Abstract: A synchronous operating system for operating a plurality of discharge tube lighting apparatuses at the same frequency and same phase includes (1) a resonant circuit including a capacitor C3 connected to at least one of primary and secondary windings, an output thereof being connected to a discharge tube, (2) switching elements Qp1 and Qn1 connected to both ends of a DC power source, (3) an oscillator to generate a triangular wave signal whose inclination for charging a capacitor C2 and inclination for discharging the same are the same, (4) a signal generation part to generate, in a period shorter than a half period of the triangular wave signal, a first drive signal having a pulse width corresponding to a current passing through the discharge tube, and (5) a signal generation part to generate a second drive signal having a pulse width substantially equal to that of the first drive signal and a phase difference of about 180 degrees with respect to the first drive signal.

Abstract: A discharge lamp lighting apparatus has a switch circuit to convert a DC voltage into an AC voltage, a transformer, a discharge lamp, an error amplifier of a reference voltage and a voltage representative of a lamp current, a control circuit generating a PWM control signal, and a soft start circuit to carry out, at the start of a lighting operation, a soft start operation that gradually extends ON intervals of the PWM control signal to gradually increase the lamp current upto a target lamp current. The soft start circuit carries out the soft start operation in such a way that an increment in ON intervals of the PWM control signal in a period from when the discharge lamp lights to when the target lamp current is attained is smaller than that in a period from when the lighting operation starts to when the discharge lamp lights.

Abstract: A time division signal (S2) for instructing a lit period and an unlit period of a discharge tube (23) is input to an error amplifier (41) of an integration circuit (40). The integration circuit (40) charges and discharges a capacitor (42) in accordance with the time division signal (S2). By utilizing this operation, a control circuit (49) adjusts a current flowing through the discharge tube (23) to light and extinguish the discharge tube (23).

Abstract: A discharge lamp lighting apparatus includes a switch circuit for DC/AC converting, a discharge lamp connected to a secondary winding of a transformer, a current detector detecting an AC output current of the discharge lamp, an error amplifier outputting an error signal to a detected current, a control circuit generating control signals that turn on/off the switching elements in such a way as to control the AC output current at a predetermined value, and a time division signal generator generating a time division signal at the start of an ON/OFF operation of the switching elements, wherein the time division signal delays a change in a burst dimming signal or has a predetermined inclination on the burst dimming signal. The error amplifier changes the error signal according to the time division signal from the time division signal generator.

Abstract: A discharge lamp lighter has an abnormality detecting circuit 7 for detecting an abnormality in an electrical load. The abnormality detecting circuit 7 includes a reference voltage part Ra1, Rb1, Ra2, Rb2 for generating a first reference voltage Vb1 and a second reference voltage Vb2, a detection voltage part Rc1, Rd1, Rc2, Rd2 for generating a first detection voltage Vc1 and a second detection voltage Vc2, a first determining part CP1 for determining the presence of abnormality in the electrical load when the second detection voltage Vc2 is outside a predetermined range with the first reference voltage Vb1 and a second determining part CP2 for determining the presence of abnormality in the electrical load when the first detection voltage Vc1 is outside the predetermined range with the second reference voltage Vb2.

Abstract: A gas-discharge lamp igniter is disclosed which has a group of gas-discharge lamps, such as those for LCD backlighting, connected in parallel with one another between the pair of outputs of an AC power supply. Provided one for each lamp to be energized, current-balancing transformers have their secondary windings serially interconnected. The lamps are connected to one of the pair of outputs of the AC power supply via the respective primary windings of the current-balancing transformers and the serial connection of the secondary windings thereof.

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 discharge lamp lighting apparatus includes switching elements to pass a current to a primary winding of a transformer and a capacitor, an oscillator to generate a triangular signal, an error amplifier to amplify an error voltage of a voltage corresponding to a current passed through a discharge lamp and receive a burst dimming signal that is a pulse signal to intermittently supply power to the discharge lamp, comparators to compare the error voltage with the triangular signal and generate PWM control signals that turn on/off the switching elements, respectively, a clamp circuit to clamp an output from the error amplifier so that the output from the error amplifier may not drop below a lower limit value of the triangular signal during an OFF period of the burst dimming signal, and breaking circuits to block the PWM control signals during the OFF period of the burst dimming signal.

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: A discharge-lamp lighting apparatus includes series circuits connected to each end of a DC power source, a transformer, FETs Qp1, Qn1, Qp2, and Qn2, and a drive circuit. The drive circuit includes transistors Q1 and Q3 to discharge gate-source capacitances of the Qp1 and Qp2, resistance elements to determine gate potentials of the transistors Q1 and Q3 when the transistors Q1 and Q3 are turned on, transistors Q2 and Q4 to charge the gate-source capacitances of the Qp1 and Qp2, constant current circuits, and switches connected in series with the series circuits of the constant current circuits and resistance elements, respectively, to turn on/off the constant current circuits.

Abstract: A time division signal (S2) for instructing a lit period and an unlit period of a discharge tube (23) is input to an error amplifier (41) of an integration circuit (40). The integration circuit (40) charges and discharges a capacitor (42) in accordance with the time division signal (S2). By utilizing this operation, a control circuit (49) adjusts a current flowing through the discharge tube (23) to light and extinguish the discharge tube (23).

Abstract: The present invention can provide a cold cathode tube lighting apparatus capable of causing no pulsating current, intermittent oscillation, or flicker-off even under light load, stably keeping a cold cathode tube lighting, safely tuning on the same, and the like. The present invention is characterized by supplying a rectangular wave voltage Vs to a series resonance circuit 12 and by driving the cold cathode tube 8 with an output of the series resonance circuit. The series resonance circuit has a constant that makes a maximum output voltage with respect to a predetermined tube current value exceed a tube voltage VL of the cold cathode tube when the cold cathode tube is turned on and in an operating load range of the cold cathode tube of negative resistance characteristic. A control circuit 15 controls a cold cathode tube current IL to a predetermined value while the cold cathode tube is in a lit state.

Abstract: The present invention can provide a cold cathode tube lighting apparatus capable of causing no pulsating current, intermittent oscillation, or flicker-off even under light load, stably keeping a cold cathode tube lighting, safely tuning on the same, and the like. The present invention is characterized by supplying a rectangular wave voltage Vs to a series resonance circuit 12 and by driving the cold cathode tube 8 with an output of the series resonance circuit. The series resonance circuit has a constant that makes a maximum output voltage with respect to a predetermined tube current value exceed a tube voltage VL of the cold cathode tube when the cold cathode tube is turned on and in an operating load range of the cold cathode tube of negative resistance characteristic. A control circuit 15 controls a cold cathode tube current IL to a predetermined value while the cold cathode tube is in a lit state.