Murata Manufacturing Co., Ltd.

Murata Mfg. Co., Ltd.

Iurata Manufacturing Co., Ltd.

Takashi Kawanami

Toshihiro Makino

Takashi Hasegawa

Hiroki Dejima

Kunisaburo Tomono

Hiroshi Marusawa

Akihito Masuda

Yasuhiro Shimizu

Takekazu Okada

Takahiro Jodo

Masakatsu Mori

Keiji Okamura

Takehiro Konoike

Takehiro Kounoike

Youhei Ishikawa

Reiji Nakajima

Nobumasa Kitamori

Makoto Tabei

Noritaka Kishi

Toshihiro Yamamoto

Kazuya Soda

Takahiro Joudo

Katsuyuki Ohara

Yoshihiko Ashida

Yasuhiro Nakagawa

Yoshihiro Murai

An amplifier circuit includes: a transistor provided between an input terminal and an output terminal and having a gate connected to the input terminal, a source connected to a ground, and a drain connected to the output terminal; an inductor connected between the source and the ground; an inductor connected between the gate and the input terminal, and switches connected to at least one of the inductors and configured to change a mutual inductance of the inductors.

Amplifier circuit

A magnetic sensor senses a magnetic field in a predetermined magnetic sensing direction. The magnetic sensor includes a chip on which at least one magnetic device is provided. The length of the chip in the magnetic sensing direction is twice or more the length of the chip in an orthogonal direction that is orthogonal or substantially orthogonal to the magnetic sensing direction.

Magnetic sensor and current sensor

A current sensor includes a substrate including a through-hole and at least one groove around the through-hole, a primary conductor extending into the through-hole and through the substrate, and through which a current to be measured flows, at least one magnetic sensor that is mounted on a first surface of the substrate and detects a strength of a magnetic field generated by the current to be measured flowing through the primary conductor, and at least one magnetic body surrounding the primary conductor and including a portion extending in the at least one groove to be fixed to the substrate.

Current sensor

A conductor includes a first flow path portion and a second flow path portion through which a current as a measurement target flows in a branched manner at a halfway position in a lengthwise direction of the conductor. The first flow path portion and the second flow path portion are located with a space therebetween in the width direction of the conductor when viewed from the thickness direction of the conductor. A region surrounded by the first flow path portion and the second flow path portion is provided when viewed from the width direction of the conductor. At least a portion of a substrate is located in the region and opposes at least one of the first flow path portion and the second flow path portion when viewed from the width direction of the conductor. The first magnetic sensor and the second magnetic sensor are arranged in the space.

Current sensor including a first flow path portion and a second flow path folder and power conversion apparatus including the same

A current sensor includes a primary conductor in which a current flows, a magnetic sensor that detects a strength of a magnetic field produced by the current, and a magnetic body that surrounds a periphery of the primary conductor and the magnetic sensor. Output characteristics of the magnetic sensor include a low-output region in which a measured voltage value lower than a virtual output voltage proportional to a value of the current is outputted. Magnetization characteristics of the magnetic body include a magnetic saturation region in which permeability decreases in ranges where an absolute value of the current is no less than a threshold. An output of the magnetic sensor is corrected such that the measured voltage value increases as a result of a magnetic field leaking from the magnetic body that is within the magnetic saturation region acting on the magnetic sensor that is in the low-output region.

Current sensor that detects a magnetic field produced by a current

An electric current sensor includes a primary conductor through which an electric current to be measured flows, and at least one magnetic sensor. The magnetic sensor includes a first magnetic sensor area, the output sensitivity of which is decreased when a magnetic field is applied to include a magnetic field component in a first direction along a sensitivity variation axis, and a second magnetic sensor area, the output sensitivity of which is increased when the magnetic field is applied to include a magnetic field component in a second direction that is opposite to the first direction.

Electric current sensor

A busbar module including a busbar through which current of a measurement subject flows and a hold portion that holds the busbar and has a recess portion), the busbar and the hold portion being integrally formed; and a magnetic sensor module including a magnetic sensor that detects an intensity of a magnetic field generated by the current flowing through the busbar, and being able to be selectively assembled with the busbar module by housing the magnetic sensor module to the recess portion of the hold portion are included.

Current sensor and electronic device incorporating the same

A non-reciprocal circuit device includes a ferrite arranged to receive a direct-current magnetic field from a permanent magnet, a first central electrode and a second central electrode arranged on the ferrite. The non-reciprocal circuit device further includes matching capacitors and a terminating resistor. When high frequency signals flow in a reverse direction, power consumption at the first central electrode is increased by decreasing an equivalent parallel resistance Rp of the first central electrode, in relation to power consumption at the terminating resistor.

