Abstract: A backlight unit includes at least one cold cathode fluorescent lamp arranged at a lower end of a bottom cover, external electrode fluorescent lamps arranged on the bottom cover above the cold cathode fluorescent lamp, and inverters disposed on a rear side of the bottom cover for driving the at least one cold cathode fluorescent lamp and the external electrode fluorescent lamps.

Abstract: A dielectric barrier discharge lamp lighting device includes a transformer that supplies a driving voltage to a dielectric barrier discharge lamp from a secondary coil, and a driving circuit that controls an input voltage to the transformer to supply a driving voltage with a driving frequency fd to the dielectric barrier discharge lamp. The self-resonant frequency fr of the secondary coil, which is measured with the primary coil of the transformer being open, is equal to the driving frequency fd or a frequency in the vicinity of the driving frequency fd. This frequency fr satisfies, for example, 0.9fd?fr?1.3fd.

Abstract: An inverter controller dives an inverter to operate at a switching frequency selectively from one of a preheating frequency (f1), a starting frequency (f2), and a lighting frequency (f3) which are different from each other, thereby giving a preheating mode, a starting mode, and a lighting mode. A reset means is provided to make the starting mode upon lowering of a voltage supplied to the inverter below a first threshold, while an inverter stop means is provided to stop the inverter upon detection of abnormality of a discharge lamp. A timer generates a signal determining the start of the preheating, starting, and/or lighting modes, and generates a reset signal disable signal for disabling the reset means, an inverter stop disable signal for disabling the inverter stop means. The inverter controller includes a frequency sweep means for varying the switching frequency gradually from the starting frequency to the lighting frequency.

Abstract: A low cost ballast circuit for fluorescent lamp is provided. A fluorescent lamp is connected in series with a resonant circuit having a transformer. A first switch and a second switch are coupled to switch the resonant circuit. A first winding of the transformer is connected in series with a capacitor to form the resonant circuit. A second winding and a third winding of the transformer are used for generating control signals in response to a switching current of the resonant circuit. The first switch and the second switch are controlled in response to the control signals. Furthermore, soft switching operation for the first switch and the second switch can be achieved by the present invention.

Abstract: A circuit (10) for powering a halogen lamp (20) comprises an inverter (100) and an output circuit (300). During operation, the inverter (100) and output circuit (300) provide a magnitude-limited current to the halogen lamp such that the lamp power during an initial period is substantially less than the lamp power during a steady-state operating period. Preferably, output circuit (300) is a non-isolated circuit that includes a current-limiting inductance, and inverter (100) includes a frequency control circuit (R2,C4,C7,Q3,R3,R5,C8) for operating the inverter at a higher frequency during the initial period so as to reduce stress upon the lamp filament and preserve the operating life of the lamp. The circuit (10) is especially suitable for powering low voltage halogen lamps.

Abstract: The present invention provides a low-cost inverter for ballast. A current transformer is connected in series with a lamp to operate the lamp. A first transistor and a second transistor are coupled to switch the resonant circuit. The current transformer is utilized to generating control signals in response to the switching current of the resonant circuit. The transistor is turned on once the control signal is higher than a first threshold. After that, the transistor is turned off once the control signal is lower than a second threshold. Therefore, a soft switching operation for the first transistor and the second transistor can be achieved.

Abstract: An optical emission spectrometry device is provided. In the optical emission spectrometry device, a discharge path is formed by connecting an ignition circuit to a discharge gap, and further connecting in parallel a plurality of sets of coils and driving circuits, each set having one coil and one driving circuit. Each driving circuit has two operation modes: an increasing operation mode of applying a predetermined potential difference to the corresponding coil of the set to increase the current passing through the corresponding coil, and a sustaining operation mode of directly connecting the corresponding coil of the set to the discharge path to sustain the current passing through the corresponding coil. Moreover, each driving circuit is controlled in such a way that the timing for the increasing operation mode in which the current passing through the coil increases alternates with the timing for the increasing operation mode of other driving circuit.

