predetermined level. When the lamp voltage becomes greater than the predetermined level, the duty cycle control circuit decreases the switching element to a second duty cycle, which is less than the first duty cycle, to reduce the voltage at the lamp. In one embodiment, the ballast regulates the lamp current to a predetermined level such that the ballast can energize a lamp which can vary in length and has a predetermined diameter.

Abstract: A circuit arrangement for igniting and operating an electrodeless discharge lamp provided with a half-bridge commutator having two switching elements each having an emitter electrode and a control electrode and a parasitic capacitance in between. Each switching element is alternately switched to a conducting state by means of a resonant control circuit. The resonant control circuit is coupled to an oscillator by way of a transformer. The resonant circuit is provided with a capacitor which forms a part of the oscillator.

Abstract: A model and computer program for designing the output stage of a high frequency electronic ballast for a fluorescent lamp. The user specifies a plurality of parameters relating to the operation of the fluorescent lamp, including lamp running power, running voltage, maximum preheating voltage for the lamp, minimum running frequency for the lamp, and an input voltage for the ballast. Based upon these parameters, the computer program calculates the values for various components of the ballast, including the inductor and capacitor of the output stage, such that the preheat frequency is greater than the ignition frequency, the ignition frequency is greater than or equal to the running frequency, the preheat voltage is less than the maximum preheat voltage, and the difference between the preheat frequency and the ignition frequency is greater than about 5 kHz.

Abstract: A ballast circuit for a gas discharge lamp with a tapless feedback circuit is disclosed. The ballast circuit comprises a d.c.-to-a.c. converter circuit with circuitry for coupling to a resonant load circuit, for inducing a.c. current therein. The converter circuit comprises a pair of switches serially connected between a bus conductor at a d.c. voltage and a reference conductor. The voltage between a reference node and a control node of each switch determines the conduction state of the associated switch. The respective reference nodes of the switches are connected together at a common node through which the a.c. current flows, and the respective control nodes of the switches are connected together. A gate drive arrangement regeneratively controls the first and second switches. It comprises a coupling circuit including an inductor for coupling to the control nodes a feedback signal representing current in the load circuit. It further comprises a tapless feedback circuit for providing the feedback signal.

Abstract: An electronic ballast is powered from a constant-magnitude DC supply voltage and provides a high-magnitude high-frequency voltage at a ballast output across which are connected two lamp-ballast series-combinations, each consisting of an instant-start fluorescent lamp series-connected with a ballasting capacitor. An auxiliary capacitor is connected in series with the ballast output, thereby having the total ballast output current flowing through it and causing an auxiliary high-frequency voltage to develop across its terminals. The constant-magnitude DC supply voltage is provided via a series-combination of a power-line-connected rectifier delivering an unfiltered full-wave-rectified power line voltage across a pair of rectifier DC terminals and an auxiliary DC power supply delivering an auxiliary DC voltage across a pair of auxiliary DC terminals from which, under open circuit condition, is available a DC voltage of magnitude equal to the peak magnitude of the full-wave-rectified power line voltage.

Abstract: An incandescent lamp with a low voltage burner (BM) and integrated voltage conversion means (VCM) having switching elements (Q1, Q2) driven by a separate control circuit (CC) comprising an integrated circuit (IC). The voltage conversion means are suitable for operation at a high temperature and causes only limited amounts of EMI.

Abstract: Control device (3) for the operation of a load, in particular at least one gas discharge lamp (10, 15). The control device (3) is divided into a first purely software controlled control unit (3a) a second control unit (3b) realized purely in hardware. The two control units (3a, 3b) are connected with one another via a bidirectional connection line, the second control unit receiving exclusively internal operating state information (I.sub.intern) and the first control unit (3a) receiving external control information (I.sub.extern) By means of the division of the control device into a purely software controlled control unit (3a) and a control unit constructed purely of hardware (3b) the control device (3) in accordance with the invention has both a speed sufficient for rapid control procedures and also a sufficient flexibility with regard to alterations. Advantageously, the control device (3) in accordance with the invention is employed in an electronic ballast for the operation of gas discharge lamps (10, 15).

