Abstract: Systems and methods for backlighting an image display by independently driving multiple backlights for the display. The display may be, for example, a LCD display panel of a portable information handling system such as a battery-powered notebook computer that employs two or more cold cathode fluorescent lamps (CCFLs) for backlighting the LCD display. The multiple backlights may be independently driven, for example, using a common inverter that is capable of independently driving two or more backlight lamps, or by driving each backlight lamp with a separate inverter.

Abstract: A transformer for driving multiple lamps includes a core, a primary winding set, a secondary winding set and a balancing winding set. The primary winding set winds around the core and includes a first primary coil. The secondary winding set winds around the core and includes a first secondary coil. The balancing winding set winds around the core and includes a first balancing coil and a second balancing coil which wind around the core in a combinative way. The primary winding set, the secondary winding set and the balancing winding set have the same magnetic-flux loop in the core.

Abstract: A discharge tube drive circuit for driving a plurality of discharge tubes is proposed with reduced number of parts and in a down-sized form. A first balance transformer is provided in a first drive circuit block, and a plurality of primary coils of a plurality of drive transformers in the first drive circuit block and a secondary coil of the first balance transformer are connected in series. A second balance transformer is provided in a second drive circuit block, and a plurality of primary coils of a plurality of drive transformers in the second drive circuit block and a secondary coil of the second balance transformer are connected in series. Further, a primary coil of the balance transformer and a primary coil of the second balance transformer are connected in series to configure the discharge tube drive circuit of the present invention.

Abstract: A multi-lamp driving system for driving a first lamp and a second lamp includes a power supply circuit, and first-stage transformers. The power supply circuit is used for supplying the first and second lamps with an AC power, and first-stage transformers coupled to the power supply circuit for performing an impedance-matching function to balance lamp currents and deliver evenly distributed current to each lamp in the multi-lamp system so that each lamp provides approximately same amount of luminance. The first-stage transformers includes a first transformer have a primary side coupled to the power supply circuit and a secondary side coupled to the first lamp, and a second transformer have a primary side coupled to the first transformer and a secondary side coupled to the second lamp.

Abstract: The present invention uses one or more transformers disposed between an inverter driver to drive a plurality of lamps. Each transformer has a first coil and a second coil magnetically coupled to each other. Each of the first and second coils has an input end and an output end. The input end of the first coil is operatively connected to the input end of the second coil for receiving an input current. Each of the first and second coils has a capacitor connected between the input and output ends. The output ends of the first and second coils are used to provide output current in two separate current paths. As such, the output end of a transformer can be separately connected to the input end of two lamps or two such transformers.

Abstract: A power system for driving a plurality of lamps includes a transformer circuit, a current balancing circuit, and a light source. The transformer circuit includes a plurality of transformers in a quantity denoted by N, and each of the transformers has a first, a second, a third, and a fourth output ends. The current balancing circuit includes a plurality of current balancing units each having two output ends. The 2Nth current balancing unit is connected to a fourth output end of the Nth transformer, and the (2N?1)th current balancing unit is connected to a first output end of the Nth transformer. The light source has a plurality of lamps each having one end connected to a respective output end of the current balancing units and another end grounded. The numbers of the current balancing units and the lamps are respectively twice and four times the quantity N of the transformers.

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: Methods and apparatus are disclosed for balancing currents passing through multiple parallel circuit branches and in some cases through parallel fluorescent lamps. Single transformers with multiple-leg magnetic cores are wound in specific manners that simplify current balancing. Conventional three-legged EE-type magnetic cores, with disclosed windings are used to balance current in circuits with three or more parallel branches, such as parallel connected Cold Cathode Fluorescent Lamps (CCFLs).

Abstract: An inductive power supply system for providing power to one or more inductively powered devices. The system includes a mechanism for varying the physical distance or the respective orientation between the primary coil and secondary coil to control the amount of power supplied to the inductively powered device. In another aspect, the present invention is directed to an inductive power supply system having a primary coil and a receptacle disposed within the magnetic field generated by the primary coil. One or more inductively powered devices are placed randomly within the receptacle to receive power inductively from the primary coil. The power supply circuit includes circuitry for adjusting the power supplied to the primary coil to optimize operation based on the position and cumulative characteristics of the inductively powered device(s) disposed within the receptacle.