Abstract: A DC/AC converter 3 performs AC conversion and a boosting function upon the reception of a DC voltage. A control unit 6 controls the DC/AC converter 3 to perform the lighting control of a discharge lamp. The DC/AC converter includes an AC conversion transformer 7, switching devices 5H, 5L and a resonance capacitor 8, and drives the switching devices to produce series resonance in the capacitor 8 and an inductance component for the transformer 7 or the inductance device 9. Before the discharge lamp 9 is turned on, the drive frequency for the switching devices gradually nears a resonance frequency f1 to increase an unloaded output, and a start signal is supplied to the discharge lamp. After the lighting of the discharge lamp has been initiated, the drive frequency is defined that is higher, by a predetermined frequency displacement value ?F, than the drive frequency immediately before the discharge lamp is turned on.

Abstract: A method of determining a zero point of a current sensor in a circuit arrangement for operating a gas discharge lamp includes switching off the current through the sensor for a short period during a first half wave and determining a first test value. Then the current through the sensor is switched off for a short period during a second half wave having a different polarity and a second test value is determined. The average value of the two test values is formed and the zero point is determined using the average value. It is prevented thereby that the zero point drifts during lamp operation, and that amplitudes of the positive and negative half waves of the lamp current are formed differently.

Abstract: An inverter comprising a low-side switching element in series with a first primary winding; a high-side switching element in series with a second primary winding, where the combination of the low-side switching element and first primary winding is connected in parallel with the combination of the high-side switching element and the second primary winding; and a clamping capacitor having one terminal connected to the first primary winding and having a second terminal connected to the second primary winding. Other embodiments are described and claimed.

Abstract: A discharge lamp lighting circuit is provided. The discharge lamp lighting circuit includes an inverter circuit which has two output ends; a series resonant circuit which includes a capacitor, an inductor and a transformer, coupled in series; a driving portion; and a controlling portion which provides a control signal for controlling said inverter circuit, said controlling portion including a first signal producing portion which produces a first signal indicative of a phase of a current flowing through said series resonant circuit; and a second signal producing portion which produces a second signal indicative of a phase of the AC voltage output from said inverter circuit, said controlling portion producing the control signal on the basis of a phase difference between the first and second signals, wherein one component of said series resonant circuit is coupled between one of said output ends, and a detection point.

Abstract: The present invention relates to an electronic ballast for driving a fluorescent lamp or the like, and more particularly to a new topology ballast that has only one switch in its oscillating part. The new ballast is an improvement over the conventional half-bridge structure, having a reduced number and size of key components, as compared to conventional designs.

Abstract: A cold cathode fluorescent lamp inverter apparatus includes a series circuit connected to a DC power source and including first and second switching elements, a series circuit connected between a connection point of the first and second switching elements and the DC power source and including a primary winding of a transformer, a reactor, and a capacitor, a cold cathode fluorescent lamp connected to a secondary winding of the transformer, a current detector connected to the cold cathode fluorescent lamp and to the secondary winding, to detect a value of a current passed through the cold cathode fluorescent lamp, and a controller to turn on/off the first and second switching elements alternately with each other according to the detected current value. The current detector detects a ripple component in the DC power source, and corrects the current of the cold cathode fluorescent lamp according to the detected ripple component.

Abstract: A discharge lamp lighting circuit is provided. The discharge lamp lighting circuit includes a power supplying portion which comprises an inverter circuit comprising a switching element; a series resonant circuit comprising a capacitor, and at least one of an inductor and a transformer; and a driving circuit which drives said switching element, said power supplying portion converting DC power to AC power and supplying the AC power to a discharge lamp; and a controlling portion which produces a frequency control signal for controlling a frequency of a drive signal output from said driving circuit, the controlling portion including a phase difference detecting portion which detects a phase difference between an input voltage and an input current that are supplied from said inverter circuit to said series resonant circuit; and a control signal producing portion which produces the frequency control signal in accordance with the phase difference.