Abstract: A fluorescent lighting system has: (A) a central power supply including: (i) a parallel-resonant self-oscillating bridge inverter operative to provide a 35 kHz sinusoidal output voltage at a pair of primary output terminals; (ii) a tank-inductor and a tank-capacitor parallel-connected across the primary output terminals; and (iii) plural pairs of secondary output terminals, each connected with the primary output terminals via its own dedicated current-limiting sub-circuit; thereby to prevent a load connected therewith from drawing more than a certain amount of power; thereby, in turn, to render each pair of secondary output terminals fire-hazard-safe and shock-hazard-safe; each pair of secondary power output terminals being connected with its own power output receptacle; and (B) a light-weight power cord plug-in-connected with one of the power output receptacles and having a pair of power conductors between which are connected a number of individually ballasted lighting units; each lighting unit having at lea

Abstract: An improved high intensity discharge ("HID") ignition circuit for a ballast uses a gapped transformer with a capacitor placed across the secondary thereof. The ballast includes a DC source, a down converter, a commutator, and the ignition circuit. The output of the commutator is supplied to the secondary winding of the gapped transformer and the lamp, which are connected in series. The lamp is an HID lamp such as, for example, a metal halide lamp, high pressure sodium lamp, high pressure mercury lamp, or a metal vapor lamp. Power is furnished to the lamp over a cable. Ignition of the lamp is handled by the ignition circuit, which in addition to the secondary winding and the capacitor includes an inductor, the primary winding of the gapped transformer, two SIDACs, and the parallel combination of a resistor and a capacitor, all connected in series between the output of the down converter.

Abstract: A circuit arrangement and method thereof for operating high intensity discharge (HID) lamps with a lower frequency rectangular current waveform, in which the frequency of the higher frequency ripple superimposed on the lower frequency rectangular current is modulated by a pseudo-random noise signal. The pseudo-random noise may be generated by a feedback shift register. The feedback shift register may incorporate run length interrupt logic to address PWM frequency stagnation by reducing the longest run length or lengths of the feedback shift register. The feedback shift register may also or alternatively include an RC low pass analog filter to address PWM frequency stagnation. The center frequency and frequency band of the pseudo-randomly generated noise may be adjustable.

Abstract: A DC/DC converter of the flyback/forward converter type includes a switch (S), a transformer (T), a first diode (D1), a first capacitor (C1), a second diode (D2) and a second capacitor (C2). The first and the second capacitor are arranged in series between the output terminals (K3, K4) of the DC/DC converter. The DC/DC converter has a high efficiency and is very suitable for operating a lamp with a DC current.

Abstract: A low-voltage ballast-free energy-efficient ultra-violet material treatment and purification system and method having an ultraviolet (UV) source comprising a gas discharge UV lamp having spaced electrodes, a source of a low-voltage, high-frequency alternating current square wave voltage and connected directly to the spaced electrodes to non-thermionically excite the gas discharge UV lamp. A flow sensor is used to proportionately control the intensity of UV generation as a function of flow rate.

Abstract: A circuit arrangement for generating an a.c. voltage, in particular the operating voltage of a high-pressure gas discharge lamp in a motor vehicle headlight, includes a transformer with a primary winding and a secondary winding which are closely linked together. These two windings form an autotransformer. The primary winding is connected at one terminal to a d.c. voltage source. At its other terminal, the intermediate tap of the transformer, it is connected to the secondary winding and also to a controlled switch. The controlled switch connects the intermediate tap to the negative terminal of the d.c. voltage source. The second terminal of the secondary winding is connected across a capacitor to a high-pressure gas discharge lamp which forms the output load. Output a.c. voltage, i.e., the operating voltage, is applied across this load. The switch is damped by the series connection of a resistor and a capacitor.

