Abstract: An inverter circuit capable of adjusting power factor transforms an AC signal of an electric power source to a pulse DC signal through a rectification unit and divides the duty cycle of minimum input voltage-maximum input voltage-minimum input voltage of the pulse DC signal to a plurality of continuous voltage pulses through an actuation unit so that a transformer outputs an altering duty cycle according to the resonant operation of each voltage pulse and enables a cold cathode lamp to blink in a dark-light-dark fashion to adjust the power factor without adding a power factor adjustment device.

Abstract: A method of commissioning a switch to control an electric luminaire in an indoor space responsive to signals from a photosensor. A first plurality of sensor signal values is calculated when the photosensor is disposed at a first location within the space. A second plurality of sensor signal values is calculated when the photosensor is disposed at a second location within the space. A first threshold value is calculated for switching on the luminaire when light in the space is less than a first value. A second threshold value is calculated for switching off the luminaire when light in the space is greater than a second value.

Abstract: FA ballast (20) for powering a gas discharge lamp (70) comprises an inverter (200) and an arc protection circuit (600). Arc protection circuit (600) monitors an electrical signal within the ballast. In response to occurrence of a disturbance in the signal, such as what occurs during output arcing, arc protection circuit (600) disables the inverter (200) for a timed shutdown period. Arc protection circuit (600) provides a timed starting period for igniting the lamp, during which time any disturbance in the electrical signal is essentially ignored and inverter (200) is allowed to continue to operate. Arc protection circuit (600) also provides a restart function for periodically attempting to ignite and operate the lamp. Arc protection circuit (600) is preferably realized using a timer integrated circuit (U1) with associated discrete circuitry, and may be adapted for use with ballasts having self-oscillating or driven type inverters.

Abstract: A multiple-CCFL parallel driving circuit and the associated current balancing control method for LCD are presented, wherein the circuit comprises a plurality of CCFLs for providing the backlight for a LCD; a boosting transformer with a plurality of outputs for providing the driving voltage and current for driving the plurality CCFLs; a plurality of ballast capacitors, the ballast capacitors connect between the boosting transformer and the CCFLs; and a multiple CCFL current balancing circuit. This invention uses a low cost current mirror circuit to equalize the driving current of a plurality of CCFLs and thus significantly improve the uniformity of the displayed image on a large-size LCD.

Abstract: A first vehicle lamp driver circuit for a light emitting diode (LED) array, the LED array having a first string of four LEDs in series and a second string of four LEDs in series. A first LED driver drives the first LED string and a second LED driver drives the second LED string. In a STOP mode of operation, the current to both LED strings is controlled by the LED driver in series with the LED string. In a TAIL mode of operation, the current is provided to only one LED string via a series connected diode and resistor. When there is reduced input voltage, operation of the LED strings is provided by switching circuits that short-out one LED in each LED string. A second vehicle lamp driver circuit comprises a first LED string and a second LED string in series with a control switch having a feedback circuit for maintaining constant current regulation to control the sum of the current in each LED string and reduce switching noise.

Abstract: Disclosed herein is a backlight inverter for a U-shaped lamp which is capable of detecting an abnormal state of an inverter circuit. The backlight inverter comprises a driver for supplying first and second transformer drive voltages in response to an operation control signal and cutting off the supply of the transformer drive voltages in response to a shutdown control signal, first and second transformers for boosting the transformer drive voltage in a turn ratio between primary and secondary windings thereof and supplying the resulting drive voltage to the U-shaped lamp, first and second voltage detectors for detecting voltages across the secondary windings, respectively, first and second current detectors for detecting currents flowing through the secondary windings of the first and second transformers, respectively, an inverter abnormal state detector for detecting an abnormal state of the inverter, and a driver controller for controlling a normal operation or shutdown of the driver.