Abstract: A feedback and protection circuit is provided for detecting voltage and current of a cold cathode fluorescent lamp (CCFL) of a liquid crystal display (LCD) panel backlight apparatus and integrating all voltage and current input signals to output single current and voltage feedback signals to a PWM controller, so as to stabilize and control the voltage and current of the CCFL and determine whether any detected input signal is abnormal. If any CCFL is short circuited (CCFL is touched by people) or open circuited (CCFL is not lit), an abnormal status protection signal will be produced and sent to the PWM controller to stop all outputs of the backlight apparatus to prevent damages to circuit components or injuries to people. The circuit is designed in an integrated circuit to achieve the effects of reducing the area occupied by the circuit component layout and lowering the overall cost.

Abstract: An apparatus of driving a lamp for a display device is provided. The driving apparatus includes an inverter (920), a lamp current sensor (940), and an inverter controller (930). The lamp current sensor (940)senses a current flowing in the lamp and output a feedback signal having a magnitude depending on the sensed current. The inverter controller (930) compares a dimming control signal from an external device with the feedback signal and controls the inverter (920) based on the comparison. The inverter (920) includes a transformer (T1) for applying a lamp drive voltage to a lamp for turning on or off the lamp and a voltage sensor (928) sensing the lamp drive voltage. The inverter (920) adjusts a turns ratio of the transformer in accordance with the sensed lamp drive voltage.

Abstract: A method and apparatus for protecting a discharge lamp lighting device from damage due to mis-wiring of a source of electrical power to the discharge lamp lighting device. The protection apparatus includes a detector, a comparer and an inhibitor. The detector samples at least one monitor point associated with the discharge lamp lighting device to obtain at least one detection voltage. The comparer compares the at least one detection voltage with a reference voltage. The inhibitor inhibits an operation of the discharge lamp lighting device when the comparer determines that a mis-wiring of the source of electrical power to the discharge lamp lighting device exists.

Abstract: A driving method for a fluorescent lamp is provided. A driving signal for driving the fluorescent lamp is generated, and an operating current of the fluorescent lamp is detected. The frequency of the driving signal is adjusted when the operating current of the fluorescent lamp reaches a first predetermined value. Besides, whether or not the operating current of the fluorescent lamp reaches a second predetermined value is detected in order to decide whether to stop generating the driving signal or not, wherein the second predetermined value is greater than the first predetermined value.

Abstract: In the case of an apparatus for providing a sinusoidally amplitude-modulated operating voltage, two switches are arranged in the form of a half bridge, and an LC element is arranged downstream of the half bridge. The first switch is driven by a first square-wave signal in a clocking with the amplitude modulation frequency per clock cycle, and the second switch (QLOW) is driven by a second square-wave signal, which is shorter than the first signal, with a temporal offset with respect to the first signal in each clock cycle. The LC element (LMOD, CMOD) acts as a filter for the signal resulting from the driving of the switches at a connection point (K) between the switches and allows a DC voltage component and a sinusoidal component of the signal with the fundamental frequency of the clocking to pass through, but substantially filters out harmonics.

Abstract: A discharge lamp driving circuit includes an inverter, a ballast capacitor, a discharge lamp, and a lamp current detecting circuit. The inverter converts a DC voltage into an AC voltage with high frequency to output the AC voltage to an output port based on a pulse width modulation control signal. The lamp current detecting circuit outputs a first voltage signal and a second voltage signal according to a voltage across the ballast capacitor to generate a lamp current sensing voltage that is proportional to a lamp current flowing through the discharge lamp. The pulse width modulation control signal has a width varying with amplitude of the lamp current so that the lamp current may be accurately detected.