Abstract: A lighting system for a fluorescent lamp includes an inverter circuit having a pair of outputs between which is connected a resonant circuit of an inductor and a capacitor in series, with the discharge lamp connected in parallel with the capacitor. An inversely frequency dependent voltage is applied between the lamp electrodes according to a predefined resonance characteristic. During a preheat period, which precedes a lightup period during which the lamp is to be lit up with the commencement of an electric discharge between the lamp electrodes, the voltage is made lower in the first half than in the second, thereby averting the sudden flow of a large preheating current through the filamentary lamp electrodes.

Abstract: The present invention provides for a starting switch circuit which is generally applicable to ballasts and fluorescent lamps having different normal rated power from each other. A starting switch circuit includes a serially-connected circuit having a first rectifier circuit, a semiconductor switching element including a control terminal, and a first resistor circuit for detecting a current flowing to the semiconductor switching element, all connected in series; a first timer circuit, connected in parallel to a series circuit of the semiconductor switching element and the first resistor circuit, for switching the semiconductor switching element to OFF state after the semiconductor switching element is in ON state for a predetermined period of time; and a control circuit for controlling the semiconductor switching element.

Abstract: A high-efficiency self-regulated electronic ballast with a single characteristic curve for operating high-pressure sodium vapor lamps by means of an AC-to-DC converter circuit, a power factor correcting regulator circuit for reducing harmonic distortion, a high-frequency DC-to-AC converter circuit, a reducing autotransformer circuit with a current limiting inductor and an igniter, and a light-controlled switching circuit. The ballast is characterized in that it supplies a controlled high-frequency alternating voltage to the assembly of the limiting inductor and the lamp, whereby the ballast has a single characteristic curve, and in that the average power consumption of the lamp is determined on the basis of the single characteristic curve of the ballast within the standard regulation trapezoid defining the average consumption of the ballast/lamp assembly.

Abstract: A circuit arrangement for operating two or more discharge lamps in parallel, includes a transformer in a resonant load circuit. Each of the lamps is part of a series arrangement of the lamp and a capacitor. The operating frequency is chosen below the frequency for which the phase shift between the voltage and current in the load circuit is minimal. During operation, the amplitude of the current in the load circuit is relatively low so that power dissipation in the load circuit is also very low.

Abstract: A ballast circuit includes a rectifier for coupling to independent first and second AC input signals, a first inverter for energizing a first lamp and a second inverter for energizing a second lamp. A boost converter can be coupled between the rectifier and the inverters. The first inverter is enabled when the first AC input signal is applied to the rectifier and the second inverter is enabled when the second AC input signal is present.

Abstract: In a self-oscillating bridge circuit, the control of the low switch (6) is derived from the control of the high switch (7) by coupling the control circuitry (SC2) of the low switch to a terminal P in the control circuitry of the high switch by means of a diode (D1). The control of the low switch is improved by incorporating control circuitry (SC3) for rendering the low switch conducting for a short period after the high switch has become non-conducting.

Abstract: A dimmer applies a phase-controlled AC voltage to a lighting assembly which includes a fluorescent lamp operated with a magnetic ballast. A microprocessor performs a calibration routine in which the phase angle used in phase control is increment from 0 toward 180 degrees. The microprocessor monitors current conducted by the lighting assembly in response to each incrementing, effectively determining an operative range of phase angles free of flickering or drop-out. During steady-state operation, the microprocessor converts nominal power settings into corresponding phase angle settings within the operative range, preventing operation in undesirable states.

Abstract: A discharge lamp operating apparatus has a glass envelope for defining a discharge space and a pair of electrodes which are hermetically sealed within the glass envelope and are opposed to each other. The apparatus includes (1) generation element for generating a waveform signal having an acoustic resonant frequency for exciting a mode, in which a discharge arc between the pair of electrodes is straightened and (2) modulation element for modulating the waveform signal so that a polarity of the center line of the waveform signal is alternately changed at a lower frequency than the acoustic resonant frequency. If the value of the amplitude of the waveform signal from peak to peak is .alpha., and the effective value of the modulated waveform signal is .beta., then the depth of modulation .alpha./.beta. at the beginning of operation is equal to or less than the depth of modulation .alpha./.beta. at an operation under rated condition.