Abstract: A backlight unit includes a plurality of fluorescent lamps driven by one inverter in a manner to prevent wave noise. A first common electrode line connects respective first ends of the odd numbered fluorescent lamps in common. A second common electrode line connects respective first ends of the even numbered fluorescent lamps in common. A third common electrode line connects the second ends of the odd and even numbered fluorescent lamps in common. Voltages having opposite phases are respectively applied to the first common electrode line and the second common electrode line.

Abstract: A discharge lamp lighting apparatus includes a triangular signal oscillator, a first control part to compare the triangular signal with an error voltage between a reference voltage and a voltage corresponding to a first current passed through a secondary winding of a transformer and generate a first PWM control signal for turning on/off switching elements Qp1 and Qn1 with a phase difference of about 180 degrees and a pulse width corresponding to the first current, and a second control part to compare the triangular signal with an error voltage between a reference voltage and a voltage corresponding to a second current passed through a secondary winding S2 of a transformer T2 and turn on/off switching elements Qp2 and Qn2 in synchronization with the first PWM control signal with a phase difference of about 180 degrees and a pulse width corresponding to the second current.

Abstract: A multi-discharge tube lighting apparatus connectable to a power source comprising a first output terminal and a second output terminal respectively outputting voltages of opposite phases, the lighting apparatus comprises first to n-th discharge tube units where n represents an integer of two or more, each of which has a first end connected to the first output terminal and a second end connected to the second output terminal and comprises at least one discharge tube, a first winding, and a second winding, which are connected in series between a first end and a second end. The first winding of the first discharge tube unit is electromagnetically coupled via a transformer to the second winding of the n-th discharge tube unit. The first windings of the second and subsequent discharge tube units are electromagnetically coupled via transformers to the second windings of the previous discharge tube units, respectively.

Abstract: In an inverter circuit for a backlight assembly, a first sinusoidal voltage and a second sinusoidal voltage having an opposite polarity to that of the first sinusoidal voltage are applied across terminals of 2n CCFLs. Each of respective primary coils of n first balance transformers are connected in series with corresponding first terminals of a first set of n CCFLs from the 2n CCFLs. Each of respective primary coils of n second balance transformers are connected in series with corresponding first terminals of a second set of n CCFLs from the 2n CCFLs. The secondary coils of the first balance transformers and the secondary coils of the second balance transformers are connected in series with each other to form a loop. Accordingly, the backlight assembly makes it easy to troubleshoot a failure in the CCFLs.

Abstract: A device of driving a plurality of lamps is provided, which includes: a transforming unit supplying driving voltages having inverted phases to adjacent lamps; and an inverter controlling the transforming unit.

Abstract: The present invention relates to a lamp lighting technique for lighting multiple lamps safely without luminance irregularities. The present lamp lighting circuit includes multiple closed loops wherein a predetermined number of lamps and the secondary windings of the predetermined number of transformers are connected serially. At least one of the primary windings of the transformers employed for each closed loop is connected to the primary winding of the transformer employed for another closed loop serially. Thus, current of the lamps included in the closed loop is made uniform, and also current is made uniform even between the closed loops by connecting the primary windings of the transformers serially. According to the present invention, with regard to serial connection of the primary windings of the transformers, even if the number of transformers is limited, current uniformity can be propagated to the entirety by subjecting closed loops to catenation consecutively.

Abstract: In an inverter circuit, inverter transformers supply AC voltage to discharge tubes. The inverter transformers are arranged such that the AC voltage at a respective first terminal of each secondary coil has an opposite polarity with respect to a corresponding second terminal of each secondary coil. Balance transformers have primary coils inserted in series between a reference terminal of the secondary coils of the inverter transformers and ground. The secondary coils of the balance transformers are connected in series to form a loop. One node of the loop is grounded and a voltage detection node is located on the loop. At least one secondary coil of the secondary coils of the balance transformers is interposed between the grounded node of the loop and the voltage detection node. Thus, an abnormal state or condition, such as an open circuit or a short circuit may be detected.

Abstract: A multi-lamp driver t disclosed, comprising a power driver coupled to a plurality of lamps to supply power thereto, a feedback circuit coupled to at least one of the lamps to generate a feedback signal, a control circuit coupled between the feedback circuit and the power driver to control the power driver according to an illumination control signal and the feedback signal for total illumination adjustment of the lamps, and at least one switch controlled by the control circuit to turn at least one of the lamps on or off. In a total illumination adjustment of the lamps, the switch turns on or off timely. The difference between the maximum and minimum value of the total illumination of the lamps is thus increased.

Abstract: Disclosed is a low-cost parallel lighting system for discharge lamps for a surface light source, which reduces nonuniform brightness and static noise, and fulfills a requirement that lamp currents of individual cold-cathode fluorescent lamps should be uniform and stabilized.