Abstract: A resonant DC/AC inverter includes a DC power source providing a DC voltage, a half-bridge power switch circuit electrically connected to the DC power source being operative to convert the DC voltage to an AC voltage, a resonant tank electrically connected between an output of the half-bridge power switch circuit and an input of a load being operative to boost and filter the AC voltage to generate an AC power voltage supplied to the load, and a controller being operative to detect a magnitude of current in the load and a magnitude of a voltage across the load and to generate pulse waveforms for turning on and off the half-bridge power switch circuit, wherein the controller substantially instantaneously varies a frequency of the pulse waveforms and a duty cycle of the pulse waveforms so as to operate the resonant DC/AC inverter near a neighborhood of a resonant frequency of the resonant tank regardless of a conduction state of the load and improve the efficiency of the inverter regardless of the higher DC volt

Abstract: There is provided a backlight unit that determines whether a lamp performs an abnormal operation by detecting a voltage that is induced in a power conversion transformer without using a complicated and expensive detection circuit. A backlight unit having a protection circuit using induced voltage detection according to an aspect of the invention includes an inverter part including a primary coil receiving power and at least one secondary coil converting the power from the primary coil to AC power set beforehand, a lamp part including at least one lamp receiving the AC power from the inverter part to emit light, a detection part including conductors detecting voltages electromagnetically induced in the secondary coil, and an abnormality determining part comparing detection voltages from the detection part with a reference voltage set beforehand.

Abstract: A controller 5 for a high intensity discharge lamp 4 includes a primary ballast for providing a primary current to the lamp 4, and a current injector which in the case shown comprises a control ballast 8 and a switch 9 (e.g. a triac) controlled by a control unit 12. The current injector injects a secondary current into the lamp 4 that is less than the primary current and can be varied by the control unit 12, e.g. by varying the amount of time within an a.c. cycle that the control ballast 8 is switched into the circuit. The controller 5 allows the lamp 4 to be controlled, for example, to operate at a constant power (variable light output) or at a constant light output (variable power).

Abstract: An anti-striation circuit employs an inverter topology including a pair of electronic switches (Q, M) that are switched between a conducting state and a nonconducting state in an alternating manner to apply an asymmetrical voltage waveform across one or more lamp (LP) to thereby control a flow of an asymmetrical current waveform (iacc) through lamps (LP). To eliminate, if not minimize, visible striations in the lamp(s) (LP), the impedances of an asymmetrical driver as connected to the control inputs (B, G) of the electronic switches (Q, M) may be unequal, and/or the impedances of an asymmetrical driver as connected to the current paths (C-E, D-S) of the electronic switches (Q, M) may be unequal. Additionally, the current gains of the electronic switches (Q, M) may be unequal, and a DC current may flow through the lamp(s) (LP).

Abstract: A circuit includes a transformer 7 for transmitting power to a discharge lamp 10 and for supplying a starting signal to the discharge lamp. The circuit includes a direct current-alternating current converting circuit 3 for supplying an output of the transformer 7 to the discharge lamp 10 after carrying out a direct current-alternating current conversion, and a starting circuit 4 for applying the starting signal to the discharge lamp 10. A primary side of the transformer 7 has a first capacitor 11, a circuit portion 13 including a rectifying element, and a switching element 14. The transformer 7 has an auxiliary winding 7v for supplying a voltage for generating the starting signal to the starting circuit. A second capacitor 12 is interposed between the auxiliary winding and the circuit portion 13 and prevents absorption of energy by the capacitor 11 in generating the starting signal and prevents attenuation of the starting signal.

Abstract: This invention presents a single-stage power converter for driving many number of Light-Emitting-Diode (LED). The power converter converts an AC input voltage into DC current source and regulates the current flowing into the LED. In addition, the AC input current is controlled to have a sinusoidal waveform synchronized with the AC input voltage so that AC input Power Factor is corrected. Hence, both of Power Factor Correction (PFC) and LED current regulation are obtained simultaneously by using a single power conversion stage. So higher efficiency with low cost can be obtained.

Abstract: A charging circuit has a battery 12, switching element 14, and resistor 16 for current detection arranged on the primary side of transformer 10. Diode 18 and capacitor 20 for storing electric power are arranged on the secondary side of transformer 10. In a normal state, the ON/OFF states of switching element 14 are repeated corresponding to output signals U1, U2 of two comparators 28, 30. However, if switching element 14 stays on or off longer than a prescribed period of time for some reason, the status of switching 14 will be switched forcibly by an auxiliary sequence of the logic parts in control logic 42.