Abstract: In a discharge lamp control circuit for a discharge lamp mounted on a vehicle, a capacitor in a starting circuit is charged by a high voltage generated by a transformer used in a direct current power source circuit. A transformer necessary for the starting circuit and the transformer necessary for the direct current power source circuit can commonly be used for cost reduction. Further, a thyristor is used in the starting circuit in place of a gap for activating the discharge lamp.

Abstract: A ballast includes a resonant inverter circuit which limits the voltage applied to a lamp when it fails to light. In one embodiment, the inverter includes first and second switching element having conduction states controlled by respective first and second control circuits. The second control circuit includes a third switching element which controls the conduction state of the second switching element. An end of life circuit includes a first threshold circuit coupled to the third switching element for disabling the inverter when the voltage applied to the lamp becomes greater than a first predetermined threshold. In another embodiment, the second control circuit includes a fourth switching element for controlling a duty cycle of the third switching element and the end of life circuit includes a second threshold circuit. When the lamp voltage becomes greater than a second predetermined threshold, the fourth switching element reduces the duty cycle of the third switching element.

Abstract: AC voltage is applied to a resonant unit provided with an inductor and a capacitor AC current is supplied to a discharge tube connected to one of the inductor and the capacitor according to the switching operation of the two power semiconductor elements connected in a bridge manner. The resonant unit and first and second voltage drop units are connected in series between I/O terminals of the bridge and the voltages of the first and the second voltage drop units are applied as signals of opposite phases to control terminals of the two power semiconductor elements.

Abstract: A lamp driver circuit for a discharge lamp in which a high frequency is used to initiate a discharge and a lower frequency is used to sustain the discharge. A tuned circuit boosts the voltage at the starting frequency. In addition, a transformer is connected to the tuned circuit to provide a further boost to the starting voltage. The transformer core may be made of a different material from that of the inductor of the tuned circuit, and is preferably selected to saturate during starting, to enhance the voltage spikes available for starting the lamp.

Abstract: Fluorescent lamp excitation circuits are provided which use a resonating piezoelectric transformer along with complementary circuit components, to efficiently convert a DC first voltage to a transformer-output AC second voltage. In the preferred embodiment of the invention, A High Displacement Piezoelectric (HDP) transformer achieves sufficiently high voltage output to "cold fire" a gas discharge lamp. The disclosed circuit may be modified using conventional electrical sub-circuitry to pre-heat the cathodes of the lamp.

Abstract: A lighting system for a fluorescent lamp includes an inverter circuit to which is connected a load circuit including a resonant circuit of an inductor and a capacitor in serial connection, with a lamp connected in parallel with the capacitor. An inversely frequency dependent voltage is applied between the lamp electrodes according to a predefined resonance characteristic such that the resonance frequency is less than a discharge start frequency at which the lamp is to start glowing. For lighting up the lamp the frequency of the inverter output voltage is changed from a first frequency that is higher than the discharge start frequency to a second frequency that is less than the resonance frequency. If the lamp accidentally goes off, the current flowing through the load circuit will advance out of phase with the inverter output voltage, possibly resulting in the destruction of the inverter switch or switches due to overcurrent.

Abstract: A current controlled dimmer for controlling the output intensity of a fluorescent lamp with a magnetic ballast. The current controlled dimmer generates an AC current which follows the shape of the AC line voltage for the fluorescent lamp. The light intensity output of the fluorescent lamp is controlled by varying the amplitude of the AC current. The AC current is generated using a pulse width modulator (PWM) to modulate the AC line voltage. The current controlled dimmer 10 utilizes a feedback control loop which applies proportional and integral (PI) control to the PWM modulation. In another embodiment of the current controlled dimmer, the AC current is generated by rectifying the AC line voltage and modulating the rectified voltage by a pulse width modulator (PWM) into positive and negative cycles to generate a 60 Hz AC current signal.