Abstract: A two-end driven lamp controlling device includes a direct-current (DC) power supply, square wave switches, a square wave controller, a plurality of lamps, a plurality of starting transformers and a plurality of lamps commonly connective transformers, wherein the plurality of starting transformers or the plurality of lamps commonly connective transformers are disposed besides the plurality of lamps and the square wave switches are connected to the sides of the plurality of starting transformers or the plurality of lamps commonly connective transformers and to the DC power supply and can receive signals from the square wave controller.

Abstract: The present invention discloses a current-balancing apparatus for lamps. The current-balancing apparatus includes a first transformer, a second transformer and a third transformer, and every transformer has a primary winding and a secondary winding. The current-balancing apparatus balances the current flowing through every lamp in response to the connection of those transformers and the electromagnetic induction of Runge-Lenz Theorem. The two side windings of the first transformer connect to a power stage via a first lamp and a second lamp respectively. The two side windings of the second transformer connect to the power stage via a third lamp and a fourth lamp respectively. The primary winding of the third transformer connects to the two side windings of the first transformer and the secondary winding of the third transformer connects to the two side windings of the second transformer.

Abstract: A cold cathode tube lighting device is provided which is capable of obtaining stable luminance when a cold cathode tube is driven by applying voltages to input terminals on both ends of the cold cathode tube. A first current flowing through each of transformer secondary sides of transformers is detected by a tube current detecting circuit from a low-voltage side of each of the transformer secondary sides and a second current flowing through each of resonance capacitors is detected by the tube current detecting circuit and a difference between the first current and the second current is calculated for every separately-excited inverter and, based on the difference, a tube current of the cold cathode tube is obtained and frequencies of driving pulse voltages are changed by a voltage controlling oscillator for setting so that the tube current maintains a predetermined value.

Abstract: A method according to on embodiment may include generating AC voltage and current and a striking voltage. The method of this embodiment may also include generating striking voltage and steady-state voltage for at least two lamp loads. The method of this embodiment may also include coupling at least two lamp loads in parallel. The method of this embodiment may also include coupling current balancing circuitry to the at least two lamp loads and providing, by the current balancing circuitry simultaneous striking voltage to the at least two lamps loads. The method of this embodiment may also include balancing, by the current balancing circuitry, AC current through the at least two lamp loads. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.

Abstract: A driving circuit uses a plurality of transformers to provide currents for driving a plurality of LEDs associated with a plurality of current paths. Each transformer has two induction coils with a coil turn ratio between to the number of turns in each induction coil. One induction coil is used to provide an output current to a different current path and the other induction coil is connected to the corresponding induction coil of other transformers for forming a current loop. The output current of each transformer has a relationship with the output current of the other transformers depending on the coil turn ratios of the connected transformers. LEDs in red, blue and green colors can be connected to different current paths so that the brightness of the LEDs in each color can be determined by the current in a current path.

Abstract: A multi-lamp backlight system is disclosed. The multi-lamp backlight system includes a plurality of lamps, an inverter circuit and a current balance circuit. The inverter circuit is capable of converting a DC input signal to a pair of AC output signals, which have a 180 degree phase shift. The pair of AC output signals are delivered to the plurality of lamps. The current balance circuit is connected to the low voltage sides of the plurality of lamps for balancing the lamp currents.

Abstract: An inverter circuit includes a power supply which outputs an alternating current voltage, an inverter transformer having one primary coil connected to an output terminal of the power supply and pairs of secondary coils which supply an alternating current high voltage, induced by the one primary coil, to pairs of discharge tubes and a plurality of balance transformers having primary coils serially connected between respective pairs of the pairs of secondary coils of the inverter transformer, and having secondary coils corresponding to the primary coils of the plurality of balance transformers, wherein the secondary coils of the plurality of balance transformers are serially connected to form a loop.

Abstract: A current balancing circuit for first and second lamp sets includes a step-up transformer and a current balancer. The step-up transformer is adapted to be coupled to a power supply for receiving an alternating-current source power, and for generating a drive signal by varying magnitude of the alternating-current source power. The step-up transformer is further adapted to be coupled to the first and second lamp sets for providing the drive signal thereto. The current balancer includes first and second shunt transformers. Each of the first and second shunt transformers includes primary and secondary windings that correspond to each other in number of turns thereof. The first and second shunt transformers are adapted to be coupled to corresponding discharge lamps of the first lamp set. The current balancer is adapted to mirror current flowing through the first and second shunt transformers to the second lamp set.