Abstract: The subject invention is a circuit for driving a cold cathode tube using a 110V power supply. Power is provided to the cold cathode tube through a direct current converter circuit. A resonance capacitor works in conjunction with the inductive storage device until the start resonance of the tube is attained as directed by a resistor/capacitor (R/C) network. Once the tube starts conducting, another R/C network maintains and controls the circuit at a run resonance. The main driver is an oscillator with a high side and low side MOSFET driver.

Abstract: A switching arrangement includes first, second and third circuits. The first circuit is connected between a first input and a first output of the switching arrangement. The first circuit has a self-inductance, a capacitor and a diode. The second circuit is connected between the first input and a second input of the switching arrangement, and includes a switching element. The third circuit is connected between the first output and a second output of the switching arrangement, and has a diode and an inductive winding.

Abstract: Gas discharge tube displays according to the present invention control power applied to the tubes using isolator/switches, which can be opto-isolators in combination with triacs, FET's or other semiconductor switching devices or devices which can form part of a switching circuit. Such displays can also use, if desired and if appropriate, isolators which also act as the switch without other switching devices or circuits to switch and otherwise control activation of the tubes on the secondary side, or high voltage side, of the power source or sources feeding the tubes. They may also use such switching devices or circuits which act as both the isolator and the switch. The opto-isolators separate or isolate the low voltage control circuitry from the high voltage tube power circuitry, in conjunction with a triac, FET, thyristor or other device, preferably a semiconductor device, that is adapted to withstand the power load yet accomplish the switching necessary to control activation of the tube in real time.

Abstract: An electronic ballast which includes a resonant load circuit (L1, C1) in series with a discharge lamp (LA), the resonant load circuit being supplied by an inverter (S1, S2) which outputs variable alternating voltages at frequencies above 200 KHZ. Alternatively, an electronic transformer incorporates a load circuit and a variable output frequency inverter for operating a low volt halogen lamp (7) at variable alternating frequencies above 200 KHZ. Passive components of the ballast and transformer are integrated into a multilayer circuit (13).

Abstract: A ballast resonant inverter with a self-oscillating driver IC powers and dims a gas discharge lamp. A feedback circuit automatically adjusts IC oscillator frequency for safe and stable inverter operation above the resonant frequency following changes in the resonant load. The feedback signal is derived from resonant inverter output voltage, by attenuating, programmed phase shifting and injecting the resulting signal in a timing circuit of the IC. The feedback circuit includes an active inverter circuit or passive RC phase boosting networks coupled in series. Phase control of the feedback signal by variable RC networks is used in transient modes of ballast-lamp operations.

Abstract: The invention provides a power supply or drive circuit for a pulsed flashlamp which utilizes a two-core component having common windings as both an inductor for arc mode drive and for breakdown triggering of the lamp. Discharge of a capacitor through the inductor and lamp is controlled by a high-speed semiconductor switch which is turned on and off by a suitable control, current flowing from the inductor through a one-way path including the lamp when the switch is off. The control maintains the ratio of the power variation through the lamp to the average power through the lamp substantially constant. The controls may also be utilized to control output pulse shape. Novel protective features are also provided for circuit components during turn on periods for the switch.

Abstract: A LED driver includes a high frequency inverter and an impedance circuit. The high frequency inverter operates to produce a high frequency voltage source whereby the impedance circuit directs a flow of alternating current through a LED array including one or more anti-parallel LED pairs, one or more anti-parallel LED strings, and/or one or more anti-parallel LED matrixes. A transistor can be employed to divert the flow of the alternating current from the LED array, or to vary the flow of the alternating current through LED array.

Abstract: An HID ballast, is powered by a power source, to control operation of a load. The HID ballast includes a switching network connected to a first bus and a second bus, and is configured to output a high-frequency voltage signal. A bridge converter section has a first leg including first and second series connected bridge diodes, and a second leg including third and fourth series connected bridge diodes. Each leg is connected to the first bus and the second bus and is configured to receive an input signal from the power source and to convert the input signal into a form usable by the switching section. The bridge converter section is integrated with the switching section to provide the usable signal to the switching section, and to contribute to the operation of the switching section. By this design, the HID ballast is defined as a single-stage ballast device.