Abstract: A power supply for a gas-discharge lamp includes a voltage source and drive circuit that produces an asymmetric output, a step-up transformer for stepping up the voltage to an appropriate level for driving the lamp, a blocking capacitor connected in series with the transformer and the lamp for preventing DC current from flowing through the transformer and the lamp to avoid core saturation of the transformer. A DC voltage is established across the lamp that prevents the formation of "bubbles" or "beads" in the gas discharge. An inverter is used to periodically reverse the polarity of the DC voltage to prevent mercury migration in mercury-containing lamps.

Abstract: A circuit arrangement comprising a DC-AC converter for operating a lamp (La). A first capacitor is connected across first and second inputs of the DC-AC converter. A first coil and a second capacitor are connected in a series circuit to first and second outputs of a rectifier circuit coupled to an AC supply voltage. Two diodes are serially connected between the first output and the first input. A third capacitor is connected between a junction point of the two diodes and a junction point between two series connected transistors of the DC-AC converter. The diodes, the coil (L1) and the second and third capacitors (C2, C3) are so dimensioned that the resonance frequency of a series circuit of the coil and the second and third capacitors connected in parallel is approximately equal to the operating frequency of the DC-Ac converter. As a result, the circuit arrangement has a high power factor.

Abstract: A high-frequency filtered dimmable electronic ballast circuit for powering low-pressure fluorescent lamps includes an input protection device; a radio-frequency filter connected to an output of the input protection device; a rectifier connected to an output of the radio-frequency filter; a power factor correcting switching power supply device connected to an output of the rectifier; a current controlled push-pull converter connected to an output of the switching power supply device; a series-parallel resonant filter composed of a capacitor in series with two inductors having a common connection in parallel with an additional capacitor connected to an output of the push-pull converter to maintain voltage wave forms essentially sinusoidal and of constant amplitude regardless of loading; a fluorescent lamp connected to an output of the resonant filter; and an external on/off switching circuit connected directly or by an optical or magnetic insulation device to an input of the push-pull converter for renotely tur

Abstract: A discharge lamp lighting device includes an inverter circuit connected through a first impedance element across output ends of a rectifier rectifying an AC source power, a smoothing capacitor inserted through a discharging diode in a power supply path to the inverter circuit, and a series circuit of a second impedance element, discharge lamp and inductor and connected between an output end of the inverter circuit and one output end of the rectifier, wherein a path for charging the smoothing capacitor is formed through a switching element included in the inverter circuit, and the discharging diode.

Abstract: A device for lighting a discharge lamp comprises a rectifier, a switching circuit having a semiconductor element to be connected to said rectifier; a direct power supplying circuit having a rectifying circuit and filtering circuit each connected to said switching circuit; and a discharge lamp and a starter which are connected after said filtering circuit; said starter having a transformer and a smoothing capacitor for generating a high voltage is provided, which has a circuit having a switching element and a resistance connected in series provided between the smoothing capacitor and said discharge lamp and further has a second capacitor connected parallel to said discharge lamp.

Abstract: A low-voltage, high-efficiency signage system comprises a housing having a translucent indicia bearing panel member. A gas discharge lighting device inside the housing is driven from a source of a low-voltage, high-frequency square wave voltage source having a pair of output terminals. A coupling circuit which is not resonant at the high frequency connects the low-voltage, high-frequency square wave voltage to the gas discharge lighting device to non-thermionically start and operate the gas discharge lighting device, and thereby illuminate the translucent indicia bearing member from inside said housing. The low voltage is from about 2 volts to about 90 volts and the frequency is from about 75 kHz to about 3.5 MHz.