Abstract: A lamp, a method of driving the lamp, a backlight assembly having the lamp, and a liquid crystal display (LCD) device having the backlight assembly are disclosed. The lamp includes a tube that contains gas and first through fourth electrodes. The first and second electrodes are disposed in the tube adjacent to first and second ends of the tube. The third and fourth electrodes are disposed at the first and second ends of the tube. Voltages applied to the electrodes are sufficient for light to be emitted throughout the lamp. The first and second voltages, third and fourth voltages, first and third voltages, and second and fourth voltages have different polarities while the first and fourth voltages and the second and third voltages have the same polarity.

Abstract: A resonant switching converter comprising a first pair of series connected switches comprising a high side switch and a low side switch coupled across a DC input voltage, there being a first switched node between the switches; a second pair of series connected switches comprising a high side switch and a low side switch coupled across a DC bus, there being a second switched node between the switches; a DC bus capacitor coupled across the DC bus; the first and second switched nodes adapted to have a load coupled therebetween; the high side switch of the first pair of switches supplying current to the load from the DC input voltage, the low side switch of the first pair of switches being switched opposite the high side switch of the first pair of switches and providing a re-circulation path to allow bi-directional current flow through the load; the high side switch of the second pair of switches supplying current to the load from the DC bus capacitor, the low side switch of the second pair of switches being swi

Abstract: An inverter for driving at least one light-emitting unit includes a switching circuit, an electric-isolated circuit and a transforming circuit. The switching circuit generates at least one switching signal according to a DC signal and at least one switching control signal. The electric-isolated circuit has an electric-isolated side and a non-electric-isolated side, which is electrically connected to the switching circuit electrically and generates a first power signal according to the switching signal. The transforming circuit is electrically connected to the electric-isolated side of the electric-isolated circuit, and generates a second power signal to drive the light-emitting unit according to the first power signal.

Abstract: Electrodeless discharge lamp lighting device. Start circuit 19 sweeps operating frequency of resonance circuit 16 from start frequency to end frequency of resonance frequency side through drive circuit 18 and DC/AC conversion circuit 15, and starts electrodeless discharge lamp 13. Control circuit 10 increases or decreases variable power into circuit 18 so that detection current comes to equal prescribed current for shifting the operating frequency to middle range frequency between the start frequency and the end frequency. The prescribed current is set so that the detection voltage in case of the middle range frequency becomes lower than that in case of the end frequency. Capacitor 106 constituting integration circuit starts suppression of operation of circuit 10 when lamp 13 is started, and holds the suppression during at least start mode. Accordingly, it is possible to stably start lamp 13 and control stress on circuit(s) after lamp 13 is successfully started.

Abstract: An ignition circuit for igniting a gas discharge lamp generates a high voltage gas breakdown pulse by building up a current through a primary winding of a transformer. After a predetermined period and thus when a predetermined current flows through the primary winding, a capacitance is switched in series with said primary winding, thereby generating said high voltage gas breakdown pulse in a secondary winding of said transformer. After generating the high voltage pulse, the capacitance is short-circuited in order to preserve energy in the primary winding. The preserved energy is employed to build up energy again for a next high voltage pulse in a short time. At a high repetition rate and high voltage of the generated pulses, the ignition circuit according to the present invention is also suitable for driving the gas discharge lamp during a take-over period following the gas breakdown of the lamp for heating the lamp electrodes.

Abstract: In a lighting circuit for a discharge lamp, the discharge lamp is kept lit without fail when a DC input voltage becomes low, while avoiding a complicated circuit configuration and control method. A DC-AC converter circuit receives a DC input voltage and converts it to an AC voltage and boosts the AC voltage. The DC-AC converter circuit is controlled by a control means having a circuit for detecting the DC input voltage “+B” to perform a lighting control of the discharge lamp. The lighting circuit comprises a transformer for AC conversion, switching elements, and resonance capacitor. The switching elements are driven to cause a series resonance of the resonance capacitor and an inductance component of the transformer for AC conversion or an inductance element.