Abstract: The invention relates to a ballast arrangement for igniting and operating a discharge lamp. The lamp is connected in a commutating bridge in series with an inductor and in parallel with a capacitor. The conductor and the capacitor jointly form a resonance circuit during an ignition phase. The bridge is then commutated at a comparatively high frequency. After the ignition phase, the lamp reaches a run-up phase, leading to a stable-operation phase. In the stable-operation phase, the bridge is commutated at a low frequency. According to the invention, the commutation frequency is lowered in steps from the comparatively high frequency during the ignition phase to the low frequency of the stable-operation phase so as to optimize current supply during the run-up phase.

Abstract: The present invention provides a high frequency electronic ballast with ignition and operation control, and method of use, comprising a ballast microcontroller (200) responsive to at least one high intensity discharge (HID) lamp feedback signal and generating an HID lamp control signal; a parallel capacitive circuit (214) operably connected parallel to the HID lamp (216); an inductive circuit (212) operably connected to the parallel capacitive circuit (214); means for switching power (252) to the inductive circuit (212) in response to the HID lamp control signal; and means for monitoring the HID lamp (216) to generate at least one high intensity discharge (HID) lamp feedback signal. In one embodiment, the HID lamp feedback signal can be an ignition voltage signal (266). In another embodiment, the HID lamp feedback signal can be a sensed rail voltage signal (256), a sensed lamp current signal (264), and a sensed lamp power signal (258).

Abstract: The invention relates to a ballast arrangement for igniting and operating a discharge lamp. The lamp is connected in a commutating bridge in series with an inductor and parallel to a capacitor. The conductor and the capacitor together form a resonance circuit. During ignition, the bridge is commutated at a comparatively high frequency that changes with respect to time. According to the invention, the series resonance circuit has a resonance frequency that is close to an odd harmonic of the comparatively high frequency.

Abstract: A high-efficiency power supply apparatus used with a driving system of a display panel and a method of designing the same to improve an electrical power efficiency by providing a non-isolated direct current (DC) power directly to a display panel driving circuit comprise: a DC power supplying circuit to improve a power factor by rectifying an alternating current (AC) power and generating the non-isolated DC power, which is not isolated from the AC power, and an isolated DC power; a display panel driving circuit to generate various driving signals for driving the display panel with the non-isolated DC power; and a video signal processing circuit to perform a predetermined video signal processing for generating data to drive the display panel with the isolated DC power.

Abstract: A voltage for light emission is applied to the positive electrode 11 and negative electrode 13 of a flash discharge tube 3 (xenon flash lamp) by a charge and discharge capacitor 17. When the voltage of the charge and discharge capacitor 17 does not reach a predetermined value, for example a voltage normally required for light emission operation of the flash discharge tube until a predetermined, for example, a time normally required to charge the charge and discharge capacitor 17, a timer circuit 39 generates a charging stop signal S3. A control circuit 35 controls to turn off the switch of a power supply 33 with reference to the signal S3 to stop the charging to the charge and discharge capacitor 17.

Abstract: The invention relates to an operating circuit for a discharge lamp with a current regulation circuit for regulating the lamp current and a detection circuit for identifying proximity to capacitive operation of the load circuit. The operating circuit is designed to reduce the nominal current value on identifying proximity to capacitive operation.

Abstract: A half-bridge circuit includes: a vertically designed n-conducting first MOS transistor that is integrated in a first semiconductor body having a front side and a rear side; and a vertically designed p-conducting second MOS transistor that is integrated in a second semiconductor body having a front side and a rear side. The first and second transistors are connected in series between a first connection terminal and a second connection terminal. The half-bridge circuit also includes a drive circuit for driving the first and second transistors. The first and second transistors are applied to a common connection plate.