Abstract: A ballast circuit 10 for a gas discharge lamp 14, incorporates a shutdown circuit 12 for limiting voltage output of a d.c.-to-a.c. converter 21. The shutdown circuit includes a pair of terminals 66 and 68 connecting across an inductor 48 in order to sense the inductive voltage of the d.c.-to-a.c. converter 21. A rectifier network 70-76 receives the inductor voltage and generates a full-wave rectified voltage. A latch 84 is arranged to receive the rectified voltage and to enter an active state when the rectified voltage is above a pre-determined value. A time delay circuit 118 located between the rectifier network 70-76 and the latch 84 provides an adjustable delay time prior to activation of the latch network. Upon activation of the latch, the inductor voltage is decreased and the ballast circuit 10 is taken out of resonance thereby lowering the voltage and current applied to the resonant circuit 28.

Abstract: An electronic ballast includes a zener diode in series with the bulk capacitor of the ballast to provide a charging voltage for a small capacitor that powers a power factor correction circuit within the ballast. A SCR in parallel with the zener diode shuts off the zener diode after the power factor correction circuit begins operation.

Abstract: An EL lamp is powered by bursts of high frequency signal repeated at low frequency, i.e. having a low duty cycle envelope, in order to shift the color of light emitted by the phosphor in the lamp without degrading the life of the lamp. The bursts include one or more consecutive cycles of a high frequency signal or several closely spaced cycles of a high frequency signal.

Abstract: The electronic ballast includes a power source circuit for transforming a conventional AC power source into a stepped-up DC voltage and a half-bridge type inverted, in response to a pair of switching driving signals, for switching the stepped-up DC voltage to make a high-intensity discharge lamp operate. The ballast also includes a digital controller for generating the pair of the switching driving signals, which have a predetermined dead time respectively between a switching-ON time interval of the switching driving signals and a phase difference of 180 degrees therebetween, in a way that frequencies of the pair of the switching driving signals are gradually shifted into some other stepped levels in turn within a predetermined bandwidth by a predetermined time interval and such a frequency shifting operation is cyclically repeated, to be supplied to the half-bridge type inverter.

Abstract: A back-up power system which can accommodate a standard electrical device that is operable from an alternating current power source when alternating current is available, but is operable by a direct-current to direct-current converter when alternating current is unavailable, the converter being powered by replaceable low voltage battery charged by the alternating current source, with the loss of alternating current being sensed to cause the disconnection of the alternating current source and connection to the low-voltage replaceable battery.

Abstract: A circuit having a full bridge configuration with a single actively biased switching element. In one embodiment, the circuit is a ballast circuit having a full bridge inverter with one switching element. The bridge includes a diode coupled to the switching element such that the diode and the switching element are coupled between positive and negative rails of the inverter. The bridge further includes first and second capacitors coupled end to end across the positive and negative rails. The ballast circuit can be coupled to a rectifier/boost circuit having a boost inductor coupled to the inverter circuit.

Abstract: A circuit for supplying AC voltage and current to a gaseous discharge lamp upon the application of DC voltage and current, the circuit comprising: a transformer including a first and a second primary windings; a first capacitance means, coupled across the primary windings to define a resonant circuit; a start-up current source coupled to a drive terminal; first and second transistors coupled to the drive terminal; at least one drive winding coupled on one end to the drive terminal and coupled on the other end to the base of one of the transistors; and first and second current-blocking devices, in one embodiment a diode and in another embodiment a transistor, each current-blocking device configured so as to block a current from flowing into the emitter element of one of the transistors.

Abstract: An electronic ballast having an RF resonant inverter and RF feedback from the inverter which provides power factor correction. The feedback is provided by a capacitor coupled between an RF resonant tank circuit of the resonant inverter and a low frequency point in the ballast. Such feedback integrates the power factor correction stage with the RF resonant inverter stage and eliminates a switch and its controller. Electronic ballasts operating at RF frequencies require fast switching isolation diodes. Ultra-fast silicon diodes with very short recovery times, which have been used as such isolation diodes, are sensitive to ambient temperature and deteriorate the power factor and total line current harmonic distortion of the ballast. Use of either GaAs or silicon carbide isolation diodes instead of silicon diodes provides the ballast with a high power factor and a low total harmonic distortion.