Abstract: A system for driving a multi-lamp, and more particularly to, a system for driving a multi-lamp for driving a parallel arrangement of a plurality of discharge lamps and a method of driving a plurality of discharge lamps and a method thereof.

Abstract: A driving device for driving discharge lamps (14) includes a first pulse circuit (11), a second pulse circuit (13), and a primary driving circuit (12). The first pulse circuit includes an input end, a first output end (1), and a second output end (2). The second pulse circuit includes an input end, a third output end (3), and a fourth output end (4). The primary driving circuit is connected between the first pulse circuit and the second pulse circuit for generating drive signals. The second output end of the first pulse circuit is connected to the third output end of the second pulse circuit, and the fourth output end of the second pulse circuit is connected to ground.

Abstract: The present invention relates to a lamp driving apparatus of a liquid crystal display capable of simplifying a structure of the liquid crystal display and in addition preventing a leakage current of the lamp driving apparatus. The lamp driving apparatus of the liquid crystal display comprises: a plurality of lamps; and an inverter block having a plurality of inverters that supply a drive current to the lamps wherein adjacent lamps have a different phase from one another.

Abstract: An electric current balancing device includes an inverting circuit having a driving unit and one or more transformers coupled together for outputting an electric current to a load device, a detecting circuit coupled to the inverting circuit for receiving and detecting an electric current of the load device and for stabilizing and sending a stabilized and calibrated electric current to the inverting circuit, and a balancing transformer device having a primary side coupled to the inverting circuit for receiving the calibrated electric current from the inverting circuit, and a secondary side coupled to the load device for comparing an electric current of the load device with the calibrated electric current from the inverting circuit and for controlling the load device.

Abstract: A backlight inverter using electromagnetic induction and full-wave rectification at a second side of a main transformer includes a drive unit for generating a first voltage and a main transformer having first and second coils. The main transformer converts the first voltage from the drive unit into a second voltage, and outputs an AC current of the second voltage to both ends of a lamp. An auxiliary transformer has a first auxiliary coil formed on a current line connecting between the second coil of the main transformer and the lamp and a second auxiliary coil inductively coupled with the first auxiliary coil. The auxiliary transformer detects the current flowing to the lamp. A full-wave rectifier rectifies the current detected by the auxiliary transformer, and a drive controller controls the PWM duty of the first voltage based on a voltage from the full-wave rectifier.

Abstract: An inverter circuit for discharge lamps for multi-lamp lighting in which the value of a negative resistance characteristic of a fluorescent lamp is controlled, and an excessively set reactance is eliminated by causing a shunt transformer to have a reactance exceeding the negative resistance characteristic. Two coils connected to a secondary winding of a step-up transformer of the inverter circuit are arranged and magnetically coupled to each other to form a shunt transformer for shunting current such that magnetic fluxes generated thereby cancel each other out. Discharge lamps are connected to the coils, respectively, with currents flowing therethrough being balanced. Each discharge lamp is lighted because a reactance of an inductance related to the balancing operation which is in an operating frequency of the inverter circuit, exceeds a negative resistance of discharge lamps.

Abstract: This invention relates to a backlight driving apparatus of a liquid crystal display device, and more particularly to a backlight driving apparatus of a liquid crystal display device that includes: first and second transformers that boost an AC voltage to a boosted AC voltage that is supplied to a U-shaped lamp; and a virtual ground fixing device that causes a virtual ground of the U-shaped lamp to be fixed at the center of a bent part of the U-shaped lamp by causing the boosted AC voltage that is output from the first and second transformers to be identical in size.

Abstract: The present invention uses one or more transformers disposed between an inverter driver to drive a plurality of lamps. Each transformer has a first coil and a second coil magnetically coupled to each other. Each of the first and second coils has an input end and an output end. The input end of the first coil is operatively connected to the input end of the second coil for receiving an input current. Each of the first and second coils has a capacitor connected between the input and output ends. The output ends of the first and second coils are used to provide output current in two separate current paths. As such, the output end of a transformer can be separately connected to the input end of two lamps or two such transformers.

