Tdk Corporation

Yoshihiro Saitoh

Mitsunari Suzuki

Masaru Wasaki

Hitomi Wasaki, Legal Representative

Hirotada Furukawa

Tetsuya Nishiyama

Noriyuki Hirabayashi

Yoshio Kaita

Hitomi Wasaki

To improve power transmission efficiency in wireless power feeding by using a magnetic body. A wireless power transmission systemfeeds power by wireless from a feeding coil Lto a receiving coil Lbased on a magnetic-field resonance phenomenon between the feeding coil Land receiving coil L. A transmission control circuitsupplies AC power to the feeding coil Lat a drive frequency so as to make the feeding coil Lfeed the AC power to the receiving coil L. A magnetic body F is disposed between the feeding coil Land receiving coil L. The magnetic body F is disposed in a space between coil surfaces of the feeding coil Land receiving coil L

Wireless power transmission system

A wireless power receiver receives, at a receiving coil, AC power fed from a feeding coil by wireless using a magnetic field resonance phenomenon between the feeding coil and receiving coil. The wireless power receiver includes a loading circuit and a power controller. The loading circuit includes a loading coil that is magnetically coupled to the receiving coil to receive the AC power from the receiving coil and a load that receives the AC power supplied from the loading coil. The power controller includes a measurement unit and an adjustment unit. The measurement unit measures the receiving power of the load. The adjustment unit brings the receiving power close to its maximum value by changing the impedance of the loading circuit.

Wireless power receiver, wireless power transmission system, and power controller

A coil apparatus and a non-contact power transmission apparatus having improved power transmission efficiency are provided. A power transmission side coil apparatus comprises: an excitation coil (second winding section) which transmits AC power supplied from a power source to a transmission coil; a resonance circuit (first resonance circuit) which is formed by a capacitor (first capacitance element) and a transmission coil (first winding section) which is connected to this capacitor and which transmits AC power from the excitation coil to a power receive side coil apparatus; and a resonance circuit (second resonance circuit) which is formed by a variable capacitor (second capacitance element) and a control coil (third winding section) which is connected to this variable capacitor and which resonates with the transmission coil.

Coil apparatus and non-contact power transmission apparatus

A noise suppressing circuit comprises: windings (W, W) inserted to conductor lines () at respective points (P, P) and coupled to each other through a magnetic core (); a winding (W) coupled to the windings (W, W) through the core (); capacitors () having ends connected to the conductor lines () at respective points (P, P) and the other ends connected to an end of the winding (W); and windings (W, W) inserted to conductor lines () at respective points (P, P) and coupled to each other through a magnetic core (). These components reduce common mode noise. Capacitors () reduce normal mode noise in cooperation with leakage inductances produced by the windings (W, W).

Noise suppressing circuit

A signal suppression filter () that inhibits high-frequency signals contained in power voltage and a signal separation filter () that prevents transmission of the high-frequency signals are provided in series on power lines (A), (B) connected to a power input terminal (T), and a common-mode signal detection circuit () and a normal-mode signal detection circuit () are provided separately from each other. While bi-directionally blocking transmission of a high-frequency signal (noise) between the power supply and the device to be measured by the signal suppression filter () and the signal separation filter (), the common mode signal and the normal mode signal generated in the device to be measured () and entering through a power output terminal (T) are detecting separately. The analysis of the cause of occurrence of a high-frequency signal produced in the device to be measured () is facilitated, and proper noise countermeasure may be taken.

Signal detector

A noise suppressor capable of preventing degradation in an attenuation characteristic by a parasitic component so as to obtain a favorable attenuation characteristic is provided. The noise suppressor includes a first winding wire disposed on a first current-carrying wire and a series circuit including a capacitor and a second winding wire which are connected to each other in series. The first winding wire and the second winding wire are magnetically coupled to each other. The inductance xL of the whole second winding wire is smaller than the inductance LL of the whole first winding wire (xL&#x3c;LL). Moreover, it is desirable that the inductance xL of the whole second winding wire is equal to or smaller than the inductance LLper turn in the first winding wire (xL&#x2266;LL).

Noise suppressor

A noise suppressing circuit () suppresses noise emerging from an electronic apparatus () and propagating through conductive lines (and). The noise suppressing circuit () comprises a low-band noise reducing circuit () and a high-band noise reducing circuit (). The low-band noise reducing circuit () is connected to the electronic apparatus () through the conductive lines (and). The high-band noise reducing circuit () is cascade-connected to the low-band noise reducing circuit () and connected to conductive lines (and) of a power line (). The high-band noise reducing circuit () comprises: a detection circuit for detecting common mode noise propagating through the conductive lines (and); a phase-inverted signal generating circuit for generating a phase-inverted signal that has a phase opposite to the phase of the noise detected by the detection circuit; and an injection circuit for injecting the phase-inverted signal generated by the phase-inverted signal generating circuit into the conductive lines (and).

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 noise suppressor capable of obtaining a favorable attenuation characteristic even in the case where a plurality of inductors on a conductive wire are magnetically coupled to each other. The noise suppressor includes a first inductor and a second inductor which are magnetically coupled to each other on a first conductive wire, a third inductor having one end connected to the other end of a first capacitor and the other end of a second capacitor and the other end connected to ground, and a fourth inductor and a fifth inductor which are magnetically coupled to each other on a second conductive wire. While it is considered that the coupling coefficients kthrough kbetween the inductors are smaller than 1 in reality, in particular, on the basis of the condition that the coupling coefficients Kthrough kare smaller than 1, the inductance of the third inductor is set to a value corresponding to the actual values of the coupling coefficients kthrough kso as to obtain a desired noise attenuation characteristic.

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

The invention has for its object to provide an organic EL display driving system and method enabling an organic EL display to be driven with neither a contrast lowering nor a false light emission phenomenon yet in simple construction. The driving system and method drive an organic EL device which comprises at least one set of scanning electrodes and data electrodes arranged in a matrix fashion and an organic material-containing organic layer located between said scanning and data electrodes and taking part in at least a light emission function, with one closed circuit formed through at least one set of electrodes. When the scanning and data electrodes are driven, a given non-selection time is provided between driving one electrode and driving the next electrode.

Growing community of inventors

Tokyo, Japan

Yoshihiro Saitoh