Abstract: A power supply circuit for transforming a direct-current voltage into an alternating-current voltage for a light source is provided. The power supply circuit includes a drive circuit, a switch, a transformer and a capacitor. The switch has a control terminal coupled to the drive circuit and a ground terminal coupled to a ground. The transformer has a primary side and a secondary side, and a winding on the primary side is coupled between the direct-current voltage and a signal terminal of the switch to generate the alternating-current voltage on the secondary side. The capacitor is coupled between the ground terminal and the signal terminal of the switch.

Abstract: A circuit is used for driving a plurality of LEDs by an external voltage source. The LEDs are coupled in series. The circuit comprises a plurality of switches coupled to the LEDs in parallel, respectively, for individually controlling the brightness of the LEDs. The circuit further includes a plurality of Pulse-Width Modulation (PWM) signals coupled to the switches, respectively, for individually controlling the switches.

Abstract: A portable fluorescent task lamp comprising at least two fluorescent bulbs of any wattage up to forty Watts and of either a non-starting type or a self-starting type; and an electronic ballast circuit for use therewith including an SPST function switch disposed in series with each fluorescent bulb, wherein the fluorescent bulbs may be ignited and sustained in illumination in parallel, simultaneously or individually, as determined by the respective SPST switches.

Abstract: The present discharge lamp lighting device is capable of rapid modulation in which a lamp current is rapidly reduced and rapidly restored. The current control circuit is provided to perform specific current control such that the brightness of a lamp is reduced by a predetermined percentage without being affected by a variation or change in lamp voltage over time, thereby reducing a lamp current.

Abstract: A video signal line driving circuit includes, for each output terminal TSj, a unit precharge circuit made of a capacitor Cpr and switches SWA1, SWA2, SWB1 and SWB2 for connecting the capacitor Cpr in parallel to a capacitive load of a liquid crystal panel. An OFF period in which first and second output buffers are electrically disconnected from the video signal line is provided between a P period in which a positive voltage is to be applied from the first output buffer in the video signal line driving circuit to the video signal lines (capacitive load) and an N period in which a negative voltage is to be applied from the second output buffer. A first and a second precharge period are set within this OFF period.

Abstract: An external electrode surface emission fluorescent lamp for LCD backlighting includes (a) a serpentine-shaped upper sheet having a section for maximizing brightness uniformity within a predetermined distance from its surface; (b) a plate-shaped lower sheet combined with the upper sheet to form mutually connected channels; (c) external electrodes installed on surfaces of both ends of the upper sheet; and (d) auxiliary electrodes installed along the surface of channels.

Abstract: An anti-cycling luminaire control system may detect repeated lamp-off conditions and interrupt power to the lamp and provide an indication of lamp cycling after a predetermined number of lamp-off conditions has been detected. The control system also provides a cool-off period after a lamp-off cycling event is detected during which time restarting of the lamp is inhibited. If the lamp does not restart after multiple restart attempts and cool-off periods, the system determines that a fault condition exists, and may provide a fault alert. The system may provide for shut-off or dimming of the lamp during the night after a portion of the night has passed. This delayed turn-off may be varied according to the length of the night. Starting and dimming the lamp at a zero voltage crossing of the line current can reduce stress on luminaire and control system components and reduce maintenance.

Abstract: A technique is described that reduces parasitic losses in circuits used to drive current through a load. An example of a system according to the technique includes four switches in series with five pins such that one pin is connected to ground. An example of an apparatus according to the technique may include four switches in series with two switches connected to ground and to a load and two switches connected to a power source. An example of a method according to the technique involves producing a voltage waveform having three phases.

Abstract: A fluorescent lamp assembly includes a fluorescent lamp ballast capable of detecting at least one of a plurality of input signals and generating an output signal. The output signal is associated with a power level that is based on the at least one detected input signal. The fluorescent lamp assembly also includes a fluorescent lamp capable of receiving the output signal and generating light. An intensity of the light is based on the power level associated with the output signal.

Abstract: A power conversion circuit improves lamp operating life and lamp efficiency by driving a fluorescent lamp with a square wave signal. The square wave signal is an alternating current signal with relatively fast transition times. The square wave signal advantageously reduces lamp current crest factor for more efficient operation of the fluorescent lamp.