Non-reciprocal circuit device

A nonreciprocal circuit device attenuates unnecessary waves having a higher frequency than that of a fundamental wave, without increasing insertion loss. The nonreciprocal circuit device in the form of a 2-port type isolator includes a ferrite on which a first central electrode and a second central electrode are arranged to cross each other and so as to be electrically insulated from each other. A bypass circuit including a phase shifter and a filter is provided between an input port and an output port, and the bypass circuit does not allow signals in the fundamental wave band to pass through and also attenuates harmonics.

Nonreciprocal circuit device

A non-reciprocal circuit element (for example, a 2-port isolator) includes a tabular yoke, permanent magnets, a ferrite to which a direct current magnetic field is applied from the permanent magnets, a first center electrode and a second center electrode disposed on the ferrite, and a circuit board. The tabular yoke is disposed on the upper surface of a ferrite magnet assembly with a dielectric layer therebetween. For example, the dielectric layer could be an adhesive agent layer made of an epoxy-based resin. The above arrangement provides a non-reciprocal circuit element having a simplified structure, a stable electrical characteristic, and a high reliability is provided.

Non-reciprocal circuit element

A nonreciprocal circuit device includes a permanent magnet, a ferrite to which the permanent magnet applies a direct-current magnetic field, first and second central electrodes arranged on the ferrite, and a circuit board. The first central electrode includes electrode layers provided on main surfaces of the ferrite connected by an electrode provided on a top surface of the ferrite. A second central electrode includes electrode layers provided on the main surfaces of the ferrite connected by electrodes arranged on top and bottom surfaces of the ferrite. The second electrode is wound at least about three turns around the ferrite. A width dimension of the outermost electrode layers of the second central electrode is greater than a width dimension of the inner electrode layers of the second central electrode.

A nonreciprocal circuit device includes permanent magnets, a ferrite core to which a DC magnetic field is applied from the permanent magnets, center electrodes disposed on the ferrite core, a circuit substrate, a magnetic yoke, and an electromagnetic shield plate. The ferrite core and the permanent magnets are longitudinally disposed on the circuit substrate, and the yoke has a ring-like shape so as to surround side surfaces of the ferrite core and the permanent magnets. The electromagnetic shield plate includes a dielectric substrate and a shield conductor made of a nonmagnetic metal conductive film on the dielectric substrate. The shield conductor includes opening areas having slits.

Nonreciprocal circuit device and communication apparatus

An isolator includes five center electrodes coupled at radio frequencies to a ferrite member to which a DC bias magnetic field is applied from a permanent magnet. First and third electrodes do not intersect each other. The first and third electrodes intersect the second, fourth and fifth electrodes with electrical insulation therebetween. Connection is established so that a magnetic field generated when current flows from one end to the other end of the first electrode and a magnetic field generated when current flows from one end to the other end of the third electrode are in phase and in the same direction. Connection is established so that a magnetic field generated when current flows from one end to the other end of the second electrode, a magnetic field generated when current flows from one end to the other end of the fourth electrode, and a magnetic field generated when current flows from one end to the other end of the fifth electrode are in phase and in the same direction. The one end of the first electrode and the other end of the third electrode define balanced input ports, and the one end of the fourth electrode defines an unbalanced output port.

Non-reciprocal circuit element, composite electronic component, and communication apparatus

An isolator includes first, second, and third center electrodes coupled in a high frequency manner with a ferrite member to which a direct-current magnetic field is applied by a permanent magnet. The first and third electrodes do not intersect with each other, and intersect with the second electrode in a mutually insulated state. Connection is established so that a magnetic field generated when a current flows from one end to the other end of the first electrode, and a magnetic field generated when a current flows from one end to the other end of the third electrode have the same phase and direction. A capacitor and a resistor are connected in parallel to the electrode, a capacitor is connected in parallel to the electrode, and a capacitor and a resistor are connected in parallel to the electrode. One end of the first electrode and the other end of the third electrode define balanced input ports, and the other end of the first electrode, one end of the second electrode, the other end of the second electrode, and one end of the third electrode define balanced output ports.

A non-reciprocal circuit element is equipped with a ferrite-magnet assembly which includes a pair of permanent magnets and a ferrite sandwiched between the permanent magnets. A first center electrode and a second center electrode defined by conducting films are provided on principal surfaces of the ferrite, such that the first center electrode and the second center electrode are insulated from each other and intersect each other. The permanent magnets have principal surfaces having substantially the same shape as the principal surfaces of the ferrite. The ferrite has upper and lower surfaces provided with recesses. The recesses have a conductor material embedded therein, whereby intermediate electrodes and connector electrodes are provided.

Growing community of inventors

Ishikawa-ken, Japan

Takashi Kawanami