Abstract: The present invention comprises a unique starter assembly for a gas discharge lamp. The starter assembly comprises a main current path with a first leg connected to one electrode of a gas discharge lamp, and a second leg connected to a second electrode of the gas discharge lamp. A starting current path is provided between the first and second electrode, and comprises an magnetic switch. The magnetic switch is actuated by an electromagnet controlled by a control circuit. The control unit may be programmed with the start time required for a particular lamp design. In an alternative embodiment, the starter assembly further comprises a radio frequency identification system. The radio frequency identification system includes a gas discharge lamp transponder. The lamp transponder is used to communicate specific lamp information to the control circuit. The control circuit may then modify the start time for that lamp based on this information.

Abstract: To prevent lamp extinction during dead time of an inverter circuit of a full bridge system, to reduce delays of the rising time and the falling time of rectangular waves which have been output by the inverter circuit and to prevent formation of a phenomenon of momentary darkening of the radiant light, the discharge lamp is operated with an alternating current with rectangular waves which is produced by an inverter circuit of a full bridge system. When the inverter circuit of the full bridge system is driven a dead time is taken in which all switching devices are turned off. In the rear stage of the inverter circuit of the full bridge system, there is an inductance. The value of the inductance is fixed such that LL≧VL/IL·Td (VL being the luminous voltage of the discharge lamp, IL being the current and Td the dead time). Current can flow in the discharge lamp during the dead time by the energy stored in this inductance.

Abstract: A high-voltage transformer for lighting a plurality of discharge lamps has a primary coil for inputting an AC voltage and a secondary coil for outputting a predetermined AC voltage higher than the AC voltage inputted. The primary coil has a starter primary winding for initially lighting the discharge lamps, and a normal lighting primary winding for normally lighting the discharge lamps.

Abstract: In accordance with one aspect of the present application, a continuous mode voltage fed inverter includes a resistor starting network configured to start a charging of the inverter. A resonant feedback circuit is configured to generate an oscillating signal following the starting of operation of the circuit by the resistor starting network. A complementary switching network has a pair of complementary common source connected switches configured to receive the oscillation signal generated by the resonant feedback circuit, wherein the oscillation signal determines a switching rate of the complementary pair of switches. A clamping circuit is configured to maintain an inverter current in an inductive mode, wherein the inductive current lags voltage across the pair of complementary common source connected switches. A fold-back circuit is connected, in one embodiment, to the complementary switching network to provide a two-level clamping action.

Abstract: A circuit efficiently drives light emitting diodes (LEDs). The circuit uses a switching regulator device instead of a standard resistor to limit current to the LEDs. The switching regulator device is in a closed loop with a current sensing device near the LED lamps. Feedback from this current sensing device switches the control method according to the current load regulating the voltage applied to the LEDs. An inductive storage device in the circuit allows the LEDs to be driven with minimal voltage input. Methods for intensifying and focusing the light produced by the LEDs driven by the circuit are also described.

Abstract: A lighting system (1) comprises a plurality of high intensity discharge lamps (9, 39, 6) and an electronic control (2) having a power input (4), an alternating current power output regulator (22), and an alternating power output (3) having an output frequency arranged to be variable within an output frequency range, the output having a first and a second output line. The lamps are connected in series with each other so that the first line is connected to the first electrode (11) of the first of the lamps, the second electrode (12) of the first of the lamps is connected to the first electrode (41) of the next lamp in the series, the second electrode (13) of the final lamp in the series being connected to the second output line. The lamps have an acoustic resonant frequency range and the output frequency range of the control is arranged to be above the acoustic resonant frequency range.

Abstract: The invention provides a high pressure discharge lamp lighting apparatus which prevents dying out or instabilities of the discharge arc inside the arc tube due to the acoustic resonance phenomena and enables to light the high pressure discharge lamp in a steady state. In the high pressure discharge lamp lighting apparatus having the high pressure discharge lamp, the lamp voltage detecting means, the high frequency power supplying means, and the control circuit, the apparatus includes an extracting means for extracting an upper limit frequency and a lower limit frequency of the resonance-free frequency band, and the control circuit includes a frequency moving means for changing the frequency of the high frequency power within a range defined by the upper limit frequency and the lower limit frequency extracted by the extracting means and then moving the frequency to a predetermined frequency which is determined based on the upper limit frequency and the lower limit frequency.

