Tdk Corporation

Tdk Electronics Company, Limited

Masaru Wasaki

Yoshihiro Saitoh

Tadashi Mitsui

Makoto Kurihara

Mitsunari Suzuki

Hirotada Furukawa

Junpei Ota

Hitomi Wasaki

Junpei Ohta

A common mode signal suppressing circuit comprises: a first winding () inserted to a conductor line (); a second winding () that is inserted to a conductor line () and coupled to the first winding () through a magnetic core () and that suppresses common mode signals in cooperation with the first winding (); and a third winding () coupled to the first and second windings () through the core (). The common mode signal suppressing circuit further comprises a phase-inverted signal transmitting circuit () connected to the third winding () and to the conductor lines (). The phase-inverted signal transmitting circuit () detects a common mode signal on the conductor lines (), and supplies a phase-inverted signal to the third winding (), the phase-inverted signal having a phase opposite to the phase of the common mode signal.

Common mode signal suppressing circuit and normal mode signal suppressing circuit

A power line communication system comprises an indoor power line and one or more power line branching apparatuses connected to the indoor power line. The power line branching apparatus comprises a communication channel that is branched off from the indoor power line and connectable to a power line communication device, and a power supply channel that is branched off from the indoor power line and connectable to electrical equipment. The power line branching apparatus further comprises an impedance matching circuit and a normal mode filter circuit. The impedance matching circuit is provided on the power supply channel, and sets the impedance of the indoor power line to a predetermined value. The normal mode filter circuit is provided on the power supply channel, and reduces normal mode noise occurring from the electrical equipment connected to the power supply channel.

Power line communication system and power line branching apparatus

In a power line noise filter, a detection circuit detecting variations in electric current in two conductive lines of an electric power line, thereby detecting common mode noise that causes a change in electric current in the power line. A phase-inverted signal generation circuit then generates a phase-inverted signal whose is inverted to that of the noise detected by the detection circuit. Further, an injection circuit causes a change in electric current corresponding to the phase-inverted signal, for the two conductive lines of the electric power line. The common mode noise causing a change in electric current in the electric power lines is thereby canceled.

Power line noise filter

A lighting apparatus for a discharge lamp (15) has a power adjustment unit (11,13) for adjusting electrical power to be supplied to the discharge lamp, an ignition pulse circuit (17) for producing at least one ignition pulse to be applied to the discharge lamp, and a computer control circuit (19) electrically connected with the power adjustment unit and the ignition pulse circuit. The computer control circuit (19) controls the power adjustment unit and the ignition pulse circuit so that at first the power adjustment unit (11,13) supplies an idling voltage to the discharge lamp, then the ignition pulse circuit (17) lights up the discharge lamp by applying at least one ignition pulse to the discharge lamp, and thereafter the power adjustment unit (11,13) controls lamp power of the discharge lamp to a target lamp power.

Discharge lamp lighting apparatus which can control a lighting process

An inductance element of the type that includes a coil bobbin having flanges at the ends thereof, a pair of pot cores engaging the bobbin, and a fastening member for fastening together the pot cores and bobbin. At least one of the bobbin flanges includes a joining part that extends outwardly from the bobbin flange and engages both the adjacent one of the pot cores and the fastening member to prevent relative rotation of the bobbin and adjacent pot core and fastening member. One of the bobbin flanges may include a stepped part having pins extending therefrom for making electrical connection to the inductance element. The stepped part is spaced from the bobbin flange, and connection wires may extend within the space.

Inductance element

The new structure of a ferrite core for the use of a power transformer and/or a choke coil has been found. The core is assembled by a pair of identical core halves, and each of core half comprises (a) a circular center boss(12), (b) a pair of outer walls(14,16) positioned at both the sides of said boss(12) so that a fan-shaped empty space is provided between the circular boss(12) and a pair of outer walls(14,16) for mounting a coil, (c) a pair of base plates(18,20) coupling said boss(12) with said outer walls(14,16) at the extreme end of those members so that those members conform substantially with the E-shaped structure, (d) the other extreme end of said boss(12), the outer walls(14,16) and the base plates(18,20) residing on a single plane, (e) each of said outer walls(14,16) being essentially rectangular with the external linear wall and the inner curved wall which is coaxial with the circular boss(12), and the width(d.sub.2) of said external linear wall is larger than the diameter(d.sub.3) of the circular boss(12), (f) each of said base plates(18,20) being essentially in the sector shaped having a pair of tapers which are gradually opened towards the outer walls(14,16), (g) the area(S.sub.3) coupling the base plates(18,20) with the outer walls(14,16) being larger than the half of the cross sectional area(1/4.pi.d.sub.3.sup.2) of the boss(12), (h) the area(S.sub.2) coupling the boss(12) with the base plates(18,20) being substantially the same as half of the cross sectional area(1/4.pi.d.sub.3.sup.2) of the boss(12), and (i) the area(S.sub.1) of the cross section of each of the outer walls(14,16) being essentially the same as half of the cross sectional area(1/4.pi.d.sub.3.sup.2) of the boss(12).

Growing community of inventors

Ichihara, Japan

Masaru Wasaki