Abstract: A cold-cathode tube lighting device uniformly lights a plurality of cold-cathode tubes using a common power source, and maintains the luminance of each cold-cathode tube uniformly in the longitudinal direction thereof at high precision. A first block converts a direct-current voltage to one pair of alternating-voltages. Since leakage impedances of step-up transformers are low, the first block functions as one pair of low-impedance power sources. Each second block is connected to each cold-cathode tube. A ballast inductor stabilizes tube current by resonating with a matching capacitor during lighting of the cold-cathode tube. A combined impedance of the matching capacitor and a peripheral stray capacitance is matched with an impedance of the ballast inductor, for each cold-cathode tube. Since a delay circuit shifts phases of two pulse waves with respect to each other, a phase difference between the alternating-voltages is shifted from 180°.

Abstract: For the purpose of lighting multiple cold-cathode tubes at uniform luminance using a cold-cathode tube lighting device incorporating a multilayer substrate with built-in capacitors through a common power source and downsizing the cold-cathode tube lighting device, the multilayer substrate with built-in capacitors comprising at least four conductor layers overlaid is formed by heating and pressing dielectric layers, on one side of each of which a conductor layer is formed, to both sides of a dielectric layer, on both sides of which a conductor layer is formed, respectively, with bonding layers P1 and P2 interposed therebetween and by press-bonding these layers mutually, and specific conductor layers are electrically connected using connection parts formed on the inner faces of through holes.

Abstract: For the purpose of providing a resonant switching power supply device having a wide output voltage variable range by changing its switching frequency, the resonance circuit thereof comprises a switching transformer, a first resonance section connected in series with the switching transformer, and a second resonance section connected in parallel with the switching transformer, wherein the resonance frequency characteristic in the case that the DC load current is large is formed using the series-connected devices of the first resonance section, and the resonance frequency characteristic in the case that the DC load current is small is formed using the first resonance section, the second resonance capacitor of the second resonance section and the switching transformer.

Abstract: A cold-cathode tube lighting device uniformly lights a plurality of cold-cathode tubes using a common power source, and maintains the luminance of each cold-cathode tube uniformly in the longitudinal direction thereof at high precision. A first block converts a direct-current voltage to one pair of alternating-voltages. Since leakage impedances of step-up transformers are low, the first block functions as one pair of low-impedance power sources. Each second block is connected to each cold-cathode tube. A ballast inductor stabilizes tube current by resonating with a matching capacitor during lighting of the cold-cathode tube. A combined impedance of the matching capacitor and a peripheral stray capacitance is matched with an impedance of the ballast inductor, for each cold-cathode tube. Since a delay circuit shifts phases of two pulse waves with respect to each other, a phase difference between the alternating-voltages is shifted from 180°.

Abstract: A cold-cathode tube lighting device uniformly lights multiple cold-cathode tubes using a common power source, and the cold-cathode tube lighting device is effectively downsized by using ballast capacitors. A substrate is divided into blocks as many as the cold-cathode tubes. Each of the blocks includes two conductor layers each including two foils. A first foil of a first conductor layer is connected to a common low-impedance power supply. Between the two conductor layers, first ballast capacitors are formed in areas where the first foils are overlapped, second ballast capacitors are formed in areas where the first and second foils are overlapped, and the third ballast capacitors are formed in areas where the second foils are overlapped. Second foils are connected to first electrodes of the cold-cathode tubes.

Abstract: A transformer is constituted of an inner core, a plurality of outer cores connected in a ring to the inner core, a primary winding which is fed with a high frequency wave and wound around the inner core, and a secondary winding wound outside the primary winding. The secondary winding has, for the two outer cores, windings which are caused to pass at least once between the inner core and each of the respective outer cores, and the windings passed in the same direction are connected in parallel. With this configuration, it is possible to achieve a transformer for a switching power supply with a low voltage regulation.

Abstract: A first block (1) converts a DC voltage (Vi) into an AC voltage (V) of a high frequency, using a high-frequency oscillator circuit (4) and a step-up transformer (5). The first block (1) acts as a low-impedance power supply owing to suppression of leakage flux in the step-up transformer (5). A second block (2) and a third block (3) are connected to each CCFL (20). A ballast inductor (LB) causes the CCFL (20) to shine through the resonance with a matching capacitor (CM), and then maintains the stable lamp current during shining of the CCFL (20). The capacitance of the matching capacitor (CM) is separately adjusted for each CCFL (20), and thereby, the total impedance of the matching capacitor (CM) and the surrounding stray capacitances is matched to the impedance of the series connection of the ballast inductor (LB) and an overcurrent protection capacitor (CP).

Abstract: A transformer is constituted of an inner core, a plurality of outer cores connected in a ring to the inner core, a primary winding which is fed with a high frequency wave and wound around the inner core, and a secondary winding wound outside the primary winding. The secondary winding has, for the two outer cores, windings which are caused to pass at least once between the inner core and each of the respective outer cores, and the windings passed in the same direction are connected in parallel. With this configuration, it is possible to achieve a transformer for a switching power supply with a low voltage regulation.

Abstract: A first block (1) converts a DC voltage (Vi) into an AC voltage (V) of a high frequency, using a high-frequency oscillator circuit (4) and a step-up transformer (5). The first block (1) acts as a low-impedance power supply owing to suppression of leakage flux in the step-up transformer (5). A second block (2) and a third block (3) are connected to each CCFL (20). A ballast inductor (LB) causes the CCFL (20) to shine through the resonance with a matching capacitor (CM), and then maintains the stable lamp current during shining of the CCFL (20). The capacitance of the matching capacitor (CM) is separately adjusted for each CCFL (20), and thereby, the total impedance of the matching capacitor (CM) and the surrounding stray capacitances is matched to the impedance of the series connection of the ballast inductor (LB) and an overcurrent protection capacitor (CP).

Abstract: A switching power supply has a switching circuit for supplying a predetermined output voltage regardless of load variations and converting input voltages into the predetermined output voltage; pulse width control circuit for controlling the switching circuit; a circuit for detecting load power; and an oscillation frequency variable oscillation circuit. Such arrangement can change the switching frequencies and prevent a decrease in efficiency under low load.