Abstract: An electronic device having an illumination circuit. The illumination circuit utilizes an AC current of an AC driving device to drive an illumination device such as an electroluminescent lamp and the remaining life of the AC driving device indicated by the brightness of illumination device.

Abstract: A high-pressure discharge lamp lighting apparatus, comprises an LC resonance circuit, a DC power source, an inverter circuit, an inverter circuit and an inverter control circuit. The resonance frequency of the LC resonance circuit is set in two to three times the oscillation frequency in the steady lighting operation of the high-pressure discharge lamp. Until the high-pressure discharge lamp is started and steadily lit up, the starting control circuit controls to operate the inverter circuit at a frequency lower than the resonance frequency and not causing acoustic resonance.

Abstract: An electronic ballast for a fluorescent lamp has a single-switch flyback inverter including a magnetizing inductance, a resonant circuit connected to the output of the inverter including a tank inductor, and a clamp circuit including a diode coupled to the primary winding of the flyback transformer for limiting the voltage across the magnetizing inductance when the switch is non-conductive. With the inverter switch conductive the resonant circuit has a first resonant frequency. With the inverter switch non-conductive, the resonant circuit, combined with the magnetizing inductance, has a second resonant frequency lower than the first. The magnetizing inductance is chosen such that the second resonant frequency is close to the first resonant frequency. The operating frequency of the inverter is controlled to be at or about the second resonant frequency, whereby zero current switching is achieved in the inverter switch.

Abstract: An electronic ballast comprises a direct current power supply configured to provide a direct current voltage. A switching circuit, including first and second switching elements, is connected in parallel with the direct current power supply, and is configured to convert the direct current voltage to a high-frequency alternating current. A load circuit, including a discharge lamp, a resonance inductor, and a resonance capacitor, is operated by the high-frequency alternating current. A driving circuit is arranged between the switching circuit and the load circuit. A driving circuit is provided with feedback windings magnetically connected to a detecting winding of the current transformer. A driving circuit is configured to control a switching frequency of the first and second switching elements according to a detected current of the detecting winding. A magnetic energy control means is configured to control a magnetic energy of the current transformer.

Abstract: A lamp assembly configured to inductively receive power from a primary coil. The inductively powered lamp assembly includes a lamp circuit including a secondary and a lamp connected in series. In a first aspect, the lamp circuit includes a capacitor connected in series with the lamp and the secondary to tune the circuit to resonance. The capacitor is preferably selected to have a reactance that is substantially equal to or slightly less than the reactance of the secondary and the impedance of the lamp. In a second aspect, The inductively powered lamp assembly includes a sealed transparent sleeve that entirely encloses the lamp circuit so that the transparent sleeve is fully closed and unpenetrated. The transparent sleeve is preferably the lamp sleeve itself, with the secondary, capacitor and any desired starter mechanism disposed within its interior.

Abstract: A discharge lamp driving circuit drives a discharge lamp using a high frequency wave, to start the lamp. A booster/chopper circuit has a switching element FET1, and boosts an input power supply voltage by switching the switching element. A boosting transformer supplies the discharge lamp with the voltage boosted by the booster/chopper circuit. A booster/driver circuit supplies the switching element FET1 of the booster/chopper circuit with a driving signal having a frequency of 10 to 200 kHz, thereby limiting the peak loss of the switching element FET1 to 200 W or less.

Abstract: A lamp lighting apparatus has a discharge drive circuit for supplying discharge current to the lamp, a voltage conversion circuit for boosting voltage from DC power and supplying the boosted voltage to the discharge drive circuit, and an arc discharge detecting circuit for detecting that a state of discharge of the lamp changes to arc discharge, and outputting an arc discharge transition signal to the voltage conversion circuit, wherein when the voltage conversion circuit receives the arc discharge transition signal which shows that the transition to the arc discharge does not take place, the voltage conversion circuit supplies a first voltage or higher to the discharge drive circuit, and when the voltage conversion circuit receives the arc discharge transition signal which shows that the transition to the arc discharge takes place, the voltage conversion circuit supplies a second voltage lower than the first voltage to the discharge drive circuit.