Abstract: A self ballasted fluorescent lamp includes a rectifier which full wave rectifies AC power from a commercial source. A smoothing capacitor smoothes the rectified power. The smoothed, rectified power is provided to a high frequency generating circuit which drives the fluorescent lamp. The capacitance value C of the smoothing capacitor is selected such that W.gtoreq..alpha.C, where W (in watts)is the rated service power of the fluorescent lamp, and .alpha. is related to a ratio of W to C0 (in .mu.F). C0 is a capacitance value of the smoothing capacitor for which the 5th harmonic component of the input current is 61% of the fundamental component of the input current when the fluorescent lamp operates under fixed conditions. When the above condition is met, the percentage of harmonic content falls within IEC standards, etc.

Abstract: An exciter circuit for an ignition system including an igniter plug. The exciter circuit includes an energy storage device comprising a pair of capacitors and a charging circuit for charging the capacitors of energy storage device to a predetermined voltage. The exciter circuit further includes a discharge circuit electrically coupled to the energy storage device and the igniter plug providing a conductive path between the energy storage device and the igniter plug. The exciter circuit periodically energizes the igniter plug by applying an output signal of the discharge circuit to the igniter plug, the output signal having a voltage magnitude sufficient to initiate a spark across electrodes of the igniter plug.

Abstract: In the circuit arrangement for the high-frequency operation of a low-power ow-pressure discharge lamp (LP) having a mains rectifier (2) and a half-bridge circuit, a diode (D1) is connected in series and in the DC non-conducting direction in the connecting line between the second electrode (E2) of the lamp (LP) and the positive or negative pole of the rectifier (2). Moreover, the tap (M2) between the diode (D1) and the second electrode (E2) is connected to the other pole of the mains rectifier (2) via a capacitor (C1), and a resistor (R9) is connected in parallel with the diode (D1). The circuit thus created acts as a passive harmonic filter which fulfills for the circuit arrangement the IEC regulations of class D with reference to line current harmonic content.

Abstract: An electronic ballast for an electron discharge lamp includes a resonant inverter driven by a high frequency switching signal supplied by a drive circuit which is substantially comprised in an integrated circuit, the lamp being connected in an output circuit of the inverter and powered thereby. The lamp intensity is controlled by changing the switching signal frequency, thereby changing the power supplied to the lamp. In order to prevent parasitic capacitance of remote wiring between the ballast and the lamp from causing inaccuracies in determination of the power being supplied to the lamp, the ballast takes into account the phase difference between lamp current and voltage in making such determination. For example, by deriving the product of rectified lamp voltage and rectified lamp current, and using the arithmetic summation of such products during each operating cycle as a measure of lamp power.

Abstract: A kit for converting a fluorescent lighting unit from inductive operation to electronic operation (using a high frequency ballast). The kit comprises a pair of sleeve-like adaptors which are adapted to be mounted at the ends of a straight fluorescent lighting tube, and a wiring assembly for electrically connecting the adapters. The components forming the electronic ballast can be mounted in one or both of the adapters, or can be mounted in the wiring assembly.

Abstract: A circuit for energizing a load includes an inverter which provides a feedback signal to a rectifier for substantially linear operation of the rectifying diodes. In one embodiment, a ballast includes a rectifier and a resonant inverter which energizes a lamp. The inverter generates a current that is split between a first path which includes the lamp and a second path which includes a feedback capacitor. A feedback path, which includes a feedback inductor, extends from the feedback capacitor to a point between the rectifying diodes. The feedback capacitor and feedback inductor resonate in series to provide a reactive feedback signal for achieving substantially linear operation of the diodes. In another embodiment, the lamp current flows to a clamp circuit for limiting the lamp current to a predetermined level.