Abstract: A lamp current balancing device comprises an electronic power switch, a transformer, a current transformer and a pulse width modulation (PWM) IC; the transformer having a primary side connected to the electronic power switch and both ends of a secondary side connected to one end of each one of two lamps respectively, with another end of each one of the two lamps connecting to one end of a primary side of the current transformer respectively, the PWM IC being coupled between a secondary side of the current transformer and the electronic power switch; since the two lamps being cascaded in series with a same current flowing through them, thus providing current balancing capability, furthermore, the current transformer being used to detect an operating current of the lamps and to feed back the operating current to the PWM IC, the PWM IC receiving and processing the operating current to obtain a control signal, then outputting the control signal to the electronic power switch to control a pulse width outputted by

Abstract: A method according to one embodiment may include supplying power to plurality of External Electrode Fluorescent Lamps (EEFLs). The method of this embodiment may also include generating signals proportional to the voltage of each EEFL. The method of this embodiment may also include generating a feedback signal indicative of the state of one or more of the plurality of EEFLs based on, at least in part, the value of at least one signal proportional to the voltage of each EEFL. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.

Abstract: An apparatus and methods for balancing current in multiple negative impedance gas discharge lamp loads. Embodiments advantageously include balancing transformer configurations that are relatively cost-effective, reliable, efficient, and good performing. Embodiments include configurations that are applicable to any number of gas discharge tubes, such as cold cathode fluorescent lamps. The balancing transformer configuration techniques permit a relatively small number of power inverters, such as one power inverter, to power multiple lamps in parallel. One embodiment of a balancing transformer includes a safety winding which can be used to protect the balancing transformer in the event of a lamp failure and can be used to provide an indication of a failed lamp.

Abstract: A discharge lamp lighting apparatus is provided for lighting a plurality of discharge lamps including one reference lamp and at least one controllable lamp. First variable inductance element and lamp current detecting unit are connected to the reference lamp, second variable inductance and lamp current unit are connected to the controllable lamp, and a lamp current controlling circuit is connected to each of the first and second variable inductance elements. An output signal from the second lamp current detecting unit and also an output signal as a reference signal from the first lamp current detecting unit are connected to the lamp current controlling circuit for the controllable lamp, whereby the lamp current of the controllable lamp is controlled. The reference output signal is also connected to a control circuit, and the lamp currents of the reference and controllable lamps are controlled further by the on/off operation of the switching elements.

Abstract: A protective and measure device for multiple cold cathode fluorescent lamps includes an electronic ballast functioning as a high-frequency power source for driving multiple cold cathode fluorescent lamps (CCFLs), primarily by parallel connecting one end of each of a plurality of CCFL to a measure element to measure the LED power source provided by the measure element's photocoupler, and concurrently serially connect the photocoupler's collect-emitter terminal, followed by employing comparators to assess the open circuit, over current, and under current among multiple cold cathode fluorescent lamps. Said electronic ballast serves to protect CCFLs, and thus contribute to the quality and protection required for large LCD monitors.

Abstract: Discharge lamps are respectively aligned and arranged, and a first alternating voltage output from an inverter circuit is supplied to one electrode of each discharge lamp, whilst a second alternating voltage output from the inverter circuit is supplied to the other electrode of the same. A signal processor compares a first voltage signal with a second voltage signal, and generates a current-limit signal when a difference in amplitude between these signals is not smaller than a predetermined value. The current-limit signal is supplied to the inverter circuit to help reduce the chance on an accidental electric shock.

Abstract: There are provided a discharge lamp drive apparatus which can detect that both ends of at least one of a plurality of discharge lamps is in an open state in a differential drive scheme, and a liquid crystal display apparatus. A first current detection circuit 31 detects a current flowing through a first discharge lamp connection terminal group P1 or a current flowing through a second discharge lamp connection terminal group P3, and generates a first current detection signal S1. A second current detection circuit 32 detects a current flowing through the second discharge lamp connection terminal group P2 or a current flowing through a fourth discharge lamp connection terminal group P4, and generates a second current detection signal S2. A signal processor 30 receives the first current detection signal S1 and the second current detection signal S2, and generates a signal S01 which is used to detect an open state of a discharge lamp based on intensities of both the current detection signals S1 and S2.

Abstract: A pathway lighting system has self-contained, battery up scaled lighting modules (20), each module including at least one secondary coil. A plurality of primary coils are housed within a carrier assembly (1) together with voltage circuitry (14). Primary and secondary coils, positioned in the carrier assembly and in the lighting modules and the respectively allow electricity to flow between these members. The secondary coil output voltage is able to be rectified with the use of a rectification circuit, housed in the lighting module. Upon a mains failure, a battery charger/changeover circuit would switch the power requirements of the light sources inside the pathway lighting module over to internal back up batteries.