Abstract: A shoot-through prevention circuit is used in a power conversion circuit that uses a passive level-shifter to drive a P-type transistor in a switching network. The shoot-through prevention circuit is coupled between a controller output that provides a driving signal to control the P-type transistor and the passive level-shifter coupled to a control terminal of the P-type transistor. The shoot-through prevention circuit couples the controller output to the passive level-shifter when the driving signal has a first logic level associated with turning on the P-type transistor and isolates the controller output from the passive level-shifter when the driving signal has a second logic level associated with turning off the P-type transistor.

Abstract: A discharge-lamp lighting apparatus includes first and second cold cathode fluorescent lamps (CCFLs) and first and second transformers. The first transformer has a primary winding and a secondary winding. The primary winding receives an AC voltage generated by turning on/off a first switching element pair that is connected to a first DC power source. The second transformer has a primary winding, a first secondary winding, and a second secondary winding. The primary winding of the second transformer receives an AC voltage generated by turning on/off a second switching element pair that is connected to a second DC power source. Polarities of the first and second secondary windings of the second transformer are set so that a voltages of each of the first and second secondary windings becomes additive to a voltage of the secondary winding of the first transformer.

Abstract: Provided herein are methods and systems for preparing signs and displays. The methods and systems include using a light engine for generating light of a plurality of colors to illuminate the body of a flexible conduit that receives light from the light engine. The conduit can be used as a sign, display, or similar lighting facility in many applications that traditionally used neon signs and displays.

Abstract: A feedback circuit for push-pull inverters aims to improve the existing push-pull inverters that provide input electricity to a discharge lamp at a phase difference of 180 degrees without feedback electricity to regulate frequency signals and cannot effectively control uniform luminance of the discharge lamp. The invention includes a feedback device to get a detection electricity of the driving electricity of the discharge lamp through non-contact coupling induction. The detection electricity is transformed by the feedback device and output to a frequency control unit. The control unit can regulate and output the frequency signal in response to the luminance of the discharge lamp to timely adjust input electricity of a push-pull inverter.

Abstract: An electronic ballast for driving a gas discharge lamp includes a rectifier, a valley-fill circuit, an inverter having first and second series-connected controllably conductive switches having complementary duty cycles, a control circuit for controlling the controllably conductive switches, and an independent cat ear power supply to provide power to the ballast control circuits. The result is a ballast having substantially improved power factor, THD, and current crest factor. In a preferred embodiment, the valley-fill circuit includes an energy storage device that stores energy in response to a controllably conductive switch. In an especially preferred embodiment, the controllably conductive switch of the valley-fill circuit is also one of the switches of the inverter.

Abstract: An electronic ballast for a lamp having a bridge circuit, includes at least one first switch and a second switch, a center point of the bridge circuit between the first and second switch, the center point coupled on one side to a reference potential via the series circuit including a first capacitor and a diode and on the other side to a first connection for the lamp via an inductance; a control unit for driving the first and second switches. The control unit has a supply connection coupled to the connection point between the first capacitor and the diode, the voltage across the supply connection being limited in terms of its amplitude, and having a measurement signal input for feeding a measurement signal to the control unit; the measurement signal input being coupled to the connection point between the first capacitor and the diode.

Abstract: There is provided a rare gas fluorescent lamp lighting apparatus including: an input power source; a transformer having a rare gas fluorescent lamp connected to the secondary side thereof; a switching element connected in series to the primary side of the transformer; and a drive block to drive the switching element. The drive block includes: a constant voltage circuit to convert the voltage of the input power source into a constant voltage as an output; a constant current circuit to output a charging current according to the voltage of the input power source; a triangular waveform oscillation circuit to increase and decrease oscillation frequency according respectively to an increase and a decrease in a voltage of the input power source; and a comparison circuit to transform a triangular waveform outputted from the triangular waveform oscillation circuit into a rectangular waveform with a predetermined duty ratio as an output.