Abstract: In the present invention, the safeguarding of the circuit and the step-up transformer can be devised without using the special high-cost components. Voltage supplied by the primary coil (21) of a step-up transformer (2) is switched by a transistor (TR) and the secondary coil (22) of the step-up transformer causes the generation of secondary voltage. In addition to applying said secondary voltage to a cold cathode tube (1), the current flowing through the cold cathode tube (1) is detected, and the transistor (TR) switching function is controlled based on the detection results. To detect the voltage generated by the secondary coil of the aforementioned step-up transformer, a voltage detection coil wrapped around the aforementioned step-up transformer (2) is provided. Abnormalities in the voltage supplied to aforementioned cold cathode tube (1) are detected based on voltage detected by this voltage detection coil (23). Switching by the aforementioned transistor (TR) is stopped when an abnormality is detected.

Abstract: The present invention relates to a device for preheating the two coil electrodes (W1, W2) of a fluorescent lamp (La) comprising an AC voltage source (10), a resonance capacitor CR, which is arranged serially between the two coil electrodes (W1, W2), a first inductance (L1), which is coupled between the AC voltage source (10) and one of the two coil electrodes (W1, W2), and a second inductance (L2), which is connected to a point between the AC voltage source (10) and the coil electrode (W1) coupled thereto, the second inductance (L2) being coupled to the first inductance (L1) in such a way that a current flow (IL2) through the second inductance (L2) leads to a reduction of the magnetization of the first inductance (L1). It furthermore relates to a corresponding method.

Abstract: A free-running circuit arrangement for operating a load, has at least one switching element, a freewheeling diode connected in an anti-parallel fashion relative to the main current direction of the at least one switching element, a load circuit and a control resonant circuit which comprises at least one control inductor and at least one self-capacitance of the at least one switching element. The at least one switching element has a control electrode, a working electrode and a reference electrode, a capacitance acting between the control and working electrodes that is coupled to the control resonant circuit such that energy is fed into the control resonant circuit by the charging and discharging current of this capacitance, the circuit arrangement having no components for feeding energy into the control resonant circuit by electromagnetic coupling.

Abstract: A hot-restrike ignition system for a high-frequency high-intensity discharge lamp includes a resonant circuit that is connectable across the lamp in parallel with a ballast circuit that is used to provide steady-state current for the lamp. The resonant circuit is temporarily energizable for producing a voltage sufficiently high for hot-restrike ignition of the lamp. The resonant circuit has two parts. The first part provides a voltage waveform with frequency approximating the steady-state voltage frequency and amplitude sufficient when combined with the steady-state voltage to produce glow discharge, and the second part provides a voltage waveform that is lower in repetition rate but of sufficiently high voltage to initiate hot-restrike ignition in the lamp.

Abstract: A lamp ignition circuit is provided which can initiate operation of a gas discharge lamp using a driving voltage which is similar in magnitude to the lamp operating voltage. The lamp ignition circuit is useful with a semi-resonant ballast and lamp circuit in which switching operations intrinsic to the lamp shock-excite a series-connected inductor and capacitor into semi-resonant operation corresponding to an energy exchange and transfer during each half-cycle of the alternating current source to drive the lamp to start and maintain operation of the lamp using line voltage. The ignitor circuit has a disabling function following ignition of the lamp which is operable when the operating voltage of the lamp is approximately the line voltage of the power source. The disabling function triggered by an increase in voltage across the ignition circuit following operation of the lamp.

Abstract: Light emitting elements with preselected or adjustable impedance characteristics are provided. Embodiments using a preselected impedance characteristic obtain significant performance benefits compared to the prior art. Embodiments having an adjustable impedance may alter the impedance associated with the light emitting component such that it has a substantially constant resistive or reactive impedance that improves certain performance attributes. This solution virtually eliminates the need for external compensation components and relieves the burden of impedance matching and circuit specialization from the driver circuit.