Abstract: A driving circuit uses a plurality of transformers to provide currents for driving a plurality of LEDs associated with a plurality of current paths. Each transformer has two induction coils with a coil turn ratio between to the number of turns in each induction coil. One induction coil is used to provide an output current to a different current path and the other induction coil is connected to the corresponding induction coil of other transformers for forming a current loop. The output current of each transformer has a relationship with the output current of the other transformers depending on the coil turn ratios of the connected transformers. LEDs in red, blue and green colors can be connected to different current paths so that the brightness of the LEDs in each color can be determined by the current in a current path.

Abstract: An apparatus and methods for balancing current in multiple negative impedance gas discharge lamp loads. Embodiments advantageously include balancing transformer configurations that are relatively cost-effective, reliable, and efficient. Embodiments include configurations that are applicable to an unrestrained number of gas discharge tubes, such as cold cathode fluorescent lamps. The balancing transformer configuration techniques permit a relatively small number of power inverters, such as one power inverter, to power multiple paralleled lamps or paralleled groups of lamps with balancing transformers coupling the lamps or groups of lamps in a zigzag topology. One embodiment of a balancing transformer includes a safety winding which can be used to protect the balancing transformer in the event of a lamp failure and can be used to provide an indication of a failed lamp.

Abstract: A technique for driving one or more EEFLs, having first and second ends, in a bank of EEFLs involves driving the EEFLs at both the first and second ends. In a non-limiting embodiment a device constructed according to the technique includes a bank of EEFLs connected in parallel. The device further includes a first transformer, wherein a secondary winding of the first transformer is coupled to the first end of the bank of EEFLs. The device further includes a second transformer, wherein a secondary winding of the second transformer is coupled to the second end of the bank of EEFLs.

Abstract: An apparatus and methods for balancing current in multiple negative impedance gas discharge lamp loads. Embodiments advantageously include balancing transformer configurations that are relatively cost-effective, reliable, efficient, and good performing. Embodiments include configurations that are applicable to any number of gas discharge tubes, such as cold cathode fluorescent lamps. The balancing transformer configuration techniques permit a relatively small number of power inverters, such as one power inverter, to power multiple lamps in parallel. One embodiment of a balancing transformer includes a safety winding which can be used to protect the balancing transformer in the event of a lamp failure and can be used to provide an indication of a failed lamp.

Abstract: A discharge lamp driving apparatus comprises a DC power supply, a control circuit, switching elements, a step-up transformer, and a lamp current controlling circuit. In the discharge lamp driving apparatus, the secondary side of the step-up transformer is connected to multiple discharge lamps respectively via variable inductance elements, a series resonant circuit is constituted by a capacitor provided between the variable inductance element and the discharge lamp, leakage inductance of the step-up transformer, and inductance of the variable inductance element, and an output of the lamp current controlling circuit is connected to the variable inductance element, wherein the inductance of the variable inductance element is varied thereby controlling the lamp current of the discharge lamp.

Abstract: A system driving a lamp set having a first lamp and a second lamp is provided. The system has a power supply circuit providing an AC signal to the lamp set, and a balance circuit having a current balancing transformer, a first impedance and a second impedance for balancing currents through the first and second iamps. The current balancing transformer includes a first winding and a second winding. The first and second windings are wound on the same magnetic core and have the same winding count. A specific relationship between the first and second impedances balances the current values through the first and second lamps effectively without increasing inductances of the current balancing transformer.

Abstract: An apparatus and methods for balancing current in multiple negative impedance gas discharge lamp loads. Embodiments advantageously include balancing transformer configurations that are relatively cost-effective, reliable, and efficient. Embodiments include configurations that are applicable to an unrestrained number of gas discharge tubes, such as cold cathode fluorescent lamps. The balancing transformer configuration techniques permit a relatively small number of power inverters, such as one power inverter, to power multiple paralleled lamps or paralleled groups of lamps with balancing transformers coupling the lamps or groups of lamps in a zigzag topology. One embodiment of a balancing transformer includes a safety winding which can be used to protect the balancing transformer in the event of a lamp failure and can be used to provide an indication of a failed lamp.

Abstract: The present invention relates to a lamp driving apparatus of a liquid crystal display capable of simplifying a structure of the liquid crystal display and in addition preventing a leakage current of the lamp driving apparatus. The lamp driving apparatus of the liquid crystal display comprises a plurality of lamps, and an inverter block having a plurality of inverters that supply a drive current to the lamps wherein adjacent lamps have a different phase from one another.