Abstract: A method and structure for energizing a flash lamp for producing a high energy light pulse, with the flash lamp energized by a flattened and extended current pulse. The method includes collecting and storing energy for delivery to the flash lamp when triggered. A triggering of the flash lamp resulting in a delivering of the collected and stored energy to the flash lamp in the form of an amplitude controlled (flattened) and duration controlled (extended) current pulse.

Abstract: A description is given of a gas-discharge lamp base (11) with a housing comprising an upper part (10) and a cover (40), a support (16) accommodated in the housing for receiving the components, with a transformer, with inductances connected in series with the lamp (1) and a capacitance connected in parallel with the lamp (1), the transformer comprising a bar transformer (23). This construction permits particularly efficient production, because the support can be constructed as a simple leadframe which permits automatic component fitting.

Abstract: To efficiently and cost-effectively produce a light source, a CCFL circuit can include a PMOS transistor, first and second NMOS transistors, and a high turns ratio transformer. The transformer can include a primary coil having a center tap, thereby forming first and second primary windings, as well as a secondary coil. The PMOS transistor can be connected to the center tap for driving the transformer. The first and second NMOS transistors can be connected to the first and second primary windings, respectively. Of importance, the first primary winding is tightly coupled to the second primary winding, whereas the first and second primary windings are loosely coupled to the secondary coil.

Abstract: An electronic ballast comprises a direct current power supply configured to provide a direct current voltage.

Abstract: The invention relates to an operating circuit for a discharge lamp, having a detection circuit for identifying the proximity to capacitive operation, which uses lamp current fluctuations for detection purposes.

Abstract: A lamp assembly in accordance with the invention includes an electrodeless bulb (14) which is symmetrical about an axis (16) and which contains a light emissive fill which emits light when the bulb is excited by a RF electrical field coupled to the fill; an electrically conductive coupler (18) comprising a plurality of turns (20) which are symmetrical about an axis of the electrically conductive coupler, the turns defining a volume (19) that at least partially contains the bulb; and a conductor (26) connected to a center portion of the electrically conductive coupler with connection of the conductor to the electrically conductive coupler providing a fixing of the coupler relative to the bulb which, when the conductor is connected to a source of RF electrical potential, conducts a RF current producing a RF electrical potential on the electrically conductive coupler that produces the RF electrical field coupled to the light emissive fill.

Abstract: Free-running half-bridge inverter (HP) for operating gas discharge lamps having a current transformer as a feedback device. The half-bridge transistors (T1, T2) are essentially voltage controlled transistors (MOSFET). The drive circuits (1, 2) for the half-bridge transistors (T1, T2) contain a voltage threshold value switch (D2, R2) which, on reaching its voltage threshold, essentially carries a current which is proportional to the load current of the half-bridge inverter (HB).

Abstract: A portable lighting ballast includes first and second transistors 20, 22 for converting direct current from a voltage source 16 into alternating current to operate a lamp 10. The lamp has an ignition voltage that is significantly higher than the voltage that the source 16 produces. The battery is a typical 6 volt cell or a combined source of 4 “D” cells, also producing six volts. The ignition voltage of the lamp 10 is approximately 600 V. A transformer 34 boosts the alternating current signal from the transistors 20, 22 to an amplitude sufficient to ignite the lamp 10. The transformer 34 boosts the signal to 1.2 kV. After lamp ignition, the transformer settles the voltage to a steady state value.

Abstract: A filament cut-back circuit comprises an impedance circuit coupled in series between either an AC voltage source and a primary filament winding, or a secondary filament winding and a filament. In response to an alternating voltage from the AC voltage source when coupled in series thereto or an alternating voltage from the secondary filament winding when coupled in series thereto, the impedance circuit operates as a short circuit when the alternating voltage is at a preheat frequency and operates as an open circuit when the alternating voltage is at an operating frequency.